A NEW ANALYTICAL EXPRESSION FOR THE INTERFACE INDEX OF METAL-SCHOTTKY CONTACTS ON SEMICONDUCTORS

Abstract-By reconsidering the effect of the penetration depth of the interface states, a new analytical expression of the interface index has been achieved to successfully explain the role of the semiconductor ionicity in the behavior of metal-Schottky contacts on semiconductors. The derived interface indices not only fit quite well with the previous experimental data but also exhibit a sharp transition from the Bardeen limit to the Schottky limit for semiconductor ionicity around 0.8, which agrees well with the experiment reports. I. INTRODU~ION The dependence of Schottky barrier height $,, ” on the metal electronegativity x,, has gained a great deal of attention in study of the characteristics of Schottky contacts [ l-81. Empirically, this correlation is assumed to be linear and the barrier heights of Schottky contacts can then be expressed as &, ” = Sx, + $J,, where the phenomenological parameter S is called the interface index of the metal/semiconductor interface