Device miniaturization requires dimensional shrinkage not only in the lateral directions but also in the vertical direction. A silicide contact in a shallow junction Si device has to be shallow, which means that in forming the silicide it may not consume more than a few hundred angstroms of Si from the substrate. A general scheme of making such a shallow silicide contact is reported here. The scheme utilizes the effect of alloying to dilute the contact reaction, and it produces a shallow contact and a protective diffusion barrier at the same time. Results of Pt-Cr alloys are presented for illustration.