Improvement of hydrogenated amorphous-silicon TFT performances with low-k siloxane-based hydrogen silsesquioxane (HSQ) passivation layer

Abstract

A low-dielectric-constant (low-k)-material siloxanebased hydrogen silsesquioxane (HSQ) is investigated as a passivation layer in bottom-gate hydrogenated amorphous-silicon thin-film transistors (a-Si: H TFTs). The low-k HSQ film passivated on TFT promotes the brightness and aperture ratio of TFT liquid-crystal display due to its high light transmittance and good planarizatiow In addition, the performance of a-Si : H TFT with HSQ passivation has been improved, compared to a conventional silicon nitride (SiNx)-passivated TFT because the hydrogen bonds of HSQ assist the hydrogen incorporation to eliminate the density of states between the back channel and passivation layer. Experimental results exhibit an improved field-effect mobility of 0.57 cm(2)/V center dot s and a subthreshold swing of 0.68 V.