Gate Oxide Local Thinning Mechanism-Induced Sub-60 mV/Decade Subthreshold Swing on Charge-Coupled MIS(p) Tunnel Transistor

摘要

The prerequisite of gate oxide local thinning (OLT) effect for subthreshold swing (SS) reduction to sub-60 mV/decade on charge-coupled metal–insulator–semiconductor (MIS) tunnel transistor is specified in this paper. The OLT process is employed by positive voltage stress, which is regarded as an efficient method to create a soft breakdown of oxides. The gate OLT process dramatically reduces the SS of the device, for instance, from the minimum SS of 79.31 to 9.7 mV/decade. Meanwhile, average SS of 28.22 mV/decade for over two current decades is acquired after the gate OLT process. The enhanced efficiency for minority carrier supply under gate oxide is responsible for the amelioration. The physical mechanism is proposed as the OLT spot-induced energy lateral transport and reduction of the energy barrier for minority carrier supply. The mechanism is then clarified by 2-D TCAD simulation. The extremely low SS and its physical insights of gate OLT effect on charge-coupled MIS tunnel transistor are believed beneficial for future developments on low-SS-related devices.