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Fourier Transformation of X-Ray Rocking Curves from Interferometer Structures

Published online by Cambridge University Press:  06 March 2019

J. M. Hudson ,
B. K. Tanner  and
R. Blunt
J. M. Hudson
Affiliation:
Physics Department, Durham University, South Road, Durham, U.K.
B. K. Tanner
Affiliation:
Physics Department, Durham University, South Road, Durham, U.K.
R. Blunt
Affiliation:
Epitaxial Products International, Cypress Drive, St. Mellons Cardiff, U.K.
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Abstract

We discuss the use of Fourier transform techniques to extract layer thickness from the interference fringes observed in high resolution X-ray diffraction rocking curves of pseudomorphic HEMT structures. The interference structure is extracted by cubic spline fitting to the extrema of the data, thereby obtaining a background envelope which is used to normalise the data. The resulting constant background is subtracted from the data and the residual Fourier transformed. Auto correlation of the residual significantly improves the result from noisy data. Satisfactory results are obtained only when the Bragg peak from the substrate is windowed out. With a limited dynamic and angular range, there is often insufficient data to separate the two closely spaced periods arising from the total layer thickness and that excluding the quantum well. The result then corresponds to the average of these two thicknesses.

Type
Research Article
Information
Advances in X-Ray Analysis , Volume 37: Forty-Second Annual Conference on Applications of X-ray Analysis, August 2-6, 1993 , 1993 , pp. 135 - 144
Copyright
Copyright © International Centre for Diffraction Data 1993

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