HfSiON High-k Layer Compatibility Study with TetraMethyl Ammonium Hydroxide (TMAH) Solution

Abstract

Compatibility of HfSiON high-k layer with wet etching using TMAH solution is studied for polycrystalline silicon dummy gate removal in high-k first gate-last process. The electrical and physical characterizations of the HfSiON layers after etching reveal that the HfSiON layer will be etched when exposed to the TMAH solution under certain conditions. No clear degradation, however, has been found after etching in a 10 vol% TMAH solution below 60◦C, suggesting a processing window for polycrystalline silicon dummy gate removal in the high-k first metal gate last process. © 2012 The Electrochemical Society. [DOI: 10.1149/2.008205esl] All rights reserved.