Identifying of series resistance and interface states on rhenium/n-GaAs structures using C–V–T and G/ω–V–T characteristics in frequency ranged 50 kHz to 5 MHz

Abstract

In this study, Re/n-GaAs with a native oxide layer based on metal–semiconductor (MS) structures were produced and then, the capacitance–voltage–temperature (C–V–T) and the conductance–voltage–temperature (G/ω–V–T) data of them were obtained in the frequency ranged 50 kHz to 5 MHz. Using the raw data, the electronic parameters was calculated by the developed LabVIEW-based program. Methodologically, the series resistance (R_s) values were calculated from the measured capacitance (C_m) and conductivity (G_m) values, while the interface state (N_ss) values were obtained from using the combined high (C_HF)–low (C_LF) frequency capacitance method by Nicollian and Brews. Experimentally, the C values increased with a decreasing frequency, while decreased with increasing temperatures in the depletion and accumulation regions. On the other hand, G/ω values decreased with increasing frequency in forward and reverse bias regions. It can be attributed that, the C and the G/ω values are quite affected by the presence of the R_s and the N_ss in the forbidden energy gap and a native oxide layer between M and S. The R_s–V–T curves have especially peaks in accumulation and depletion regions at low frequency values, whereas these peaks decreased at high frequencies. In addition, the N_ss–V–T curves give peaks in the range of − 0.1 V to 0.7 V at variable temperatures and the N_ss values decrease with increasing temperature and shift towards negative bias regions. Experimental results indicate that the R_s and N_ss are important parameters and so, these parameters must be considered in sensor applications based on Re/n-GaAs structures.