We have examined impacts of gate insulator (Al₂O₃ or HfO₂) and gate electrode (TiN or W) on electrical performance of ZnSnO/Si bilayer tunneling fieldeffect transistors (TFETs). It is found from the capacitance-voltage ( ${C}$ - ${V}$ ) characteristics that the W gate is effective to reduce the counter-clockwise hysteresis. Additionally, the optimal temperature of post-metallization annealing (PMA) is different for each gate stack, and this optimization is critically important for the high ON-state current ( ${I} _{\mathrm{ ON}}$ ) and steep ON/OFF switching. The W/Al₂O₃/ZnSnO/Si bilayer TFET provides the hysteresis-free steep ON/OFF switching with the minimum sub-threshold swing (SS) of 65.4 mV/dec. and average SS of 72.0 mV/dec. in a gate-voltage swing of 0.3 V, which are 19% and 18% lower than the control TiN/Al₂O₃/ZnSnO/Si bilayer TFET. When the gate stack is replaced by W/HfO₂/Al₂O₃, the TFET exhibits less steep ON/OFF switching in spite of thinning capacitance equivalent thickness (CET) from 5.9 and 2.3 nm. These results indicate the importance of improvement in the gate stack quality on the sub-threshold characteristics of the bilayer TFETs.

中文翻译：

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W/Al2O3 栅极堆叠改善 ZnSnO/Si 双层 TFET 的电气特性

我们已经研究了栅极绝缘体（Al ₂ O ₃或 HfO ₂）和栅极电极（TiN 或 W）对 ZnSnO/Si 双层隧道场效应晶体管 (TFET) 电性能的影响。由电容-电压（ ${C}$ —— ${V}$ ) W 门有效减少逆时针滞后的特性。此外，每个栅极堆叠的后金属化退火 (PMA) 的最佳温度是不同的，这种优化对于高导通状态电流至关重要（ ${I} _{\mathrm{ ON}}$ ) 和陡峭的开/关切换。W/Al ₂ O ₃ /ZnSnO/Si 双层 TFET 提供无滞后的陡峭 ON/OFF 开关，并且具有最小的亚阈值摆幅（SS) 65.4 mV/dec。和平均SS72.0 mV/dec。栅极电压摆幅为 0.3 V，比对照 TiN/Al ₂ O ₃ /ZnSnO/Si 双层 TFET低 19% 和 18% 。当栅极堆叠被 W/HfO ₂ /Al ₂ O ₃替代时，尽管电容等效厚度 (CET) 从 5.9 和 2.3 nm 变薄，但 TFET 表现出不那么陡峭的开/关切换。这些结果表明提高栅极堆叠质量对双层 TFET 的亚阈值特性的重要性。