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  • 51.
    Janzén, Erik
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Bergman, Peder
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Danielsson, Örjan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Hallin, Christer
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    ul-Hassan, Jawad
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Kakanakova-Gueorguie, Anelia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Persson, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Wahab, Qamar Ul
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    SiC and III-nitride Growth in a Hot-wall CVD Reactor2005Ingår i: Materials Science Forum, ISSN 0255-5476, volume 483-485, Trans Tech Publications , 2005, Vol. 483-485, s. 61-66Konferensbidrag (Refereegranskat)
  • 52.
    Janson, M. S.
    et al.
    Royal Inst Technol KTH, Dept Microelect & Informat Technol, S-16440 Kista, Sweden .
    Linnarsson, M. K.
    Royal Inst Technol KTH, Dept Microelect & Informat Technol, S-16440 Kista, Sweden .
    Hallen, A.
    Royal Inst Technol KTH, Dept Microelect & Informat Technol, S-16440 Kista, Sweden .
    Svensson, B. G.
    Royal Inst Technol KTH, Dept Microelect & Informat Technol, S-16440 Kista, Sweden .
    Achtziger, N.
    Univ Jena, Inst Festkorperphys, D-07743 Jena, Germany .
    Unéus, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Lloyd-Spets, Anita
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Hydrogen in the wide bandgap semiconductor silicon carbide2004Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T108, s. 99-112Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper we give a review of our recent results related to the incorporation of hydrogen (H) in silicon carbide (SiC) and its interaction with acceptor doping atoms and implantation induced defects. Hydrogen is an abundant impurity in the growth of epitaxial SiC since it is present in the precursor gases and since H-2 is used as the carrier gas. High concentrations of hydrogen are indeed incorporated into highly doped p-type epi-layers and it is shown that the main source is the carrier gas. Furthermore, it is revealed that the entire substrate becomes homogeneously filled with hydrogen during growth and that this hydrogen is more thermally stable than that in the epi-layer. Incorporation of hydrogen from an H-2 ambient, at temperatures considerably lower than those used for epitaxy, is also demonstrated in p-type samples coated with a catalytic metal film. This effect is most likely the cause for the increased series resistance observed in p-type SiC Schottky sensor devices using a catalytic metal gate after annealing at 600 degrees C in a H-2 containing ambient. Hydrogen is found to passivate the acceptors Al and B by forming electrically neutral H-acceptor complexes. Unlike in Si and GaAs, the two H-acceptor complexes in SiC exhibit very different dissociation energies, suggesting that the atomic configurations of the complexes are significantly different. The migration of mobile hydrogen in the presence of externally applied, or internal built-in, electric fields further reveals that hydrogen is present as H+ in p-type SiC. Finally, the redistribution and subsequent out-diffusion of low energy implanted H-1 and H-2 is investigated. Two annealing phases for the redistribution are observed, and the activation energies for the processes are extracted.

  • 53.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Linnarsson, M. K.
    Solid State Electronics, Royal Institute of Technology, SE-164 40, Kista, Sweden.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Aluminum doping of epitaxial Silicon Carbide2003Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 253, nr 1-4, s. 340-350Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intentional doping of aluminum in 4H and 6H SiC has been performed using a hot-wall CVD reactor. The dependence of aluminum incorporation on temperature, pressure, C/Si ratio, growth rate, and TMA flow has been investigated. The aluminum incorporation showed to be polarity dependent. The high aluminum incorporation on the Si-face is closely related to the carbon coverage on the SiC surface. Changes in process parameters changes the effective C/Si ratio close to the SiC surface. Increased growth rate and C/Si ratio increases the aluminum incorporation on the Si-face. Diffusion limited incorporation occurs at high growth rate. Reduced pressure increases the effective C/Si ratio, and at low growth rate, the aluminum incorporation increases initially, levels off at a critical pressure, and continues to decrease below the critical pressure. The aluminum incorporation showed to be constant in a temperature range of 50°C. The highest atomic concentration of aluminum observed in this study was 3×1017 and 8×1018 cm−3 in Si and C-face, respectively.

  • 54. Kakanakova-Georgieva, A
    et al.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Hallin, Christer
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Persson, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Storasta, Liutauras
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Pozina, Galia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Birch, Jens
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Implementation of hot-wall MOCVD in the growth of high-quality GaN on SiC2003Ingår i: Materials Science Forum, Vols. 433-436, Trans Tech Publications , 2003, Vol. 433-4, s. 991-994Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on the growth of high-quality GaN layers on SiC substrates by hotwall MOCVD. Use of AlN buffer with a thickness exceeding 50 nm is employed for the GaN deposition and it is found to encompass most of the misfit defects. A narrower X-ray rocking curve over asymmetric than over symmetric reflection is measured - full width at a half maximum (FWHM) of 350 arcsec vs. FWHM of 490 arcsec for 10.4 and 00.2 peaks, respectively, indicating high overall quality of the film. The free exciton photoluminescence emission peak has rather narrow FWHM of 5 meV. The typical thickness of the GaN layers is about 2 mum and they are completely depleted according to the capacitance-voltage profiling, which corresponds to estimated residual doping of less than 5x10(14) cm(-3). Only in some cases when the GaN layer is not depleted, deep level transient spectroscopy is performed and two deep traps with activation energies of 0.26 and 0.59 eV below the conduction band are measured.

