Device Performance Improvement Based on Transient Enhanced Diffusion Suppression in the Deep Sub-Quarter Micron Scale

Abstract

In the deep sub-quarter micron scale, the transient enhanced diffusion (TED) of the gate channel region gives rise to the variation of device characteristics due to the influence of interstitial silicon atoms generated by the extension ion implantation damage. The channel impurity variation caused by TED becomes a dominant factor and brings about a more severe fluctuation of the threshold voltage (Vth) than the physical gate channel length (Lgate) or the gate-oxide (Gox) thickness variation does. This work presents the results of suppressing the reverse short channel effect (RSCE) which is shown due to TED by using the local channel implantation process. In the case of using a boron source as an n-type channel (n-channel) dopant, the 10% improvement of the RSCE and the 70% reduction of the Vth fluctuation are achieved through TED suppression by rapid thermal anneal (RTA) treatment. Furthermore, we not only demonstrates the 15% increase of the current driving capability but also clearly removes the RSCE by realizing the super-steep retrograded (SSR) channel doping profile with an indium species as the n-channel dopant and adopting RTA process.