Effect of Excimer Laser Annealing on Ultra-low Temperature Gate Dielectrics

The effect of excimer laser annealing on the properties of ultra-low temperature (150°C) plasma enhanced chemical vapor deposited (PECVD) oxides was investigated. Annealing was performed using a 308 nm excimer laser incident directly on the oxides, at fluences up to the melting of the silicon and for as many as 3000 pulses. Following multiple shot irradiations below the silicon melt threshold, the CV threshold voltage was observed to decrease by ≍15V volts, coupled with an increase in the slope near threshold. Leakage currents measured by IV were not significantly changed. Property modifications are shown to be comparable to a 450°C thermal soak anneal. These results suggest that excimer laser annealing has potential to improve ultra-low temperature gate dielectrics for poly-Si Thin Film Transistors (TFTs) on plastic substrates.