Effects of backgate voltage on electrical characteristics of poly-Si thin film transistors fabricated on stainless-steel substrate

High mobility p-channel polycrystalline Si thin film transistors (poly-Si T FTs) are fabricated on flexible stainless-steel substrates coated with 500- nm-thick SiO2 and 50-nm-thick SiN films. The electrical characteristics of mobility, threshold voltage and subthreshold slope are first measured as a function of backgate voltage V-BG of from -26V to +20V applied on stainless -steel substrate, Mobilities show small dependence on VBG Threshold voltage s, however, have dependence of decreasing with increasing V-BG. Subthreshol d slopes also show concave-shaped dependence on VBG The results indicate th at electrical characteristics of poly-Si TFTs are controlled by simply appl ying voltages to the substrate. Thus, application of backgate voltage are v ery important for design advanced poly-Si TFT integrated circuits and to se cure stable operation of the circuits.