Realizing Efficient Volume Depletion in SOI Junctionless FETs

Abstract

In this paper, we provide a simple and effective solution to realize efficient volume depletion and therefore, significantly reduce the OFF-state leakage current of a junctionless FET (JLFET) by replacing the SiO2 by HfO2 in the buried oxide (BOX). Using calibrated 2-D simulations, we show that the JLFET with a high-k BOX (HB JLFET) exhibits a considerably high ${\mathrm{ I}}_{\mathrm{ ON}} /{\mathrm{ I}}_{\mathrm{ OFF}} $ ratio of $\sim 10^{6}$ even for a channel length of 20 nm. Further, we demonstrate that the use of a high-k BOX leads to a reduction in both gate capacitance ${\mathrm{ C}}_{\mathrm{ g}} $ and gate-to-drain feedback (Miller) capacitance ${\mathrm{ C}}_{\mathrm{ gd}} $ .