Growth and Microstructure of Epitaxial Ti3SiC2 Contact Layers on SiC

Growth and microstructure of ternary Ti3SiC2 compound layers on 4H-SiC, which play am important role in formation of TiAl-based ohmic contacts to p-type SiC, were investigated in this study. The Ti3SiC2 layer was fabricated by deposition of Ti/Al contacts (where a slash / indicates the deposition sequence) on the 4H-SiC(0001) substrate and subsequent rapid thermal anneal at 1000 degrees C in ultra high vacuum. After annealing, reaction products and microstructure of the Ti3SiC2 layer were investigated by X ray diffraction analysis and transmission electron microscopy observations in order to understand the growth processes of the Ti3SiC2 layer and determination of the Ti3SiC2/4H-SiC interface structure. The Ti3SiC2 layers with hexagonal plate shape were observed to grow epitaxially on the SiC(0001) surface by anisotropic lateral growth process. The interface was found to have a hetero-epitaxial orientation relationship of (0001)(TSC)//(0001)(S) and [0 (1) over bar 10](TSC)// [0 (1) over bar 10](S) where TSC and S represent Ti3SiC2 and 4H-SiC, respectively, and have well-defined ledge-terrace structures with low density of misfit dislocations due to an extremely low lattice mismatch of 0.4% between Ti3SiC2 and 4H-SiC. [doi: 10.2320/matertrans.MC200831]