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Title: Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements

Abstract

W/C/W tri-layer thin film samples have been deposited on c-Si substrates in a home-built Ion Beam Sputtering system at 1.5 × 10{sup −3} Torr Ar working pressure and 10 mA grid current. The tri-layer samples have been deposited at different Ar{sup +} ion energies between 0.6 and 1.2 keV for W layer deposition and the samples have been characterized by specular and non-specular grazing incidence X-ray reflectivity (GIXR) measurements. By analyzing the GIXR spectra, various interface parameters have been obtained for both W-on-C and C-on-W interfaces and optimum Ar{sup +} ion energy for obtaining interfaces with low imperfections has been found. Subsequently, multilayer W/C samples with 5-layer, 7-layer, 9-layer, and 13-layer have been deposited at this optimum Ar{sup +} ion energy. By fitting the specular and diffused GIXR data of the multilayer samples with the parameters of each interface as fitting variables, different interface parameters, viz., interface width, in-plane correlation length, interface roughness, and interface diffusion have been estimated for each interface and their variation across the depth of the multilayers have been obtained. The information would be useful in realizing W/C multilayers for soft X-ray mirror application in the <100 Å wavelength regime. The applicability of the “restart of the growth at themore » interface” model in the case of these ion beam sputter deposited W/C multilayers has also been investigated in the course of this study.« less

Authors:
; ;  [1]; ; ;  [2];  [3]
  1. Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
  2. Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, VIZAG Centre, Visakhapatnam 530012 (India)
  3. Indus Synchrotron Utilization Division, Raja Raman Centre for Advanced Technology, Indore 452013 (India)
Publication Date:
OSTI Identifier:
22492876
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARGON IONS; CORRELATIONS; DEPOSITION; DEPTH; DIFFUSION; INTERFACES; ION BEAMS; KEV RANGE 01-10; LAYERS; REFLECTIVITY; SOFT X RADIATION; SPUTTERING; SUBSTRATES; THIN FILMS; WAVELENGTHS

Citation Formats

Biswas, A., E-mail: arupb@barc.gov.in, Bhattacharyya, D., Sahoo, N. K., Maidul Haque, S., Tripathi, S., De, Rajnarayan, and Rai, S. Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements. United States: N. p., 2015. Web. doi:10.1063/1.4934746.
Biswas, A., E-mail: arupb@barc.gov.in, Bhattacharyya, D., Sahoo, N. K., Maidul Haque, S., Tripathi, S., De, Rajnarayan, & Rai, S. Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements. United States. doi:10.1063/1.4934746.
Biswas, A., E-mail: arupb@barc.gov.in, Bhattacharyya, D., Sahoo, N. K., Maidul Haque, S., Tripathi, S., De, Rajnarayan, and Rai, S. Wed . "Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements". United States. doi:10.1063/1.4934746.
@article{osti_22492876,
title = {Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements},
author = {Biswas, A., E-mail: arupb@barc.gov.in and Bhattacharyya, D. and Sahoo, N. K. and Maidul Haque, S. and Tripathi, S. and De, Rajnarayan and Rai, S.},
abstractNote = {W/C/W tri-layer thin film samples have been deposited on c-Si substrates in a home-built Ion Beam Sputtering system at 1.5 × 10{sup −3} Torr Ar working pressure and 10 mA grid current. The tri-layer samples have been deposited at different Ar{sup +} ion energies between 0.6 and 1.2 keV for W layer deposition and the samples have been characterized by specular and non-specular grazing incidence X-ray reflectivity (GIXR) measurements. By analyzing the GIXR spectra, various interface parameters have been obtained for both W-on-C and C-on-W interfaces and optimum Ar{sup +} ion energy for obtaining interfaces with low imperfections has been found. Subsequently, multilayer W/C samples with 5-layer, 7-layer, 9-layer, and 13-layer have been deposited at this optimum Ar{sup +} ion energy. By fitting the specular and diffused GIXR data of the multilayer samples with the parameters of each interface as fitting variables, different interface parameters, viz., interface width, in-plane correlation length, interface roughness, and interface diffusion have been estimated for each interface and their variation across the depth of the multilayers have been obtained. The information would be useful in realizing W/C multilayers for soft X-ray mirror application in the <100 Å wavelength regime. The applicability of the “restart of the growth at the interface” model in the case of these ion beam sputter deposited W/C multilayers has also been investigated in the course of this study.},
doi = {10.1063/1.4934746},
journal = {Journal of Applied Physics},
number = 16,
volume = 118,
place = {United States},
year = {Wed Oct 28 00:00:00 EDT 2015},
month = {Wed Oct 28 00:00:00 EDT 2015}
}
  • Using synchrotron grazing-incidence X-ray diffraction (GIXD) and reflectivity (XR), the authors have determined the in-plane and out-of-plane structure of phospholipid monolayers at the air-water interface as a function of hydrophilic lipid headgroup size. Di-stearoyl-phosphatidyl-ethanolamine (DSPE) lipid monolayers were systematically modified by chemically grafting hydrophilic poly(ethylene glycol) (PEG) chains of MW = 90 g/mol (2 ethylene oxide, EO, units), MW = 350 g/mol (8 EO units), and MW = 750 g/mol (17 EO units) to the lipid headgroups. The monolayers were studied in the solid phase at a surface pressure of 42 mN/m. At these high lipid packing densities, the PEGmore » chains are submerged in the water subphase. The increased packing stresses from these bulky polymer headgroups distort the unit cell and the in-plane packing modes of the monolayers, leading to large out-of-plane alterations and staggering of the lipid molecules. Surprisingly, a change in the molecular packing of the monolayer toward higher packing densities (lower area per molecule) was observed on increasing the PEG MW to 750 g/mol (17 EO units). This rearrangement of the monolayer structure may be due to a conformational change in the PEG chains.« less
  • W/Si multilayers four samples have been deposited on silicon substrate using ion beam sputtering system. Thickness of tungsten (W) varies from around 10 Å to 40 Å while the silicon (Si) thickness remains constant at around 30 Å in multilayers [W-Si]{sub x4}. The samples have been characterized by grazing incidence X-ray diffraction (GIXRD) and X-ray reflectivity technique (XRR). GIXRD study shows the crystalline behaviour of W/Si multilayer by varying W thickness and it is found that above 20 Å the W film transform from amorphous to crystalline phase and X-ray reflectivity data shows that the roughnesses of W increases onmore » increasing the W thicknesses in W/Si multilayers.« less
  • No abstract prepared.
  • A new multipurpose x-ray reflectometer station has been developed and augmented at the microfocus beamline (BL-16) of Indus-2 synchrotron radiation source to facilitate synchronous measurements of specular x-ray reflectivity and grazing incidence x-ray fluorescence emission from thin layered structures. The design and various salient features of the x-ray reflectometer are discussed. The performance of the reflectometer has been evaluated by analyzing several thin layered structures having different surface interface properties. The results reveal in-depth information for precise determination of surface and interface properties of thin layered materials demonstrating the immense potential of the combined measurements of x-ray reflectivity and grazingmore » incidence fluorescence on a single reflectometer.« less