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Stenberg, Pontus
Publications (8 of 8) Show all publications
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
Booker, I. D., Janzén, E., Son, N. T., Hassan, J., Stenberg, P. & Sveinbjörnsson, E. (2016). Donor and double donor transitions of the carbon vacancy related EH6/7 deep level in 4H-SiC. Journal of Applied Physics, 119(23), Article ID 235703.
Open this publication in new window or tab >>Donor and double donor transitions of the carbon vacancy related EH6/7 deep level in 4H-SiC
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2016 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, no 23, article id 235703Article in journal (Refereed) Published
Abstract [en]

Using medium- and high-resolution multi-spectra fitting of deep level transient spectroscopy (DLTS), minority carrier transient spectroscopy (MCTS), optical O-DLTS and optical-electrical (OE)-MCTS measurements, we show that the EH6∕7 deep level in 4H-SiC is composed of two strongly overlapping, two electron emission processes with thermal activation energies of 1.49 eV and 1.58 eV for EH6 and 1.48 eV and 1.66 eV for EH7. The electron emission peaks of EH7 completely overlap while the emission peaks of EH6 occur offset at slightly different temperatures in the spectra. OE-MCTS measurements of the hole capture cross section σp 0(T) in p-type samples reveal a trap-Auger process, whereby hole capture into the defect occupied by two electrons leads to a recombination event and the ejection of the second electron into the conduction band. Values of the hole and electron capture cross sections σn(T) and σp(T) differ strongly due to the donor like nature of the deep levels and while all σn(T) have a negative temperature dependence, the σp(T) appear to be temperature independent. Average values at the DLTS measurement temperature (∼600 K) are σn 2+(T) ≈ 1 × 10−14 cm2, σn +(T) ≈ 1 × 10−14 cm2, and σp 0(T) ≈ 9 × 10−18 cm2 for EH6 and σn 2+(T) ≈ 2 × 10−14 cm2, σn +(T) ≈ 2 × 10−14 cm2, σp 0(T) ≈ 1 × 10−20 cm2 for EH7. Since EH7 has already been identified as a donor transition of the carbon vacancy, we propose that the EH6∕7 center in total represents the overlapping first and second donor transitions of the carbon vacancy defects on both inequivalent lattice sites.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2016
Keywords
4H-SiC, DLTS, MCTS, Carbon vacancy, EH6/7; Z1/2, UT-1, Negative-U, Trap Auger, Deep level
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-121544 (URN)10.1063/1.4954006 (DOI)000379038800035 ()
Funder
Swedish Foundation for Strategic Research Swedish Research Council
Note

At the time for thesis presentation publication was in status: Manuscript

Funding agencies: Swedish Foundation for Strategic Research (SSF); Swedish Research Council (VR)

Available from: 2015-09-24 Created: 2015-09-24 Last updated: 2017-12-01Bibliographically approved
Ul-Hassan, J., Bae, H., Lilja, L., Farkas, I., Kim, I., Stenberg, P., . . . Janzén, E. (2014). Fast growth rate epitaxy on 4((degrees)under-bar) off-cut 4-inch diameter 4H-SiC wafers. In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2: . Paper presented at 15th International Conference on Silicon Carbide and Related Materials (ICSCRM), Miyazaki, Japan, 29 Sptember - 4 October 2013 (pp. 179-182). Trans Tech Publications, 778-780
Open this publication in new window or tab >>Fast growth rate epitaxy on 4((degrees)under-bar) off-cut 4-inch diameter 4H-SiC wafers
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2014 (English)In: SILICON CARBIDE AND RELATED MATERIALS 2013, PTS 1 AND 2, Trans Tech Publications , 2014, Vol. 778-780, p. 179-182Conference paper, Published paper (Refereed)
Abstract [en]

We report the development of over 100 mu m/h growth rate process on 4-inch diameter wafers using chlorinated growth. The optimized growth process has shown extremely smooth epilayers completely free of surface step-bunching with very low surface defect density, high uniformity in thickness and doping and high run to run reproducibility in growth rate, controlled doping and defect density.

