Metal silicides: Active elements of ULSI contacts

As device dimensions scale to the 0.1 mu m regime, the self-aligned silicide (SALICIDE) contact technology increasingly becomes an integral part of both the ultra-shallow junction and the metal oxide semiconductor field-effect transistor device itself. This paper will discuss the effect of silicide materials and formation processes on silicide stability, junction consumption, the ability to accurately profile shallow junctions, and contact resistance in series with the channel. The use of silicides as diffusion sources (SADS) provides an important pathway toward optimization of silicide technology. Diffusion of boron and arsenic from nearly epitaxial layers of CoSi2, formed from bilayers of Ti and Co, offer good silicide stability, ultra-shallow, low-leakage junctions, and low contact resistance.