Towards the Routine Fabrication of P in Si Nanostructures: Understanding P Precursor Molecules on Si(001)

Abstract

AbstractThe ability to controllably position individual phosphorus dopant atoms in silicon sur-faces is a critical first step in creating nanoscale electronic devices in silicon, for example a phosphorus in silicon quantum computer. While individual P atom placement in Si(001) has been achieved, the ability to routinely position P atoms in Si for large-scale device fabrication requires a more detailed understanding of the physical and chemical processes leading to P atom incorporation. Here we present an atomic-resolution scanning tunneling microscopy study of the interaction of the P precursor molecule phosphine (PH3) with the Si(001) surface. In particular, we present the direct observation of PH3 dissociation and diffusion on Si(001) at room temperature and show that this dissociation is occasionally complete, leaving a P monomer bound to the surface. Such surface bound P monomers are important because they are the most likely entry point for P atoms to incorporate into the substrate surface at elevated temperature.