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Van der Pauw method

About: Van der Pauw method is a research topic. Over the lifetime, 1682 publications have been published within this topic receiving 25364 citations.


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TL;DR: In this paper, a set of samples were prepared comparing various thicknesses of SiO2 (60, 120, 190, 240 and 520 nm) as an intermediate bonding layer between the two materials, and a variety of test structures such as Van der Pauw structures, linear transfer-length measurement arrays and resistors were fabricated in the Si layers using standard Si processing.
Abstract: Multiple 50 mm hybrid Si-on-SiC substrates consisting of thin film [100] Si (1 µm) on bulk semi-insulating [0001] 6H-SiC wafers were fabricated using low-temperature (150 °C) wafer bonding and slicing techniques. A set of samples were prepared comparing various thicknesses of SiO2 (60, 120, 190, 240 and 520 nm) as an intermediate bonding layer between the two materials. A variety of test structures such as Van der Pauw structures, linear transfer-length measurement arrays and resistors were fabricated in the Si layers using standard Si processing (such as lithography, B-diffusion, etching and oxidation) in order to characterize the robustness as well as the electrical and thermal properties of the hybrid substrates. Bulk Si and Si-on-insulator (SOI) substrates were used for comparison. We report the Si layers on the hybrid Si-on-SiC substrates to be device-grade in terms of mobility and crystal structure, and that their device-to-device electrical isolation properties are superior to those of bulk Si and comparable to those of SOI. Furthermore, electrical test structures on hybrid Si-on-SiC substrates exhibit vastly superior heat dissipation compared to equivalent devices on bulk Si or SOI. Specifically, the temperature rise can be as much as 102 °C lower in resistor devices made on Si-on-SiC (Tj= 191 °C) compared to on bulk Si (Tj= 293 °C) under high-power density operation (67 kW/cm2). We also describe the effects of intermediate oxide thickness on thermal resistance.

6 citations

Journal ArticleDOI
TL;DR: In this paper, annealing was applied to InAsSb epilayers with cut off wavelength of 12.5 μm by GAO et al. They reported an electron mobility of 4.83 x 10 4 cm 2 /Vs and a carrier density of 8 x 10 15 cm -3 for InAs 0.04 Sb 0.96 epilayer at 77 K.
Abstract: We have reported narrowed band gap InAsSb single crystals with cut off wavelength of 8-12 pm grown by a new method of Melt Epitaxy (ME) (GAO et al. 1999). In this paper, we firstly present the improvement of low temperature mobility of the InAsSb epilayers with cut off wavelength of 12.5 μm by annealing treatment. The electrical properties were investigated by Van der Pauw measurements at 300 K and 77 K. After an annealing treatment for 11 hours, an electron mobility of 4.83 x 10 4 cm 2 /Vs and a carrier density of 8 x 10 15 cm -3 have been obtained for an InAs 0.04 Sb 0.96 epilayer at 77 K. This is the best result so far for the InAsSb materials with cut off wavelength of 8-12 μm. The mechanism of the improvement of the electrical properties for this material after annealing treatment was studied by observing the etch pits on the surface of the sample before and after heat treatments.

6 citations

Journal ArticleDOI
Yali Liu1, Weilong Li1, Mei Qi1, X. J. Li1, Yixuan Zhou1, Zhaoyu Ren1 
TL;DR: In this paper, the authors investigated the temperature-dependent carrier transport property of the bilayer graphene, synthesized on Cu foils by a home-built chemical vapor deposition (CVD) with C 2 H 2.
Abstract: In order to investigate the temperature-dependent carrier transport property of the bilayer graphene, graphene films were synthesized on Cu foils by a home-built chemical vapor deposition (CVD) with C 2 H 2 . Samples regularity, transmittance ( T ) and layer number were analyzed by transmission electron microscope (TEM) images, transmittance spectra and Raman spectra. Van Der Pauw method was used for resistivity measurements and Hall measurements at different temperatures. The results indicated that the sheet resistance ( R s ), carrier density ( n ), and mobility ( μ ) were 1096.20 Ω/sq, 0.75×10 12 cm −2 , and 7579.66 cm 2 V −1 s −1 at room temperature, respectively. When the temperature increased from 0 °C to 240 °C, carrier density ( n ) increased from 0.66×10 12 cm −2 to 1.55×10 12 cm −2 , sheet resistance ( R s ) decreased from 1215.55 Ω/sq to 560.77 Ω/sq, and mobility ( μ ) oscillated around a constant value 7773.99 cm 2 V −1 s −1 . The decrease of the sheet resistance ( R s ) indicated that the conductive capability of the bilayer graphene film increased with the temperature. The significant cause of the increase of carrier density ( n ) was the thermal activation of carriers from defects and unconscious doping states. Because the main influence on the carrier mobility ( μ ) was the lattice defect scattering and a small amount of impurity scattering, the carrier mobility ( μ ) was temperature-independent for the bilayer graphene.

6 citations

Journal ArticleDOI
TL;DR: In this paper, electrical resistivities were measured in the range from 1.94 Ω-cm to 0.37 ǫ-cm using the lowest monomer addition and increased sintering treatment.
Abstract: Electrically conductive alumina ceramic has been successfully fabricated by sintering of dried gelcast alumina in an inert atmosphere. The process was developed similar to the conventional gelcasting method except for varying the amount of monomer in the premix solution. The sintering treatment was carried out in argon gas from 1100 °C to 1700 °C. Van der Pauw's method was used to measure the electrical resistivity. The results showed that increasing monomer addition and sintering treatment were significantly affecting in lowering electrical resistance. Using the lowest monomer addition and increased sintering treatment, the measured electrical resistivities were in the range from 1.94 Ω-cm to 0.37 Ω-cm. The material exhibited ohmic behavior and rendered two regimes of Arrhenius profile in the plot of electrical conductivity against increasing temperature from 20 °C to 600 °C. All conduction processes were governed by the presence of carbon that caused the alumina grains in polygonal morphology typical of densification. Furthermore, physical tests were conducted to describe the electrical conduction behavior of the material.

6 citations

Journal ArticleDOI
TL;DR: In this article, the surface morphology, crystalline microstructure and electrical resistivity were investigated by field-emission scanning electron microscopy, X-ray diffraction and Van der Pauw method, respectively.
Abstract: Copper agglomeration in Cu(100nm)/Ta(50urn)/Si structure deposited by ion beam deposition was examined. Copper thin films were annealed at 650°C for 1 to 60 min in hydrogen atmosphere. The surface morphology, crystalline microstructure and electrical resistivity were investigated by field-emission scanning electron microscopy, X-ray diffraction and Van der Pauw method, respectively. Experimental results revealed that nucleation and growth of voids ocurred in the copper film annealed for 5 min. Further annealing made the film a connected island structure and then isolated island structure.

6 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202328
202241
202128
202030
201960
201867