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Title: Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity

Abstract

Microstructure and composition analysis of periodic multilayer structure consisting of a low electron density contrast (EDC) material combination by grazing incidence hard X-ray reflectivity (GIXR), resonant soft X-ray reflectivity (RSXR), and transmission electron microscopy (TEM) are presented. Measurements of reflectivity at different energies allow combining the sensitivity of GIXR data to microstructural parameters like layer thicknesses and interfacing roughness, with the layer composition sensitivity of RSXR. These aspects are shown with an example of 10-period C/B{sub 4}C multilayer. TEM observation reveals that interfaces C on B{sub 4}C and B{sub 4}C on C are symmetric. Although GIXR provides limited structural information when EDC between layers is low, measurements using a scattering technique like GIXR with a microscopic technique like TEM improve the microstructural information of low EDC combination. The optical constants of buried layers have been derived by RSXR. The derived optical constants from the measured RSXR data suggested the presence of excess carbon into the boron carbide layer.

Authors:
; ; ; ;  [1];  [2];  [1]
  1. Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)
  2. (India)
Publication Date:
OSTI Identifier:
22596676
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 24; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BORON CARBIDES; CARBON; ELECTRON DENSITY; GRAZING; HARD X RADIATION; LAYERS; MICROSTRUCTURE; PERIODICITY; REFLECTIVITY; ROUGHNESS; SCATTERING; SENSITIVITY; SOFT X RADIATION; THICKNESS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Rao, P. N., E-mail: pnrao@rrcat.gov.in, Rai, S. K., Srivastava, A. K., Ganguli, T., Naik, P. A., Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400 094, and Dhawan, R. Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity. United States: N. p., 2016. Web. doi:10.1063/1.4954679.
Rao, P. N., E-mail: pnrao@rrcat.gov.in, Rai, S. K., Srivastava, A. K., Ganguli, T., Naik, P. A., Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400 094, & Dhawan, R. Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity. United States. doi:10.1063/1.4954679.
Rao, P. N., E-mail: pnrao@rrcat.gov.in, Rai, S. K., Srivastava, A. K., Ganguli, T., Naik, P. A., Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400 094, and Dhawan, R. 2016. "Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity". United States. doi:10.1063/1.4954679.
@article{osti_22596676,
title = {Microstructure and composition analysis of low-Z/low-Z multilayers by combining hard and resonant soft X-ray reflectivity},
author = {Rao, P. N., E-mail: pnrao@rrcat.gov.in and Rai, S. K. and Srivastava, A. K. and Ganguli, T. and Naik, P. A. and Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400 094 and Dhawan, R.},
abstractNote = {Microstructure and composition analysis of periodic multilayer structure consisting of a low electron density contrast (EDC) material combination by grazing incidence hard X-ray reflectivity (GIXR), resonant soft X-ray reflectivity (RSXR), and transmission electron microscopy (TEM) are presented. Measurements of reflectivity at different energies allow combining the sensitivity of GIXR data to microstructural parameters like layer thicknesses and interfacing roughness, with the layer composition sensitivity of RSXR. These aspects are shown with an example of 10-period C/B{sub 4}C multilayer. TEM observation reveals that interfaces C on B{sub 4}C and B{sub 4}C on C are symmetric. Although GIXR provides limited structural information when EDC between layers is low, measurements using a scattering technique like GIXR with a microscopic technique like TEM improve the microstructural information of low EDC combination. The optical constants of buried layers have been derived by RSXR. The derived optical constants from the measured RSXR data suggested the presence of excess carbon into the boron carbide layer.},
doi = {10.1063/1.4954679},
journal = {Journal of Applied Physics},
number = 24,
volume = 119,
place = {United States},
year = 2016,
month = 6
}
  • Soft x-ray resonant magnetic reflectivity measurements on thin films and multilayers in a {ital transverse} geometry using linear polarized photons are presented. Magneto-optic calculations taking into account the layer roughness allows us to reproduce all the experimental features of the angular and energy reflectivity curves as well as the asymmetry ratio in both cases. Application to Fe{sub x}Mn{sub 1{minus}x} alloy films epitaxially grown on Ir(001) brings more insights on the magnetic transition occurring at x=0.75. {copyright} {ital 1998 American Institute of Physics.}
  • No abstract prepared.
  • Energy dependence of the optical constants of boron carbide in the short period Ru/B4C and Mo/B4C multilayers (MLs) are evaluated from complete reflectivity scans across the boron K edge using the energy-resolved photon-in-photon-out method. Differences between the refractive indices of the B4Cmaterial inside and close to the surface are obtained from the peak profile of the first order ML Bragg peak and the reflection profile near the critical angle of total external reflection close to the surface. Where a Mo/B4C ML with narrow barrier layers appears as a homogeneous ML at all energies, a Ru/B4C ML exhibits another chemical naturemore » of boron at the surface compared to the bulk. From evaluation of the critical angle of total external reflection in the energy range between 184 and 186 eV, we found an enriched concentration of metallic boron inside the Ru-rich layer at the surface, which is not visible in other energy ranges.« less
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  • Soft x-ray reflectivity (SXR) of Cr/Sc multilayer with bilayer thickness of {lambda}=1.56 nm was increased by 100% by an intentional introduction of nitrogen during magnetron sputtering. Multilayers deposited at background pressures of {<=}2x10{sup -6} Torr exhibited amorphous layers with flat interfaces. At 2x10{sup -5} Torr, understoichiometric CrN{sub x}/ScN{sub y} multilayer with a nitrogen content of {approx}34 at. % was formed. CrN{sub x}/ScN{sub y} multilayer comprising of only 100 periods exhibited a SXR of 11.5%. X-ray and electron microscopy analyses showed that the improvement in performance is a result of reduced interfacial diffusion yielding interface widths of {<=}0.29 nm. The CrN{submore » x}/ScN{sub y} multilayer exhibited thermal stability up to >380 deg. C.« less