堇青石基体化学气相沉积碳化硅薄膜及其性能表征

采用等温等压化学气相沉积技术，分别以CH3SiCl3-H2和SiCl4-CH4-H2为气源，在沉积温度1100和1000℃、压力101 kPa条件下，制备了SiC薄膜. 利用SEM和XRD、显微拉曼光谱、EDAX元素分析、HRTEM等测试技术对沉积薄膜的结构和组成进行了表征. 结果表明，1100℃时，以CH3SiCl3-H2为气源沉积得到纯净的SiC薄膜，以b-SiC (111)面择优定向生长，由微米级的金字塔锥形结构组成，硅含量随着沉积温度降低而增加；以SiCl4-CH4-H2为气源沉积得到非晶态碳掺杂的SiC薄膜，碳含量随着沉积温度降低而增加. 此外，以CH3SiCl3-H2为气源沉积的SiC颗粒平均粒径均比以SiCl4-CH4-H2为气源的粒径大. 前者SiC薄膜的方块电阻在kW级以上，且随着沉积温度的下降急剧升高；后者1100℃时制备的薄膜的方块电阻在kW级以上，且随着沉积温度的降低而急剧下降，1000℃时降低到W级.

Preparation and Characterization of SiC Thin Film on Cordierite with Chemical Vapor Deposition

Thin film of SiC on porous cordierite was prepared from CH3SiCl3-H2 and SiCl4-CH4-H2 gaseous sources by isothermal and isobaric chemical vapor deposition (CVD) at the temperatures of 1100 and 1000℃ and ambient pressure. The as-deposited thin film was characterized with scanning electron microscopy, X-ray diffraction, Raman micro-spectrum, high-resolution transmission electron microscopy and EDAX elementary analysis. The results indicated that the surface morphology of SiC thin film deposited from CH3SiCl3-H2 source showed pyramid structure which was significantly different from that from SiCl4-CH4-H2 source. Pyramid structure revealed that (111) plane of b-SiC was the preferred orientation in the XRD pattern. In most cases, the average size of pyramid shaped particles deposited from CH3SiCl3-H2 source was bigger than that from SiCl4-CH4-H2. The thin film deposited from CH3SiCl3-H2 source consisted of pure b-SiC phase, and its Si content increased with decreasing temperature. However, the SiC film from SiCl4-CH4-H2 source was amorphous carbon-doped SiC. Its C content increased with decreasing temperature. Additionally, sheet resistance of the SiC film from CH3SiCl3-H2 source was above a kW scale, increasing with temperature decreasing, while that from SiCl4-CH4-H2 source decreased rapidly with decreasing temperature. Sheet resistance of the SiC film deposited at 1100℃ from SiCl4-CH4-H2 source was above a kW scale, falling to a W scale at 1000℃.