Effect of the vacuum degree on the orientation and the microstructure of β-SiC films prepared by laser chemical vapour deposition

β-SiC films were prepared on AlN substrates by laser chemical vapour deposition (LCVD) using a diode laser and hydrido-polycarbosilane as a precursor at different vacuum degrees. The effect of the vacuum degree on the orientation and the microstructure of the β-SiC films was investigated. The preferred orientation of β-SiC films shifted from (111) to (311), the surface morphologies changed from faceted to rectangular and the columnar cross-section became thicker while increasing the vacuum degree from 0.4 to 7 KPa. The high deposition rate ranged from 180 to 240 µm/h.