Effect of deposition parameters on the optical and structural properties of silicon-hydrogen films deposited by RF magnetron sputtering

Abstract

This study reports the deposition of amorphous hydrogenated silicon thin films by radio frequency magnetron sputtering and their optical characterization by UV–visible spectroscopy and FTIR Spectroscopy. Structural characterization and morphological studies are also performed. It investigates the effect of process factors such as RF power, hydrogen concentration, and deposition temperature on the optical properties of the deposited films. The impact of process parameters like RF power, hydrogen flow, and substrate temperature on the bandgap, refractive index and hydrogen concentration has been studied. The study draws a comparison due to the crucial interactions among RF power, hydrogen flow, and substrate temperature which affect the optical and structural characteristics of a-Si:H thin films. For a particular application, the critical control of these parameters is necessary to provide the requisite film qualities. The films prepared with optimized deposition parameters of RF power of 80 W, hydrogen flow of 5 sccm, and deposition temperature of 150 °C, resulted in a bandgap value of 1.80 eV, refractive index of 2.3, and hydrogen concentration of 5.15% which can be useful as absorber layer in photovoltaic applications. Despite the amorphous nature of all the films, achieving a high-quality a-Si:H thin film requires control over the growth structures, where hydrogen plays a crucial role in passivating the defects.