Investigation of the Frequency and Voltage Dependent Dielectric Properties of Au/n-SiC Metal Semiconductor (MS) and Au/Al2O3/n-SiC Metal-Insulator-Semiconductor (MIS) Structures

Abstract

In this study, we investigated the fabrication of Au/n-SiC (MS) and Au/Al2O3/n-SiC (MIS) type structures with atomic layer deposition (ALD) technique and their dielectric properties. The dielectric characteristics of structures were analyzed at frequency range of 1 kHz-500 kHz and by applying a (-3V)-(9V) bias voltage at 300 K. The significant dielectric parameters such as dielectric constant (ε') and dielectric loss (ε"), real and imaginary parts of electrical modulus (M' and M"), loss tangent (tan) were calculated by depending on frequency and voltage from capacitance-voltage (C-V) and conductance-voltage (G/-V) data. Thereby, the effect of frequency on MS and MIS was searched in detail. The effect of the interface states occurred in the low frequency region can be attributed to the variation of the characteristic behavior of these parameters. It is clear that the dielectric parameters highly depend on the frequency and voltage at depletion and accumulation regions. Moreover, the peak position of M shifts to the left side of the graphic due to the effect of the insulating layer. It can be deduced from the obtained results that the interfacial polarization is easier at low frequencies. Also the interfacial polarization can contribute more to the variation of the dielectric properties.