Abstract
Thick (>150 μm) beryllium coatings are studied as an ablator material of interest for fusion fuel capsules for the National Ignition Facility. DC magnetron sputtering is used because of the relative controllability of the processing temperature and energy of the deposits. However, coatings produced by DC magnetron sputtering leak the fuel gas D2. By using ion-assisted DC magnetron, sputtered coatings can be made that are leak-tight. Transmission electron microscopy (TEM) studies revealed microstructural changes that lead to leak-tight coating. Ultrasmall angle x-ray spectroscopy is used to characterize the void distribution and volume along the spherical surface along with a combination of focused ion beam, scanning electron microscope, and TEM. An in situ multibeam optical stress sensor was used to measure the stress behavior of thick beryllium coatings on flat substrates as the material was being deposited.
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S.W. Haan, D.A. Callahan, M.J. Edwards, B.A. Hammel, D.D. Ho, O.S. Jones, J.D. Lindl, B.J. Macgowan, M.M. Marinak, D.H. Munro, S.M. Pollaine, J.D. Salmonson, B.K. Spears, and L.J. Suter: Rev3 update of requirements for NIF ignition targets. Fusion Sci. Technol. 55, 227 (2009).
R. Mceachern, C. Alford, R. Cook, D. Makowcki, and R. Wallace: Sputter-deposited Be ablators for NIF target capsules. Fusion Technol. 31, 435 (1997).
H.W. Xu, A. Nikroo, J.R. Wall, R. Doerner, M. Baldwin, and J.H. Yu: Be coating on spherical surface for NIF target development. Fusion Sci. Technol. 49, 778 (2006).
H.W. Xu, C.S. Alford, J.C. Cooley, L.A. Dixon, R.E. Hackenberg, S.A. Letts, K.A. Moreno, A. Nikroo, J.R. Wall, and K.P. Youngblood: Beryllium capsule coating development for NIF targets. Fusion Sci. Technol. 51, 547 (2007).
A. Nikroo, H.W. Xu, K.A. Moreno, K.P. Youngblood, J. Cooley, C.S. Alford, S.A. Letts, and R.C. Cook: Investigation of deuterium permeability of sputtered beryllium and graded copper-doped beryllium shells. Fusion Sci. Technol. 51, 553 (2007).
K. Robbie and M.J. Brett: Sculptured thin films and glancing angle deposition: Growth mechanisms and applications. J. Vac. Sci. Technol. A 15(3), 1460 (1997).
J. Dalla Torre, G.H. Gilmer, D.L. Windt, R. Kalyanaraman, F.H. Baumann, P.L. O’Sullivan, J. Sapjeta, T. Diaz de la Rubia, and M. Djafari Rouhani: Microstructure of thin tantalum films sputtered onto inclined substrates: Experiments and atomistic simulations. J. Appl. Phys. 94, 264 (2003).
J.A. Thornton: High rate thick film growth. Annu. Rev. Mater. Sci. 7, 239 (1977).
U. Helmersson, M. Lattemann, J. Bohlmark, A.P. Ehiasarian, and J.T. Gudmudsson: Ionized physical vapor deposition (IPVD): A review of technology and applications. Thin Solid Films 513, 1 (2006).
K. Tao, D. Mao, and J. Hopwood: Ionized physical vapor deposition of titanium nitride: A global plasma model. J. Appl. Phys. 91, 4040 (2002).
J. Hopwood: Ionized physical vapor deposition of integrated circuit interconnects. Phys. Plasmas 5, 1624 (1998).
D.R. Juliano, D.N. Ruzic, M.M.C. Allain, and D.B. Hayden: Influences on ionization fraction in an inductively coupled ionized physical vapor deposition device plasma. J. Appl. Phys. 91, 605 (2002).
V. Arunachalam, S. Rauf, D.G. Coronell, and P.L.G. Ventzek: Integrated multi-scale model for ionized plasma physical vapor deposition. J. Appl. Phys. 90, 64 (2001).
E. Chason, B.W. Sheldon, L.B. Freund, J.A. Floro, and S.J. Hearne: Origin of compressive residual stress in polycrystalline thin films. Phys. Rev. Lett. 88, 156103 (2002).
C. Friesen and C.V. Thompson: Reversible stress relaxation during precoalescence interruptions of Volmer-Weber thin film growth. Phys. Rev. Lett. 89, 126103 (2002).
B.W. Sheldon, K.H.A. Lau, and A. Rajamani: Intrinsic stress, island coalescence, and surface roughness during the growth of polycrystalline films. J. Appl. Phys. 90, 5097 (2001).
S.C. Seel and C.V. Thompson: Tensile stress generation during island coalescence for variable island-substrate contact angles. J. Appl. Phys. 93, 9038 (2003).
A. Detor, A. Hodge, E. Chason, Y. Wang, H. Xu, M. Conyers, A. Nikroo, and A. Hamza: Stress and microstructure evolution in thick sputtered films. Acta Mater. 57, 2055 (2009).
E.L. Alfonso, J.S. Jaquez, and A. Nikroo: Gas permeation barrier characterization by mass spectrometry. Fusion Sci. Technol. 49, 773 (2006).
J. Ilavsky and P.R. Jemian: Irena: Tool suite for modeling and analysis of small-angle scattering. J. Appl. Crystallogr. 42, 347 (2009).
L.B. Freund and S. Suresh: Thin film materials: Stress, defect formation, and surface evolution (Cambridge University Press, Cambridge, 2003).
K. Okimura and T. Nakamura: Ionic densities and ionization fractions of sputtered titanium in radio frequency magnetron sputtering. J. Vac. Sci. Technol. A 21, 988 (2003).
S.M. Rossnagel and J. Hopwood: Metal ion deposition from ionized magnetron sputtering discharge. J. Vac. Sci. Technol. B 12, 449 (1994).
D. Aquaro and M. DiPrinzio: Molecular dynamics simulation of surface vaporization in beryllium plasma facing components. Fusion Eng. Des. 82, 1681 (2007).
L.A. Zepeda-Ruiz, E. Chason, G. Gilmer, Y. Wang, H. Xu, A. Nikroo, and A. Hamza: Understanding the relation between stress and surface morphology in sputtered films: Atomistic simulations and experiments. Appl. Phys. Lett. 95, 151910 (2009).
Acknowledgments
This work was supported by U.S. DOE under contract DE-AC52-06NA27279. Authors would like to acknowledge J. Ilavsky for the USAXS experiments and the APS, which was supported by the U.S. Department of Energy under Contract DE-AC02-06CH11357.
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Xu, H., Alford, C., Chason, E. et al. Thick beryllium coatings by ion-assisted magnetron sputtering. Journal of Materials Research 27, 822–828 (2012). https://doi.org/10.1557/jmr.2011.378
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DOI: https://doi.org/10.1557/jmr.2011.378