Numerical analysis of electrical characteristicsof polysilicon thin film transistors fabricated byexcimer laser crystallisation

Abstract
The authors have performed a 2D numerical analysis of the electrical characteristics of polysilicon thin-film transistors (TFTs), made by excimer laser crystallisation (ELC), with high field-effect mobility (> 300 cm2/Vs) and low threshold voltage (< 1.5 V). In spite of the highly non-uniform defect distribution in ELC-polysilicon (mainly localised at the grain boundaries), the authors show that the device characteristics can be adequately described by using, in the numerical analysis, an effective density of states uniformly distributed within the semiconductor. This model, already verified in solid phase crystallised polysilicon TFTs, allows the analysis of ELC-polysilicon devices to be simplified.