  • 55.
    Danielsson, E.
    et al.
    KTH, Dept. Microelectron./Info. Technol., P.O. Box Electrum 229, S-164 40 Kista, Sweden.
    Zetterling, C.-M.
    KTH, Dept. Microelectron./Info. Technol., P.O. Box Electrum 229, S-164 40 Kista, Sweden.
    Domeij, M.
    KTH, Dept. Microelectron./Info. Technol., P.O. Box Electrum 229, S-164 40 Kista, Sweden.
    Ostling, M.
    Östling, M., KTH, Dept. Microelectron./Info. Technol., P.O. Box Electrum 229, S-164 40 Kista, Sweden.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Investigation of thermal properties in fabricated 4H-SiC high power bipolar transistors2003Ingår i: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 47, nr 4, s. 639-644Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silicon carbide bipolar junction transistors have been fabricated and investigated. The transistors had a maximum current gain of approximately 10 times, and a breakdown voltage of 450 V. When operated at high power densities the device showed a clear self-heating effect, decreasing the current gain. The junction temperature was extracted during self-heating to approximately 150 °C, using the assumption that the current gain only depends on temperature. Thermal images of a device under operation were also recorded using an infrared camera, showing a significant temperature increase in the vicinity of the device. The device was also tested in a switched setup, showing fast turn on and turn off at 1 MHz and 300 V supply voltage. Device simulations have been used to analyze the measured data. The thermal conductivity is fitted against the self-heating, and the lifetime in the base is fitted against the measurement of the current gain. © 2003 Elsevier Science Ltd. All rights reserved.

  • 56.
    Danielsson, Örjan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Predicted nitrogen doping concentrations in silicon carbide epitaxial layers grown by hot-wall chemical vapor deposition2003Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 250, nr 3-4, s. 471-478Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple quantitative model for the surface adsorption of nitrogen has been developed to simulate the doping incorporation in intentionally doped 4H-SiC samples during epitaxial growth. Different reaction schemes are necessary for the two faces of SiC. The differences are discussed, and implications to the necessary model adjustments are stressed. The simulations are validated by experimental values for a large number of different process parameters with good agreement.

  • 57.
    Danielsson, Olof
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för nervsystem och rörelseorgan.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Predictions of nitrogen doping in SiC epitaxial layers2003Ingår i: Materials Science Forum, Vols. 433-436, 2003, Vol. 433-4, s. 137-140Konferensbidrag (Refereegranskat)
    Abstract [en]

    Growth of device quality epitaxial layers requires precise control of thickness and doping uniformities. Computer simulations can provide growers with the necessary knowledge for improving and optimizing the growth process. In this work, the CVD process is simulated in three dimensions, using a reaction-mass transport model. A simplified quantitative model for the nitrogen incorporation in intentionally doped 4H-SiC samples has been developed and applied to a wide range of process parameters. Different reaction schemes are necessary for the two faces of SiC to account for the different doping incorporation behavior. The simulations are validated by experimental data measured by SIMS with good agreement.

  • 58. Koo, SM
    et al.
    Domeij, M
    Zetterling, CM
    Ostling, M
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Simulation and measurement of switching characteristics of 4H-SiC buried-gate JFETs2003Konferensbidrag (Refereegranskat)
    Abstract [en]

    Buried-gate junction field-effect transistors (JFETs) have been fabricated in 4H polytype silicon carbide (SiC). The dynamic switching characteristics of the JFETs in a circuit with inductive load have been characterized. The drain voltage rise/fall time of similar to30 ns and 25 ns have been observed for turn-off and turn-on, respectively. The results have been compared to numerical mixed-mode circuit simulations with finite element structures.

  • 59.
    Danielsson, E.
    et al.
    KTH.
    Zetterling, C.M.
    KTH.
    Domeij, M.
    KTH.
    Östling, M.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Switching Peformance for Fabricated and Simulated 4H-SiC High Power Bipolar Transistors2003Ingår i: Solid State Electronics, Vol. 47, 2003, s. 639-Konferensbidrag (Refereegranskat)
  • 60.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Linnarsson, MK
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan. Swedish Royal Institute of Technolology, Kista, Sweden.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Aluminum doping of epitaxial silicon carbide grown by hot-wall CVD, Effect of process parameters2002Ingår i: Proceedings of the International Conference on Silicon Carbide and Related Materials, Tsukuba, 2001 / [ed] S. Yoshida, S. Nishino, H. Harima and T. Kimoto, 2002, Vol. 389-3, s. 203-206Konferensbidrag (Refereegranskat)
    Abstract [en]

    Intentional doping of aluminum in 4H and 6H SiC has been performed using a hot-wall CVD reactor. The dependence of aluminum incorporation on temperature, pressure, C/Si ratio, growth rate, and TMA flow has been investigated. The aluminum incorporation showed to be polarity dependent. The high aluminum incorporation on the Si-face is closely related to the carbon coverage on the SiC surface. Changes in process parameters changes the effective C/Si ratio close to the SiC surface. Increased growth rate and C/Si ratio increases the aluminum incorporation on the Si-face. Diffusion limited incorporation occurs at high growth rate. Reduced pressure increases the effective C/Si ratio, and at low growth rate, the aluminum incorporation increases initially, levels off at a critical pressure, and continues to decrease below the critical pressure. The aluminum incorporation showed to be constant in a temperature range of 50°C. The highest atomic concentration of aluminum observed in this study was 3·1017 and 8·1018 cm-3 in Si and C-face, respectively.

  • 61.
    Henry, Anne
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Ellison, A
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Okmet AB, SE-58330 Linkoping, Sweden.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Magnusson, Björn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Pozina, Galia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Characterization of bulk and epitaxial SiC material using photoluminescence spectroscopy2002Ingår i: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, s. 593-596Konferensbidrag (Refereegranskat)
    Abstract [en]

    We are using low temperature photoluminescence (LTPL) to evaluate the quality of SiC wafers and are able to characterize up to 2 inch diameter wafers (with or without epilayers) at low temperature (2K). Polytype maps for bulk material can be drawn, as well as nitrogen concentration maps for both bulk and epilayer wafers in the very large doping range available today (from low 10(14) cm(-3) to 10(19) cm(-3)).

