Characteristics of Hydrogen Effusion from the Si-H Bonds in Si Rich Silicon Oxynitride Films for Nanocrystalline Silicon Based Photovoltaic Applications

Abstract

This work is devoted to determination of characteristics of hydrogen effusion from SiH bonds in Si rich silicon oxynitride (SRON) films, obtained by plasma enhanced chemical vapor deposition, as a result of thermal anneals at temperatures from 400 to 800°C. The values of the concentrations of SiH bonds in HSi (Si3nOn) (0 n 3) complexes contributing to the structure of SRON films are obtained from the analysis of infrared absorption spectra in the range of 2000-2400 cm1. The kinetics of the decrease of SiH concentrations as a result of anneals is described in the framework of a model with distributed activation energy of hydrogen emission. The median value and the mean-square deviation of this distribution as well as the attempt frequencies of SiH bond breaks are determined from the comparison of experimental and calculated SiH concentrations in SRON films. These characteristics are compatible with such characteristics found for the case of the depassivation of PbH centers at the Si/SiO2 interfaces. Obtained results are useful for the controlled formation of the layers of Si nanocrystals in dielectric matrix for Si based tandem solar cells applications.