Lower subthreshold swing and improved miller capacitance heterojunction tunneling transistor with overlapping gate

Abstract

In this paper, gate oxide overlapping technique is implemented in heterojunctions to obtain better subthreshold swing, high ON state current and improved miller capacitance for beyond-CMOS technologies. Inter band tunneling (BTBT) of hetero-transistor is increased which in turn causes ON-OFF state current ratio increased, on other hand standby current decreases. Low bandgap materials such as Ge or GeSi materials are used in the fabrication process for better performance in the device level of abstraction. The low voltage operation of HETT in subthreshold region is very useful for power-efficient memory applications. This work also demonstrates the device level variations between HETT and traditional MOSFET in detail. The N-type heterojunction (NHETT) with gate oxide overlap is designed and implemented. The subthreshold swing of 16 mV/dec at operating supply voltage 1.2 V is obtained. The improved Miller capacitance can be obtained because of oxide overlap and low band gap materials.