  • 62.
    Kakanakova-Georgieva, Anelia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Persson, P.O.A.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Epitaxial growth of AlN layers on SiC substrates in a hot-wall MOCVD system2002Ingår i: Phys. Stat. Sol. (c), Vol. 0, Issue 1, 2002, Vol. n 1, s. 205-208Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this study we report the successful growth of AlN and AlN/GaN on SiC substrates in a MOCVD process based on a hot-wall susceptor design. Different features of AlN growth are established depending on the total reactor pressure, temperature, off-cut SiC substrate orientation and V-to-III gas-flow ratio. The feasibility of the hot-wall MOCVD concept is demonstrated by the performance of AlN/GaN structures with state-of-the-art properties with strong potential for further optimization. A narrower X-ray rocking curve over the asymmetric 10.4 than the symmetric 00.2 reflection clearly underlines the high overall crystal quality of the GaN layers on AlN buffers grown in this type of MOCVD reactor.

  • 63. Zhang, J
    et al.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Isacson, M
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Okmetic AB, SE-58330 Linkoping, Sweden.
    Ellison, A
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Okmetic AB, SE-58330 Linkoping, Sweden.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Kordina, Olle
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Okmetic AB, SE-58330 Linkoping, Sweden.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Growth characteristics of SiC in a hot-wall CVD reactor with rotation2002Ingår i: Materials Science Forum(ISSN 0255-5476) Volume 389-3, 2002, Vol. 389-3, s. 191-194Konferensbidrag (Refereegranskat)
    Abstract [en]

    SiC epitaxy has been studied in a horizontal hot-wall CVD reactor with rotation by gas foil levitation. A capacity of three 2 inch wafers has been realized, and the thickness uniformity over a 2 inch wafer is below 1% and the n-doping uniformity over a 35mm wafer, below 10%. Both n- and p-type doping is readily achieved with no memory effect. The layer morphology has been investigated and a featureless surface has been obtained through process optimization and a modification of the hot zone.

  • 64. Zhang, J.
    et al.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Isacson, M.
    Ellison, A.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Kordina, O.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Growth characteristics of SiC in a hot-wall CVD reactor with rotation2002Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 241, nr 4, s. 431-438Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A version of the hot-wall reactor, where rotation has been added is investigated for the growth of SiC. The capacity of the reactor is 2 in wafers. The rotation is realized by gas foil levitation of a single plate carrying all three wafers. Uniformities of thickness and doping below 1% and 5%, respectively have been obtained. The run to run reproducibility of n-type doping is within ±10%. The morphology is studied and greatly improved through a modification of the hot-zone, which however made the thickness uniformity marginally worse. © 2002 Published by Elsevier Science B.V.

  • 65.
    Kakanakova-Georgieva, Anelia
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Magnusson, Björn
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Yakimova, Rositsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Growth of AlN films by hot-wall CVD and sublimation techniques: Effect of growth cell pressure2002Ingår i: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, s. 1469-1472Konferensbidrag (Refereegranskat)
    Abstract [en]

    Aluminum nitride (AlN) films were grown on off-axis, Si-terminated 4H-SiC substrates by hot-wall CVD and sublimation techniques. The films were investigated by Infrared reflectance, Optical microscopy, Energy Dispersive X-ray analysis and Cathodoluminescence in a Scanning Electron Microscope with respect to their thickness, morphological, compositional and luminescence properties, in order to examine the influence of the growth cell pressure in either of the two deposition methods. Good quality thick AlN films were obtained by hot-wall CVD at temperature of 1200degreesC and reduced pressure of 100 mbar as reflected in the near stoichiometric N/Al ratio in these layers and in the appearance of the characteristic AlN near band edge emission. The AlN sublimation grown films at temperature of 2100degreesC suffered from island growth irrespective of the background pressure. The supersaturation conditions that affect strongly the growth mode became more favorable when the temperature was reduced to 1900degreesC.

  • 66.
    Linnarsson, MK
    et al.
    Royal Inst Technol, SE-16440 Kista, Stockholm, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Univ Oslo, Dept Phys, NO-0316 Oslo, Norway.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Jensen, Mona
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Svensson, BG
    Incorporation of hydrogen (1H and 2H) into 4H-SiC during epitaxial growth2002Ingår i: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, s. 565-568Konferensbidrag (Refereegranskat)
    Abstract [en]

    The hydrogen depth distribution in 4H-SiC after epitaxial growth at 1600 degreesC has been studied in detail with secondary ion mass spectrometry. Both H-1 and H-2 have been employed as carrier gas to trace the origin of the incorporated hydrogen. In particular the substrate as a prospective hydrogen source has been considered. After growth H-2 is detected throughout the whole substrate (similar to400 mum) and a considerable quantity remains after annealing at 1500 degreesC for 15 minutes.

  • 67.
    Koo, SM
    et al.
    Royal Inst Technol, KTH, Dept Microelect & Informat Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Lee, Sun Kyun
    Zetterling, CM
    Royal Inst Technol, KTH, Dept Microelect & Informat Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Ostling, M
    Royal Inst Technol, KTH, Dept Microelect & Informat Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Influence of trenching effect on the characteristics of buried-gate SiC junction field-effect transistors2002Ingår i: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, s. 1235-1238Konferensbidrag (Refereegranskat)
    Abstract [en]

    Two different structures of junction field-effect transistors in 4H-SiC, with and without trenching effect in the channel region, have been fabricated and characterized. The devices formed with metal mask show a trenching profile (>similar to0.2 mum) after dry etch in the channel groove region and exhibited static induction transistor (SIT)-like characteristics in the sub-threshold region of I-V curves as the channel thickness decreases. The devices without trenching effect have been processed by using a wet-etched oxide mask resulting in a sloped dry-etch profile (theta=similar to30degrees) in the channel, and consequently showed well-saturated drain characteristics for all the channel thicknesses. The conduction mechanisms in these JFETs are examined by the potential profiles from two dimensional numerical simulations.

