Effects of X-ray radiation on hydrogenated amorphous silicon thin-film transistors and characteristics of tungsten shield layer

Hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) which have tungsten shield layer for AMOLED were fabricated. E-beam evaporation is useful method to prepare cathode layer above organic layers with high throughput and no damage to the organic layers but TFTs are damaged by X-ray radiation generated during the e-beam process. When the thickness of the tungsten layer was increased to 2000 Å, it was found that the characteristics of TFTs, such as threshold voltage, field effect mobility and sub-threshold slope, were slightly varied by X-ray radiation.