Soft Reflectometer for Characterization of Thin Film Coatings

The reflectometer, enclosed within a 1.3m3 vacuum vessel, is equipped with two interchangeable x-ray sources, one with an Al target and the other with a Cu target. The operational vacuum 1e-5mbar is reached with a pump-down time of 4 hours, the ultimate pressure is 5e-8mbar.

A high direct beam intensity is delivered by the versatile KB system with Zeiss optics which provides a parallel beam 2.5mm high and 0.5mm wide for both sources. The KB optics system is optimized for Cu Kα Bragg reflection and Al Kα total external reflection, so the Al source requires the use of a flat multilayer monochromator. The source and collimating mirrors can be sealed off from the main vessel vacuum, such that the sources may be interchanged with practically no additional pump time.

A multi-sample holder situated on a x-y-z linear stage makes it straight forward to characterize many samples without breaking the vacuum.

The encoded theta and 2-theta goniometers provide the user with a wide range of scattering angles with a high resolution. For Al Kα the range of scattering angles 2q extends from 0 to 35deg whereas for the Cu Kα radiation the 2q range extends from 0 to 20deg.

The 2D detector is optimized for the detection of low energy photons, providing the capability of 6 orders of magnitude detection for both sources within 10s integration time. The detector active area is 26.6mm wide and 6.7mm high.

The vessel is equipped with 4 large viewports which provide an excellent overview of the system during operation. The custom Al target source and collimating KB mirror setup is developed together with AXO DRESDEN GmbH.