Variation of passivation behavior induced by sputtered energetic particles and thermal annealing for ITO/SiOx/Si systemProject supported by the National Natural Science Foundation of China (Grant Nos. 61274067, 60876045, and 61674099) and the Research and Development Foundation of SHU-SOENs PV Joint Laboratory, China (Grant No. SS-E0700601)

• Published in: Chinese physics B 2017-04, Vol.26 (4)
• Main Authors: Gao, Ming, Du, Hui-Wei, Yang, Jie, Zhao, Lei, Xu, Jing, Ma, Zhong-Quan
• Format: Article
• Language: English
• Subjects: c-Si interface; effective minority carrier lifetime; SiO; sputtered damage; XPS
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/26/4/045201

The damage on the atomic bonding and electronic state in a SiOx(1.4-2.3 nm)/c-Si(150 μ m) interface has been investigated. This occurred in the process of depositing indium tin oxide (ITO) film onto the silicon substrate by magnetron sputtering. We observe that this damage is caused by energetic particles produced in the plasma (atoms, ions, and UV light). The passivation quality and the variation on interface states of the SiOx/c-Si system were mainly studied by using effective minority carrier lifetime ( τeff ) measurement as a potential evaluation. The results showed that the samples' τeff was reduced by more than 90% after ITO formation, declined from 107 μ s to 5 μ s. Following vacuum annealing at 200 ° C, the τeff can be restored to 30 μ s. The components of Si to O bonding states at the SiOx/c-Si interface were analyzed by x-ray photoelectron spectroscopy (XPS) coupled with depth profiling. The amorphous phase of the SiOx layer and the "atomistic interleaving structure" at the SiOx/c-Si interface was observed by a transmission electron microscope (TEM). The chemical configuration of the Si-O fraction within the intermediate region is the main reason for inducing the variation of Si dangling bonds (or interface states) and effective minority carrier lifetime. After an appropriate annealing, the reduction of the Si dangling bonds between SiOx and near the c-Si surface is helpful to improve the passivation effect.