Self-aligned CoSi/sub 2/-formation by ion beam mixing and its application to MOS-devices

Shallow junctions with CoSi/sub 2/ as contact metallization were formed using the technique of implantation through metal (ITM). Implantation with boron or arsenic ions was used to perform both mixing of the Co/Si interface and junction doping. CoSi/sub 2/ formation and dopant activation was carried out subsequently in a single annealing step (RTA). Low contact resistivities between CoSi/sub 2/ and highly doped n/sup +/ and p/sup +/Si and shallow junctions were achieved using a thermal treatment of only 750 degrees C, 15 s and 800 degrees C, 10 s for arsenic and boron doped junctions, respectively. Junction depths of 0.1 mu m and 0.16 mu m below the silicide were obtained for CoSi/sub 2//n/sup +/ (As)p and CoSi/sub 2//p/sup +/ (B)n structures. CBKR structures were used for contact resistance measurements. For CoSi/sub 2//p/sup +/ contacts a specific contact resistance of rho /sub C/=3.4*10/sup -8/ Omega cm/sup 2/ was determined. CoSi/sub 2//n/sup +/ (As)p and CoSi/sub 2//p/sup +/ (B)n diodes produced by this technique showed leakage current densities of about 3 nA/cm/sup 2/ and 20 nA/cm/sup 2/, respectively. N-channel MOS-transistors with silicided source/drain regions fabricated by ITM showed adequate I-V characteristics.<
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