Effects of Frequency and Bias Voltage on Dielectric Properties and Electric Modulus of Au/Bi4Ti3O12/n-Si (MFS) Capacitors

Yıl 2017, , 1003 - 1008, 20.12.2017

Perihan Durmuş Çiğdem Bilkan Mert Yıldırım

https://doi.org/10.2339/politeknik.369147

Cited By: 1

Öz

In this work, a metal-ferroelectric-semiconductor (MFS) type capacitor
was fabricated and admittance measurements were held in a wide frequency range
of 1 kHz-5 MHz at room temperature for the investigation of frequency and
voltage dependence of complex dielectric constant, complex electric modulus and
electrical conductivity of the MFS
capacitor. Bismuth titanate (Bi₄Ti₃O₁₂) with high dielectric constant was used as
interfacial ferroelectric material and the structure of MFS capacitor was
obtained as Au/Bi₄Ti₃O₁₂/n-Si. Experimental
results showed that dielectric, modulus and conductivity parameters are strong
functions of frequency and voltage especially in depletion and accumulation
regions due to the existence of surface states (N_ss), series
resistance (R_s), interfacial polarization and interfacial layer. It
was found that R_s of the structure and interfacial ferroelectric
layer are efective in accumulation region whereas surface states (N_ss)
and interfacial polarization are efective in
depletion region. Also the changes in dielectric, modulus and conductivity
parameters become considerably high particularly at low frequencies due to high
values of R_s and N_ss. The observed anomalous peak in voltage dependent plots of
capacitance and dielectric constant was atributed to the particular density
distribution of N_ss, R_s and minority carrier injection.
Moreover, the value of conductivity
at low and intermediate frequencies is almost independent of frequency thus low
frequency data was used to extract d.c. conductivity. This work showed that the use of high-dielectric Bi₄Ti₃O₁₂
as ferroelectric interfacial layer in a MFS capacitor is preferable due to high
values of its dielectric constant compared with traditional insulator layer
materials such as SiO₂ and SnO₂. Therefore, a MFS
capacitor with Bi₄Ti₃O₁₂ interfacial layer can
store more energy thanks to its high dielectric constant.

Anahtar Kelimeler

MFS capacitors, frequency and voltage dependence, surface states and interfacial polarization, dielectric properties and electrical modulus

Kaynakça

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