Evolutionary phase diagrams for the deposition of silicon films from hydrogen-diluted silane

Abstract

Phase diagrams that describe plasma-enhanced chemical vapor deposition (PECVD) of Si films at low substrate temperature (200°C) have been established using real time spectroscopic ellipsometry (RTSE) as a probe of film microstructural evolution and optical properties. These deposition phase diagrams describe the regimes over which predominantly amorphous and microcrystalline Si phases are obtained as a function of the accumulated film thickness and the hydrogen-to-silane gas flow ratio, R=[H 2]/[SiH 4]. The diagrams for different substrate materials demonstrate how general principles can be formulated and verified for design of optimized multistep i-layer components of amorphous silicon solar cells.