Electrical properties of B-doped polycrystalline silicon thin films prepared by rapid thermal chemical vapour deposition

• Published in: Thin solid films 2006-02, Vol.497 (1-2), p.157-162
• Main Authors: Ai, Bin, Shen, Hui, Liang, Zongcun, Chen, Zhi, Kong, Guanglin, Liao, Xianbo
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Chemical vapour deposition; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Doping and impurity implantation in germanium and silicon; Electrical properties and measurements; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Polycrystalline silicon; Scanning electron microscopy; Structure of solids and liquids; crystallography
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.10.069

In this paper, about 30 μm thick B-doped polycrystalline silicon (poly-Si) thin films were deposited on quartz substrates, n-type single crystalline silicon wafers and p++-type poly-Si ribbons by a rapid thermal chemical vapour deposition system in a temperature range from 1000 to 1150 °C. Activation energy measurement and room temperature/temperature dependent Hall effect measurement were performed on the poly-Si thin films prepared on the former two kinds of substrates, respectively. It seems that the electrical properties of as-prepared poly-Si thin films could be qualitatively explained by Seto's grain boundary (GB) trapping theory although there is a big difference between our samples and Seto's in grain size and film thickness etc. The experimental results reconfirm that GB itself is a kind of most effective recombination center with trapping level near the midgap and trapping state density in the order of 1012 cm−2 magnitude. Electron beam induced current measurements on the poly-Si thin films prepared on the poly-Si ribbons also show that severe recombination occurs at the positions of GBs.