Electric and dielectric parameters in Au/n-Si (MS) capacitors with metal oxide-polymer interlayer as function of frequency and voltage

Abstract

In the present work, Au/(MgO-PVP)/n-Si (MPS) capacitors were fabricated and their electric and dielectric parameters were examined via impedance spectroscopy method (ISM) and compared with each other between – 2 and 3 V biases and 10 kHz/5 MHz frequencies. Both the capacitance (C) and conductance (G/ω) values have large dispersion in inversion, depletion, and accumulation regions due to the existence of surface states/traps (Nss/Dit), interface/dipole polarizations, series resistance (Rs), and (MgO-PVP) organic interlayer. Among them, Nss and polarization are effective in inversion and depletion regions at low–intermediate frequencies, but Rs and interlayer are effective only at accumulation region at high frequencies. The voltage and frequency-dependent Nss and Rs were extracted from the Hill–Coleman and Nicollian–Brews methods, respectively. Some basic electrical parameters such as diffusion potential (VD), Fermi energy (EF), depletion region width (WD), and barrier height (ΦB) were calculated from the intercept and slope of the linear regimes C−2–V curves as function of frequency. Additionally, the real and imaginary parts of complex dielectric constant (e*), complex electric modulus (M*), and ac conductivity (σac) were extracted from the C and G/ω data as function of frequency and voltage. The e' value of the (MgO-PVP) interlayer was found as 5.0 even at 10 kHz which is very high when compared conventional insulator layer by traditional method such as SiO2 above 10 kHz in respect of easy grown processes, low cost, flexibility and high mechanical strength. These results show that the used (MgO-PVP) polymer interlayer leads to a large polarization and more storage charges/energy in the MPS-type capacitors rather than MOS capacitors.