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System for monitoring the growth of crystalline films on stationary substrates

United States Patent

5,588,995
December 31, 1996
View the Complete Patent at the US Patent & Trademark Office
National Renewable Energy Laboratory - Visit the NREL Technology Transfer Website
A system for monitoring the growth of crystalline films on stationary or rotating substrates includes a combination of some or all of the elements including a photodiode sensor for detecting the intensity of incoming light and converting it to a measurable current, a lens for focusing the RHEED pattern emanating from the phosphor screen onto the photodiode, an interference filter for filtering out light other than that which emanates from the phosphor screen, a current amplifier for amplifying and convening the current produced by the photodiode into a voltage, a computer for receiving the amplified photodiode current for RHEED data analysis, and a graphite impregnated triax cable for improving the signal to noise ratio obtained while sampling a stationary or rotating substrate. A rotating stage for supporting the substrate with diametrically positioned electron beam apertures and an optically encoded shaft can also be used to accommodate rotation of the substrate during measurement.
Sheldon; Peter (Lakewood, CO)
Midwest Research Institute (Kansas City, MI)
08/ 434,181
May 3, 1995
CONTRACTUAL ORIGIN OF THE INVENTION The United States Government has rights in this invention under Contract No. DE-AC0283CH10093 between the U.S. Department of Energy and the National Renewable Energy Laboratory, a Division of Midwest Research Institute.