Properties of alloyed AuGeNi-contacts on GaAs/Ga/AlAs-heterostructures

Jucknischke, D.; Bühlmann, H.‐J.; Houdré, R.; Ilegems, M.; Py, M.A.; Jeckelmann, B.; Schwitz, W.

doi:10.1109/tim.1990.1032923

Cited by 17 publications

(6 citation statements)

References 6 publications

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“…Therefore, the technique used in optoelectronics devices to contact bulk GaAs was modified to take into account the presence of the AlGaAs layer and the modulation doping technique. The result is to sequentially evaporate an alloy of AuGeNi [64]. First, a layer of AuGe eutectic alloy is evaporated, then a layer of Ni, and finally a layer of Au.…”

Section: The Ohmic Contacts To the 2degmentioning

confidence: 99%

The quantum Hall effect as an electrical resistance standard

2001

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The quantum Hall effect (QHE) provides an invariant reference for resistance linked to natural constants. It is used worldwide to maintain and compare the unit of resistance. The reproducibility reached today is almost two orders of magnitude better than the uncertainty of the determination of the ohm in the International System of Units SI. This article is a summary of a recently published review article which focuses mainly on the aspects of the QHE relevant for its metrological application.

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Section: The Ohmic Contacts To the 2degmentioning

confidence: 99%

The quantum Hall effect as an electrical resistance standard

2001

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“…Contact resistances in the quantum Hall regime were well below 0.2 ~-mm for all samples tested, with the best values attained lying in the range from 0.01 to 0.02 ~-mm (19). The mechanical and electrical properties of the contacts remain stable following numerous heating and cool-down cycles.…”

Section: Resultsmentioning

confidence: 83%

“…Further measurements carried out in the quantized Hall conduction regime at temperatures of T = 1.2 and 0.3 K confirm that the conducting properties of the alloyed AuGe/Ni/Au contacts are conserved at ultralow temperatures. Contact resistances in the quantum Hall regime were well below 0.2 ~-mm for all samples tested, with the best values attained lying in the range from 0.01 to 0.02 ~-mm (19). The mechanical and electrical properties of the contacts remain stable following numerous heating and cool-down cycles.…”

Section: Resultsmentioning

confidence: 83%

Characterization of AuGe / Ni / Au Contacts on GaAs / AlGaAs Heterostructures for Low‐Temperature Applications

Bühlmann

Ilegems

1991

J. Electrochem. Soc.

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We show that the Ge-to-Ni ratio in the three-level AuGe/Ni/Au contact metallization is an important parameter which determines the value of the contact resistance. An optimum atomic ratio Xc~,./XN~ around 0.8-1.0 is found to reproducibly yield contact resistivities in the range of 10 '-10 2 ~l-mm. The role of the Ge/Ni ratio was observed for contacts to heavily doped GaAs surface layers and for contacts to A1GaAs/GaAs heterostructures used for two-dimensional electron gas (2DEG) transistors and quantum Hall resistance standards. The contacts obtained on 2DEG heterostructure samples maintain their characteristics down to the lowest temperatures tested (0.3 K), showing that this system is suitable for contacts to critical structures such as quantum Hall resistance standards used for metrological purposes.The Au-Ge/Ni/Au metallization system has been intensively investigated for its use as low-resistance ohmic contacts to n-type GaAs and other III-V compounds (1-4) and is still widely used today for the fabrication of a wide range of electronic and optoelectronic devices (5). Because of the recent interest in two-and one-dimensional transport phenomena in semiconductors, the study of the contact behavior at low temperatures has taken on new significance. The Au-Ge/Ni/Au metallization system is suitable for contacts to critical structures such as quantum Hall resistance standards used for metrological purposes at temperatures down to 0.3 K.

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“…After the lift-off procedure, the metal layers were alloyed with the heterostructure at 460°C in H/Ar ͑5:95͒ atmosphere. 19 The magnetotransport measurements were performed at low temperatures in top-loading 3 He or dilution refrigerators equipped with 8 and 12 T superconducting magnets, respectively ͑Oxford instruments͒. The magnetic field was applied perpendicular to the plane of the 2DEG.…”

Section: Methodsmentioning

confidence: 99%

Effect of the surface on the electronic properties of a two-dimensional electron gas as measured by the quantum Hall effect

et al. 2010

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The effect of the surface treatments on the transport properties of a two-dimensional electron gas was studied at the quantum limit. The surface of the Al 0.36 Ga 0.64 As/ GaAs heterostructure was either coated with gold or etched with HCl solution, or etched and then coated by a self-assembled monolayer ͑SAM͒ of either phosphonated ͑ODP-C 18 H 39 PO 3 ͒ or thiolated ͑ODT-C 18 H 37 S͒ molecules. The etching process was found to reduce significantly both the mobility and the charge density. This effect was reversed upon sequential adsorption of the phosphonated SAM. We propose fine tuning of the device performance by the flexible chemistry of the assembled molecules, two of them demonstrated here. The results indicate that the surface oxidation does not necessarily play the dominant role in this respect and, in particular, that octadecane phosphonic acid ͑ODP͒ can protect the substrate from both oxidation and the formation of a passivating carbon layer. In contrast, octadecanethiol ͑ODT͒ is not stable enough and is not effective in eliminating surface states, as a result devices covered with ODT behave like those with etched surfaces.

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Properties of alloyed AuGeNi-contacts on GaAs/Ga/AlAs-heterostructures

Cited by 17 publications

References 6 publications

The quantum Hall effect as an electrical resistance standard

The quantum Hall effect as an electrical resistance standard

Characterization of AuGe / Ni / Au Contacts on GaAs / AlGaAs Heterostructures for Low‐Temperature Applications

Effect of the surface on the electronic properties of a two-dimensional electron gas as measured by the quantum Hall effect

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