Frequency and gate voltage effects on the dielectric properties of Au/SiO2/n-Si structures

To determine the dielectric constant (ε′), dielectric loss (ε″), loss tangent (tan δ), the ac electrical conductivity (σac) and the electric modulus of Au/SiO2/n-Si structure, the measurement admittance technique was used. Experimental results show that the values of ε′, ε″, tan δ, σac and the electric modulus show fairly large frequency and gate bias dispersion especially at low frequencies due to the interface charges and polarization. An increase in the values of the ε′ and ε″ were observed with both a decrease in frequency and an increase in frequency. The σac is found to increase with both increasing frequency and voltage. In addition, the experimental dielectrical data have been analyzed considering electric modulus formalism. It can be concluded that the interface charges and interfacial polarization have strong influence on the dielectric properties of metal–insulator–semiconductor (MIS) structures especially at low frequencies and both in depletion and accumulation regions.