Positron studies of arsenic precipitation in low-temperature GaAs grown by molecular beam epitaxy

S. Fleischer, C. Surya, Y. F. Hu, C. D. Beling, S. Fung, M. Missous

Research output: Contribution to conferencePaper

Abstract

Gallium arsenide grown at low substrate temperature by molecular beam epitaxy has been studied using a variable-energy slow positron beam. As-grown LT-GaAs was found to have a higher concentration of vacancy-related defects (approximately 1017 cm-3) than the semi-insulating substrate. After annealing at 600 °C, the positron S parameter results suggest the formation of clusters which we associate with arsenic precipitation. The lowering of the S parameter at the surface was thought to be due to oxygen and this was confirmed by XPS measurements. For the first time, we have examined aluminum delta-layers using a positron beam and found that the Al-layers can be resolved to depths of at least 1700 angstroms by this method. The lowering of the S parameter after annealing would suggest that the Al forms AlxGa1-xAs, and that the presence of the Al layers may inhibit the diffusion of arsenic, thereby reducing the formation of vacancy-defects.

Original languageEnglish
Pages123-127
Number of pages5
Publication statusPublished - Dec 1 1997
Externally publishedYes
EventProceedings of the 1997 IEEE Hong Kong Electron Devices Meeting - Hong Kong, Hong Kong
Duration: Aug 30 1997Aug 30 1997

Conference

ConferenceProceedings of the 1997 IEEE Hong Kong Electron Devices Meeting
CityHong Kong, Hong Kong
Period8/30/978/30/97

ASJC Scopus subject areas

  • Engineering(all)

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    Fleischer, S., Surya, C., Hu, Y. F., Beling, C. D., Fung, S., & Missous, M. (1997). Positron studies of arsenic precipitation in low-temperature GaAs grown by molecular beam epitaxy. 123-127. Paper presented at Proceedings of the 1997 IEEE Hong Kong Electron Devices Meeting, Hong Kong, Hong Kong, .