4H-SiC Epitaxial Growth on 2° Off-Axis Substrates using Trichlorosilane (TCS)

Abstract

4H-SiC epitaxial growth on 2˚ off-axis substrates using trichlorosilane (TCS) is presented. Good surface morphology was obtained for epilayers with C/Si ratios of 0.6 and 0.8 at a growth temperature of 1600°C. The triangle defect density was reduced to a level below 5 cm-2 at 1600°C and below 1 cm-2 at 1625°C for a C/Si ratio of 0.8. Photoluminescence (PL) measurements were carried out with band-pass filters of 420 nm, 460 nm, and 480 nm to detect stacking faults. A stacking fault density of below 5 cm-2 was achieved at 1600°C and 1625°C with a C/Si ratio of 0.8. The optimal conditions for TCS growth were a C/Si ratio of 0.8 and a growth temperature of 1600°C. The evaluation of stacking faults and etch pit density indicated that the use of 2˚ off-axis substrates and TCS is effective for reducing basal plane dislocations. Comparing these results to those using silane (SiH4) with HCl added, it was demonstrated that TCS is much more suitable for obtaining high-quality epilayers on 2º off-axis substrates.