| 1. |
- Syväjärvi, Mikael, et al.
(författare)
-
Growth of 6H and 4H-SiC by sublimation epitaxy
- 1999
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 197:1-2, s. 155-162
-
Tidskriftsartikel (refereegranskat)abstract
- The epitaxial sublimation growth process of SiC has been investigated. Layers with specular surfaces and growth rates up to 2 mm/h have been obtained. No step bunching is observed by optical microscopy even on very thick layers which indicates a stable step growth mechanism. Under certain growth conditions the morphology degrades. The morphological stability is investigated and discussed in relation to the growth kinetics. Impurities in the epitaxial layers are investigated by secondary ion mass spectroscopy and low-temperature photoluminescence. The carrier concentration is measured by capacitance–voltage measurements. The structural quality of the grown material is improved compared to the substrate as shown by X-ray diffraction measurements.
|
|
| 2. |
- Tuominen, M., et al.
(författare)
-
Investigation of domain evolution in sublimation epitaxy of SiC
- 1998
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 193:1-2, s. 101-108
-
Tidskriftsartikel (refereegranskat)abstract
- High resolution X-ray diffractometry has been applied to study domain misorientation in SiC epi-layers grown by the sublimation epitaxy method. A pronounced effect of the growth conditions on the mosaicity of the epi-layer has been observed. The results are discussed in terms of domain evolution and structural changes during the epi-growth under different growth conditions.
|
|
| 3. |
- Forsberg, Urban, 1971-, et al.
(författare)
-
Growth of high quality AlN Epitaxial Films by Hot-Wall Chemical Vapour Deposition
- 1998
-
Ingår i: Proceedings of the International Conference on Silicon Carbide, III-Nitrides and Related Materials, 1997. ; , s. 1133-1136
-
Konferensbidrag (refereegranskat)abstract
- 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.
|
|
| 4. |
- Kakanakova-Georgieva, Anelia, 1970-, et al.
(författare)
-
Microhardness of 6H-SiC epitaxial layers grown by sublimation
- 1999
-
Ingår i: Crystal research and technology (1981). - 0232-1300 .- 1521-4079. ; 34:8, s. 943-947
-
Tidskriftsartikel (refereegranskat)abstract
- Knoop microhardness of 6H-SiC layers grown by sublimation epitaxy was investigated. The microhardness-load curves for all of the samples were measured and then used to extract the load-independent microhardness values. The relationships of these values to the growth time and growth rate were studied. The microhardness-depth profiles indicated that the layer/substrate interface region had a microhardness value that differed significantly from that of both the epi-layer and the substrate.
|
|
| 5. |
- Nguyen, Son Tien, 1953-, et al.
(författare)
-
Photoluminescence and Zeeman effect in chromium-doped 4H and 6H SiC
- 1999
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 86:8, s. 4348-
-
Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence (PL) and Zeeman effect measurements in near-infrared luminescence bands in Cr-doped 4H and 6H SiC are presented. The PL spectrum consists of two no-phonon lines (NPLs) at 1.1583 and 1.1898 eV in 4H SiC and three NPLs at 1.1556, 1.1797, and 1.1886 eV in 6H SiC. The observed Zeeman splittings and temperature dependence studies reveal the spin triplet of the ground state and the orbital doublet structure of the excited state of the Cr-related center. All the triplets have almost isotropic g values close to 2 with trigonal symmetry and small zero-field splitting values D. In contrast, the effective g values of the excited state of the center are very anisotropic with g|| in the range of 0.22-0.64 and g[perpendicular] = 0 for different NPLs in both polytypes. Based on the Zeeman results, the PL is attributed to the internal transition 1E(D)-->3A2(F) within the d shell of a substitutional, neutral chromium (Cr4 + ) in the 3d2 electronic configuration.
|
|
| 6. |
- Syväjärvi, Mikael, et al.
(författare)
-
Kinetics and morphological stability in sublimation growth of 6H and 4H-SiC epitaxial layers
- 1999
-
Ingår i: Materials Science and Engineering: B. - 0921-5107. ; 61-62, s. 161-164
-
Tidskriftsartikel (refereegranskat)abstract
- Very high growth rates (>2 mm h−1) in SiC epitaxy have been achieved. The rate determining mechanism changes from diffusion to kinetics when the growth pressure decreases below 5–10 mbar. At low pressures it is shown that sublimation of the SiC source is the rate determining step and that there is a free molecular transport from source to substrate. The growth rate is constant during several hours of growth and Si losses from the crucible are very small. These facts show that our growth system is stable. The obtained apparent activation energy (130 kcal mol−1) is attributed to the sublimation rate of the SiC source material. The morphology is smooth and the surfaces are specular if the growth conditions are selected within the given parameter window for morphological stability. The origin of the growth disturbances is discussed.
|
|
