Influence of interface states on the temperature dependence and current-voltage characteristics of Ni/p-InP Schottky diodes

The ideality factor n and the barrier height Phi(ap) of the sputtered Ni/p-InP Schottky diodes have been calculated from their experimental Current-voltage (I-V) characteristics in the temperature range of 60-400 K with steps of 10 K The n and Phi(ap) values for the device have been obtained as 1.27 and 0.87 eV at 300 K and 1.13 and 0.91 eV at 400 K respectively. The n values larger than unity at high temperatures indicate the presence of a thin native oxide layer at the semiconductor/metal interface. The barrier height (BH) has been assumed to be bias dependent due to the presence of an interfacial layer and interface states located at the interfacial layer-semiconductor interface. Interfacial layer-thermionic emission current mechanism has been fitted to experimental I-V data by considering the bias-dependence of the BH at each temperature. The best fitting values of the series resistance R-s and interface state density N-s together with the bias-dependence of the BH have been used at each temperature, and the R-s and N-s versus temperature plots have been drawn. It has been seen that the experimental and theoretical forward bias I-V data are in excellent agreement with each other in the temperature range of 60-400 K It has been seen that the R, and Ns values increase with a decrease in temperature, confirming the results in the literature. (C) 2009 Elsevier Ltd. All rights reserved.