  • 68.
    Danielsson, Örjan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Henry , Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik. Linköpings universitet, Tekniska högskolan.
    Investigation of the temperature profile in a hot-wall SiC chemical vapour deposition reactor2002Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 235, nr 1-4, s. 352-364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chemical vapor deposition (CVD) technique is widely used to grow epitaxial layers of silicon carbide. To meet the demands for high quality epitaxial layers, which have good morphology and a minimum variation of the doping and thickness, a good knowledge of the CVD process is essential. The present work uses a simulation tool to investigate several parameters influencing the heating of <!--[if !vml]--><!--[endif]-->a hot-wall CVD reactor. The simulations are set up as 2D axisymmetric problems and validation is made in a 2D horizontal hot-wall CVD reactor. By applying the knowledge achieved from the simulations, the temperature profile is optimized to give as large area as possible with homogeneous temperature. New susceptor and coil designs are tested. A very good agreement between the simulated and the measured results is obtained. The new design has a temperature variation of less than 0.5% over more than 70% of the total susceptor length at an operating temperature of 1650°C. In addition, the power input needed to reach the operating temperature is decreased by 15% compared to the original design. 3D simulations are performed to show that the changes made in the 2D case give similar results for the real 3D case.

  • 69. Danielsson, E
    et al.
    Zetterling, CM
    KTH, Dept Microelect & Informat Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Ostling, M
    KTH, Dept Microelect & Informat Technol, SE-16440 Kista, Sweden Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Investigation of thermal properties in fabricated 4H-SiC high-power bipolar transistors2002Ingår i: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, s. 1337-1340Konferensbidrag (Refereegranskat)
    Abstract [en]

    Silicon Carbide bipolar junction transistors have been fabricated and investigated. The transistors had a maximum current gain of approximately 10 times, and a breakdown voltage of up to 600 V. When operated at high power densities the device showed a clear self-heating effect, decreasing the current gain. The junction temperature was extracted during self-heating to approximately 150 degreesC, using the assumption that the current gain only depends on temperature. Thermal images of a device under operation were also recorded using an infrared camera, showing a significant temperature increase in the vicinity of the device. Physical device simulations have been used to analyze the measured data. The thermal conductivity is fitted to model the measured self-heating, and the lifetime in the base is fitted against the measurement of the current gain.

  • 70.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Linnarsson, M. K.
    Solid State Electronics, Royal Institute of Technology, SE-164 40 Kista, Sweden.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Nitrogen doping of epitaxial Silicon Carbide2002Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 236, nr 1-3, s. 101-112Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Intentional doping with nitrogen of 4H- and 6H-SiC has been performed using a hot-wall CVD reactor. The nitrogen doping dependence on the temperature, pressure, C/Si ratio, growth rate and nitrogen flow has been investigated. The nitrogen incorporation for C-face material showed to be C/Si ratio independent, whereas the doping decreased with increasing C/Si ratio for the Si-face material in accordance with the “site-competition” model. The nitrogen incorporation was constant in a temperature “window” of 75°C on Si-face material indicating a mass transport limited incorporation. Increasing the growth rate resulted in a decrease of nitrogen incorporation on Si-face but an increase on C-face material. Finally, a comparison between previously published results on cold-wall CVD-grown material and the present hot-wall-grown material is presented.

  • 71.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    CVD Growth of Silicon Carbide for High Frequency Applications2001Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Silicon Carbide (SiC) is an important wide band gap semiconductor with outstanding electronic properties. With figures of merit far better than silicon, SiC is believed to replace and outcompete silicon in many applications using high frequencies, high voltage and high temperatures. With the introduction of seeded sublimation technique, a realisation of substrates with large diameter and high quality became possible. Recent progress in the bulk growth using high temperature chemical vapour deposition (HTCVD) has shown excellent results with high purity substrates with semi insulating (SI) properties. The availability of high quality SI substrates allows the fabrication of microwave devices with low rf losses such as the Metal Schottky Field Effect Transistor (MESFET). With the introduction of the hot-wall CVD technique, thick low doped n-type epitaxial layers have been grown for high power devices (> 4 kV) such as the PiN diode.

    The main contribution of the present work relates to the investigation of growth of MESFET structures. The goal has been to demonstrate the ability to grow MESFET structures using the hot-wall CVD technique. The challenge with abrupt interfaces and controlled doping has been investigated. A comprehensive investigation has been made on how nitrogen and aluminum dopant atoms incorporate into the SiC lattice using the hot-wall CVD technique. Fundamental research of MESFET structures has been combined with growth of device structures for both Swedish and European groups as well as industries. The research has been focused towards the understanding of dopant incorporation, characterization of doped epitaxial layers, the growth of device structures, the modelling of temperature distribution in a hot-wall susceptor and the development of growth systems for future up scaling.

    In paper 1 we present how the nitrogen dopant is incorporated into the SiC lattice. The influence of several different growth parameters on the nitrogen incorporation is presented. Equilibrium thermodynamical calculations have been performed to give a further insight into the incorporation mechanism. The investigation shows that the N2 molecule itself does not contribute directly to the nitrogen incorporation, however, molecules like the HCN and HNC are more likely.

    In paper 2 the incorporation of the aluminum dopant into the SiC lattice is investigated in a similar way as the nitrogen incorporation in paper 1. The results show that the aluminum incorporation in SiC is mainly controlled by the carbon coverage on the SiC surface. The investigation shows that it is difficult to obtain high aluminum doping on carbon face whereas the silicon face is sensitive to changes of the growth parameters. High growth rate resulted in a diffusion controlled incorporation.

    In Paper 3 we present the results from the growth of MESFET structures as well as characterization of the structures and final device properties. Knowledge taken from paper 1 and 2 was used to improve the abruptness of the grown structures.

    Paper 4 presents the results obtained by low temperature photoluminescence (LTPL) on separately grown 4H-SiC epitaxial layers. Doping calibration curves for nitrogen in the doping range from 1⋅1014 to 2⋅1019 cm-3 are presented. A discussion concerning the Mott transition is also presented.

