On the determination of interface state density in n-InP Schottky structures by current–voltage measurements: Comparison with DLTS results

Abstract

Current voltage ( I–V g) and deep level transient spectroscopy (DLTS) techniques have been carried out to study Schottky and ultraviolet oxidised Schottky diodes realised on n-type indium phosphide. For the oxidised structures, the ideality factor n versus voltage exhibits a peak around 0.2 V, from which the interface state density can be estimated to have a maximum value of 4×10 12 cm −2 eV −1. Comparable results for the same structures have been obtained from DLTS measurements. For the Schottky diodes, no peak appears in the plot of n versus voltage and no information on interface states can be deduced from I–V g measurements. However, DLTS measurements reveal an electrically active defect localised at the InP interface. This study shows that the I–V g measurements may be used as a fast technique for interface states investigation.