Effect of dual gating on electrical characteristics of amorphous indium‐tin‐gallium‐zinc‐oxide TFTs

Abstract

AbstractIn this study, the effect of dual gating on the electrical characteristics of amorphous indium‐tin‐gallium‐zinc‐oxide (a‐ITGZO) thin‐film transistors (TFTs) is investigated. The composition (In:Sn:Ga:Zn = 1.4:0.2:2.0:1.0 at.) of the a‐ITGZO channel layer sputtered at 20°C is close to that (In:Sn:Ga:Zn = 1.6:0.2:2.0:1.0 at.) of the ceramic target. The electrical characteristics of a dual‐gated TFT are superior to those of top‐ and bottom‐gated TFTs. This dual‐gating effect is analyzed with vertical electric fields, electron concentrations, and potential contours in the gated channels obtained by performing technology computer‐aided design (TCAD) simulations. The relatively higher mobility and on‐current are attributed to the reduction of a vertical electric field in the channel induced by the dual gating. Moreover, the relatively steeper subthreshold swing of the dual‐gated TFT is associated with bulk accumulation formed by the dual gating.