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Deminskyi, P., Rouf, P., Ivanov, I. G. & Pedersen, H. (2019). Atomic layer deposition of InN using trimethylindium and ammonia plasma. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 37(2), Article ID 020926.
Open this publication in new window or tab >>Atomic layer deposition of InN using trimethylindium and ammonia plasma
2019 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 2, article id 020926Article in journal (Refereed) Published
Abstract [en]

Indium nitride (InN) is a low bandgap, high electron mobility semiconductor material of interest to optoelectronics and telecommunication. Such applications require the deposition of uniform crystalline InN thin films on large area substrates, with deposition temperatures compatible with this temperature-sensitive material. As conventional chemical vapor deposition (CVD) struggles with the low temperature tolerated by the InN crystal, the authors hypothesize that a time-resolved, surface-controlled CVD route could offer a way forward for InN thin film deposition. In this work, the authors report atomic layer deposition of crystalline, wurtzite InN thin films using trimethylindium and ammonia plasma on Si(100). They found a narrow atomic layer deposition window of 240-260 degrees C with a deposition rate of 0.36 A/cycle and that the flow of ammonia into the plasma is an important parameter for the crystalline quality of the film. X-ray diffraction measurements further confirmed the polycrystalline nature of InN thin films. X-ray photoelectron spectroscopy measurements show nearly stoichiometric InN with low carbon level (amp;lt;1 at. %) and oxygen level (amp;lt;5 at. %) in the film bulk. The low carbon level is attributed to a favorable surface chemistry enabled by the NH3 plasma. The film bulk oxygen content is attributed to oxidation upon exposure to air via grain boundary diffusion and possibly by formation of oxygen containing species in the plasma discharge. Published by the AVS.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2019
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-155541 (URN)10.1116/1.5079279 (DOI)000460437200030 ()
Note

Funding Agencies|Swedish Foundation for Strategic Research through the project "Time-resolved low temperature CVD for III-nitrides" [SSF-RMA 15-0018]; Knut and Alice Wallenberg foundation through the project "Bridging the THz gap" [KAW 2013.0049]; VR [VR 2016-05362]; Carl Trygger Foundation

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-04-18
Stenberg, P., Danielsson, Ö., Erdtman, E., Sukkaew, P., Ojamäe, L., Janzén, E. & Pedersen, H. (2017). Matching precursor kinetics to afford a more robust CVD chemistry: a case study of the C chemistry for silicon carbide using SiF4 as Si precursor. Journal of Materials Chemistry C, 5, 5818-5823
Open this publication in new window or tab >>Matching precursor kinetics to afford a more robust CVD chemistry: a case study of the C chemistry for silicon carbide using SiF4 as Si precursor
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2017 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, p. 5818-5823Article in journal (Refereed) Published
Abstract [en]

Chemical Vapor Deposition (CVD) is one of the technology platforms forming the backbone of the semiconductor industry and is vital in the production of electronic devices. To upscale a CVD process from the lab to the fab, large area uniformity and high run-to-run reproducibility are needed. We show by a combination of experiments and gas phase kinetics modeling that the combinations of Si and C precursors with the most well-matched gas phase chemistry kinetics gives the largest area of of homoepitaxial growth of SiC. Comparing CH4, C2H4 and C3H8 as carbon precursors to the SiF4 silicon precursor, CH4 with the slowest kinetics renders the most robust CVD chemistry with large area epitaxial growth and low temperature sensitivity. We further show by quantum chemical modeling how the surface chemistry is impeded by the presence of F in the system which limits the amount of available surface sites for the C to adsorb.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-137446 (URN)10.1039/c7tc00138j (DOI)000403571200024 ()
Note

Funding agencies: Knut & Alice Wallenberg Foundation (KAW) project Isotopic Control for Ultimate Material Properties; Swedish Foundation for Strategic Research project SiC - the Material for Energy-Saving Power Electronics [EM11-0034]; Swedish Government Strategic Research

Available from: 2017-05-16 Created: 2017-05-16 Last updated: 2018-10-08Bibliographically approved
Danielsson, Ö., Li, X., Ojamäe, L., Janzén, E., Pedersen, H. & Forsberg, U. (2016). A model for carbon incorporation from trimethyl gallium in chemical vapor deposition of gallium nitride. Journal of Materials Chemistry, 4(4), 863-871
Open this publication in new window or tab >>A model for carbon incorporation from trimethyl gallium in chemical vapor deposition of gallium nitride
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2016 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 4, no 4, p. 863-871Article in journal (Refereed) Published
Abstract [en]

