Frequency effect on electrical and dielectric performance of Au/n–GaAs structure with RF sputtering MoO₃ interfacial layer

Abstract

The effect of frequency on the electrical and dielectric properties of the metal–semiconductor structure with Molybdenum trioxide (MoO₃) interfacial layer was investigated. MoO₃ thin film was deposited n-type (100)-oriented GaAs substrate using RF magnetron sputtering method at substrate temperatures of 200 °C. Au was chosen as the metal, and electrical analysis of the Au/n–GaAs structure with MoO₃ interfacial layer was performed using capacitance–voltage–frequency ($C$–V–f) conductance–voltage–frequency ($G/\omega$–V–f) measurements. $C$–V–f and $G/\omega$–V–f outputs were examined, and it was seen that they have inversion, depletion and accumulation regions. According to the experimental results, it was determined that the $C$ and $G/\omega$ values were strongly dependent on frequency and voltage, especially in the accumulation and depletion regions. Here, both $C$ and $G/\omega$ values decrease with increasing frequency. The structural resistance was obtained by using the $C$ and $G/\omega$ data with the Nicollian–Brews method and the series resistance (${R}_{\text{s}}$) values were determined from there. At 3 V, the ${R}_{\text{s}}$ values were calculated 454 Ω and 102 Ω for 30 kHz and 1 MHz, respectively. In addition, the $C$ and $G/\omega$ values were corrected for the 1 MHz value and a comparative evaluation of the corrected and noncorrected values was made. Moreover, the dielectric parameters of the structure were calculated using the measured $C$ and $G/\omega$ data. It was indicated that while dielectric constant and dielectric loss decreased with increasing frequency as in $C$ and $G/\omega$, ac conductivity increased due to a decrease in polarization as frequency increased.