    Paper 5 presents the results of the use of simulation to investigate the heating of a hot-wall CVD reactor. New susceptor and coil design are tested. The simulation has been verified with experimental heating tests which show excellent agreement. The new design has a temperature variation of less than 0.5 % over more than 70% of the total susceptor length in addition to a decreased power input of 15 %.

    In the final two papers, paper 6 and 7, we present work of growth of AlN on SiC. Thin films were grown and characterized with different techniques concerning crystal quality and thickness. The use of infrared reflectance and the features of the AlN reststrahl reflectance band allowed us to determine the thickness of AlN films as thin as 250 Å.

    Delarbeten
    1. Nitrogen doping of epitaxial Silicon Carbide
    Öppna denna publikation i ny flik eller fönster >>Nitrogen doping of epitaxial Silicon Carbide
    Visa övriga...
    2002 (Engelska)Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 236, nr 1-3, s. 101-112Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Intentional doping with nitrogen of 4H- and 6H-SiC has been performed using a hot-wall CVD reactor. The nitrogen doping dependence on the temperature, pressure, C/Si ratio, growth rate and nitrogen flow has been investigated. The nitrogen incorporation for C-face material showed to be C/Si ratio independent, whereas the doping decreased with increasing C/Si ratio for the Si-face material in accordance with the “site-competition” model. The nitrogen incorporation was constant in a temperature “window” of 75°C on Si-face material indicating a mass transport limited incorporation. Increasing the growth rate resulted in a decrease of nitrogen incorporation on Si-face but an increase on C-face material. Finally, a comparison between previously published results on cold-wall CVD-grown material and the present hot-wall-grown material is presented.

    Ort, förlag, år, upplaga, sidor
    ScienceDirect, 2002
    Nyckelord
    A1. Doping, A3. Hot wall epitaxy, B2. Superconducting materials
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15068 (URN)10.1016/S0022-0248(01)02198-4 (DOI)
    Anmärkning
    The status of this article on the day of the defence was: Submitted and the title of the article was "Nitrogen doping of Silicon Carbide: Effect of Process Parameters"Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    2. Aluminum doping of epitaxial Silicon Carbide
    Öppna denna publikation i ny flik eller fönster >>Aluminum doping of epitaxial Silicon Carbide
    Visa övriga...
    2003 (Engelska)Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 253, nr 1-4, s. 340-350Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Intentional doping of aluminum in 4H and 6H SiC has been performed using a hot-wall CVD reactor. The dependence of aluminum incorporation on temperature, pressure, C/Si ratio, growth rate, and TMA flow has been investigated. The aluminum incorporation showed to be polarity dependent. The high aluminum incorporation on the Si-face is closely related to the carbon coverage on the SiC surface. Changes in process parameters changes the effective C/Si ratio close to the SiC surface. Increased growth rate and C/Si ratio increases the aluminum incorporation on the Si-face. Diffusion limited incorporation occurs at high growth rate. Reduced pressure increases the effective C/Si ratio, and at low growth rate, the aluminum incorporation increases initially, levels off at a critical pressure, and continues to decrease below the critical pressure. The aluminum incorporation showed to be constant in a temperature range of 50°C. The highest atomic concentration of aluminum observed in this study was 3×1017 and 8×1018 cm−3 in Si and C-face, respectively.

    Ort, förlag, år, upplaga, sidor
    ScienceDirect, 2003
    Nyckelord
    A1. Doping; A1. Growth models; A3. Chemical vapor deposition processes; A3. Hot wall epitaxy; B2. Semiconducting silicon carbide
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15055 (URN)10.1016/S0022-0248(03)01045-5 (DOI)
    Anmärkning
    The status of the article on the defence day was: Submitted and the original title was "Aluminum doping of Silicon Carbide: Effect of Process Parameters".Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    3. Growth and characterisation 4H-SiC MESFET structures grown by Hot-Wall CVD
    Öppna denna publikation i ny flik eller fönster >>Growth and characterisation 4H-SiC MESFET structures grown by Hot-Wall CVD
    Visa övriga...
    2001 (Engelska)Ingår i: Proc. of the MRS 2000 Fall Meeting, 2001, s. H2.3.2-Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Metal semiconductor field effect transistor structures have been grown in a hot-wall CVD reactor. Using trimethylaluminium and nitrogen, p- and n-type epitaxial layers were grown on semi insulating substrates. A comprehensive characterization study of thickness and doping of these multi structures has been performed by using scanning electron microscopy , secondary ion mass spectrometry, capacitance-voltage and low temperature photoluminescence. Optimisation of growth parameters has resulted in very abrupt doping profiles. The grown metal semiconductor field effect transistor structures have been processed and parts of the transistor properties are presented.

    Nyckelord
    Hot-Wall CVD, MESFET, Silicon carbide, SEM, SIMS
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15062 (URN)
    Konferens
    MRS 2000 Fall Meeting
    Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2016-08-31Bibliografiskt granskad
    4. Determination of nitrogen doping concentration in doped 4H-SiC epilayers by low temperature photoluminescence
    Öppna denna publikation i ny flik eller fönster >>Determination of nitrogen doping concentration in doped 4H-SiC epilayers by low temperature photoluminescence
    2005 (Engelska)Ingår i: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 72, nr 2-3, s. 254-257Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A complete calibration of nitrogen concentration in doped 4H-SiC material is presented. This is done in the very large range of doping available today, i.e. from low 1014 to 1019 cm-3. The samples are 4H-SiC films fabricated by hot-wall chemical vapour deposition. Low temperature photoluminescence is used as the experimental tool. For doping concentrations less than 8 × 1017 cm-3 comparison between the intensity of various luminescence lines is used, whereas for doping higher than 3 × 1018 cm-3 the energy position of an observed broad band allows the determination of the doping level.

