Evaluation of Schottky barrier parameters of Pd/Pt Schottky contacts on n-InP (100) in wide temperature range

The current–voltage measurements of Pd/Pt/n-InP Schottky barrier diodes were carried out in the temperature range of 230–410 K. The current–voltage characteristics show an abnormal decrease of apparent barrier height and increase of ideality factor at low temperatures. The nonlinearity in the Richardson plot and strong dependence of barrier height and ideality factor on temperature indicates the spatial inhomogeneity in the interface. The series resistance estimated from the forward current–voltage characteristics is strongly temperature-dependent and the series resistance is decreased with an increase in temperature. A ΦbΦb versus (2kT)−1(2kT)−1 plot was drawn to obtain the mean barrier height (Φ¯bo (T=0K)) and the standard deviation (σoσo) at zero bias which was found to be 0.97 eV, 151 meV respectively. The effective Richardson constant (3.85 A cm−2 K−2) obtained from the modified Richardson plot is closer to the theoretical value (9.4 A cm−2 K−2). The temperature-dependent behavior of the Pd/Pt Schottky contact has been interpreted by the assumption of a Gaussian distribution of barrier heights due to barrier inhomogeneities at the metal–semiconductor interfaces.