Characteristics of cylindrical surrounding-gate GaAsxSb1−x/InyGa1−yAs heterojunction tunneling field-effect transistors**Project supported by the National Natural Science Foundation of China (Grant Nos. 61176038 and 61474093), the Science and Technology Planning Project of Guangdong Province, China (Grant No. 2015A010103002), and the Technology Development Program of Shaanxi Province, China (Grant No. 2016GY-075).

Abstract

A III–V heterojunction tunneling field-effect transistor (TFET) can enhance the on-state current effectively, and GaAsx Sb1−x/InyGa1−yAs heterojunction exhibits better performance with the adjustable band alignment by modulating the alloy composition. In this paper, the performance of the cylindrical surrounding-gate GaAsx Sb1−x/InyGa1−yAs heterojunction TFET with gate–drain underlap is investigated by numerical simulation. We validate that reducing drain doping concentration and increasing gate–drain underlap could be effective ways to reduce the off-state current and subthreshold swing (SS), while increasing source doping concentration and adjusting the composition of GaAsx Sb1−x/InyGa1−yAs can improve the on-state current. In addition, the resonant TFET based on GaAsx Sb1−x/InyGa1−yAs is also studied, and the result shows that the minimum and average of SS reach 11 mV/decade and 20 mV/decade for five decades of drain current, respectively, and is much superior to the conventional TFET.