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/n-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 n-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 (I-V) characteristics of the diode in 60-400K range with steps of 10K. The X-ray photoelectron spectroscopy (XPS) have been carried out to characterize the surfaces of both n-GaAs wafer and HfO2 thin films. The series resistance value from the temperature-dependent I-V characteristics decreased with decreasing temperature, which is a desired positive result for the devices developed from the MOS capacitor. The BH value of 0.94eV (300K) has been obtained for the device with the HfO2 layer which is a higher value than the value of 0.77eV (300K) 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 I-V 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. © 2019 World Scientific Publishing Company.