A method for forming a semiconductor device structure is provided. The method includes forming a fin structure over a semiconductor substrate and forming a gate stack over the fin structure. The method also includes forming an epitaxial structure over the fin structure, and the epitaxial structure is adjacent to the gate stack. The method further includes forming a dielectric layer over the epitaxial structure and forming an opening in the dielectric layer to expose the epitaxial structure. In addition, the method includes applying a metal-containing material on the epitaxial structure while the epitaxial structure is heated so that a portion of the epitaxial structure is transformed to form a metal-semiconductor compound region.