Sub-0.1 /spl mu/m CMOS with source/drain extension spacer formed using nitrogen implantation prior to thick gate re-oxidation

Abstract

Source/drain (S/D) extensions with low R/sub s/ and low C/sub gd/ are required for high performance CMOS. In this work, we report on a new process whereby an extension spacer is formed after gate etch using a blanket nitrogen ion implantation (N I/I) prior to thick gate reoxidation (GROX). The new process reduces n, pMOS C/sub gd/ by 12% and 20%, respectively and nMOS C/sub gate/ by 10%, compared to a conventional device, while maintaining high I/sub drive/. The nitrogen retards formation of a thick oxide on active regions allowing for a well controlled low energy extension implant, even with a thick gate re-ox spacer. The impact of nitrogen introduced after gate-etch but before the GROX on devices is also described for the first time.