Gallium nitride (GaN) semiconductor material can become semi-insulating when doping with carbon. Semi-insulating buffer layers are utilized to prevent leakage currents in GaN high power devices. Carbon is inherently present during chemical vapor deposition (CVD) of GaN from the use of trimethyl gallium (TMGa) as precursor. TMGa decomposes in the gas phase, releasing its methyl groups, which could act as carbon source for doping. It is previously known that the carbon doping levels can be controlled by tuning the CVD process parameters, such as temperature, pressure and precursor flow rates. However, the mechanism for carbon incorporation from TMGa is not yet understood. In this paper, a model for predicting carbon incorporation from TMGa in GaN layers grown by CVD is proposed. The model is based on ab initio quantum chemical calculations of molecular adsorption and reaction energies. Using Computational Fluid Dynamics, with a chemical kinetic model for decomposition of the precursors and reactions in the gas phase, to calculate gas phase compositions at realistic process conditions, together with the proposed model, we obtain good correlations with measurements, for both carbon doping concentrations and growth rates, when varying the inlet NH3/TMGa ratio. When varying temperature (800 – 1050°C), the model overpredicts carbon doping concentrations at the lower temperatures, but predicts growth rates well, and the agreement with measured carbon doping concentrations is good above 1000°C.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2016
National Category
Physical Sciences Physical Chemistry
Identifiers
urn:nbn:se:liu:diva-118113 (URN)10.1039/c5tc03989d (DOI)000368839700027 ()
Note

Funding agencies: Swedish Foundation for Strategic Research (SSF); Swedish Defence Material Administration (FMV)

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Available from: 2015-05-22 Created: 2015-05-22 Last updated: 2017-12-04Bibliographically approved
Bergsten, J., Li, X., Nilsson, D., Danielsson, Ö., Pedersen, H., Janzén, E., . . . Rorsman, N. (2016). AlGaN/GaN high electron mobility transistors with intentionally doped GaN buffer using propane as carbon precursor. Japanese Journal of Applied Physics, 55, 05FK02-1-05FK02-4, Article ID 05FK02.
Open this publication in new window or tab >>AlGaN/GaN high electron mobility transistors with intentionally doped GaN buffer using propane as carbon precursor
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2016 (English)In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 55, p. 05FK02-1-05FK02-4, article id 05FK02Article in journal (Refereed) Published
Abstract [en]

AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on a heterostructure grown by metalorganic chemical vapor deposition using analternative method of carbon (C) doping the buffer are characterized. C-doping is achieved by using propane as precursor, as compared to tuningthe growth process parameters to control C-incorporation from the gallium precursor. This approach allows for optimization of the GaN growthconditions without compromising material quality to achieve semi-insulating properties. The HEMTs are evaluated in terms of isolation anddispersion. Good isolation with OFF-state currents of 2 ' 10%6A/mm, breakdown fields of 70V/μm, and low drain induced barrier lowering of0.13mV/V are found. Dispersive effects are examined using pulsed current–voltage measurements. Current collapse and knee walkout effectslimit the maximum output power to 1.3W/mm. With further optimization of the C-doping profile and GaN material quality this method should offer aversatile approach to decrease dispersive effects in GaN HEMTs.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-128077 (URN)10.7567/JJAP.55.05FK02 (DOI)000374697600081 ()
Funder
Swedish Foundation for Strategic Research Swedish Research Council
Available from: 2016-05-16 Created: 2016-05-16 Last updated: 2017-11-30
Pedersen, H. (2016). Time as the Fourth Dimension: Opening up New Possibilities in Chemical Vapor Deposition. Chemistry of Materials, 28(3), 691-699
Open this publication in new window or tab >>Time as the Fourth Dimension: Opening up New Possibilities in Chemical Vapor Deposition
2016 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 28, no 3, p. 691-699Article in journal (Refereed) Published
Abstract [en]

Thin films of inorganic materials are essential to several technologies we take for granted in our everyday lives. They form the basis of touch screens in smart phones and the electronic components in computers. Dating back more than a century, chemical vapor deposition (CVD) is one of the most common methods to form these films. In CVD, the atoms needed for the thin film are typically supplied by a continuous flow of gaseous precursor molecules and incorporated into the film by gas phase and surface chemical reactions. The continuous demand for more precise thin film fabrication on more complex shapes at lower temperatures sets a demand for more advanced CVD methods. The development of better designed precursor molecules is one important path to evolve CVD; the other path is to evolve the way in which we do CVD. In this perspective I will describe how using time as a fourth dimension in CVD can enable fabrication of new thin film materials and material structures at lower temperatures and on more complex substrate geometries by accessing new types of CVD chemistries available in time-resolved CVD.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2016
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-125808 (URN)10.1021/acs.chemmater.5b04553 (DOI)000370112200002 ()
Available from: 2016-03-08 Created: 2016-03-04 Last updated: 2017-11-30
Yazdanfar, M., Kalered, E., Danielsson, Ö., Kordina, O., Nilsson, D., Ivanov, I. G., . . . Pedersen, H. (2015). Brominated chemistry for chemical vapor deposition of electronic grade SiC. Chemistry of Materials, 27(3), 793-801
Open this publication in new window or tab >>Brominated chemistry for chemical vapor deposition of electronic grade SiC
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2015 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 27, no 3, p. 793-801Article in journal (Refereed) Published
Abstract [en]

