Spin-on low-k passivation is achieved on inverted-staggered back-channel-etched hydrogenated amorphous silicon thin-film transistors (TFT). The low-k passivation material, siloxane-based hydrogen silsesquioxane (HSQ), has been investigated for different process temperatures. Performance is improved with decreased temperature. At 300 °C, the TFT performance of HSQ passivation is superior to those of other TFTs. The hydrogen bonds of HSQ assist hydrogen incorporation to eliminate the density of states between the back channel and the passivation layer. The characteristics of HSQ passivated TFT have been studied in this work.