Growth kinetics of nc-Si:H deposited at 200 °C by hot-wire chemical vapour deposition

Abstract

The authors report on the growth kinetics of hydrogenated nanocrystalline silicon, with specific focus on the effects of the deposition time and hydrogen dilution on the nano-structural properties. The growth in the crystallite size, attributed to the agglomeration of smaller nano-crystallites, is accompanied by a reduction in the compressive strain within the crystalline region and an improved ordering and reduction in the tensile stress in the amorphous network. These changes are intimately related to the absorption characteristics of the material. Surface diffusion determines the growth in the amorphous regime, whereas competing reactions between silicon etching by atomic hydrogen and precursor deposition govern the film growth at the highdilution regime. The diffusion of hydrogen within the film controls the growth during the transition from amorphous to nanocrystalline silicon.