Self-aligned silicided (PtSi and CoSi2) ultra-shallow p+/n junctions

Ultra-shallow p+/n junctions (<100 nm) demonstrating excellent I-V characteristics have been fabricated with self-aligned PtSi. Junctions were formed by rapid thermal annealing (RTA) 〈100〉 Si preamorphized with Sn+ and implanted with BF2+. Subsequently, low-temperature RTA in N2of sputter-deposited Pt produced a 55-nm-thick PtSi layer possessing a remarkably smooth surface and interface, and demonstrating excellent resistance to the aqua regia etch solution. The silicided junctions displayed a sheet resistance of 14 Ω/sq with less than -2-nA . cm^-2reverse-bias leakage at -5 V. In a comparative scheme, similar junction characteristics were obtained using a self-aligned 39-nm-thick CoSi2overlayer.