Impact of thermal treatments on the schottky barrier height reduction at the Ti-TiOx-Si interface for contact resistance reduction

Metal-Insulator-Semiconductor (MIS) Schottky diodes were fabricated to study Fermi level unpinning by use of a thin TiO_x insulator. For Ti-TiO_x-n-Si junctions, the Schottky barrier height (SBH) was pinned due to O diffusion from TiO_x into Ti during thermal anneals, as observed from XPS depth profiles. A thin AlO_x barrier inserted between the Ti and the TiO_x prevented O diffusion from TiO_x into Ti, allowing SBH unpinning to be maintained after 450 °C anneals.