Ultra thin silicon nitride films on Si(1 0 0) studied with core level photoemission

Abstract

Ultra thin films of pure silicon nitride are grown on a Si(1 0 0) surface by exposing the surface to a microwave excited nitrogen plasma with a high content of N atoms at various substrate temperatures. These processes are monitored with synchrotron radiation induced core level photoemission spectroscopy. Below 500 °C the films grow uniformly with an amorphous character, but at higher growth temperatures, we find evidence showing that the growing nitride is microcrystalline as for Si(1 1 1), which we studied earlier. The interface between the substrate and the nitride film shows a different coordination for the Si(1 0 0) surface than for the Si(1 1 1) surface, at all temperatures. The growth of nitride in this process is self limiting with a final thickness, which increases with growth temperature. It is a clear indication from our studies that the Si(1 0 0)/nitride interface is less sharp and has a lower electrical quality than the Si(1 1 1)/nitride interface.