Degradation mechanism in low-temperature p-channel polycrystalline silicon TFTs under dynamic stress

Pronounced device degradation and temperature dependence of p-channel polycrystalline silicon thin-film transistors (polysilicon TFTs) under dynamic stress were investigated. This device degradation is due to the trap states produced by repetition between electron injection and hole injection. The degradation is strongly dependent on the number of trapped holes and the location of the hole-injection region. The analysis of activation energy affirms that the rapid degradation at high temperature is caused by an increase in the number of trapped holes, to which the negative-bias-temperature stress significantly contributes.