Substrate dependence of crystallization of silicon films prepared by hydrogen radical CVD method

In production of microcrystalline silicon (μc-Si:H) films, a substrate is a significant element by which the crystallization of films is affected. By using a hydrogen radical CVD method, we investigated how the growth of μc-Si:H is affected by differences of substrate surfaces. Three types of substrate surface were used: a glass plate and evaporated aluminum thin films electrically floated and grounded. Differences between influences of substrate surfaces were confirmed clearly at the initial growth of μc-Si:H films. The highest crystallinity was obtained on the grounded aluminum and the lowest was on the floated aluminum. These results suggest that differences of electrical potential of substrate surface affect strongly the initial growth of microcrystalline films. Hydrogen ions seem to suppress crystallization of deposited films.