    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15063 (URN)10.1238/Physica.Regular.072a00254 (DOI)
    Anmärkning
    On the day of the defence the status of article IV was: Submitted to Applied Physics Letter.Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    5. Investigation of the temperature profile in a hot-wall SiC chemical vapour deposition reactor
    Öppna denna publikation i ny flik eller fönster >>Investigation of the temperature profile in a hot-wall SiC chemical vapour deposition reactor
    2002 (Engelska)Ingår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 235, nr 1-4, s. 352-364Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The chemical vapor deposition (CVD) technique is widely used to grow epitaxial layers of silicon carbide. To meet the demands for high quality epitaxial layers, which have good morphology and a minimum variation of the doping and thickness, a good knowledge of the CVD process is essential. The present work uses a simulation tool to investigate several parameters influencing the heating of <!--[if !vml]--><!--[endif]-->a hot-wall CVD reactor. The simulations are set up as 2D axisymmetric problems and validation is made in a 2D horizontal hot-wall CVD reactor. By applying the knowledge achieved from the simulations, the temperature profile is optimized to give as large area as possible with homogeneous temperature. New susceptor and coil designs are tested. A very good agreement between the simulated and the measured results is obtained. The new design has a temperature variation of less than 0.5% over more than 70% of the total susceptor length at an operating temperature of 1650°C. In addition, the power input needed to reach the operating temperature is decreased by 15% compared to the original design. 3D simulations are performed to show that the changes made in the 2D case give similar results for the real 3D case.

    Ort, förlag, år, upplaga, sidor
    ScienceDirect, 2002
    Nyckelord
    A1. Computer simulation, A1. Heat transfer, A3. Chemical, vapor deposition, A3. Hot-wall epitaxy, B2. Semiconducting silicon carbide
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15064 (URN)10.1016/S0022-0248(01)01831-0 (DOI)
    Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    6. Growth of high quality AlN Epitaxial Films by Hot-Wall Chemical Vapour Deposition
    Öppna denna publikation i ny flik eller fönster >>Growth of high quality AlN Epitaxial Films by Hot-Wall Chemical Vapour Deposition
    Visa övriga...
    1998 (Engelska)Ingår i: Proceedings of the International Conference on Silicon Carbide, III-Nitrides and Related Materials, 1997, 1998, Vol. 264-268, s. 1133-1136Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Epitaxial films of high quality AlN have been grown on SiC substrates at 1200 °C and 1450 °C, using a hot-wall CVD reactor. The thickness of the epitaxial layers were measured using room temperature infrared reflectance. To verify the crystal quality, X-ray diffraction (XRD) rocking curves of the ALN 0002 peak were measured. A 250 Å thick film grown at 1450°C had a full width half maximum (FWHM) of 42 arcsec, whereas a 1000 Å thick film grown at 1200 °C had a FWHM of 100 arcsec. A TEM image of the sample grown at the lower temperature showed thickness of around 950 Å, thereby verifying the infrared reflectance measurements. We conclude that the higher temperature the better the crystal quality we obtain.

     

    Nyckelord
    Hot-Wall CVD, Thin Film, XRD, TEM, Infrared reflectance
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15065 (URN)
    Konferens
    International Conference on Silicon Carbide, III-Nitrides and Related Materials, 1997
    Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2013-06-12Bibliografiskt granskad
    7. Infrared Reflectance of Extremely Thin AlN Epi Films Deposited on SiC Substrates
    Öppna denna publikation i ny flik eller fönster >>Infrared Reflectance of Extremely Thin AlN Epi Films Deposited on SiC Substrates
    Visa övriga...
    1998 (Engelska)Ingår i: Materials Science Forum Vols. 264-268, 1998, Vol. 264-268, s. 649-652Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    The room temperature reflectance of thin (£ 1000Å) AlN epi-films deposited on n type 6H SiC has been measure. These epi-films are too thin to produce interference fringes, from which epi-films thickness is often extracted, within the measured spectral region. However, features from the AlN reststrahl reflectance band can be clearly seen for AlN epi-films as thin as 250Å. Thicknesses are extracted from the measured spectra by comparing them directly to calculated spectra with the epi-film thickness being the only fitting parameter. The accuracy of these thickness determinations is confirmed by comparing them to thickness measured on samples studied by cross sectional TEM.

    Nyckelord
    Epi-film Thickness, Reflectance, TEM
    Nationell ämneskategori
    Övrig annan teknik
    Identifikatorer
    urn:nbn:se:liu:diva-15066 (URN)
    Konferens
    Conference on Silicon Carbide, III-Nitrides and Related Materials, 1997
    Tillgänglig från: 2008-10-13 Skapad: 2008-10-13 Senast uppdaterad: 2016-08-31Bibliografiskt granskad
  • 72. Danielsson, Ö
    et al.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Enlarging the usable growth area in a hot-wall silicon carbide CVD reader by using simulation2001Ingår i: Materials Science Forum, Vols. 353-356, 2001, Vol. 353-3, s. 99-102Konferensbidrag (Refereegranskat)
    Abstract [en]

    The chemical vapor deposition (CVD) growth of large area silicon car-bide epitaxial layers with homogeneous properties requires a large area with homogeneous temperature in the CVD reactor. In the present work we show that by changing the design of the CVD reactor, but keeping the overall dimension the same, this area can be enlarged by at least a factor of three.. By using a simulation tool new designs can be tried out and optimized in the computer before testing them in practice. The simulation is set up as a 2D axisymmetric problem and validation is made in a 2D horizontal hot-wall CVD reactor. Very good agreements between simulated and measured results are obtained. The zone with a temperature variation of less than 5 degrees at an operating temperature of 1650 degreesC increased to 64% of the whale susceptor length. In addition, the power input needed to reach the operating temperature decreased by 15%.

