大気圧プラズマCVD法によるアモルファスSiCの高速成膜に関する研究(第1報)

成膜速度および膜構造の検討

抄録

Using atmospheric pressure plasma CVD (chemical vapor deposition) technique, hydrogenated amorphous Si_1-xC_x (a-Si_1-xC_x:H) films were deposited with extremely high deposition rate. The films were prepared on Si(001) wafers in atmospheric pressure VHF (very high frequency) plasma of gas mixtures containing He, H2, SiH4 and CH4. Film properties (structure, density and composition of a-Si_1-xC_x:H) were studied as a function of CH4 concentration by TEM (transmission electron microscopy), AES (Auger electron spectroscopy) and IR (infrared) absorption spectroscopy. Relation between IR absorption spectra and chemical resistance of the films to 15% KOH solution was also investigated. The maximum deposition rate was 50nm/s, which was more than 10 times faster than that achieved by the conventional plasma CVD technique. It was found that CH4 molecules contributed to the film growth when SiH4 was co-existed with SiH4 to CH4 concentration ratio of 1/10. In this case, C to Si composition ratio in the film was 2 (a-Si_0.33C_0.67:H). The density of a-Si_1-xC_x:H film was about .1.5g/cm3 being less than half of the crystalline value of SiC. The a-Si_0.33C_0.67:H film was not etched by KOH solution, which was supported by IR analysis of the Si-C stretching vibration mode.