Complex dielectric permittivity, electric modulus and electrical conductivity analysis of Au/Si_3N_4/p-GaAs (MOS) capacitor

摘要

RF magnetron sputtering was used to grow silicon nitride (Si_3N_4) thin film on GaAs substrate to form metal-oxide-semiconductor (MOS) capacitor. Complex dielectric permittivity (ε~*), complex electric modulus (M~*) and complex electrical conductivity (σ~*) of the prepared Au/Si_3N_4/p-GaAs (MOS) capacitor were studied in detail. These parameters were calculated using admittance measurements performed in the range of 150 K-350 K and 50 kHz-1 MHz. It is found that the dielectric constant (ε') and dielectric loss (ε") value decrease with increasing frequency. However, as the temperature increases, the ε' and ε" increased. Ac conductivity (σ_(ac)) was increased with increasing both temperature and frequency. The activation energy (E_a) was determined by Arrhenius equation. Besides, the frequency dependence of σ_(ac) was analyzed by Jonscher's universal power law (σ_(ac) = Aω~s). Thus, the value of the frequency exponent (s) were determined.