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

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

^*Corresponding author for this work

Hong Kong Polytechnic University

Research output: Contribution to conference › Paper › peer-review

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 Al_xGa_1-xAs, and that the presence of the Al layers may inhibit the diffusion of arsenic, thereby reducing the formation of vacancy-defects.

Original language	English
Pages	123-127
Number of pages	5
Publication status	Published - 1 Dec 1997
Event	Proceedings of the 1997 IEEE Hong Kong Electron Devices Meeting - Hong Kong, Hong Kong Duration: 30 Aug 1997 → 30 Aug 1997

Conference

Conference	Proceedings of the 1997 IEEE Hong Kong Electron Devices Meeting
City	Hong Kong, Hong Kong
Period	30/08/97 → 30/08/97

Cite this

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title = "Positron studies of arsenic precipitation in low-temperature GaAs grown by molecular beam epitaxy",

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.",

author = "S. Fleischer and C. Surya and Hu, {Y. F.} and Beling, {C. D.} and S. Fung and M. Missous",

year = "1997",

month = dec,

day = "1",

language = "English",

pages = "123--127",

note = "Proceedings of the 1997 IEEE Hong Kong Electron Devices Meeting ; Conference date: 30-08-1997 Through 30-08-1997",

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TY - CONF

T1 - Positron studies of arsenic precipitation in low-temperature GaAs grown by molecular beam epitaxy

AU - Fleischer, S.

AU - Surya, C.

AU - Hu, Y. F.

AU - Beling, C. D.

AU - Fung, S.

AU - Missous, M.

PY - 1997/12/1

Y1 - 1997/12/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=0031346116&partnerID=8YFLogxK

M3 - Paper

AN - SCOPUS:0031346116

SP - 123

EP - 127

T2 - Proceedings of the 1997 IEEE Hong Kong Electron Devices Meeting

Y2 - 30 August 1997 through 30 August 1997

ER -

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

Abstract

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