Disordered intermixing at the platinum:silicon interface demonstrated by high-resolution cross-sectional transmission electron microscopy, Auger electron spectroscopy, and MeV ion channeling

Abstract

The metallurgical interaction at the interface between single-crystal silicon substrates and thin films of elemental platinum has been examined using the complementary techniques of high-resolution cross-sectional transmission electron microscopy (HRXTEM), Auger sputter profiling, and MeV ion channeling. We identify the existence of a 30-Å-thick layer of intermixed platinum and silicon which forms at the metal-silicide interface when 50 Å of Pt is electron beam evaporated onto room-temperature Si. The interfacial layer is evident in the HRXTEM as a uniform band of dark and noncrystalline contrast. In Auger sputter profiling, the evolution of the Si LVV line shape indicates the presence of a platinum silicide region adjacent to the film/Si interface but not at the surface of the Pt film. MeV ion channeling reveals that ∼1.5×1016 Si atoms/cm2 are displaced from their substrate lattice sites upon Pt deposition. In addition, the HRXTEM reveals islands of unreacted Pt and occasional grains of Pt2Si on top of the intermixed layer of Pt and Si.