The effect of Cr as a barrier between PtSi and Al is studied by analyzing the reactions of the Al/Cr/Pt/Si (2000 Å/1000 Å/1000 Å/Si substrate) structures. Electrical measurement shows a rapid rise in sheet resistance after annealing at 400 °C. Structural analysis shows extensive reactions between Al and Cr at such temperatures. The PtSi formed remains little changed until 550 °C, and is converted to PtAl2 at higher temperatures. The results are compared with those using W, Ti-W, and carbon barriers, and the roles of barrier materials on the stability of the Al/PtSi metallurgy are discussed.