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Title: The role of proximity caps during the annealing of UV-ozone oxidized GaAs

Abstract

This study provides a deeper insight into the chemistry and physics of the common engineering practice of using a proximity cap, while annealing compound semiconductors such as GaAs. We have studied the cases of a GaAs proximity cap, a Si proximity cap, and no proximity cap. Using x-ray photoelectron spectroscopy, it has been found that annealing increases the gallium to arsenic ratio in the oxide layer in all cases. During the annealing of UV-ozone oxidized GaAs, it has been observed that GaAs proximity caps also serve as a sacrificial layer to accelerate the desorption of oxide species. In all cases surface deterioration due to pit formation has been observed, and the depth of pits is found to depend on the effective role played by the capping material. Energy dispersive x-ray analysis provides additional evidence that pits mainly consist of elemental As and gallium oxide, with most of the elemental As situated at the pit-substrate interface. Deposition of a thin layer of gold and subsequent annealing to 500 deg. C for 300 s under different capping conditions shows the use of a proximate cap to be practically insignificant in annealing Au deposited films.

Authors:
; ; ;  [1];  [2];  [2];  [3]
  1. Center for Emerging Device Technologies, Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)
  2. (Canada)
  3. (Canada) and Center for Emerging Device Technologies, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)
Publication Date:
OSTI Identifier:
20979422
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 11; Other Information: DOI: 10.1063/1.2740359; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; ARSENIC; CHEMICAL ANALYSIS; DEPOSITION; DESORPTION; GALLIUM; GALLIUM ARSENIDES; GALLIUM OXIDES; GOLD; LAYERS; OXIDATION; OZONE; SEMICONDUCTOR MATERIALS; SILICON; SUBSTRATES; THIN FILMS; X RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Ghosh, S. C., Biesinger, M. C., LaPierre, R. R., Kruse, P., Surface Science Western, Room G-1, Western Science Center, University of Western Ontario, London, Ontario N6A 5B7, Center for Emerging Device Technologies, Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, and Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1. The role of proximity caps during the annealing of UV-ozone oxidized GaAs. United States: N. p., 2007. Web. doi:10.1063/1.2740359.
Ghosh, S. C., Biesinger, M. C., LaPierre, R. R., Kruse, P., Surface Science Western, Room G-1, Western Science Center, University of Western Ontario, London, Ontario N6A 5B7, Center for Emerging Device Technologies, Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, & Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1. The role of proximity caps during the annealing of UV-ozone oxidized GaAs. United States. doi:10.1063/1.2740359.
Ghosh, S. C., Biesinger, M. C., LaPierre, R. R., Kruse, P., Surface Science Western, Room G-1, Western Science Center, University of Western Ontario, London, Ontario N6A 5B7, Center for Emerging Device Technologies, Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, and Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1. Fri . "The role of proximity caps during the annealing of UV-ozone oxidized GaAs". United States. doi:10.1063/1.2740359.
@article{osti_20979422,
title = {The role of proximity caps during the annealing of UV-ozone oxidized GaAs},
author = {Ghosh, S. C. and Biesinger, M. C. and LaPierre, R. R. and Kruse, P. and Surface Science Western, Room G-1, Western Science Center, University of Western Ontario, London, Ontario N6A 5B7 and Center for Emerging Device Technologies, Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 and Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1},
abstractNote = {This study provides a deeper insight into the chemistry and physics of the common engineering practice of using a proximity cap, while annealing compound semiconductors such as GaAs. We have studied the cases of a GaAs proximity cap, a Si proximity cap, and no proximity cap. Using x-ray photoelectron spectroscopy, it has been found that annealing increases the gallium to arsenic ratio in the oxide layer in all cases. During the annealing of UV-ozone oxidized GaAs, it has been observed that GaAs proximity caps also serve as a sacrificial layer to accelerate the desorption of oxide species. In all cases surface deterioration due to pit formation has been observed, and the depth of pits is found to depend on the effective role played by the capping material. Energy dispersive x-ray analysis provides additional evidence that pits mainly consist of elemental As and gallium oxide, with most of the elemental As situated at the pit-substrate interface. Deposition of a thin layer of gold and subsequent annealing to 500 deg. C for 300 s under different capping conditions shows the use of a proximate cap to be practically insignificant in annealing Au deposited films.},
doi = {10.1063/1.2740359},
journal = {Journal of Applied Physics},
number = 11,
volume = 101,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • The effects of thermal annealing on GaInAs/GaAs and GaInAsN/GaAs quantum wells, grown by molecular beam epitaxy, were investigated. Optical and structural properties were examined upon annealing when the samples had a 200 nm thick SiO{sub 2} cap layer, or were placed in a so-called GaAs box or were left uncapped. The GaAs box gave rise to the strongest photoluminescence without significant blueshift or structural changes at moderate annealing temperature. Capping with SiO{sub 2} impaired the samples and caused a more pronounced blueshift for the GaInAs quantum wells than for the GaInAsN ones. These results consolidate our understanding of the blueshiftmore » mechanisms.« less
  • No abstract prepared.
  • The effect of postgrowth rapid thermal annealing (RTA) on GaAs proximity-capped structures with self-assembled InAs/GaAs quantum dots (QDs) is investigated using transmission electron microscopy (TEM) and photoluminescence (PL). As can be seen from the TEM images, QDs increase their lateral sizes with increasing annealing temperature (up to 700 C). QDs cannot be distinguished after RTA at temperature 800 C or higher, and substantial thickening of the wetting layer can be seen instead. The main PL peak blueshifts as a result of RTA. We propose that in the as-grown sample as well, as in samples annealed at temperatures up to 700more » C, the peak is due to the QDs. After RTA at 800 C and higher the PL peak is due to a modified wetting layer. Relatively fast dissolution of QDs is explained in terms of strain-induced lateral Ga/In interdiffusion. It is proposed that such a process may be of importance in proximity-capped RTA, when no group-III vacancy formation takes place at the sample/capping interface.« less
  • We have investigated the redox reaction on the surface of Ta/CoFeB/MgO/CoFeB magnetic tunnel junction stack samples after annealing at 300, 350, and 400 °C for 1 h using angle-resolved X-ray photoelectron spectroscopy for precise analysis of the chemical bonding states. At a capping tantalum layer thickness of 1 nm, both the capping tantalum layer and the surface of the underneath CoFeB layer in the as-deposited stack sample were naturally oxidized. By comparison of the Co 2p and Fe 2p spectra among the as-deposited and annealed samples, reduction of the naturally oxidized cobalt and iron atoms occurred on the surface of the CoFeB layer.more » The reduction reaction was more significant at higher annealing temperature. Oxidized cobalt and iron were reduced by boron atoms that diffused toward the surface of the top CoFeB layer. A single CoFeB layer was prepared on SiO{sub 2}, and a confirmatory evidence of the redox reaction with boron diffusion was obtained by angle-resolved X-ray photoelectron spectroscopy analysis of the naturally oxidized surface of the CoFeB single layer after annealing. The redox reaction is theoretically reasonable based on the Ellingham diagram.« less
  • No abstract prepared.