Reduction in Specific Contact Resistivity to n+ Ge Using TiO2 Interfacial Layer

We report a metal-insulator-semiconductor (MIS) contact using a TiO2 interfacial layer on highly doped n(+) Ge to overcome the problem of metal-Fermi-level pinning on Ge, which results in a large electron barrier height. A specific contact resistivity of 1.3 x 10(-6) Omega . cm(2) was achieved, which represents a 70x reduction from conventional contacts. For the first time, interfacial layer conductivity is experimentally identified as an important consideration for high-performance MIS contacts. New insights on the mechanism responsible for contact resistance reduction are presented.