Effects of Chamber Wall Heating and Quartz Window on Fast Deposition of Microcrystalline Silicon Films by High-Density Microwave Plasma

Abstract

The effects of chamber wall heating and quartz window on oxygen contamination and film crystallinity have been demonstrated in a high-density microwave plasma of a SiH4 and H2 mixture. With increasing chamber wall temperature, the film crystallinity deteriorates with higher concentration of oxygen impurity. The content of the oxygen impurity from the quartz window in the films is also significant with increasing working pressure and flow rate ratio of H2 to SiH4. The combination of higher flux of SiH4 and appropriate pressure of 150–300 mTorr is effective in suppressing the oxygen impurity while maintaining high film crystallinity. As a result, µc-Si film with a low defect density of 1–1.2×1016 cm-3 has been fabricated at a deposition rate of ∼50 Å/s.