Structural quality of smooth AIC poly-Si films on glass substrates

A method for removing Si precipitations from the surface of AIC (aluminium-induced crystallisation) poly-Si films is introduced. The basic idea is to remove the aluminium oxide layer that is present between the poly-Si film and the Si precipitates and thus enable a lift-off process. Furthermore, a detailed structural investigation of the resulting smooth AIC poly-Si film prepared on SiN-coated planar glass is performed. Based on Raman, UV reflectance and plan-view TEM, the overall crystal quality is found to be excellent for a poly-Si film on glass. Especially the fact that 10-micron grains without dendritic growth pattern are obtained is encouraging. However, there is still room for improvement as both Raman and plan-view TEM reveal areas (∼10% of total surface area) of sub-micron grains and/or twinned grains. Work is in progress to understand the mechanism behind these results.