Al/W/TiN/sub x//TiSi/sub y//Si barrier technology for 1.0- mu m contacts

A reliable contact diffusion barrier has been successfully formed by sintering in nitrogen a physically sputtered W/Ti bilayer. After a 650 degrees C furnace anneal, a TiN/sub x//TiSi/sub y/ layer on contact with the silicon substrate was formed beneath the overlying W. No reaction between N/sub 2/ and W was observed. Arsenic implanted in the silicon substrate tended to retard the silicidation of titanium. Substantial redistribution of both B and As across the silicide layer was also observed during the contact sintering process. The 1.0- mu contacts fabricated with the Al/W/TiN/sub x//TiSi/sub y//Si barrier technology exhibited low and tightly distributed contact resistivities (less than 10/sup -6/ Omega -cm/sup 2/). No excessive leakage of the shallow junctions was observed even after thermally stressing the sample at 400 degrees C for 8 h.<
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