Application of nitrogen in a cobalt-silicide-forming system

Implanted nitrogen exhibited an interesting fast diffusion in cobalt films evaporated onto a crystalline silicon substrate. A nitride barrier layer forms at the Co-Si interface and prevents reaction between cobalt and silicon for annealing temperatures up to 5500C. A Co-Ni shallow contact structure was tested using this nitride barrier. Nitrogen implanted into silicon inhibits the silicon flux which is responsible for CoSi growth. Nitrogen redistribution and preferential growth of Co2Si over CoSi was observed. Silicide growth was monitored by megaelectronvolt 4He+ Rutherford backscattering spectrometry, and 15N was profiled by 15N(p,α)12C nuclear reaction analysis. (Auth.)