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 SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> by HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> 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 I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ratio of ~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> 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 C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> and gate-to-drain feedback (Miller) capacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</sub> .