Interface-structure of the Si/SiC heterojunction grown on 6H-SiC

The Si/SiC heterojunctions were prepared on 6H-SiC (0001) C-face by low-pressure chemical vapour deposition at 850 similar to 1050 degrees C. Transmission electron microscopy and selected area electron diffraction were employed to investigate the interface-structure of Si/SiC heterojunctions. The Si/6H-SiC heterostructure of large lattice-mismatch follows domain matching epitaxy mode, which releases most of the lattice-mismatch strain, and the coherent Si epilayers can be grown on 6H-SiC. Si(1-11)/6H-SiC(0001) heterostructure is obtained at 900 degrees C, and the in-plane orientation relationship of Si/6H-SiC heterostructure is (1-11)[1-1-2](Si)//(0001)[-2110](6H-SiC). The Si(1-11)/6H-SiC(0001) interface has the same 4: 5 Si-to-SiC matching mode with a residual lattice-mismatch of 0.26% along both the Si[1-1-2] and Si[110] orientations. When the growth temperature increases up to 1000 degrees C, the < 220 > preferential orientation of the Si film appears. SAED patterns at the Si/6H-SiC interface show that the in-plane orientation relationship is (-220)[001](Si)//(0001)[2-1-10](6H-SiC). Along Si[110] orientation, the Si-to-SiC matching mode is still 4: 5; along the vertical orientation Si[001], the Si-to-SiC mode change to approximate 1: 2 and the residual mismatch is 1.84% correspondingly. The number of the atoms in one matching-period decreases with increasing residual lattice-mismatch in domain matching epitaxy and vice versa. The Si film grows epitaxially but with misfit dislocations at the interface between the Si film and the 6H-SiC substrate. And the misfit dislocation density of the Si(1-11)/6H-SiC(0001) and Si(-220)/6H-SiC(0001) obtained by experimental observations is as low as 0.487 x 10(14) cm(-2) and 1.217 x 10(14) cm(-2), respectively, which is much smaller than the theoretical calculation results. (C) 2015 AIP Publishing LLC.