Zr is proposed to be the capping layer for nickel silicide to obtain a stable low resistance contact system even at an annealing temperature as high as 850degreesC. A NiSi monolayer is the only phase observed in those samples annealed from 500 to 850degreesC. Experimental results from transmission electron microscopy and X-ray diffractometry analysis show that the agglomeration and precipitate of nickel silicide problems which are usually encountered in the NiSi system are eliminated. (C) 2003 The Electrochemical Society.