Total-Dose Effect of X-ray Irradiation on Low-Temperature Polycrystalline Silicon Thin-Film Transistors

Abstract

In this paper, the total-dose effect of X-ray irradiation on low-temperature polycrystalline-silicon (LTPS) thin film transistors (TFTs) is studied. Experiments under different conditions, including fixed intensity, fixed time, fixed total dose, short shot with different frequencies and high/low intensity for short/long time were performed and analyzed. With an increase of the irradiation dose, the threshold voltage ( ${V}_{ {th}}$ ) shifts negatively, the subthreshold swing ( $S.S$ .) degrades and the field effect mobility decreases owing to positive trapped charges and interface traps. All magnitude of negative shifts of ( ${V} _{ {th}}$ ), ( $ {S.S.}$ ) and field effect mobility for LTPS TFTs are well correlated to the total accumulated dose. The results are consistent with ( ${V} _{ {th}}$ ) shift due to trapped holes and the interface traps for mobility.