Place, publisher, year, edition, pages
Trans Tech Publications, 2014
Series
Materials Science Forum, ISSN 1662-9752 ; 778-780
Keywords
Fast epitaxial growth; high growth rate; chlorinated growth; atomic force microscopy
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:liu:diva-108193 (URN)10.4028/www.scientific.net/MSF.778-780.179 (DOI)000336634100042 ()
Conference
15th International Conference on Silicon Carbide and Related Materials (ICSCRM), Miyazaki, Japan, 29 Sptember - 4 October 2013
Available from: 2014-06-26 Created: 2014-06-26 Last updated: 2016-06-02Bibliographically approved
Ivanov, I. G., Yazdanfar, M., Lundqvist, B., Chen, J.-T., ul-Hassan, J., Stenberg, P., . . . Janzén, E. (2014). High-Resolution Raman and Luminescence Spectroscopy of Isotope-Pure (SiC)-Si-28-C-12, Natural and C-13 - Enriched 4H-SIC. In: Silicon Carbide and Related Materials 2013, PTS 1 AND 2: . Paper presented at 15th International Conference on Silicon Carbide and Related Materials (ICSCRM 2013), 29 September - 4 October 2013, Miyazaki, Japan (pp. 471-474). Trans Tech Publications Inc., 778-780
Open this publication in new window or tab >>High-Resolution Raman and Luminescence Spectroscopy of Isotope-Pure (SiC)-Si-28-C-12, Natural and C-13 - Enriched 4H-SIC
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2014 (English)In: Silicon Carbide and Related Materials 2013, PTS 1 AND 2, Trans Tech Publications Inc., 2014, Vol. 778-780, p. 471-474Conference paper, Published paper (Refereed)
Abstract [en]

The optical properties of isotope-pure (SiC)-Si-28-C-12, natural SiC and enriched with C-13 isotope samples of the 4H polytype are studied by means of Raman and photoluminescence spectroscopies. The phonon energies of the Raman active phonons at the Gamma point and the phonons at the M point of the Brillouin zone are experimentally determined. The excitonic bandgaps of the samples are accurately derived using tunable laser excitation and the phonon energies obtained from the photoluminescence spectra. Qualitative comparison with previously reported results on isotope-controlled Si is presented.

Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2014
Series
Materials Science Forum, ISSN 1662-9752 ; 778-780
Keywords
isotope-pure SiC; isotope-enriched SiC; Raman spectroscopy; photoluminescence; bandgap variation with isotope content
National Category
Ceramics
Identifiers
urn:nbn:se:liu:diva-108198 (URN)10.4028/www.scientific.net/MSF.778-780.471 (DOI)000336634100110 ()
Conference
15th International Conference on Silicon Carbide and Related Materials (ICSCRM 2013), 29 September - 4 October 2013, Miyazaki, Japan
Available from: 2014-06-26 Created: 2014-06-26 Last updated: 2014-10-28Bibliographically approved
Yazdanfar, M., Stenberg, P., Don Booker, I., Gueorguiev Ivanov, I., Pedersen, H., Kordina, O. & Janzén, E. (2013). Morphology optimization of very thick 4H-SiC epitaxial layers. In: SILICON CARBIDE AND RELATED MATERIALS 2012: . Paper presented at 9th European Conference on Silicon Carbide and Related Materials (ECSCRM 2012) (pp. 251-254). Trans Tech Publications, 740-742
Open this publication in new window or tab >>Morphology optimization of very thick 4H-SiC epitaxial layers
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2013 (English)In: SILICON CARBIDE AND RELATED MATERIALS 2012, Trans Tech Publications , 2013, Vol. 740-742, p. 251-254Conference paper, Published paper (Refereed)
Abstract [en]

Epitaxial growth of about 200 gm thick, low doped 4H-SiC layers grown on n-type 8 degrees off-axis Si-face substrates at growth rates around 100 mu m/h has been done in order to realize thick epitaxial layers with excellent morphology suitable for high power devices. The study was done in a hot wall chemical vapor deposition reactor without rotation. The growth of such thick layers required favorable pre-growth conditions and in-situ etch. The growth of 190 gm thick, low doped epitaxial layers with excellent morphology was possible when the C/Si ratio was below 0.9. A low C/Si ratio and a favorable in-situ etch are shown to be the key parameters to achieve 190 gm thick epitaxial layers with excellent morphology.

