Ohmic contact to n-type Ge with compositional Ti nitride

Fermi-Level pinning at Ge surface results in high Schottky barrier height (SBH) for nearly all metal/n-Ge contacts. By varying composition of the TiNx, modulation of the SBH was demonstrated for TiNx/n-Ge contact. The effective SBH of the TiN0.1/n-Ge Schottky contact was found decreased to 0.45 eV, as compared to the Ti/n-Ge contact SBH which was originally pinned at 0.56 eV. Ohmic contact to n-type Ge was realized by increasing the nitrogen composition to x = 0.8 in TiNx. Dipoles formed by the difference of the Pauling electronegativities for Ge and N at the contact interface is proposed to alleviate the Fermi-Level pinning effect.