The inverted staggered hydrogenated amorphous silicon thin film transistors (a-Si:H TFT) were fabricated on 6 mum thick polyimide substrate at temperatures below 300 degreesC. The a-Si:H TFT off current is below 10(-12) A, the on/off current ratio is similar to10(7), the threshold voltage is similar to2-3 V, field effect mobility is similar to0.5 cm(2)/Vs, and the subthreshold slope is similar to0.4 V/decade. The stabilities of a-Si:H TFTs were studied and the device parameters determined before and after a bias stress of V-GS = 20 V for t = 10, 10(2), 10(3) and 10(4) s. The threshold voltages shifted to higher values and on/off ratio decreased with the duration of bias stress. The device characteristics were measured in the dark and under the light illumination. Threshold voltages and on/off current ratio both decreased. Temperature dependant measurements of transfer and output characteristic of a-Si:H TFT in the range from 22 degreesC to 125 degreesC were also investigated. When temperature is increased threshold voltages decreased and the field effect mobility increased. (C) 2005 Elsevier Ltd. All rights reserved.