Thermal stability of Ni monosilicide formed with Ti capping layer

Abstract

NiSi was formed with a Ti-capping layer to improve the thermal stability. Ni and Ti films were deposited and then annealed in the N/sub 2/ ambient at 300-800/spl deg/C in a RTA (rapid thermal annealing) system. Four point probe, FESEM, and AES were used to study the thermal properties of Ti-capped NiSi layers. The Ti-capped NiSi was stable up to 700/spl deg/C for 100 sec. RTA, while the uncapped NiSi layers showed high sheet resistance after 600/spl deg/C. The AES results revealed that the Ni diffusion further into the Si substrate was retarded by the capping layer, resulting in the suppression of agglomeration of NiSi films.