Temperature dependent barrier characteristics of Pt/n-Si0.76Ge0.24/n-Si Schottky diodes based on I-V-T measurements

Abstract

n-type (100) oriented Si0.76Ge0.24 Samples used in this work were grown by silicon molecular beam epitaxy (Si-MBE). The formation of Schottky junction is made by deposition Pt on n-Si0.76Ge0.24. The electrical properties of Pt/n-Si0.76Ge0.24/n-Si diodes were studied by current-voltage (I-V) measurements. These measurements have done under different temperatures and Schottky barrier heights have determined. The I-V analysis based on thermionic emission (TE) theory has revealed an abnormal decrease of apparent barrier height and increase of ideality factor at low temperature. The conventional Richardson plot exhibits non-linearity at low temperatures. It demonstrates that these anomalies result due to the barrier height inhomogeneities prevailing at the metal-semiconductor interface. The temperature dependence of the I-V characteristics of the Pt/n-Si0.76Ge0.24/n-Si Schottky barrier diode can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the barrier heights. Furthermore, the value of the Richardson constant found is much closer than that obtained without considering the inhomogeneous barrier height.