Modulation effect of plasma power on crystalline volume fraction of silicon films in the phase transition from a-Si:H to /spl mu/c-Si:H

While depositing of a-Si:H thin films in PECVD technique, crystalline volume fraction (X/sub c/) is commonly modified by varying hydrogen dilution. In this paper the modulation effect of plasma power on X/sub c/ of films in the phase transition from a-Si:H to (/spl mu/c-Si:H, deposited by VHF-PECVD method, has been investigated. It is found that at appropriate hydrogen dilution (R=H/sub 2//SiH/sub 4/) the crystalline volume fraction, which is a symbol of order of silicon network, has a nonlinear relationship with plasma power. At a low power, the films have a high X/sub c/. While increasing glow power continuously X/sub c/ decreases at first, and then increases. Using this modulation effect of glow power on X/sub c/, combined with varying hydrogen dilution, the X/sub c/ could be controlled expediently. The tendency of X/sub c/ with power at different hydrogen dilution also has been forecasted in this paper.