Contact resistivity of shallow junctions formed by implantation through Pt or PtSi

The specific contact resistance (ρ{variant}_c) of PtSi/p⁺ and PtSi/n⁺ contacts formed by ion implantation through Pt or PtSi was studied. A simple process to form self-aligned six-terminal Kelvin structure was developed in order to measure the specific contact resistance. For the PtSi/p⁺ contact system, a ρ{variant}_c lower than 1 × 10^-6 ω-cm² was achieved by BF₂⁺ implantation at 40 keV to a dose of 5 × 10¹⁵ cm^-2. Increase of dose or energy could further decrease the ρ_c to be lower than 5 × 10^-7 ω-cm². The ρ_c of the PtSi/n⁺ contact system was lower than that of the PtSi/p⁺ contact system and a ρ{variant}_c of 1 × 10^-7 ω-cm² was obtained. These results indicate that although the PtSi-contacted junction is formed at temperatures lower than 800°C, the ρ{variant}_c is low enough to satisfy the requirements of submicrometer technology. We suggest that PtSi should be a favorable material to form shallow junctions and contacts simultaneously for future VLSI processes and to satisfy low thermal budget requirement.