Design and theoretical calculation of novel GeSn fully-depleted n-tunneling FET with quantum confinement model for suppression on GIDL effect

Abstract

In this paper, a novel fully-depleted Ge1-xSnx n-Tunneling FET (FD Ge1-xSnx nTFET) with field plate is investigated theoretically based on the experiment previously published. The energy band structures of Ge1-xSnx are calculated by EMP and the band-to-band tunneling (BTBT) parameters of Ge1-xSnx are calculated by Kane's model. The electrical characteristics of FD Ge1-xSnx nTFET and FD Ge1-xSnx nTFET with field plate (FD-FP Ge1-xSnx nTFET) having various Sn compositions are investigated and simulated with quantum confinement model. The results indicated that the GIDL effect is serious in FD Ge1-xSnx nTFET. By employing the field plate structure, the GIDL effect of FD-FP Ge1-xSnx nTFET is suppressed and the off-state current Ioff is decreased more than 2 orders of magnitude having Sn compositions from 0 to 0.06 compared with FD Ge1-xSnx nTFET. The impact of the difference of work function between field plate metal and channel Φfps is also studied. With the optimized Φfps = 0.0 eV, the on-state current Ion = 4.6 × 10−5 A/μm, the off-state current Ioff = 1.6 × 10−13 A/μm and the maximum on/off ration Ion/Ioff = 2.9 × 108 are achieved.