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

초록

In 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 & DEG;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.

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