Refinements on the diffusion into the underlying silicon of dopants implanted in a silicide layer

In this work a theoretical model is presented to analyze the technique recently suggested to form shallow p-n junctions. According to this technique a suicide acts as a source of dopant. A controlled diffusion anneal causes the dopant to penetrate into the silicon wafer. In our analysis the dopant diffusion in the suicide layer itself is taken into account. The dependence of the p-n junction depth on process parameters is discussed. Two cases of dopant penetration into Si are considered in the analysis, namely, with evaporation of the dopant and without it. Experimental data for B diffusion from CoSi₂ acting as the source are used to evaluate our theoretical model and the agreement between theoretical and experimental results is satisfactory.