Physical and technological aspects of anomalous current-voltage characteristics of Schottky diodes at low temperatures

Abstract

ABSTRACT Schottky diodes often exhibit anomalous current—voltage characteristics at low temperatureswith temperature dependent ideality factors and apparent barrier heights evaluated for the thermionic emission. In this paper theoretical expressions are first presented for thetemperature dependencies of the ideality factor and the apparent barrier height for the thermionic-field (T—F) emission including the bias dependence of barrier height. Expressions are also presented to evaluate the characteristic energy E00 and the bias dependence ofbarrier height from the temperature dependence of the ideality factor. Model calculations has been performed using these expressions, and their results are compared with the available experimental data. It is shown that the mechanism responsible for the temperature dependent ideality factors and apparent barrier heights often is the T-F emission with anomalously high characteristic energies. The possible causes of the high characteristic energies are discussed.