Optimization of RF Performance of Metallic Source/Drain SOI MOSFETs Using Dopant Segregation at the Schottky Interface

Abstract

This letter presents a detailed investigation of the impact of dopant segregation (DS) on radio-frequency (RF) performance of p-type 110-nm undoped ultrathin-body Schottky-barrier (SB) silicon-on-insulator MOSFETs. It is shown that optimizing this dopant-segregated layer via careful control of the dopant concentration ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SEG</sub> ) and lateral extension ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SEG</sub> ) reduces the apparent potential barrier height at the Schottky junctions. This results in highly reduced source/drain (S/D) contact resistances, along with a peak f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> value obtained at very low dc power consumption (45 muW/mum at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = -2 V), which is very promising to address low-power low-voltage analog applications. Finally, the source resistance extracted from this RF study ( ~120 Omegamiddotmum) clearly demonstrates the ability of the DS SB S/D architecture to pursue the silicon roadmap beyond the 22-nm node.