Effects of high-k zirconium oxide (ZrO2) interlayer on the electrical and transport properties of Au/n-type InP Schottky diode

The structural, chemical, electrical and carrier transport properties of high-k ZrO2 on n-type InP with Au electrode have been studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), current-voltage (IV) and capacitance-voltage (CV) techniques at room temperature. Results show that the high barrier height is achieved for the Au/ZrO2/n-InP metal-insulator-semiconductor (MIS) diode as compared to the Au/n-InP metal-semiconductor (MS) diode. Using Cheung's functions, the barrier height, ideality factor and series resistance are estimated for the MS and MIS diodes. The barrier heights are determined by IV, Cheung's and surface potential-forward voltage plot for both the MS and MIS diodes which are found to be in good agreement with each other. Results indicate that the interface state density of Au/ZrO2/n-InP MIS diode is lower than that of Au/n-InP MS diode. This may be attributed to the fact that the introduction of the high-k ZrO2 interlayer led to reduction of the interface state density in the Au/n-InP MS diode. Results indicate that the Poole-Frenkel emission is the dominant conduction mechanism in the lower bias region while Schottky emission is dominant in the higher bias region for both the Au/n-InP MS and Au/ZrO2/n-InP MIS diodes.