Low Thermal Budget Poly-Si Thin Film Transistors on Glass

Abstract

A new low thermal budget processing approach for polycrystalline silicon thin film transistors on 7059 glass is presented. This processing incorporates three unique steps: low temperature crystallization by broad beam tungsten halogen lamps of low temperature plasma enhanced chemical vapor deposited a-Si:H, the use of high quality gate oxide magnetron sputter deposited at 400°C, and extremely short time hydrogen passivation using an electron cyclotron resonance source. These TFT's, produced with this processing on glass, were found to have mobilities in the 60 cm²/V·s range. The subthreshold slope of these devices was in the 1 V/decade range, the threshold voltage was around 5 volts and the on/off current ratio was approximately 10⁶.