High performance 0.18 um nMOSFET by TED suppression

Abstract

In deep sub-quarter micron, Transient Enhanced Diffusion (TED) of gate channel (Lgate) region seriously gives rise to the variation of device characteristics due to the increase of interstitial silicon atoms. Channel impurity variation by this TED becomes more dominant factor to bring about the severe fluctuation of threshold voltage than the gate length or the gate oxide thickness variation does. This work presents the results of suppressing Reverse Short Channel Effect (RSCE) which severely is showed in the selectively implanted channel process using local implant process. In case of using boron as the n-channel dopant, the 10% improvement of RSCE and the 35% reduction of Vth fluctuation are achieved through TED suppression by Rapid Thermal Anneal (RTA) treatment. We not only demonstrated the 15% increase of current drive but also removed RSCE clearly by realizing of Super-Steep Retrograded (SSR) channel doping profile with indium.