Chlorinated chemical vapor deposition (CVD) chemistry for growth of homoepitaxial layers of silicon carbide (SiC) has paved the way for very thick epitaxial layers in short deposition time as well as novel crystal growth processes for SiC. Here, we explore the possibility to also use a brominated chemistry for SiC CVD by using HBr as additive to the standard SiC CVD precursors. We find that brominated chemistry leads to the same high material quality and control of material properties during deposition as chlorinated chemistry and that the growth rate is on average 10 % higher for a brominated chemistry compared to chlorinated chemistry. Brominated and chlorinated SiC CVD also show very similar gas phase chemistries in thermochemical modelling. This study thus argues that brominated chemistry is a strong alternative for SiC CVD since the deposition rate can be increased with preserved material quality. The thermochemical modelling also suggest that the currently used chemical mechanism for halogenated SiC CVD might need to be revised.

National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:liu:diva-111075 (URN)10.1021/acs.chemmater.5b00074 (DOI)000349934500016 ()
Available from: 2014-10-07 Created: 2014-10-07 Last updated: 2018-06-19Bibliographically approved
Li, X., Bergsten, J., Nilsson, D., Danielsson, Ö., Pedersen, H., Rorsman, N., . . . Forsberg, U. (2015). Carbon doped GaN buffer layer using propane for high electron mobility transistor applications: Growth and device results. Applied Physics Letters, 107(26), 262105
Open this publication in new window or tab >>Carbon doped GaN buffer layer using propane for high electron mobility transistor applications: Growth and device results
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2015 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, no 26, p. 262105-Article in journal (Refereed) Published
Abstract [en]

The creation of a semi insulating (SI) buffer layer in AlGaN/GaN High Electron Mobility Transistor (HEMT) devices is crucial for preventing a current path beneath the two-dimensional electron gas (2DEG). In this investigation, we evaluate the use of a gaseous carbon gas precursor, propane, for creating a SI GaN buffer layer in a HEMT structure. The carbon doped profile, using propane gas, is a two stepped profile with a high carbon doping (1.5 x 10(18) cm(-3)) epitaxial layer closest to the substrate and a lower doped layer (3 x 10(16) cm(-3)) closest to the 2DEG channel. Secondary Ion Mass Spectrometry measurement shows a uniform incorporation versus depth, and no memory effect from carbon doping can be seen. The high carbon doping (1.5 x 10(18) cm(-3)) does not influence the surface morphology, and a roughness root-mean-square value of 0.43 nm is obtained from Atomic Force Microscopy. High resolution X-ray diffraction measurements show very sharp peaks and no structural degradation can be seen related to the heavy carbon doped layer. HEMTs are fabricated and show an extremely low drain induced barrier lowering value of 0.1 mV/V, demonstrating an excellent buffer isolation. The carbon doped GaN buffer layer using propane gas is compared to samples using carbon from the trimethylgallium molecule, showing equally low leakage currents, demonstrating the capability of growing highly resistive buffer layers using a gaseous carbon source. (C) 2015 AIP Publishing LLC.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2015
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-125161 (URN)10.1063/1.4937575 (DOI)000368442300020 ()
Note

Funding Agencies|Swedish Defense Materiel Administration (FMV); Swedish Foundation for Strategic Research (SSF)

Available from: 2016-02-15 Created: 2016-02-15 Last updated: 2017-11-30
Imam, M., Gaul, K., Stegmueller, A., Höglund, C., Jensen, J., Hultman, L., . . . Pedersen, H. (2015). Gas phase chemical vapor deposition chemistry of triethylboron probed by boron-carbon thin film deposition and quantum chemical calculations. Journal of Materials Chemistry C, 3(41), 10898-10906
Open this publication in new window or tab >>Gas phase chemical vapor deposition chemistry of triethylboron probed by boron-carbon thin film deposition and quantum chemical calculations
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2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 41, p. 10898-10906Article in journal (Refereed) Published
Abstract [en]

