Papers by Author: Nikoletta Jegenyes

Abstract: Chemical vapour deposition in a cold wall reactor working at atmospheric pressure was used to study the homoeptaxial growth of 4H-SiC on 4°ff misoriented substrates from silane and propane precursors. The effect of various growth parameters (temperature 1450-1650°C, C/Si ratio 1-7, thickness 2.5-10 µm) were studied in order to determine the best conditions for obtaining smooth surfaces after epitaxy. It is shown that the main source of roughness is surface undulation which easily appears during growth, especially at low C/Si ratios and high temperature (up to 1600°C). Temperatures above 1600°C and C/Si ratio of 1 give the best results. When reducing temperature, a trade-off has to be found between defects formation and surface undulation.

Abstract: In this work we report on the study of twin boundary (TB) evolution during heteroepitaxial growth of 3C-SiC on patterned 4H-SiC(0001) substrate by vapour-liquid-solid (VLS) mechanism. Ge₅₀Si₅₀ melt was used at a temperature of 1450°C. 3C-SiC deposit was obtained on top and outside the mesas. Some lateral enlargement of these mesas was observed but it was systematically homoepitaxial. Elimination of TBs inside the 3C-SiC deposit on top of the mesas was observed for specific mesa shape and/or orientation of the sidewalls. Though three–fold or six-fold symmetry mesas are recommended for TB elimination, originally circular mesas lead also to the same result due to initial faceting toward hexagonal shape.