Selective deposition of tungsten on ITM-CoSi2

In the present work a silane reduced selective tungsten deposition on ITM processed SALICIDE CoSi2 was evaluated. The contact resistance of W/CoSi2/Si contacts are lower compared to WSi contacts. CoSi2 was formed by a selective silicide formation process using a single RTA step. During the ion implantation the interface between cobalt and silicon was mixed up and a possible native oxide has been cracked. This promotes a better metal-silicon reaction. Contact resistance and sheet resistance measurements were performed using Kelvin structures (CBKR) and contact chains or van der Pauw structures, respectively. A processing window was determined with respect to a good selectivity and low contact resistances. SIMS measurements were made in order to investigate the influence of the flow ratio of SiH4WF6 on the sheet resistance.