Schottky barrier height modulation in metal/N-Ge system

Fermi level pinning at the Ge valence band results in a high Schottky barrier height (SBH) for all metal/n-Ge contacts. In this work, by inserting an ultrathin insulator between metal and germanium, the SBH of Al/Ge can be reduced from 0.6 eV to about 0.3 eV. Barrier height reduction was measured and compared for several inserted insulators. This structure has application as a low resistance ohmic contact for Ge nMOSFETs.