Defining nanoscale metal features on an atomically clean silicon surface with a stencil

Metal features with nanometer scale edge definition have been created on an atomically clean Si(001) surface with a stencil. These features were subsequently characterized by scanning tunneling microscopy and scanning electron microscopy. The stencil was brought into contact with the substrate while allowing the stencil to pivot so that it self-aligned parallel to the substrate surface. With this simple method, feature edge spreading was reduced to less than 10 nm in the best case. At the same time, atomic resolution images of the metal feature/silicon boundary showed significant spreading of a sub-monolayer of metal beyond the deposited area. This spreading may pose a limit on the ultimate resolution that can be achieved for metals deposited on atomically clean silicon surfaces.