In this paper, we report the electrical characteristics of thin active layer indium–gallium–zinc-oxide thin-film transistors (IGZO TFTs) having an asymmetric dual gate structure. It was observed that the performance of IGZO TFTs significantly improved when the TFT is operated in the dual gate mode though the performance of the top gate mode shows very poor performance of low field-effect mobility and large subthreshold slope. We found that the channel electrons are coupled in the bulk region when the active layer is very thin, and top gate biasing provides additional electrons to the coupled channel region, which improves the electrical performance of dual gate mode IGZO TFTs. Bias stress instability measurements also indicate that dual gate mode IGZO TFTs show better stability compared to the other mode because coupled electrons are mainly formed in the bulk region, which reduce the effect of interfacial defect density of states. Therefore, the improvements of performance of dual gate electrode IGZO TFTs can be realized regardless of the relatively poor performance of the top gate mode.

中文翻译：

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具有薄有源层和不对称双栅结构的固溶铟-镓-氧化锌薄膜晶体管性能改进的起源

在本文中，我们报告了具有非对称双栅结构的薄有源层铟-镓-氧化锌薄膜晶体管（IGZO TFT）的电学特性。观察到，尽管顶栅模式的性能表现出很差的低场效应迁移率和大亚阈值斜率性能，但是当以双栅模式工作时，IGZO TFT的性能得到了显着改善。我们发现，当有源层非常薄时，沟道电子将在体区中耦合，并且顶栅偏置将额外的电子提供给耦合的沟道区，从而提高了双栅模式IGZO TFT的电性能。偏置应力不稳定性测量结果还表明，与其他模式相比，双栅极模式IGZO TFT显示出更好的稳定性，因为耦合电子主要形成在体区中，从而降低了状态界面缺陷密度的影响。因此，不管顶栅模式的相对较差的性能如何，都可以实现双栅电极IGZO TFT的性能的提高。