Optical properties and chemical bonding characteristics of amorphous SiNX:H thin films grown by the plasma enhanced chemical vapor deposition method

Abstract

Amorphous silicon nitride (SiNX:H) thin films grown by the plasma enhanced chemical vapor deposition (PECVD) method are presently the most important antireflection coatings for crystalline silicon solar cells. In this work, we investigated the optical properties and chemical bonding characteristics of the amorphous SiNX:H thin films deposited by PECVD. Silane (SiH4) and ammonia (NH3) were used as the reactive precursors. The dependence of the growth rate and refractive index of the SiNX:H thin films on the SiH4/NH3 gas flow ratio was studied. The chemical bonding characteristics and the surface morphologies of the SiNX:H thin films were studied using the Fourier transform infrared spectroscopy and atomic force microscopy, respectively. We also investigated the effect of rapid thermal processing on the optical properties and surface morphologies of the SiNX:H thin films. It was found that the rapid thermal processing resulted in a decrease in the thickness, increase in the refractive index, and coarser surfaces for the SiNX:H thin films.