Negative Schottky barrier between titanium and n-type Si(0 0 1) for low-resistance ohmic contacts

A metal-semiconductor contact should have a negative Schottky barrier if the metal has a work function less than the electron affinity of the semiconductor. Such a contact would behave ohmically with a low internal resistance. In reality, the electronic states on the semiconductor surface pin the surface Fermi level and make almost all the metals to show a positive Schottky barrier. By eliminating surface states on Si(0 0 1) with a monolayer of selenium, ohmic contacts with a negative Schottky barrier are demonstrated between titanium and n-type Si(0 0 1). These contacts are found to be thermally stable up to 400 °C.