A quantitative study of Phosphorous implantation damage on the thick gate oxide of the 28 nm node

Abstract

The tilted Phosphorous implantation has for a long time been adopted to form the lightly doped drain (LDD). For the first time, we report the implantation damage due to this on the thick gate oxide of the NMOSFET devices for 28nm technology. During the Time Dependent Dielectric Breakdown (TDDB) test, the breakdown time of the thick gate oxide of NMOSFET was found to be a function of implantation energy and dose. In this work, an empirical model was established to characterize the implantation induced gate oxide lifetime reduction, which was correlated to the effective oxide thickness reduction. Our results showed that a careful implantation scheme needs to be chosen to balance the reliability requirements and the device performance for the scaled 28nm process and beyond.