Tunneling in Schottky Barrier Rectifiers

Abstract

When a metal is brought into intimate contact with a semiconductor there sometimes arises a potential barrier within the semiconductor which impedes the flow of electrons between it and the metal. The formation of such Schottky barriers will be described by Professor Mead and this chapter will be mainly concerned with the tunneling of electrons through them. Clearly, if a bias is applied between a metal and a semiconductor, current will flow. If the barriers are sufficiently thin and the temperature is sufficiently low, then the current flow will be primarily by electron tunneling. Conversely, for thicker barriers and higher temperatures the current flow will be due to thermionic emission over the barrier. We will also consider intermediate ranges of thickness and temperature, where the current is primarily due to tunneling of thermally excited carriers. This is the socalled TF emission first introduced by Dolan and Dyke (¹) in connection with field emission from a metal tip.