A
metal /
semiconductor /
metal (MSM) back-to-back
Schottky diode, a resistance memory device using the MSM
diode, and associated fabrication processes are provided. The method includes: providing a substrate; forming a
metal bottom
electrode overlying the substrate, having a first
work function; forming a
semiconductor layer overlying the metal bottom
electrode, having a second
work function, less than the first
work function; and, forming a metal top
electrode overlying the
semiconductor layer, having a third work function, greater than the second work function. The metal top and bottom electrodes can be materials such as Pt, Au, Ag,
TiN, Ta, Ru, or TaN. In one aspect, the metal top electrode and metal bottom electrode are made from the same material and, therefore, have identical work functions. The semiconductor layer can be a material such as
amorphous silicon (a:Si), polycrystalline Si, InOx, or ZnO.