A two-dimensional (2-D) technology computer-aided design (TCAD)-based simulation study of the back bias in the ultrathin silicon-on-insulator (SOI) tunnel field-effect transistor (TFET) is presented. The transfer characteristics of a conventional TFET called the back-bias TFET (BB-TFET) depend on the back bias and the oxide thickness below the TFET epitaxial layer. The back bias affects the electric field at the source/channel and drain/channel junctions, hence both the ON-state current (\(I_{\mathrm{ON}}\)) and the ambipolar current (\(I_{\mathrm{AMB}}\)) reduce with a negative back-bias voltage. This reduction in \(I_{\mathrm{ON}}\) is not desirable in a TFET, hence a modified TFET structure called the back-bias underdrain TFET (BBUD-TFET) is proposed. In the BBUD-TFET, the back bias is applied on a p-Si pocket placed under the drain region, which is isolated using an ultrathin oxide. The back bias in the proposed BBUD-TFET mainly affects the electric field at the drain/channel interface, having a negligible impact on the source/channel interface. The BBUD-TFET structure is analyzed with \({\mathrm{SiO}}_2\) or \({\mathrm{HfO}}_2\) as the gate oxide. In the BBUD-TFET with \({\mathrm{HfO}}_2\) as the gate oxide, the back bias completely suppresses the ambipolar current without reducing \(I_{\mathrm{ON}}\). Furthermore, the oxide thickness and back-bias voltage are optimized for the BBUD-TFET structure. In this study, 2-D TCAD simulations are carried out to investigate and analyze the performance of the BB-TFET and BBUD-TFET.

中文翻译：

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利用背偏置效应控制超薄SOI隧道FET中的双极性电流

提出了基于二维（2-D）技术的计算机辅助设计（TCAD）的超薄绝缘体上硅（SOI）隧道场效应晶体管（TFET）中的背偏置仿真研究。称为背偏置TFET（BB-TFET）的常规TFET的传输特性取决于背偏置和TFET外延层下方的氧化物厚度。反偏压会影响源极/沟道和漏极/沟道结处的电场，因此会导通状态电流（\（I _ {\ mathrm {ON}} \））和双极性电流（\（I _ {\ mathrm {AMB}} \））以负的反向偏置电压降低。这种减少在\（I _ {\ mathrm {ON}} \）TFET在TFET中是不可取的，因此提出了一种改进的TFET结构，称为后偏置暗漏TFET（BBUD-TFET）。在BBUD-TFET中，将反向偏压施加在位于漏极区下方的p- Si凹穴上，该凹穴使用超薄氧化物隔离。提出的BBUD-TFET中的反向偏置主要影响漏极/沟道界面处的电场，对源/沟道界面的影响可忽略不计。使用\（{\ mathrm {SiO}} _ 2 \）或\（{\ mathrm {HfO}} _ 2 \）作为栅极氧化物来分析BBUD-TFET结构。在以\（{\ mathrm {HfO}} _ 2 \）作为栅极氧化物的BBUD-TFET中，背偏置完全抑制了双极性电流，而不减小\（I _ {\ mathrm {ON}} \）。此外，针对BBUD-TFET结构优化了氧化物厚度和背偏置电压。在这项研究中，进行了二维TCAD仿真以研究和分析BB-TFET和BBUD-TFET的性能。