  • 73.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Rorsman, N.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Eriksson, J.
    Linnarsson, M. K.
    Solid State Electronics, Royal Institute of Technology, SE-164 40 Kista, Sweden.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Storasta, Liutauras
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Growth and characterisation 4H-SiC MESFET structures grown by Hot-Wall CVD2001Ingår i: Proc. of the MRS 2000 Fall Meeting, 2001, s. H2.3.2-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Metal semiconductor field effect transistor structures have been grown in a hot-wall CVD reactor. Using trimethylaluminium and nitrogen, p- and n-type epitaxial layers were grown on semi insulating substrates. A comprehensive characterization study of thickness and doping of these multi structures has been performed by using scanning electron microscopy , secondary ion mass spectrometry, capacitance-voltage and low temperature photoluminescence. Optimisation of growth parameters has resulted in very abrupt doping profiles. The grown metal semiconductor field effect transistor structures have been processed and parts of the transistor properties are presented.

  • 74.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Linnarsson, M.K.
    Royal Institute of Technology.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Influence of growth parameters on the nitrogen incorporation in 4H- and 6H-SiC epilayers grown by hot-wall chemical vapour deposition2001Ingår i: Proc. of the MRS Spring Meeting 2001, 680E, 2001Konferensbidrag (Refereegranskat)
  • 75.
    Wahab, Qamar Ul
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Ellison, A
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Zhang, J
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Duranova, E
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Madsen, LD
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Designing, physical simulation and fabrication of high-voltage (3.85 kV) 4H-SiC Schottky rectifiers processed on hot-wall and chimney CVD films2000Ingår i: Materials Science Forum, Vols. 338-342, 2000, Vol. 338-3, s. 1171-1174Konferensbidrag (Refereegranskat)
    Abstract [en]

    Physical simulation, fabrication and characterization of high-voltage Ni/4H-SiC Schottky rectifiers are studied. We demonstrate a blocking voltage of 3.85 kV by utilizing a 43 mum thick low doped 4H-SiC epilayer in vertical hot-wall Chimney CVD reactor. A high breakdown voltage of 3.56 kV was achieved on a layer grown by conventional hot-wall CVD reactor. The reverse leakage current on CVD sample was as low as 5 x 10(-6) A cm(-2) at 3.5 kV just before the breakdown.

  • 76.
    Lindquist, OPA
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Arwin, Hans
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Bergman, JP
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Järrendahl, Kenneth
    Linköpings universitet, Tekniska högskolan.
    Optical characterization of 4H-SiC by variable angle of incidence spectroscopic ellipsometry2000Ingår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 338-3, s. 575-578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A variable angle of incidence spectroscopic ellipsometer equipped with a compensator has been used to determine the dielectric functions in the 0.74 - 6 eV photon energy range of n-type bulk 4H-SiC with doping concentrations between 10(17) and 10(19) cm(-3). The resulting dielectric function for different SiC wafers depends on the doping concentration, especially around the absorption onset and higher photon energies. Measurements on different wafers with the same doping show good reproducibility. Simulations and preliminary measurements show that ellipsometry might be useful for thickness determination of thin (<1 m) homoepitaxial films.

  • 77.
    Forsberg, Urban
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Linnarsson, MK
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden Royal Inst Technol, SE-16440 Kista, Sweden.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Photoluminescence study of CVD layers highly doped with nitrogen2000Ingår i: Materials Science Forum, Vols. 338-342, 2000, Vol. 338-342, s. 619-622Konferensbidrag (Refereegranskat)
    Abstract [en]

    From a systematic study of highly doped n-type 4H-SiC epilayers we observe a photoluminescence spectrum, which was previously associated with the recombination of a bound exciton at the neutral boron acceptor. Electrical measurements performed on these layers show clearly n-type conductivity. It was feasible to dope and measure reproducibly the layers from low 10(17) to mid 10(18) cm(-3). It was not possible to determine the doping from Capacitance Voltage measurements for the samples grown with the highest doping (>6.10(18) cm(-3)). However Secondary Ion Mass spectrometry did not reveal any boron impurities in the layers and shows good agreement with electrical measurements regarding the nitrogen concentration.

  • 78.
    Wahab, Qamar Ul
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ellson, A.
    Zhang, J.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Duranova, E.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Madsen, L.D.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Power Schottky rectifiers and microwave transistors in 4H-SiC2000Ingår i: Proc. of the International Workshop on Semiconductor Devices, 2000, s. 668-671Konferensbidrag (Refereegranskat)
    Abstract [en]

    The physical simulation, fabrication and characterization of 4H-SiC power Schottky diodes and physical simulations of power microwave transistors an presented. A record blocking voltage of 3.85 kV was achieved for a Schottky diode with a 43 μm thick epilayer grown by chimney CVD. For hot-wall CVD grown layers a blocking voltage of 3.6 kV was obtained. Simulations of power MESFETs showed maximum drain currents above 300 mA/mm and a drain breakdown above 150 volt An RF analysis showed the cut-off and the maximum frequency of oscillation for a device with a gate length of 0.5 μm to be 13 and 45 GHz respectively. The maximum achievable gain was above 10 dB ep to 26 GFz.

  • 79.
    Forsberg, Urban
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    MacMillan, M. F.
    Persson, P. O. Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Growth of high quality AlN Epitaxial Films by Hot-Wall Chemical Vapour Deposition1998Ingår i: Proceedings of the International Conference on Silicon Carbide, III-Nitrides and Related Materials, 1997, 1998, Vol. 264-268, s. 1133-1136Konferensbidrag (Refereegranskat)
    Abstract [en]

    Epitaxial films of high quality AlN have been grown on SiC substrates at 1200 °C and 1450 °C, using a hot-wall CVD reactor. The thickness of the epitaxial layers were measured using room temperature infrared reflectance. To verify the crystal quality, X-ray diffraction (XRD) rocking curves of the ALN 0002 peak were measured. A 250 Å thick film grown at 1450°C had a full width half maximum (FWHM) of 42 arcsec, whereas a 1000 Å thick film grown at 1200 °C had a FWHM of 100 arcsec. A TEM image of the sample grown at the lower temperature showed thickness of around 950 Å, thereby verifying the infrared reflectance measurements. We conclude that the higher temperature the better the crystal quality we obtain.

