Investigation of Backgate-Biasing Effect for Ultrathin-Body III-V Heterojunction Tunnel FET

This paper investigates the impact of backgate biasing (VBS) on the drain current (ID) of ultrathin-body III-V heterojunction tunnel FET (HTFET). Compared with homojunction TFET and III-V/Ge MOSFET, this paper indicates that HTFET exhibits significantly higher IOFF(IDat VGS = 0 V and VDS= 0.5 V) modulation efficiency and the influence of VBSrapidly decreases with increasing VGS. In addition, it is observed that the change of source available states with VBSdetermines the IDmodulation efficiency of p-type HTFET (pHTFET). Depending on the source doping concentration and operating VGS, the IDof HTFET under forward VBScan be anomalously smaller than that at VBS= 0 V. Furthermore, the impacts of source/drain doping concentrations and junction properties are discussed and shown to be critical in determining the IDmodulation efficiency of HTFET. We find that, under controlled ambipolar current, reverse backgate biasing can be utilized to suppress the IOFFof HTFET, and the modulation efficiency increases with decreasing source doping concentration. Our study may provide insights for device/circuit designs with advanced TFET technologies.