Semiconductor integrated circuit device with nitride barrier layer ion implanted with resistivity decreasing elements

Claim 1

A semiconductor circuit device comprising a first polycrystalline silicon or polycide interconnect formed on a top surface of an impurity diffused region formed in a Si single crystal substrate or over an insulating film, an intermediate insulating film formed over said first interconnect, a second polycrystal silicon interconnect having at least, in part, a high resistance region of first resistance value therealong and connected to said first interconnect through at least one contact hole in said intermediate insulating film, a nitride film having a thickness in the range of 50 Å to 300 Å formed at the contact interface between said first interconnect and said second interconnect, said nitride film selected from the group consisting of Si 3 N 4 , TiN, WN, MoN and CN, an impurity implanted at 35 keV to 150 keV with a concentration in the range of 5×10 13 /cm 2 to 5×10 16 /cm 2 to provide said nitride film with a second resistance value, said impurity selected from the group consisting of B, P, Mo, W, Cr, Ni and Cu, said second resistance value being lower than the first resistance value of said high resistance region, said nitride film preventing the infiltration of impurity from said diffusion region into said high resistance region decreasing said first resistance value.