Quantization, gate dielectric and channel length effect in double-gate tunnel field-effect transistor

Abstract

In this work, we investigate the effects of changing device parameters such as channel length and gate dielectric of n-type double gate (DG) silicon tunneling field effect transistor (TFET). As the quantization effects can alter the device performance, our objective is to minimize the effect of it on gate capacitance. Device sub-threshold slope (SS), threshold voltage and ION/IOFF the ratio are also considered to find the performance of the device. We find that DG TFET with the short channel length, high gate dielectric material, and material with effective mass equal to or more than 0.04 mo (mo is free electron mass) shows promising performance. SS of TFET is much less than 60 mV/dec, which is the limiting factor of a conventional MOSFET. The materials having an effective mass of electrons less than 0.04 mo shows step-like behaviors, which reduce the gate capacitance. As a result, the control over the gate decreases and increases the short channel effect. Our optimized device shows that for high dielectric constant gate materials, SS is 33 mV/dec, the threshold voltage is 0.71 V and ION/IOFF ratio is 109 .