Ion‐beam‐assisted deposition of Pt onp‐InP at room temperature was performed in order to produce Pt epitaxial films with high quality and Pt/p‐InP (100) heterostructures with sharp interfaces. From the x‐ray diffraction analysis, the grown film was found to be a Pt heteroepitaxial film. Auger electron spectroscopy measurements showed that the composition of the as‐grown film was Pt and that the interface quality between the Pt and the InP was relatively good. Transmission electron microscopy showed that the grown Pt was an epitaxial film. These results indicate that the Pt epitaxial films grown onp‐InP (100) can be used for both stable contacts in optoelectronic devices and Pt/InP metal‐semiconductor‐field‐effect transistors and that the Pt/InP heterostructures can give good motivation for the fabrication of Pt/InP superlattices. ©1996 American Institute of Physics.