异质栅介质双栅隧穿场效应晶体管TCAD仿真研究

TCAD Simulation of Heterogeneous Gate Dielectric Double-Gate Tunnel FET

采用异质栅介质结构,加入高k介质Pocket区,对双栅隧穿场效应晶体管进行了改进。通过搭建不同模型,分析了栅介质的长度、介电常数以及Pocket区厚度等参数对器件开态电流Ion、双极性特性、亚阈值摆幅等的影响。TACD仿真结果表明,Ion随介电常数的增大可提升至5.17×10-5A/μm,且双极性电流也有极大的增幅,亚阈值摆幅因开态电流的改善降低至28.3 mV/dec,而异质栅介质的不同长度对器件性能并无明显影响;在双极性上,Pocket区厚度的增加使得栅漏隧穿宽度增大,双极性电流减小至1.0×10-17A/μm,抑制了双极性导通,同时对器件其他特性未产生明显影响。

Heterogeneous gate dielectric double-gate tunneling field effect transistors have a special structure that improves the electrical characteristics of the devices compared to conventional DGTFET.In this study,different DGTFETs were built with or without HD and Dielectric Pocket structures,the effects of the gate dielectric length,dielectric constant,and Pocket thickness on the device open state current(lon),the bipolar characteristics,and the subthreshold swing(SS)were quantitatively analyzed.The results indicate that Ion can be enhanced to 5.17×10-5 A/μm with increasing dielectric permittivity,but bipolar currents is similarly increased,Ss was reduced to 28.3 mV/dec due to the improvement of switching-state current,while the different length of the gate dielectric didn't have any significant effect on the device performance.On the bipolarity,the increase in the thickness of the Pocket region makes the gate-drain tunneling width increase and the Iamb can be reduced to the order of 1.O×10-17 A/μm,thus suppressing the bipolarity,with no significant effect on other features of the device.