Impact of an As implant before CoSi2 formation on the sheet resistance and junction breakdown voltage

Germanium implantation for silicon amorphization before silicide formation, for both titanium and cobalt, and its impact on morphological and electrical properties has been reported in literature. The benefits in terms of improved silicide formation on narrow lines are stress relaxation and silicided junction leakage current reduction. In this work the results of arsenic implantation instead of germanium are reported in the case of Cobalt Salicide technology for its scaling below 90 nm technology node. A baseline process without implant has been compared with arsenic implantation performed at different process conditions. As implantation before CoSi2 growth can improve the diode breakdown voltage although a slight increase in sheet resistances is observed. Electrical results are in agreement with morphological evidences by TEM, SEM and AFM techniques showing a reduction of the silicide grain size and a smoothening of the silicide by increasing the implant energy.