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Device for Accurately Fixing Extremely Thin Measuring Samples for X-Ray Fluorescence

IP.com Disclosure Number: IPCOM000036613D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 94K

Publishing Venue

IBM

Related People

Hoffmeister, W: AUTHOR [+3]

Abstract

X-ray fluorescence (XRF) is used to effectively determine the elements/ composition and/or thickness of evaporated metal films. A problem arising with very thin films of, say, 10 to 100 nm, is a background signal which is unfavorably high compared with the low signal resulting from such films. Normally, the KaI lines are used to determine the elements/composition and/or thickness. For this purpose, the substrates on which the thin films are evaporated for testing have to be as thin as possible (using, for example, aluminum foils of a thickness of some m).

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Device for Accurately Fixing Extremely Thin Measuring Samples for X-Ray Fluorescence

X-ray fluorescence (XRF) is used to effectively determine the elements/ composition and/or thickness of evaporated metal films. A problem arising with very thin films of, say, 10 to 100 nm, is a background signal which is unfavorably high compared with the low signal resulting from such films. Normally, the KaI lines are used to determine the elements/composition and/or thickness. For this purpose, the substrates on which the thin films are evaporated for testing have to be as thin as possible (using, for example, aluminum foils of a thickness of some
m).

For measurement, these foils are fixed in a sample holder A in a plane parallel fashion for maximum reproducibility. For determining elements with a low atomic number, such as Si or P, the foils are analyzed in a vacuum or in a helium atmosphere. This leads to great mechanical stress and even rupture of the foil in the XRF spectrometer.

To avoid such unwanted effects, a device in the form of a cross has been developed which is made of ultrapure aluminum with a TEFLON* coating. The edges of the cross retain the aluminum foils in the sample holder and additionally ensure planarity. The advantage of such a cross-type device over a cylinder, which would also be suitable for this purpose, is that the area required for accurately fixing the foils is reduced. As a result, there is a lower background signal and thus a higher degree of a...