Effect of mechanical and electrical stresses on the performance of an a-Si:H TFT on plastic substrate

We studied the effect of mechanical and electrical stresses on the performance of an hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) adopting an organic layer as the first gate insulator on plastic. The TFT with the maximum deposition temperature of 150 deg C exhibited a field-effect mobility of 0.4 cm2/Vs and a threshold voltage of 1.5 V and the leakage current of less than 10-14 A/mum. The individual transistors were strained by inward (compression) or outward (tension) cylindrical bending with parallel to the source-drain current path. The TFT performance was approximately unchanged until the strain was plus/minus 1%. The mobility had a linear relationship with strain near the flat region, which appeared to be due to the change in the disorder by bending. The bias-stress effect on the TFT performance depended on the strain induced on the a-Si:H by mechanical bending.