Analytical modeling of Schottky tunneling source impact ionization MOSFET with reduced breakdown voltage

In this paper, we have investigated a novel Schottky tunneling source impact ionization MOSFET (STS-IMOS) to lower the breakdown voltage of conventional impact ionization MOS (IMOS) and developed an analytical model for the same. In STS-IMOS there is an accumulative effect of both impact ionization and source induced barrier tunneling. The silicide source offers very low parasitic resistance, the outcome of which is an increment in voltage drop across the intrinsic region for the same applied bias. This reduces operating voltage and hence, it exhibits a significant reduction in both breakdown and threshold voltage. STS-IMOS shows high immunity against hot electron damage. As a result of this the device reliability increases magnificently. The analytical model for impact ionization current (IiiIii) is developed based on the integration of ionization integral (M). Similarly, to get Schottky tunneling current (ITunITun) expression, Wentzel–Kramers–Brillouin   (WKB) approximation is employed. Analytical models for threshold voltage and subthreshold slope is optimized against Schottky barrier height (ϕBϕB) variation. The expression for the drain current is computed as a function of gate-to-drain bias via integral expression. It is validated by comparing it with the technology computer-aided design (TCAD) simulation results as well. In essence, this analytical framework provides the physical background for better understanding of STS-IMOS and its performance estimation.