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Frequency And Voltage Dependence Of The Dielectric Properties Of Ni/SiO2/P-Si (MOS) Structure
Published 2019 · Materials Science
The frequency (10 - 107 Hz), temperature (303-363 K) or /and bias voltage (−2 to 2 V) dependence of the dielectric properties of Ni/SiO2/p-Si (MOS), have been investigated using the broadband dielectric spectrometer (BDS). Molecular structure and microstructure have been characterized using X - ray diffraction (XRD) and scanning electron microscope (SEM), respectively. From the experimental results, the capacitance–frequency (C-f) characteristics for MOS structure described as a series capacitance (Cs) in the oxide layer (SiO2) and a depletion layer in the semiconductor (p-Si). Interestingly, the capacitance over the whole frequency range for all temperatures are hardly distinguished particularly in the accumulation region, exploring enhancements of the electrical performance for MOS structure. Value of the flat band voltage (VFB) separating the accumulation and depletion regions was determinate at −0.5 V. Furthermore, thickness of the interfacial layer (SiO2) found to be ~580 Å. Both C and ε' found to be strongly temperature and frequency dependent particularly at high temperatures and low frequencies due to creation of an inhomogeneous layer at the SiO2/p-Si interface, exploring Maxwell-Wagner or interfacial polarization. Variation of ε' and ε'' with frequency revealed to the existence of surface states or traps (Nss) located at interfacial layer (SiO2), dipole or/and surface polarization. The average conductivity value of MOS structure found to be 1.2 × 10−7 S/cm, exploring semiconducting feature.