We present triethylboron (TEB) as a single-source precursor for chemical vapor deposition (CVD) of BxC thin films and study its gas phase chemistry under CVD conditions by quantum chemical calculations. A comprehensive thermochemical catalogue for the species of the gas phase chemistry of TEB is examined and found to be dominated by beta-hydride eliminations of C2H4 to yield BH3. A complementary bimolecular reaction path based on H-2 assisted C2H6 elimination to BH3 is also significant at lower temperatures in the presence of hydrogen. Furthermore, we find a temperature window of 600-1000 degrees C for the deposition of X-ray amorphous BxC films with 2.5 less than= x less than= 4.5 from TEB. Films grown at temperatures below 600 degrees C contain high amounts of H, while temperatures above 1000 degrees C result in C-rich films. The film density and hardness are determined to be in the range of 2.40-2.65 g cm(-3) and 29-39 GPa, respectively, within the determined temperature window.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2015
National Category
Physical Sciences Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-122673 (URN)10.1039/c5tc02293b (DOI)000363252200030 ()
Note

Funding Agencies|European Spallation Source ESS AB; Knut and Alice Wallenberg Foundation; German Science Foundation (Research Training Group 1782); Beilstein Foundation (Frankfurt/Germany)

Available from: 2015-11-16 Created: 2015-11-13 Last updated: 2017-09-29
Chubarov, M., Pedersen, H., Högberg, H., Henry, A. & Czigany, Z. (2015). Initial stages of growth and the influence of temperature during chemical vapor deposition of sp(2)-BN films. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 33(6), 061520
Open this publication in new window or tab >>Initial stages of growth and the influence of temperature during chemical vapor deposition of sp(2)-BN films
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2015 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 33, no 6, p. 061520-Article in journal (Refereed) Published
Abstract [en]

Knowledge of the structural evolution of thin films, starting by the initial stages of growth, is important to control the quality and properties of the film. The authors present a study on the initial stages of growth and the temperature influence on the structural evolution of sp(2) hybridized boron nitride (BN) thin films during chemical vapor deposition (CVD) with triethyl boron and ammonia as precursors. Nucleation of hexagonal BN (h-BN) occurs at 1200 degrees C on alpha-Al2O3 with an AlN buffer layer (AlN/alpha-Al2O3). At 1500 degrees C, h-BN grows with a layer-by-layer growth mode on AlN/alpha-Al2O3 up to similar to 4 nm after which the film structure changes to rhombohedral BN (r-BN). Then, r-BN growth proceeds with a mixed layer-by-layer and island growth mode. h-BN does not grow on 6H-SiC substrates; instead, r-BN nucleates and grows directly with a mixed layer-by-layer and island growth mode. These differences may be caused by differences in substrate surface temperature due to different thermal conductivities of the substrate materials. These results add to the understanding of the growth process of sp(2)-BN employing CVD. (C) 2015 American Vacuum Society.

Place, publisher, year, edition, pages
A V S AMER INST PHYSICS, 2015
National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:liu:diva-123831 (URN)10.1116/1.4935155 (DOI)000365503800054 ()
Note

Funding Agencies|Swedish Research Council (VR) [621-2013-5585]; Carl Tryggers Stiftelse [12:175]; CeNano Program at Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; Bolyai Janos research scholarship of Hungarian Academy of Sciences

Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2017-12-01
Li, X., Bergsten, J., Nilsson, D., Danielsson, Ö., Pedersen, H., Rorsman, N., . . . Forsberg, U. (2015). Intentionally carbon doped GaN buffer layer for HEMT application: growth and device results.
Open this publication in new window or tab >>Intentionally carbon doped GaN buffer layer for HEMT application: growth and device results
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2015 (English)Manuscript (preprint) (Other academic)
Abstract [en]

The creation of a semi-insulating (SI) buffer layer in AlGaN/GaN HEMT devices is crucial for preventing a current path beneath the two-dimensional electron gas (2DEG). Here we evaluate the use of a carbon precursor, propane, for creating a SI GaN buffer layer. The carbon doping profile obtained from SIMS measurement shows a very uniform incorporation versus depth and no significant memory effect from carbon doping is seen, allowing for the creation of a very abrupt profile. The high carbon doping (1.5×1018 cm-3) does not influence the surface morphology. HRXRD ω rocking curve showed a FWHM of 200 arcsec of the (0002) and 261 arcsec for (10-12) reflection of the GaN, respectively. HEMT devices were processed on the epitaxial layers. An extremely low drain induced barrier lowering value of 0.1 mV/V was measured for a HEMT with a gate length of 0.2 𝜇m. This demonstrates the capability of growing a highly resistive buffer layer using intentional carbon doping.

National Category
Physical Sciences Physical Chemistry
Identifiers
urn:nbn:se:liu:diva-118112 (URN)
Available from: 2015-05-22 Created: 2015-05-22 Last updated: 2016-08-31Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7171-5383

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