THE CURRENT–VOLTAGE CHARACTERISTICS OVER THE MEASUREMENT TEMPERATURE OF 60–400 K IN THE Au/Ti/n-GaAs CONTACTS WITH HIGH DIELECTRIC HfO2 INTERFACIAL LAYER

Abstract

The Au/Ti/HfO2/[Formula: see text]-GaAs metal/insulating layer/semiconductor structures have been fabricated using standard thermal atomic layer deposition. We experimentally showed whether or not the HfO2 interfacial layer grown on the [Formula: see text]-GaAs wafer modifies the barrier height (BH) of the device at the room temperature. Besides, we investigated the measurement based on temperature dependence of the device parameters from the current–voltage ([Formula: see text]–[Formula: see text]) characteristics of the diode in 60–400[Formula: see text]K range with steps of 10[Formula: see text]K. The X-ray photoelectron spectroscopy (XPS) have been carried out to characterize the surfaces of both [Formula: see text]-GaAs wafer and HfO2 thin films. The series resistance value from the temperature-dependent [Formula: see text]–[Formula: see text] characteristics decreased with decreasing temperature, which is a desired positive result for the devices developed from the MOS capacitor. The BH value of 0.94[Formula: see text]eV (300[Formula: see text]K) has been obtained for the device with the HfO2 layer which is a higher value than the value of 0.77[Formula: see text]eV (300[Formula: see text]K) of the device without HfO2 layer. Therefore, we can say that the HfO2 thin layer at the metal/GaAs interface can also be used for the BH modification as a gate insulator for GaAs MOS capacitor and MOSFETs. When the temperature-dependent [Formula: see text]–[Formula: see text] characteristics at low temperatures have been considered, it has been observed that the current prefers to flow through the lowest BHs due to the BH inhomogeneities.