Patent ID: 7879722

Claim:
A method of manufacturing a semiconductor device comprising forming a NiSi layer on a silicon substrate, wherein said forming a NiSi layer comprises: a first step forming a Ni film on the silicon of said substrate; a second step forming a metal nitride film on said Ni film, the second step includes forming a first layer adjacent to said Ni film and forming a second layer adjacent to said first layer, said first layer has a first nitrogen concentration greater than a second nitrogen concentration said second layer; a third step annealing said silicon substrate having said metal nitride film provided thereon at a first temperature not lower than 200° C. and not higher than 350° C., so as to react nickel in said Ni film and silicon in said silicon substrate, to thereby form a Ni 2 Si layer on said silicon of said substrate, and to thereby introduce nitrogen into said Ni 2 Si layer in the region thereof ranging from the surface to a predetermined depth; a fourth step, after said third step, selectively removing an unreacted portion of said Ni film; and a fifth step, after said fourth step, annealing said silicon substrate at a second temperature different from said first temperature, so as to form, said NiSi layer which comprises a first region containing substantially no nitrogen, and a second region in contact with the upper portion of said first region, and being nitrided, wherein, in said first step, said Ni film formed on said silicon substrate has a thickness of 10 nm or below.