Place, publisher, year, edition, pages
Trans Tech Publications, 2013
Keywords
CVD; Chloride-based; Thick epitaxial layer; Morphology
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-96507 (URN)10.4028/www.scientific.net/MSF.740-742.251 (DOI)000319785500060 ()
Conference
9th European Conference on Silicon Carbide and Related Materials (ECSCRM 2012)
Available from: 2013-08-23 Created: 2013-08-20 Last updated: 2015-03-11
Yazdanfar, M., Stenberg, P., Don Booker, I., Gueorguiev Ivanov, I., Kordina, O., Pedersen, H. & Janzén, E. (2013). Process stability and morphology optimization of very thick 4H-SiC epitaxial layers grown by chloride-based CVD. Journal of Crystal Growth, 380, 55-60
Open this publication in new window or tab >>Process stability and morphology optimization of very thick 4H-SiC epitaxial layers grown by chloride-based CVD
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2013 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 380, p. 55-60Article in journal (Refereed) Published
Abstract [en]

The development of a chemical vapor deposition (CVD) process for very thick silicon carbide (SiC) epitaxial layers suitable for high power devices is demonstrated by epitaxial growth of 200 nm thick, low doped 4H-SiC layers with excellent morphology at growth rates exceeding 100 nm/h. The process development was done in a hot wall CVD reactor without rotation using both SiCl4 and SiH4+HCl precursor approaches to chloride based growth chemistry. A C/Si ratio andlt;1 and an optimized in-situ etch are shown to be the key parameters to achieve 200 nm thick, low doped epitaxial layers with excellent morphology.

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
Crystal morphology, CVD, Chloride-based, SiC
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-98217 (URN)10.1016/j.jcrysgro.2013.05.037 (DOI)000324042000011 ()
Note

Funding Agencies|Swedish Energy Agency||Swedish Research Council (VR)||Swedish Foundation for Strategic Research (SSF)||

Available from: 2013-10-03 Created: 2013-10-03 Last updated: 2017-12-06
Lundqvist, B., Raad, P., Yazdanfar, M., Stenberg, P., Liljedahl, R., Komarov, P., . . . Janzén, E. (2013). Thermal Conductivity of Isotopically Enriched Silicon Carbide. In: Thermal Investigations of ICs and Systems (THERMINIC), 2013: . Paper presented at 19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC), 25-27 September 2013, Berlin, Germany (pp. 58-61). IEEE
Open this publication in new window or tab >>Thermal Conductivity of Isotopically Enriched Silicon Carbide
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2013 (English)In: Thermal Investigations of ICs and Systems (THERMINIC), 2013, IEEE , 2013, p. 58-61Conference paper, Published paper (Refereed)
Abstract [en]

Since the semiconductor silicon carbide presents attractive opportunities for the fabrication of novel electronic devices, there is significant interest in improving its material quality. Shrinking component sizes and high demands for efficiency and reliability make the capability to release excess heat an important factor for further development. Experience from Si and Diamond tells us that isotopic enrichment is a possible way to increase the thermal conductivity. We have produced samples of 4H-SiC that contain Si-28 and C-12 to a purity of 99.5%. The thermal conductivity in the c-direction of these samples has been measured by a transient thermoreflectance method. An improvement due to enrichment of at least 18% was found. The result is valid for a temperature of 45K above room temperature. A preliminary study of the temperature dependence of the thermal conductivity demonstrates a strong temperature dependence in agreement with earlier reports for 4H.

Place, publisher, year, edition, pages
IEEE, 2013
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-106995 (URN)10.1109/THERMINIC.2013.6675243 (DOI)000335321100010 ()978-1-4799-2271-0 (ISBN)
Conference
19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC), 25-27 September 2013, Berlin, Germany
Available from: 2014-06-03 Created: 2014-06-02 Last updated: 2014-06-11Bibliographically approved
Booker, I. D., Hassan, J., Stenberg, P., Janzén, E. & Sveinbjörnsson, E.Carrier lifetime in p- and n-type 4H-SiC.
Open this publication in new window or tab >>Carrier lifetime in p- and n-type 4H-SiC
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Temperature-dependent time-resolved photoluminescence measurements made in the temperature range from 77 K to 1000 K on free-standing as grown n-type 4H-SiC and p-type 4H-SiC epilayers, which are either as-grown or annealed at 1000 °C, 1400 °C or 1700 °C, are analyzed. The development of the instantaneous carrier lifetime over temperature, calculated from the decay curves of all n- and p-type samples, is found to be identical in the entire temperature range. With increasing annealing temperature only the magnitude of the lifetime in p-type 4H-SiC decreases while the trend remains identical to that in the as-grown n-type sample. Annealing thus only increases the density of the main recombination center which appears to control lifetime in as-grown n- and p-type material. The results implies that the lifetime in all samples may be governed by the same intrinsic defect, which we suggest to be Z1/2.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-121543 (URN)
Available from: 2015-09-24 Created: 2015-09-24 Last updated: 2015-09-24
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