Low Temperature Deposition of Polycrystalline Silicon thin Films by Hot-Wire CVD

Abstract

ABSTRACTIn this study, we have deposited polycrystalline silicon (poly-Si) thin films by hot-wire Chemical Vapor Deposition (CVD) using hydrogen and disilane as the reactive gases. We selectively activate hydrogen and let disilane bypass the hot tungsten filament assembly and enter the reactor downstream from hydrogen. This may provide a better process chemistry, and by this approach, we have deposited poly-Si films at a substrate temperature as low as 310°C and at a growth rate as high as 100 Å/min. The substrate temperature is more than 2000C lower and the growth rate is more than twice higher compared to those of LPCVD poly-Si films. The effect of hydrogen flow rate, disilane flow rate and substrate temperature on the deposition rate and structural properties of the polysilicon films are investigated. The deposited films are characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and X-ray diffraction.