On the Nature of the “Low-Temperature Anomaly” in Metal–Semiconductor Schottky-Barrier Contacts

Abstract

It is shown that the “low-temperature anomaly” of the I-V characteristics of homogeneous metal–semiconductor Schottky-barrier contacts (an increase in the ideality factor n and a decrease in the barrier height ϕbm, measured using the saturation current, with decreasing temperature, as well as the fact that their product ϕbn≡ nϕbm coincides very closely with the actual barrier height ϕb(V)) is a consequence of two factors: (1) the nonlinear dependence of the actual barrier height on the bias, resulting in an increase in the ideality factor with increasing bias voltage (current) and (2) measurement of the parameters n and ϕbm for the same current for all temperatures. A new expression for the flat-band barrier height ϕbf is derived.