Local oxidation of metal and metal nitride films

Abstract

Oxide growth on sputter-deposited thin films is studied on the local scale by atomic force microscope (AFM)-assisted lithography. We investigate the group IV reactive metals Zr, Hf, Ti, and their nitrides. The nitrogen content of the deposition plasma affects the film crystal structure and electrical resistivity, which in turn alter the local oxidation rates. Mass transport plays an important role, producing features with heights ranging from a few nanometers up to hundreds of nanometers. The heights of the largest features are one to two orders of magnitude greater than observed in other material systems, and the growth is well controlled. We use various techniques to investigate the solid-state reaction and transport mechanisms involved in this oxidation driven by a highly localized electric field. Our results demonstrate the potential of AFM lithographic techniques for characterizing oxidation processes across a wide range of time and length scales.