Dopant and thermal interaction on SPE formed SiC for NMOS performance enhancement

Abstract

The dopant and thermal interaction on solid phase epitaxy (SPE) formed SiC has been investigated. We have studied the impact on substitutional carbon concentration ([C]sub) from various thermal steps including low temperature anneal, SiGe epitaxy thermal budget, RTP, and laser anneal (LSA). Regarding the integration scheme for implementing embedded SiC (eSiC) S/D on NMOS performance enhancement, both post-LDD and post-S/D schemes were studied. The higher [C]sub in post-LDD scheme was observed and the S/D dopants were found to enhance the carbon precipitation into interstitial with conventional RTP/LSA activation thermal processes. The phosphorous implant is also found to degrade [C]sub in comparison to As implant. The higher [C]sub and proximity to channel of formed eSiC in post-LDD scheme are beneficial to device performance. The fabricated eSiC S/D NMOS shows 31% mobility improvement and 7% current enhancement.