On the profile of frequency dependent dielectric properties of (Ni/Au)/GaN/Al0.3Ga0.7N heterostructures

Date
2010-10-12
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Source Title
Microelectronics Reliability
Print ISSN
0026-2714
Electronic ISSN
Publisher
Elsevier
Volume
51
Issue
3
Pages
581 - 586
Language
English
Type
Article
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Abstract

The voltage (V) and frequency (f) dependence of dielectric characteristics such as dielectric constant (ε′), dielectric loss (ε″), dielectric loss tangent (tan δ) and real and imaginary part of electrical modulus (Μ′ and M″) of the (Ni/Au)/GaN/Al0.3Ga 0.7N heterostructures have been investigated by using experimental admittance spectroscopy (capacitance-voltage (C-V) and conductance-voltage (G/w-V)) measurements at room temperature. Experimental results show that the values of the ε′, ε″, tan δ and the real and imaginary parts of the electric modulus (M′ and M″) obtained from the C and G/w measurements were found to be strong function of frequency and applied bias voltage especially in depletion region at low frequencies. These changes in dielectric parameters can be attributed to the interfacial GaN cap layer, interface polarization and a continuous density distribution of interface states and their relaxation time at metal/semiconductor interface. While the values of the ε ′ decrease with increasing frequencies, tan δ,M′ and M″ increase with the increasing frequency. Also, the dielectric loss (ε″) have a local maximum at about frequency of 100 kHz. It can be concluded that the interface polarization can occur more easily at low frequencies with the number of interface states located at the metal/semiconductor interface.

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Keywords
Admittance spectroscopies, Applied bias voltage, Capacitance voltage, Density distributions, Depletion region, Dielectric characteristics, Dielectric constants, Dielectric loss tangent, Dielectric parameters, Electric modulus, Electrical modulus, Frequency dependent, Function of frequency, GaN cap layers, Heterostructures, Imaginary parts, Interface state, Local maximum, Low frequency, Metal/semiconductor interface, Room temperature, Crystals, Dielectric devices, Gallium nitride, Polarization, Tanning, Dielectric losses
Citation
Published Version (Please cite this version)