Annealing behavior of Au(Te)/n-GaAs contacts

Journal Article · Sat May 01 04:00:00 EDT 1993 · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena

DOI:https://doi.org/10.1116/1.586803· OSTI ID:147001

Piotrowska, A; Kaminska, A ^[1]; Lin, X W ^[2]

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1. Institute of Electron Technology, Warsaw (Poland)
2. Univ. of California, Berkeley, CA (United States); and others

The microstructure and electrical properties of Au/Te/Au/n-GaAs contacts annealed in the temperature range 360-480 {degrees}C, either with or without an insulating capping layer, have been investigated by the combined use of Rutherford backscattering spectrometry, x-ray diffraction, transmission electron microscopy, and current-voltage characterization. In addition, a thin-film collector method was applied to measure evaporative losses of As and Te, in view of their high volatility during heat treatment. The results give evidence that the thermally activated contact reaction strongly depends on the application of the capping layer. Contacts annealed without capping layer become ohmic at 420 {degrees}C. In the uncapped system, the contact reaction is dominated by the Au-GaAs interaction as indicated by the appearance of Au{sub 7}Ga{sub 2} phase and large arsenic losses. Moreover, tellurium is shown to partly evaporate during the heat treatment. For the sealed contacts, the losses of both Te and As are limited. Suppression of As vaporation restrains the Au-GaAs reaction, while reduction of Te sublimation activates the Te-GaAs reaction. Ga{sub 2}Te{sub 3} and As{sub 2}Te{sub 3} and As {sub 2}Te{sub 3} are the main reaction products, apart from unreacted Au. These reactions, however, do not lead to the formation of ohmic contacts to n-GaAs. Our results do not support the heterojunction model of ohmic contact, but rather testify in favor of the doping model. 36 refs., 8 figs., 2 tabs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 147001
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 3 Vol. 11; ISSN 0734-211X; ISSN JVTBD9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
ELECTRICAL PROPERTIES
GALLIUM ARSENIDES
GOLD TELLURIDES
MICROSTRUCTURE
TELLURIUM
TRANSMISSION ELECTRON MICROSCOPY
VOLATILITY
X-RAY DIFFRACTION