Fermi Level Pinning in Metal-Insulator-Diamond Structures

Abstract
Capacitance-voltage (\cv) and electron-beam-induced current (EBIC) measurements were performed on metal-insulator-semiconductive (MIS) diamond structures. Utilizing \bto (BTO) as the gate insulator of diamond MIS structures, experimental results indicate pinning of the Fermi energy at ∼1.7 eV above the valence band edge, which is in excellent agreement with the 1/3 band-gap rule of Mead and Spitzer. This is due to the existence of surface states on diamond presumably induced by oxygen adsorption. Employing \caf in place of BTO reduced the Fermi level pinning to a large extent by virtue of its oxygen-free process.