Fabrication and its characteristics of low-temperature polycrystalline silicon thin films

Abstract

In order to reduce the cost of solar cells or flat-panel display, it is very important to synthesis polycrystalline silicon films on low cost substrate such as glass at low temperature. In this work, electron cyclotron resonance (ECR) plasma enhanced chemical vapor deposition (PECVD) system was successfully applied to synthesize poly-Si thin-film on common glass substrate using H2 as the plasma source and SiH4 (Ar:SiH4=19:1) as the precursor gas at low temperature. Since the multicusp cavity-coupling ECR plasma source was adopted to provide active precursors, the growth temperature decreased to lower than 200°C. In the plasma, the electron temperatures kTe are ∼2–3 eV and the ion temperatures kTi≤1 eV. This leads to non-remarkable ion impacts during the film deposition. The characteristic of poly-Si films was investigated. It was shown that the crystalline fraction Xc of the films can be up to 90% even deposit at room temperature, and the film was (220) preferably oriented. The growth behaviors of the film between the interface of glass and Si films were also discussed in detail.