     

  • 80.
    MacMillan, Mike F.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Persson, P.O.Å.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Infrared Reflectance of Extremely Thin AlN Epi Films Deposited on SiC Substrates1998Ingår i: Materials Science Forum Vols. 264-268, 1998, Vol. 264-268, s. 649-652Konferensbidrag (Refereegranskat)
    Abstract [en]

    The room temperature reflectance of thin (£ 1000Å) AlN epi-films deposited on n type 6H SiC has been measure. These epi-films are too thin to produce interference fringes, from which epi-films thickness is often extracted, within the measured spectral region. However, features from the AlN reststrahl reflectance band can be clearly seen for AlN epi-films as thin as 250Å. Thicknesses are extracted from the measured spectra by comparing them directly to calculated spectra with the epi-film thickness being the only fitting parameter. The accuracy of these thickness determinations is confirmed by comparing them to thickness measured on samples studied by cross sectional TEM.

  • 81.
    Hsu, Chih-Wei
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lundskog, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Persson, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Karlsson, K. Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Controlled Growth of GaN Pyramidal template hosting InGaN Quantum DotsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The emission properties of InGaN grown on hexagonal GaN pyramids with various pitch distances (PD) are studied. Emissions associated with InGaN quantum wells (QWs) and InGaN quantum dots (QDs) can be identified. The emission energies of InGaN QWs and QDs shift toward opposite directions with increasing PD; red-shift for QWs and blue-shift for QDs. Based on the source supply mechanism in a selective area growth process, the formation of InGaN QDs on GaN pyramids is believed to be a combined effect of Stranski-Krastanow growth mode and spinodal decomposition taking place at the microscopic (0001) surfaces on GaN pyramids.

  • 82.
    Chen, Jr-Tai
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Persson, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Persson, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan. Classic WBG Semiconductors AB, LEAD, Sweden.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Growth optimization of AlGaN/GaN HEMT structure on 100 mm SiC substrate: Utilizing bottom-to-top approachManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The structure of high electron mobility transistors (HEMTs) based on group-III nitride materials generally consists of three important blocks; a nucleation layer, a semi-insulating (SI) GaN buffer layer, and active layers. In this work, we present an overall growth optimization, which leads to superior crystalline quality and ultra-low thermal boundary resistance (TBR) of a 35-nm AlN nucleation layer, excellent crystalline quality of carbon-doped GaN buffer layer, and high mobility (> 2000 cm2/Vs) of two-dimensional gas (2DEG) in a simple AlGaN/GaN heterostructure grown on a SI SiC substrate.

  • 83.
    Bergsten, Johan
    et al.
    Microwave Electronics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden.
    Chen, Jr-Tai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Sebastian
    Microwave Electronics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Thorsell, Mattias
    Microwave Electronics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Rorsman, Niklas
    Microwave Electronics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden.
    Impact of AlGaN/GaN interface sharpness on HEMT performanceManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The impact of the design and sharpness of the AlGaN/GaN interface in GaN-based HEMTs is investigated. Three structures with different AlGaN/GaN interface properties were grown with hot-wall MOCVD. One structure has a 2-nmthick AlN exclusion layer in between the AlGaN and the GaN, while the other two differ in their sharpness of the Al transition at the AlGaN/GaN interface. The structures with AlN exclusion layer and optimized sharpness of the interface show similar electron mobilities (1760 and 1740 cm2/Vs). HEMTs were processed and evaluated. Gated Hall-measurements indicate that the sharper interface maintains a higher mobility when the electrons are close to the interface compared both to the AlNexclusion layer and the non-optimized structure. The higher mobility manifests as lower parasitic resistance yielding better DC and high frequency performance. Pulsed IV measurements indicate that the sharper interface provide less dispersive effects compared both to the AlN exclusion layer and the optimized interface.

  • 84.
    Ciechonski, Rafal
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Kakanakova-Georgieva, Anelia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Pedersen, Henrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Lundskog, Anders
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Forsberg, Urban
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    In-situ treatment of GaN epilayers in hot-wall MOCVDManuskript (Övrigt vetenskapligt)
  • 85.
    Lundskog, Anders
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hsu, Chih-Wei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Nilsson, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Karlsson, K Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Polarization-controlled photon emission from site-controlled InGaN quantum dotsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The optical polarization properties of hot-wall MOCVD grown of InGaN quantum dots (QDs) located at the apex of elongated hexagonal GaN pyramids are presented. The QDs showed spectrally narrow and strongly linearly polarized emission lines with average polarization ratios above 0.8 in the microphoto-luminescence spectra. By a comprehensive statistical analysis including more than 1000 InGaN QDs it was concluded that the polarization direction of the QDs follows the spatial elongation of the underlying GaN pyramids when elongated in the <2110> directions.

  • 86.
    Lundskog, Anders
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hsu, Chih-Wei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Karlsson, K Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Persson, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Holtz, Per-Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Unexpected behavior of InGaN quantum dot emission energy located at apices of hexagonal GaN pyramidsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    InGaN quantum dots (QDs) have been grown at the apices of hexagonal GaN pyramids. The pyramids were selectively grown on a (0001) oriented GaN template through circular apertures in a SiN mask positioned in square arrays. The emission of the InGaN QDs was shifted towards higher energies when the center-to-center distance of the pyramids was increased, while the emission from InGaN quantum wells located on the {1101} facets of the pyramids was energetically shifted towards lower energies. No energy shift was observed for (0001) truncated pyramids with truncation diameters larger than 100 nm.

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