Thin film structural analysis using variable-period x-ray standing waves

DOI: 10.1103/PhysRevB.98.165402

Authors: Joshua S. Gibson (University of Nottingham) , Karen L. Syres (University of Nottingham) , Matthew Buckley (University of Nottingham) , Tien-lin Lee (Diamond Light Source) , Pardeep K. Thakur (Diamond Light Source) , Robert G. Jones (University of Nottingham)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 98 , PAGES 165402

State: Published (Approved)
Published: October 2018
Diamond Proposal Number(s): 9118

Abstract: Variable-period x-ray standing wave (VPXSW) studies have been carried out using 3 keV x rays and photoelectron detection. Two model surfaces have been used, a native SiO2 layer (20 Å thick) on bulk silicon, and a purpose-built multilayer surface comprising a chloroform/water marker layer (12 Å thick) on an ionic liquid spacer layer (211 Å thick) deposited on a SiO2/Si substrate at 90 K. By using photoelectron detection, both chemical and elemental sensitivity were achieved. The surfaces were modeled using dynamic x-ray scattering for x-ray intensity, and attenuation of photoelectrons transmitted through the layers, to produce simulations which accurately reproduced the experimental VPXSW measurements. VPXSW measurements made using the substrate, spacer layer, and marker layer photoelectron signatures produced consistent structural values. This work demonstrates that VPXSW can be used to determine chemically specific layer thicknesses within thick (300 Å) surface structures composed of the light elements B, C, N, O, F, and Cl with an accuracy of 10 to 15 Å, perpendicular to the surface.

Journal Keywords: Surface & interfacial phenomena; Surface adsorption; Multilayer thin filmsSurfaces; Hard x-ray photoelectron spectroscopy; X-ray reflectivity; X-ray standing waves

Subject Areas: Physics, Materials, Chemistry


Instruments: I09-Surface and Interface Structural Analysis