This study investigated the effects of different Ga contents on the performance of single amorphous InGaZnO (a-IGZO) and bilayer InGa(0.5%)ZnO/InGa(1%)ZnO thin-film transistors (TFTs). Through rational design, a bilayer TFT exhibiting the best performance, including a ${V}_{\text {th}}$ of 1.2 V, ${I}_{\text {on}}/{I}_{\text {off}}$ of $1\times 10^{{8}}$ , SS of 0.28 V/decade, and $\mu _{\text {FE}}$ of 32.5 cm2/Vs, was obtained. This improved performance was attributed to the InGa(0.5%)ZnO front layer enhancing the $\mu _{\text {FE}}$ with low surface defect and high ${N}_{\text {e}}$ and the InGa(1%)ZnO back layer controlling the ${V}_{\text {th}}$ with low ${V}_{\text {O}}$ and ${N}_{\text {e}}$ in the bilayer device. Owing to the formation of energy band bending, the electrons transferred from the InGa(0.5%)ZnO to InGa(1%)ZnO layer. This resulted in the accumulation of free electrons near the interface, thereby enhancing the $\mu _{\text {FE}}$ of the bilayer device. Moreover, a minor shift in the ${V}_{\text {th}}$ (0.4 and −0.5 V) of InGa(0.5%)ZnO/InGa(1%)ZnO TFTs with HfO2/Al2O3 dual passivation layer (PVL) was observed under positive and negative gate bias light illumination stress with relative humidity 60% condition. This was attributed to the HfO2/Al2O3 PVL protecting the channel from oxygen adsorption/desorption and environmental influences. Thus, the designed bilayer InGa(0.5%)ZnO/InGa(1%)ZnO TFTs with HfO2/Al2O3 PVL have enabled new pathways for achieving high-performance and highly stable oxide TFTs.

中文翻译：

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不同Ga含量Al2O3/HfO2钝化层双层InGaZnO薄膜晶体管的合理设计

本研究研究了不同Ga含量对单层非晶InGaZnO (a-IGZO)和双层InGa(0.5%)ZnO/InGa(1%)ZnO薄膜晶体管(TFT)性能的影响。通过合理的设计，双层TFT表现出了最佳的性能，包括 ${V}_{\text {th}}$1.2V， ${I}_{\text {开}}/{I}_{\text {关}}$的 $1\乘以10^{{8}}$ ，SS 为 0.28 V/十倍频程，并且 $\mu _{\text {FE}}$获得 32.5 cm2/Vs。这种性能的提高归因于 InGa(0.5%)ZnO 前层增强了 $\mu _{\text {FE}}$具有低表面缺陷和高 ${N}_{\text {e}}$和InGa(1%)ZnO背层控制 ${V}_{\text {th}}$与低 ${V}_{\文本{O}}$和 ${N}_{\text {e}}$在双层器件中。由于能带弯曲的形成，电子从InGa(0.5%)ZnO层转移到InGa(1%)ZnO层。这导致界面附近自由电子的积累，从而增强了 $\mu _{\text {FE}}$双层装置。此外，一个微小的转变 ${V}_{\text {th}}$在相对湿度 60% 条件下，在正负栅极偏压光照应力下观察具有 HfO2/Al2O3 双钝化层 (PVL) 的 InGa(0.5%)ZnO/InGa(1%)ZnO TFT（0.4 和 -0.5 V）。这归因于 HfO2/Al2O3 PVL 保护通道免受氧气吸附/解吸和环境影响。因此，设计的具有HfO2/Al2O3 PVL的双层InGa(0.5%)ZnO/InGa(1%)ZnO TFT为实现高性能和高稳定性氧化物TFT提供了新途径。