Fully-depleted SOI devices with TaSiN gate, HfO2 gate dielectric, and elevated source/drain extensions

Abstract

We report for the first time performance of ultra-thin film fully-depleted (FD) silicon-on-insulator (SOI) CMOS transistors using HfO2 gate dielectric and TaSiN gate material. The transistors feature 100-150 Å silicon film thickness and selective epitaxial silicon growth in the source/drain extension regions. TaSiN-gate shows good threshold voltage control using an undoped channel, which reduces threshold voltage variation with silicon film thickness and discrete, random dopant placement. Device processing for CMOS fabrication is drastically simplified by the use of the same gate material for both n- and p-MOSFETs. Electrical characterization results illustrate the combined impact of using high K dielectric and metal gate on the performance of ultrathin film FD SOI devices.