Real‐time extraction of growth rates from rotating substrates during molecular‐beam epitaxy
作者:
D. A. Collins,
G. O. Papa,
T. C. McGill,
期刊:
Journal of Vacuum Science&Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena
(AIP Available online 1995)
卷期:
Volume 13,
issue 5
页码: 1953-1959
ISSN:1071-1023
年代: 1995
DOI:10.1116/1.588114
出版商: American Vacuum Society
关键词: DIGITAL SYSTEMS;IMAGE PROCESSING;MOLECULAR BEAM EPITAXY;REAL TIME SYSTEMS;SUBSTRATES
数据来源: AIP
摘要:
We present a method for measuring molecular‐beam epitaxy growth rates in near real‐time on rotating substrates. This is done by digitizing a video image of the reflection high‐energy electron diffraction screen, automatically tracking and measuring the specular spot width, and using numerical techniques to filter the resulting signal. The digitization and image and signal processing take approximately 0.4 s to accomplish, so this technique offers the molecular‐beam epitaxy grower the ability to actively adjust growth times in order to deposit a desired layer thickness. The measurement has a demonstrated precision of approximately 2%, which is sufficient to allow active control of epilayer thickness by counting monolayers as they are deposited. When postgrowth techniques, such as frequency domain analysis, are also used, the reflection high‐energy electron diffraction measurement of layer thickness on rotating substrates improves to a precision of better than 1%. Since all of the components in the system described are commercially available, duplication is straightforward.
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