SiO 2 and polycrystalline Si layers were sequentially grown on (100) Si. NiSi was formed on this substrate from a 20nm Ni layer or a 20nm Ni/5nm Ti bilayer by rapid thermal annealing (RTA) at 300 500 ? C to compare thermal stability. In addition, MOS capacitors were fabricated by depositing a 20nm Ni layer on the Poly-Si/ SiO 2 substrate, RTA at 400 ? C to form NiSi, BF 2 or As implantation and finally drive- in annealing at 500 800 ? C to evaluate electrical characteristics. When annealed at 400 ? C , NiSi made from both a Ni monolayer and a Ni/Ti bilayer showed excellent thermal stability. But NiSi made from a Ni/Ti bilayer was thermally unstable at 500 ? C . This was attributed to the formation of insignificantly small amount of NiSi due to suppressed Ni diffusion through the Ti layer. PMOS and NMOS capacitors made by using a Ni monolayer and the SADS(silicide as a dopant source) method showed good C-V characteristics, when drive-in annealed at 500 ? C for 20sec., and 600 ? C for 80sec. respectively.