The Instability of n-type LTPS TFTs Alternately operated in OFF region with drain biased

The instability characteristics of n-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) which are dynamically stressed in the OFF region with drain biased is investigated. Through the gate dynamically stressed in the OFF state with negative drain dc bias, the degradation mechanism of TFTs could be clarified and the defects are mainly generated in the source region. The higher the gate pulse frequency is, the more the TFTs devices degrade. A degradation model is proposed to explain the degradation mechanism of LTPS TFTs, according to three electrical measuring items, including the sampling currents, saturation forward & reverse I-V (FR-IV) transfer curves and C-V curves.