A study of the vacancy-defect distribution in a GaAs/AlxGa1-xAs multi-layer structure grown at low temperature

S. Fleischer, C. Surya, Y. F. Hu, C. D. Beling, S. Fung, T. L. Smith, K. M. Moulding, M. Missous

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We have grown a multilayer structure of GaAs and AlxGa1-xAs (x = 0.25) by molecular beam epitaxy at low substrate temperature (250°C) in order to investigate the effects of annealing on arsenic precipitation and vacancy-defect formation. The as-grown heterostructure contained ∼5 × 1017 cm-3 gallium vacancies, but information about the individual layers was lost because the layer width ( ∼ 45 nm) was smaller than the average positron diffusion length ( ∼ 70 nm). Annealing at 500 and 600°C showed increases in the S-parameter (above the bulk value) of ∼2.5% and ∼1.5%, respectively, smaller than for a single LT-GaAs layer (∼3-4%). We explain this phenomenon by suggesting that the excess arsenic which migrates from the material with the higher precipitate/matrix energy (LT-AlxGa1-xAs) reduces the gallium vacancy concentration in the LT-GaAs and hence the S-parameter. This hypothesis is supported by SIMS data which shows a build-up of As in the LT-GaAs layers, and TEM images which indicate that arsenic precipitation occurs to a greater extent in the LT-GaAs than in the LT-AlxGa1-xAs.

Original languageEnglish
Pages (from-to)53-61
Number of pages9
JournalJournal of Crystal Growth
Volume196
Issue number1
DOIs
Publication statusPublished - Jan 1 1999
Externally publishedYes

Fingerprint

Arsenic
laminates
Vacancies
Scattering parameters
arsenic
Gallium
Defects
defects
Annealing
gallium
Positrons
Secondary ion mass spectrometry
Molecular beam epitaxy
Temperature
annealing
Heterojunctions
Precipitates
Multilayers
diffusion length
secondary ion mass spectrometry

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

A study of the vacancy-defect distribution in a GaAs/AlxGa1-xAs multi-layer structure grown at low temperature. / Fleischer, S.; Surya, C.; Hu, Y. F.; Beling, C. D.; Fung, S.; Smith, T. L.; Moulding, K. M.; Missous, M.

In: Journal of Crystal Growth, Vol. 196, No. 1, 01.01.1999, p. 53-61.

Research output: Contribution to journalArticle

Fleischer, S. ; Surya, C. ; Hu, Y. F. ; Beling, C. D. ; Fung, S. ; Smith, T. L. ; Moulding, K. M. ; Missous, M. / A study of the vacancy-defect distribution in a GaAs/AlxGa1-xAs multi-layer structure grown at low temperature. In: Journal of Crystal Growth. 1999 ; Vol. 196, No. 1. pp. 53-61.
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AU - Beling, C. D.

AU - Fung, S.

AU - Smith, T. L.

AU - Moulding, K. M.

AU - Missous, M.

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