Thermal Behavior of Amorphous Silicon Thin Film Transistor and Its Application to Micromachined Uncooled Infrared Sensors

This work reports a new uncooled infrared sensor based on amorphous silicon thin film transistors (a-Si TFTs). The temperature coefficient of channel current (TCC) of the a-Si TFT is given. Analysis shows that the a-Si TFT working in the saturation region is preferred for the sensitive element with a TCC value of 3.8-6.0 %/K. The a-Si TFT is placed on a suspended microbridge to reduce the thermal conductance by using micro-electro-mechanical system (MEMS) technology. The a-Si TFT-based IR sensor with a monolithic architecture is fabricated. Preliminary experimental results show that a responsivity of 40.8 kV/W, a thermal response time of 5.5 ms and a NETD of 90 mK are achieved.