采用低压化学气相沉积方法在C面蓝宝石衬底上异质外延生长出高结晶质量和良好表面形貌的6H—SiC薄膜,研究了C3Hs气体流速对薄膜结晶质量的影响.随着C3H8气体流速的降低,薄膜的结晶质量先增加后降低,表明薄膜的生长在开始阶段受表面反应控制,而后受质量输运控制.所得到的结晶质量最好的6H-SiC薄膜,其摇摆曲线半高宽为0.6°,已经达到单晶水平.没有使用AlN过渡层,制备出结晶质量更好的SiC薄膜,表明对于蓝宝石衬底上SiC薄膜的生长,起决定性因素的是温度,过渡层不是影响SiC薄膜结晶质量的主要因素.
6H-SiC films with high crystal quality and good surface morphology were grown on C- plane Al2O3 (0001) substrates by a low-pressure vertical chemical vapor deposition (LPCVD). It is found that the crystalline quality of the films initially increase and then decrease with the decrease of flow rate of C3H8, suggesting that the transport control process changed from surface transport control at the initial growth state and then changed to mass transport control. The film with best crystalline quality has a full width half maximum (FWHM) value of 0.6°, showing the film is of single crystalline. SiC film with better crystal quality was obtained without the AIN buffer. So it is inferred that the crucial factor is not the buffer layer but the growth temperature for SiC films grown on Al2O3 substrate.