Ohmic contact penetration and encroachment in GaAs/AlGaAs and GaAs FETs

Goronkin, H.; Tehrani, S.; Remmel, T.; Fejes, Peter; Johnston, K.J.

doi:10.1109/16.19927

Cited by 41 publications

(13 citation statements)

References 11 publications

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“…The inhomogeneous microstructure within the top metal layer of the contact is consistent with previous studies. 7,14,15 The top is Au-rich and there are Ni-and As-rich inclusions positioned just above the interface with the GaAs. The inclusions are typically 0.1-0.5 µm in size and are well spaced apart, although the one large inclusion on the right protrudes through to the surface of the ohmic contact.…”

mentioning

confidence: 99%

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

Beauchamp

Dimitriadis

Nicholls

et al. 2020

Applied Physics Letters

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To cool a high mobility two-dimensional electron gas (2DEG) at a GaAs-AlGaAs heterojunction to milliKelvin temperatures, we have fabricated low resistance ohmic contacts based on alloys of Au, Ni and Ge. The ohmic contacts have a typical contact resistance of R C ≈ 0.8 Ω at 4.2 K, which drops to 0.2 Ω below 0.9 K. Scanning electron microscope images establish that the contacts have the same inhomogeneous microstructure that has been observed in previous studies. Measurements of the contact resistance R C , the four-terminal resistance along the top of a single contact, and the vertical resistance R V , all show that there is a superconductor in the ohmic contact which can be turned completely normal with a magnetic field of 0.15 T. We briefly discuss how this superconductivity may be affecting the electrical transport measurements of 2DEGs, especially how it may hinder the cooling of electrons in a 2DEG below 0.1 K.

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mentioning

confidence: 99%

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

Beauchamp

Dimitriadis

Nicholls

et al. 2020

Applied Physics Letters

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“…Since the diffusion rate of these alloys into GaAs crystals is very high, the gold atoms diffuse deep down into the device and hence form Ohmic regions [11]. The diffusion of these alloys, into the device layer structure, was also confirmed by a manufacturer of compound semiconductor devices [12].…”

Section: Boundary Conditionsmentioning

confidence: 94%

Hot‐electron numerical modelling of short gate length pHEMTs applied to novel field plate structures

Hussain¹,

Cole²,

Snowden³

2002

Int J Numerical Modelling

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SUMMARYHot-electron numerical simulations were carried out in order to simulate the DC parameters of pseudomorphic high electron mobility transistors (pHEMTs). The hot-electron effects were studied by simulating several HEMT device structures. Hot-carrier injection in the substrate and the formation of the peak of electric field in the channel were studied in detail. The inclusion of a field-plate contact in a multiple recessed pHEMT structure lowered the peak value of the electric field by 24% compared with the conventional pHEMT. These devices were modelled by solving the two-dimensional Poisson, current continuity and energy transport equations consistently with the time-independent Schr . o odinger wave equation. Appropriate Ohmic boundaries are discussed here and implemented in the simulations of pHEMT structures. A new integral approximation is used to calculate electron densities and electron energy densities for degenerate approximations.

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“…It is estimated to be around -0.3 i~m from literature data (4,8,9). The penetration of the alloyed contacts to the buried channel was checked on samples of type A. Measurements of the transmission lines were done before and after removal of the cap layer between the contact areas by etching.…”

Section: Methodsmentioning

confidence: 99%

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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Ohmic contact penetration and encroachment in GaAs/AlGaAs and GaAs FETs

Cited by 41 publications

References 11 publications

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

Hot‐electron numerical modelling of short gate length pHEMTs applied to novel field plate structures

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

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