Low Temperature Range Dielectric Properties and AC Conductivity Behavior of Ta2O5 Thin Film Capacitor Formed with Sol-Gel Spin Coating Method

Abstract

The dielectric constant ε¢ and the dielectric loss factor ε² and AC conductivity of 75 nm thickness tantalum pentaoxide (Ta2O5)thin film capacitor, produced by sol-gel spin coating process on Corning glass substrates, have been investigated in the frequency range of 10 Hz – 100 kHz and the temperature range of 293–193 K. It was found that dielectric constant ε¢ of the Ta2O5 thin film capacitor changes between 9 and 7 at 1 kHz with decreasing temperature in the range of 293–193 K. The dielectric constant ε¢ and dielectric loss ε² were found to decrease with decreasing frequency and temperature. The maximum barrier height Wm is calculated from the frequency dependence of the dielectric loss ε" at different temperatures. Its value obtained 0.14 eV and 0.093 eV at 10 Hz–2 kHz and 2 kHz–12 kHz frequency range respectively. This type of dielectric properties was associated with a carrier hopping process, interfacial and dipolar polarization processes. The AC conductivity of Ta2O5 thin film capacitor was found more dependent on temperature in the low frequency region than in the high frequency region. It has been determined that the temperature dependence of AC conductivity is compatible with the Correlated Barrier Hopping (CBH) model.

Keywords

• Sol-Gel
• Thin Film Capacitor
• Dielectric Properties
• AC Conductivity