Method for self-aligned formation of silicide contacts using metal silicon alloys for limited silicon consumption and for reduction of bridging

Abstract

A method of substantially reducing Si consumption and bridging during metal silicide contact formation comprising the steps of: (a) forming a metal silicon alloy layer over a silicon-containing substrate containing an electronic device to be electrically contacted, said silicon in said alloy layer being less than about 30 atomic % and said metal is Co, Ni or mixtures thereof; (b) annealing said metal silicon alloy layer at a temperature of from about 300° to about 500° C. so as to form a metal rich silicide layer that is substantially non-etchable compared to said metal silicon alloy or pure metal; (c) selectively removing any non-reacted metal silicon alloy over non-silicon regions; and (d) annealing said metal rich silicide layer under conditions effective in forming a metal silicide phase that is in its lowest resistance phase. An optional oxygen barrier layer may be formed over the metal silicon alloy layer prior to annealing step (b).