Photon emission and related hot-carrier effects in polycrystalline silicon thin-film transistors

The photon emission induced by the drain avalanche in polycrystalline silicon thin-film transistors (polysilicon TFTs) has been studied in wide drain and gate voltage ranges. As the photon emission phenomenon is closely related to hot-carrier effects, the gate and drain bias conditions for maximum device degradation have been determined from measurements of the emitted light intensity. In n-channel polysilicon TFTs, the effects of bias stressing at the maximum light emission are related to hot-hole trapping into the gate oxide near the drain and to formation of acceptor-like interface states consisted of midgap states and band tails. (C) 1999 American Institute of Physics. [S0021-8979(99)06009-0].