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Browse Prior Art Database

Digital Diffraction Pattern Processor

IP.com Disclosure Number: IPCOM000102510D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Cline, C: AUTHOR [+6]

Abstract

As molecular-beam epitaxy (MBE) is currently practiced, reflection high-energy electron diffraction (RHEED) patterns are used to calibrate growth rates, determine the surface atomic configuration, and monitor the dynamic changes at the growth surface. To improve uniformity the substrate is rotated during growth. However, rotation must be stopped for RHEED pattern observation. Stopping rotation can result in uneven heating of the substrate and nonuniform layer growth (particularly doping and composition inhomogeneities). Therefore, it is highly desirable to be able to monitor RHEED patterns while the substrate is rotating.

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Digital Diffraction Pattern Processor

       As molecular-beam epitaxy (MBE) is currently practiced,
reflection high-energy electron diffraction (RHEED) patterns are used
to calibrate growth rates, determine the surface atomic
configuration, and monitor the dynamic changes at the growth surface.
To improve uniformity the substrate is rotated during growth.
However, rotation must be stopped for RHEED pattern observation.
Stopping rotation can result in uneven heating of the substrate and
nonuniform layer growth (particularly doping and composition
inhomogeneities).  Therefore, it is highly desirable to be able to
monitor RHEED patterns while the substrate is rotating.

      Using a high-sensitivity video camera coupled with a computer-
controlled image acquisition system to process the RHEED pattern
images one could transform the information from the rotating
substrate to a static pattern displayed on a video monitor.  With
such a system the intensity of the specular beam spot or any other
spot could be integrated over a selected area and plotted in real
time, and saved images could be stored for reference by simply
pressing a hot key.  Because real-time processing of diffraction
patterns and images (bright and dark field) is important to electron
microscopy, this system (in its most general configuration) could
have a wide variety of applications. The capabilities would include:
the ability to define a window for capturing at least 10 frames
during a one or two...