Impedance characterization of AlGaN/GaN Schottky diodes with metal contacts

Donahue, Mary J.; Lübbers, B.; Kittler, M.; Mai, Patrick; Schober, Andreas

doi:10.1063/1.4801643

Cited by 18 publications

(17 citation statements)

References 7 publications

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“…Equations (2a) and (2b) show that for high frequencies the equivalent circuit can be reduced to a simple serial R-C circuit, as already reported for other devices. 59 Remarkably is that the behavior is about the same for different ferroelectric materials, grown on substrates with different orientations and having different top electrodes. The exception is Al, in which case the results strongly support the formation of the thin layer of aluminum oxide affecting the properties of the interface and the equivalent dielectric constant of the ferroelectric capacitor.…”

Section: Discussionmentioning

confidence: 89%

General equivalent circuit derived from capacitance and impedance measurements performed on epitaxial ferroelectric thin films

Pintilie

Hrib

Pasuk

et al. 2014

Journal of Applied Physics

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Voltage and frequency dependent capacitance measurements were performed on epitaxial BaTiO3 and Pb(Zr0.2Ti0.8)O3 thin films deposited on single crystal SrTiO3 substrates with (001) and (111) orientations. The measured capacitors have common bottom SrRuO3 contact and different metals as top electrodes: SrRuO3, Pt, Cu, Al, and Au. The capacitance-voltage characteristics were used to extract information regarding the density of the free carriers and the linear contribution to the static dielectric constant. The frequency dependent impedance was used to develop a suitable equivalent circuit for the epitaxial ferroelectric capacitors. It was found that the frequency dependence of the imaginary part of the impedance can be well simulated, in all cases, using a circuit composed of Schottky-type capacitance related to electrode interfaces, contact resistance, and the R-C parallel connection related to the ferroelectric volume of the film. Values for the components of the equivalent circuit were obtained by fitting the experimental data with the simulated curves. These were then used to extract quantities such as dielectric constant in the ferroelectric volume, the width of the depletion layers, and the apparent built-in potential. It was found that, although the investigated capacitors are of different ferroelectric materials, grown on substrates with different orientations, and having different metals as top electrodes, the values for the capacitance associated with the Schottky contacts and the apparent built-in potential are not very different. The results suggest a strong influence of ferroelectric polarization on the electrode interface properties in the case of epitaxial ferroelectric films.

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Section: Discussionmentioning

confidence: 89%

General equivalent circuit derived from capacitance and impedance measurements performed on epitaxial ferroelectric thin films

Pintilie

Hrib

Pasuk

et al. 2014

Journal of Applied Physics

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“…Because of the Fermi level pinning and hence the same potential offset at metal/AlGaN interface, the increase in the gate leakage current is thought to be in large quantity of traps underneath the gate metal [10]. Subsequently, capacitance-voltage (C-V) characteristics were evaluated because the influence of traps results in the appearance of frequency dispersion in the C-V characteristics [11]. Note that the drain bias was not applied before the measurements of the C-V characteristics.…”

Section: Results and Disucussionmentioning

confidence: 99%

Advantage of TiN Schottky gate over conventional Ni for improved electrical characteristics in AlGaN/GaN HEMT

Kawanago

Kakushima

Kataoka

et al. 2013

2013 Proceedings of the European Solid-State Device Research Conference (ESSDERC)

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Metal induced effects on electrical characteristics in AlGaN/GaN Schottky HEMT are reported. Focus is given to the collapse of drain current attributed to Schottky metal. Of particular interest for discussion is that TiN gate can suppresses the collapse of drain current compared with conventional Ni gate. Nitrogen concentrations in TiN gate are found to be correlated to the current collapse, indicating that the nitrogen vacancy is responsible for the traps in AlGaN/GaN HEMT. The reduction in a concentration gradient of nitrogen should be accomplished for preventing the formation of the traps. Because of the metal dependent collapse of the drain current, the traps are considered to be formed under the gate edge on the drain side in AlGaN layer.I.

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“…Then, we have used this technique to understand the charge transport and study the conductance mechanism in the AlGaN/GaN/Si HEMTs. At an applied frequency, the complex impedance of a system can be written as [19] :…”

Section: Impedance Measurementsmentioning

confidence: 99%

Impedance Characterization of AlGaN/GaN/Si High Electron Mobility Transistors

Mosbahi

Gassoumi

Zaïdi

2021

Silicon

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AlGaN/GaN HEMTs grown on high resistive silicon (111) substrate grown by molecular beam epitaxy have been investigated using impedance measurements. Passivation of the HEMT devices is made in order to improve the electron transport. As has been found from conductance data, the electron traps are eliminated after passivation. The impedance spectroscopy has been, on the other hand, studied from the electrical transport. As a result, a complex impedance plot was revealed an equivalent circuit models indicating single semicircles and the solid interface.

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Impedance characterization of AlGaN/GaN Schottky diodes with metal contacts

Cited by 18 publications

References 7 publications

General equivalent circuit derived from capacitance and impedance measurements performed on epitaxial ferroelectric thin films

General equivalent circuit derived from capacitance and impedance measurements performed on epitaxial ferroelectric thin films

Advantage of TiN Schottky gate over conventional Ni for improved electrical characteristics in AlGaN/GaN HEMT

Impedance Characterization of AlGaN/GaN/Si High Electron Mobility Transistors

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