Tight-binding analysis of current oscillation in nanoscale In0.53Ga0.47As Schottky MOSFET

Abstract

A comprehensive study of band structure effect on the quantum transport of nanoscale In0.53Ga0.47As Schottky MOSFET for the implementation of III–V MOSFET with low source/drain series resistance is presented. Rigorous treatment of the full band structure in ultra-thin body MOSFET is employed using sp3d5s* tight-binding approach. Strong transverse confinement increases the energy of subbands and, indeed, the effective Schottky barrier height. Due to enhanced Schottky barriers and at low drain voltages, a double barrier gate modulated potential well is created along the channel that results in source-to-drain confinement of states. As tunnelling is the main current component in this device, longitudinal confinement induces drain current oscillation at low temperatures. Important factors that may affect current oscillation are demonstrated. Current oscillation that alters the normal performance of the device is investigated in nanowire Schottky MOSFET, as well. Additional quantum confinement in nanowire Schottky MOSFET provides higher effective Schottky barrier height than the double gate structure. Accordingly, the drain current oscillation is more apparent in nanowire Schottky MOSFET than in the double gate device and is gradually smoothed out as the gate length shrinks down in ultra-scaled structure. Effect of diffusive scattering on the quantum transport of the device is investigated, too. What is prominent in our result is that the drain current oscillations degrade as the channel mobility is decreased. The results in this paper are paving a way to elucidate the feasibility of this device in the nanoscale regime.