Optical Emission Spectroscopy Studies in ECR Plasma Used for the Deposition of Silicon Oxide Film

Abstract

The Optical Emission Spectroscopy (OES) is used as a diagnostic tool for analyzing the plasma spectrum of Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) in solar silicon oxide thin film process. In this study, the correlation between spectrum variation trend and a-SiOx film properties will be discussed.The results reveal when the total flow rate and working pressure are fixed, the silicon oxide deposition rate can be interpreted by SiH* spectroscopy. On the premise that the bond energy of reaction species is lower than the bond energy of Si-O bond, the O* spectroscopy intensity tends to to be a positive correlation with oxygen content of thin film. Based on the above results, we can develop and use the database from plasma spectra corresponding to film properties, and the processing time required for optimization of silicon oxide process can be reduced significantly. In addition to the film properties, it is noted that a different and opposite finding compared with PECVD is that the photo-conductivity of a-SiO x film increases and dark-conductivity decreases when microwave power augments. Finally, in 800W power, 200°C process temperaure and 5mTorr working pessure, it is found that the hydrogenated amorphous silicon oxide will transform to the crystalline phase when CO 2 /SiH 4 ratio is less than 0.2 and H 2 /SiH 4 ratio is greater than 10.

Electrical and Optical Characterization of Boron-doped Microcrystalline SiH Films Prepared by ECR-CVD for Solar Cell

“…It is necessary to develop a way for in-situ monitor for the purpose of making it in such fast changes in processing variations. In previous studies (1), the relationship between the process parameters and experimental results was investigated. However, the correlation of plasma with thin film property is a main objective worthy of further study.…”

“…In this study, we discuss not only the relations of process parameters and characteristics of thin film, but also use the OES to analyze the effect of plasma on the thin film. According to previous research (1), OES measurement can be taken as an indicator for quality of film. So it is worthy further try in analyzing the connection between spectrum and property of doping film to obtain optimized process in doping conditions.…”