Transparent highly oriented 3C-SiC bulks by halide laser CVD

Transparent and highly oriented 3C-SiC bulks were speedily fabricated at deposition temperature (Tdep) of 1623 K by halide laser chemical vapor deposition (HLCVD). The effect of total pressure (Ptot) on the optical transmittance, preferred orientation, microstructure, deposition rate (Rdep) and micro-hardness were investigated. The maximum Rdep of the transparent 3C-SiC reached 2450 μm/h at Ptot = 10 kPa. With an increase in Ptot, the transmittance of 3C-SiC bulks increased firstly, and then decreased. At Ptot = 10 kPa, 3C-SiC bulk, a highly <111>-oriented and low density of defects, showed the highest transmittance, greater than 55% in the wavelength range of 800-1100 nm. At Ptot = 4 kPa and 20 kPa, 3C-SiC bulks showed much lower transmittance, in which contained poorly oriented grains and numerous defects. The Vickers micro-hardness of 3C-SiC bulks increased with increasing Ptot and showed the highest value of 34.8 GPa at Ptot = 40 kPa.