Thermal stability of nickel silicides in different silicon substrates

Thermal stability of nickel monosilicide (NiSi) on single crystalline silicon (c-Si), poly-crystalline silicon (poly-Si) and amorphous silicon (a-Si) has been investigated. NiSi is stable and can show low resistivity on c-Si and poly-Si up to around 700/spl deg/C forming gas anneal (FGA), but is quite unstable on a-Si substrate even after corresponding annealing at only 400/spl deg/C. However, NiSi pure gate formed on poly-Si and a-Si films are both found to be quite stable with temperature up to 1000/spl deg/C FGA and on 1000 /spl Aring/ gate oxide.