Abnormal Subthreshold Leakage Current at High Temperature in InGaZnO Thin-Film Transistors

Abnormal subthreshold leakage current is observed at high temperature in amorphous InGaZnO thin-film transistors. The transfer curve exhibits an apparent subthreshold current stretch-out phenomenon that becomes more serious with increasing temperatures. The negative bias temperature instability experiment has been used to prove high-temperature-induced hole generation. Furthermore, the transfer characteristics with different drain voltages have been also used to confirm the status of hole accumulation. These pieces of evidence clearly defined the stretch-out phenomenon, which is caused by thermal-induced hole generation and accumulation at the source region that leads to source-side barrier lowering.