A High-Performance Source Engineered Charge Plasma-Based Schottky MOSFET on SOI

Abstract

In this paper, we address an important issue of low ON current in a Schottky barrier (SB) MOSFET by proposing a novel structure of Schottky MOSFET on silicon on insulator. The proposed Schottky device employs a dual material at the source side and is being named as the source engineered SB MOSFET (SE-SB-MOSFET). Erbium silicide (ErSi1.7) is used as the main source material, and Hafnium is used as a source extension. The use of Hafnium as a source extension induces an n+-type charge plasma in an undoped silicon film, which significantly reduces the SB thickness. A calibrated simulation study has shown that the ON current ( $I_{{{\mathrm{{\scriptscriptstyle ON}}}}}$ ) and $I_{{{\mathrm{{\scriptscriptstyle ON}}}}}/I_{{{\mathrm{{\scriptscriptstyle OFF}}}}}$ have increased by 225 and $65\times $ , respectively, in the proposed device in comparison with the conventional SB-MOSFET device. The ac analysis has shown that the cutoff frequency ( $f_{T}$ ) in the proposed SE-SB-MOSFET ( $\sim 200$ GHz) has increased by $200\times $ as compared with the conventional SB-MOSFET ( $\sim 1$ GHz). Furthermore, the performance of the proposed device has been tested at the circuit level also. It has been observed from the transient analysis that a significant reduction in switching ON delay ( $65\times $ ) and switching OFF delay (33%) has been achieved in the proposed SE-SB-MOSFET-based inverter in comparison with the conventional device-based inverter. Furthermore, the use of the charge plasma concept makes the fabrication of the proposed device relatively easy as it uses low thermal budget.