The relationship between $I_{{\rm H}_{\rm \alpha } } /(I_{{\rm SiH}}^* )^2$ and crystalline volume fraction in microcrystalline silicon growth

Optical‐emission‐intensity ratio of $I_{{\rm H}_{\rm \alpha } } /(I_{{\rm SiH}}^* )$ during film growth has been used as a simple indicator to predict crystallinity (crystal‐volume fraction: X C ) in the resulting microcrystalline silicon (µc‐Si:H) thin films. The relationship between $I_{{\rm H}_{\rm \alpha } } /(I_{{\rm SiH}}^* )$ and X C has been checked under a wide variety of film‐preparation conditions including low‐deposition‐rate (<0.1 nm/s) and high‐deposition‐rate (>5 nm/s) cases. On the basis of theoretical consideration, we have proposed optical‐emission‐intensity ratio of $I_{{\rm H}_{\rm \alpha } } /(I_{{\rm SiH}}^* )^2 $ as a new indicator of X C during film growth of µc‐Si:H.