A quick convergent-beam laboratory X-ray reflectometer using a simultaneous multiple-angle dispersive geometry

Area of Science:

• Materials Science
• Surface Science
• Analytical Chemistry

Background:

• Accurate characterization of thin films and surfaces is crucial for materials development.
• Traditional X-ray reflectivity methods can be time-consuming and limited by diffuse scattering.
• Need for rapid, sensitive techniques for analyzing material interfaces.

Purpose of the Study:

• To present a novel laboratory X-ray reflectometer for quick specular X-ray reflectivity measurements.
• To demonstrate the instrument's capability for accurate measurement of low reflectivities.
• To showcase time-resolved reflectivity measurements.

Main Methods:

• Utilized a bent-twisted crystal to monochromatize and focus diverging X-rays (Cu Kα1) from a laboratory point source.
• Employed a two-dimensional detector to record reflected X-rays.
• Developed a method to separate specularly reflected X-rays from diffuse scattering background without instrument rotation.

Main Results:

• Achieved reflectivity measurements down to 10⁻⁶ for a gold thin film on silicon within 100 seconds.
• Demonstrated accurate measurement of low reflectivities (down to 10⁻⁵ in 10 seconds).
• Successfully measured reflectivity curves for silicon wafers, liquid ethylene glycol, and performed time-resolved measurements on a TiO₂ surface during UV irradiation.

Conclusions:

• The developed X-ray reflectometer offers a fast and accurate method for specular reflectivity analysis.
• The instrument's ability to suppress diffuse scattering enables precise measurements of low reflectivities.
• The system is suitable for various applications, including thin film characterization and in-situ surface studies.