Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation

Eero Ristolainen, M. Puga-Lambers, B. Panthanay, Xia Holloway, Hannu Ronkainen, J. Saarilahti, V. Fisher, Kim Holloway

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.
Original languageEnglish
Pages (from-to)1419-1421
Number of pages3
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume12
Issue number3
DOIs
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

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Ohmic contacts
Passivation
Desorption
Vacuum
Sulfur
Oxides
Thermal evaporation
Carrier concentration
Spectroscopy
Annealing
Ions
Substrates
Air
Metals
Temperature

Cite this

Ristolainen, Eero ; Puga-Lambers, M. ; Panthanay, B. ; Holloway, Xia ; Ronkainen, Hannu ; Saarilahti, J. ; Fisher, V. ; Holloway, Kim. / Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation. In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures. 1994 ; Vol. 12, No. 3. pp. 1419-1421.
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title = "Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation",
abstract = "Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.",
author = "Eero Ristolainen and M. Puga-Lambers and B. Panthanay and Xia Holloway and Hannu Ronkainen and J. Saarilahti and V. Fisher and Kim Holloway",
year = "1994",
doi = "10.1116/1.587311",
language = "English",
volume = "12",
pages = "1419--1421",
journal = "Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics",
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Ristolainen, E, Puga-Lambers, M, Panthanay, B, Holloway, X, Ronkainen, H, Saarilahti, J, Fisher, V & Holloway, K 1994, 'Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation', Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 12, no. 3, pp. 1419-1421. https://doi.org/10.1116/1.587311

Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation. / Ristolainen, Eero; Puga-Lambers, M.; Panthanay, B.; Holloway, Xia; Ronkainen, Hannu; Saarilahti, J.; Fisher, V.; Holloway, Kim.

In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 12, No. 3, 1994, p. 1419-1421.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation

AU - Ristolainen, Eero

AU - Puga-Lambers, M.

AU - Panthanay, B.

AU - Holloway, Xia

AU - Ronkainen, Hannu

AU - Saarilahti, J.

AU - Fisher, V.

AU - Holloway, Kim

PY - 1994

Y1 - 1994

N2 - Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.

AB - Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.

U2 - 10.1116/1.587311

DO - 10.1116/1.587311

M3 - Article

VL - 12

SP - 1419

EP - 1421

JO - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics

JF - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics

SN - 2166-2746

IS - 3

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