Design and Simulation of Steep-Slope Silicon Cold Source FETs With Effective Carrier Distribution Model

Abstract

The cold source field-effect transistor (CSFET), enabled by novel source engineering, is a promising alternative to achieve sub-60 mV/dec steep-slope switching. For the first time, we develop an industry-standard TCAD approach for the CSFET with an effective cold carrier density of states (DOS) model which captures the underlying physics of DOS engineering, cold carrier injection, and thermalization in the device. The simulation scheme uses nonequilibrium Green’s function (NEGF) simulation for calibration. The effects of source engineering, rethermalization, and channel tunneling are extensively investigated on a Si-based double-gate CSFET. Its merits are highlighted by comparison with a conventional MOSFET under various temperatures, thicknesses, and gate lengths, showing improved ${I} _{ {\mathrm{\scriptscriptstyle ON}}}/{I} _{ {\mathrm{\scriptscriptstyle OFF}}}$ in ultrascaled MOSFET.