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Contact resistance

About: Contact resistance is a research topic. Over the lifetime, 15262 publications have been published within this topic receiving 232144 citations. The topic is also known as: electrical contact resistance & ECR.


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Journal ArticleDOI
TL;DR: In this article, the relationship between annealing temperature, interfacial microstructure, and contact resistance is examined, and the inclusions are shown to be a Ti-nitride, having an Al/Au-rich metallurgical barrier layer surrounding them.
Abstract: AuTiAlTi/AlGaN/GaN ohmic contact structures rapid thermal annealed at 650, 750, 850, and 950 °C have been analyzed using complementary transmission electron microscopy and electrical characterization techniques. The relationship between annealing temperature, interfacial microstructure, and contact resistance is examined. Annealing temperatures of 750 °C or higher are required to produce an ohmic contact. Contacts annealed at 750 and 850 °C show a planar interface between contact and the AlGaN layer, with minimal consumption of the AlGaN and the formation of a thin TiN interfacial layer. Annealing at 950 °C produces the lowest contact resistance, with a structure showing inclusions through the AlGaN/GaN layer. These inclusions are also shown to be a Ti-nitride, having an Al/Au-rich metallurgical barrier layer surrounding them. However, this metallurgical layer does not produce an electrical barrier.

91 citations

Journal ArticleDOI
TL;DR: Very low resistance ohmic contacts to p-type SiC were fabricated by depositing a 90-10 wt.% alloy of Al and Ti followed by a high temperature anneal of approximately 1000°C for 2 min this article.
Abstract: Very low resistance ohmic contacts to p-type SiC were fabricated by depositing a 90-10 wt.% alloy of Al and Ti followed by a high temperature anneal of approximately 1000°C for 2 min. Specific contact resistances ranged from approximately 5 × 10 −6 to 3 × 10 −5 Ω cm 2 on material with a doping of 1.3 × 1019 cm−3. The initial AlTi thickness before annealing was found to be critical to controlling the AlTi sheet resistance during the anneal. In addition, chemically etching the AlTi layer after annealing revealed pitting indicative of severe reaction between the AlTi and SiC surface, as confirmed by Rutherford Backscattering. In contrast, ohmic contacts to the same SiC material were fabricated by depositing pure Ti and annealing at 800°C for 1 min. These contacts were ohmic with a specific contact resistance between 2 × 10 −5 and 4 × 10 −5 Ω cm 2 . Examination of the SiC surface after chemically etching away the annealed contact revealed a smooth surface, suggesting a much more planar Ti/SiC interface.

90 citations

Journal ArticleDOI
TL;DR: In this article, an ion implanted aperture was used to improve the lateral confinement over SiNx apertures by enabling a planar ITO design, while the multi-layer ITO contact minimizes scattering losses due to its epitaxially smooth morphology.
Abstract: We report on our recent progress in improving the performance of nonpolar III-nitride vertical-cavity surface-emitting lasers (VCSELs) by using an Al ion implanted aperture and employing a multi-layer electron-beam evaporated ITO intracavity contact. The use of an ion implanted aperture improves the lateral confinement over SiNx apertures by enabling a planar ITO design, while the multi-layer ITO contact minimizes scattering losses due to its epitaxially smooth morphology. The reported VCSEL has 10 QWs, with a 3 nm quantum well width, 1 nm barriers, a 5 nm electron-blocking layer, and a 6.95- λ total cavity thickness. These advances yield a single longitudinal mode 406 nm nonpolar VCSEL with a low threshold current density (∼16 kA/cm2), a peak output power of ∼12 μW, and a 100% polarization ratio. The lasing in the current aperture is observed to be spatially non-uniform, which is likely a result of filamentation caused by non-uniform current spreading, lateral optical confinement, contact resistance, and...

90 citations

Journal ArticleDOI
TL;DR: In this article, vanadium suboxide (V2Ox) capped with a thin Ni layer was used as a hole transport layer trying to avoid both the intrinsic amorphous silicon layer and the TCO contact layer.
Abstract: Over the last few years, transition metal oxide layers have been proposed as selective contacts both for electrons and holes and successfully applied to silicon solar cells. However, better published results need the use of both a thin and high quality intrinsic amorphous Si layer and TCO (Transparent Conductive Oxide) films. In this work, we explore the use of vanadium suboxide (V2Ox) capped with a thin Ni layer as a hole transport layer trying to avoid both the intrinsic amorphous silicon layer and the TCO contact layer. Obtained figures of merit for Ni/V2Ox/c-Si(n) test samples are saturation current densities of 175 fA cm−2 and specific contact resistance below 115 mΩ cm2 on 40 nm thick V2Ox layers. Finally, the Ni/V2Ox stack is used with an interdigitated back-contacted c-Si(n) solar cell architecture fully fabricated at low temperatures. An open circuit voltage, a short circuit current and a fill factor of 656 mV, 40.7 mA cm−2 and 74.0% are achieved, respectively, leading to a power conversion efficiency of 19.7%. These results confirm the high potential of Ni/V2Ox stacks as hole-selective contacts on crystalline silicon photovoltaics.

90 citations

Journal ArticleDOI
TL;DR: In this article, the stability in time of the current-voltage characteristics of organic thin-film devices on glass substrates was studied, and it was shown that the resistance of the devices gradually changes under the application of an electrical bias depending on the sodium content of the glass substrate used in the experiment.
Abstract: We study the stability in time of the current–voltage characteristics of organic thin-film devices on glass substrates. We find for poly(3-hexylthiophene) and for pentacene that the resistance of the devices gradually changes under the application of an electrical bias depending on the sodium content of the glass substrates used in the experiment. For devices on a very common type of glass (with a Na2O content of about 6%) and on sodalime glass (14% Na2O) substrates, the prolonged application of a voltage bias results in a substantial decrease (up to two orders of magnitude) of the bulk and contact resistances, whereas for sodium-free glass substrates the gradual changes in current–voltage characteristics are much smaller. A systematic study of the electrical behavior complemented by chemical analysis shows that the instabilities observed are due to Na+ ions diffusing from the substrate into the organic film, and moving inside the organic material as a result of the applied electric field. Our results show in detail how ion motion in organic materials results in substantial hysteresis and device instabilities.

90 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023213
2022432
2021286
2020384
2019528
2018503