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YBCO Films and YSZ Buffer Layers Grown in Situ on Silicon by Pulsed Laser Deposition

  • D. K. Fork
  • G. A. N. Connell
  • D. B. Fenner
  • J. B. Boyce
  • Julia M. Phillips
  • T. H. Geballe

Abstract

Attempts to grow high quality YBCO (Y1Ba2Cu3O7−δ) films on bare silicon substrates have been hindered by substrate-film reactions, which are substantial even at growth temperatures as low as 550 C (Fenner et al., 1990b). In an effort to circumvent this problem, buffer layers have been introduced as part of the thin film growth process. Recently, we have shown that YSZ |(Y2O3)x (ZrO2)1−x| is a most promising buffer-layer (Connell et al., 1989). It has two ideal properties: first, at temperatures below 800 C, reactions with Si and YBCO are minimal under appropriate conditions; second, for compositions in the range 0.08 < x < 0.4, bulk YSZ exists in the cubic fluorite structure and at x =0.1 has a lattice constant that is within 6% of both the near neighbor distance between Si atoms on the (100) surface and the basal plane dimensions in YBCO (Golecki et al., 1983). Table 1, which summarizes our earlier results on surface morphology, interface
Table 1

Variation of structural and electrical parameters with x in YSZ [(Y2O3)x (ZrO2)1−x] . The surface roughness and intensity of the [005] 2θ diffraction peak are measued relative to the parameters for the x = 0 film

x [mole fraction]

0

0.05

0.1

0.2

Surface Roughness

1

0.2

0.1

0.1

Intensity [005]-Peak

1

90

100

110

Tco [K]

Insulating

62

77

70

∆Tc [K]

Insulating

28

13

20

P300 [μΩ.cm]

Insulating

24,000

6,300

13,000

P300/P100

Insulating

1.8

2.2

1.85

and crystal structure, and conductivity, demonstrates that the value of x plays a critical role in preparing the YSZ buffer layer for the subsequent growth of YBCO. That many of the properties were optimized near x =0.1 is suggestive that the cubic YSZ phase is forming, lattice matched and oriented relative to the Si. Our electron microscopy results supported this conjecture, albeit under the deposition conditions used, the cubic and tetragonal phases were intermixed and had a high density of defects, and there was only weak preferred orientation.

Keywords

YBCO Film Target Holder Zirconia Substrate Critical Current Measurement High Quality YBCO 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Boyce, J.B., Connell, G.A.N., Fork, D.K., Fenner, D.B., Char, K., Ponce, F.A., Bridges, F., Tramontana, J., Viano, A.M., Laderman, S.S., Taber, R.C. and Geballe, T.H., 1990, In-situ growth of superconducting YBa2Cu3Oy films by pulsed laser deposition, Proceedings of the SPIE, 1187: 136.ADSCrossRefGoogle Scholar
  2. Connell, G.A.N., Fenner, D.B., Fork, D.K., Boyce, J.B., Ponce, F.A., Bridges, F., and Geballe, T.H., 1990, YBCO films and buffer-lavers grown in-situ bypulsed laser deposition, Symp. M Fall MRS Meeting(in press).Google Scholar
  3. Dietrich, M.R., Fietz, W.H., Ecke, J. and Politis, C., 1987, Structure and superconductivity of La1.8Sr0.2CuO4 and YBa2Cu3O7 under high pressure, Jpn. J. Appl. Phys., Suppl. 26–3: 1113Google Scholar
  4. Fenner, D.B., Biegelsen, D.K., and Bringans, R.D., 1989, Silicon surface passivation by hydrogen termination: A comparative study of preparation methods, J. Appl. Phys., 66: 419.ADSCrossRefGoogle Scholar
  5. Fenner, D.B., Fork, D.K., Connell, G.A.N., Boyce, J.B., Ponce, F.A., Tramontana, J.C., Viano, A.M., and Geballe, T.H., 1990a, Heteroepitaxial metal oxides on Si by laser ablation, Symp. N Spring MRS Meeting (in press)Google Scholar
  6. Fenner, D.B., Viano, A.M., Connell, G.A.N., Fork, D.K., Boyce, J.B., Ponce, F.A., and Tramontana, J.C., 1990b, Reaction at the interface of thin films of Y-Ba-Cuand Zr-oxides with Si substrates, Appl. Phys. Lett.,(submitted).Google Scholar
  7. Fork, D.K., Char, K., Bridges, F., Tahara, S., Lairson, B., Boyce, J.B., Connell, G.A.N., and Geballe, T. H., 1989, YBCO films on YSZ and Al2O3 by pulsed laserdeposition, Physica C, 162–164: 121.Google Scholar
  8. Fork, D.K., Fenner, D.B., Connell, G.A.N., Phillips, J.M., and Geballe, T.H., 1990b, Epitaxial yttria stabilized zirconia on hydrogen terminated Si by pulsed laser deposition, Appl. Phys. Lett. (submitted).Google Scholar
  9. Fork, D.K., Fenner, D.B., and Geballe, T.H., 1990a, Growth of epitaxial PrO2 thin films on hydrogen terminated Si(111) by pulsed laser ablation, Appl. Phys.Lett. (submitted).Google Scholar
  10. Fukumoto, H., Imura, T., and Osaka, Y., 1988, Heteroepitaxial growth of yttriastabilized zirconia (YSZ) on silicon, Jpn. J. Appl. Phys., 27: L1404.ADSCrossRefGoogle Scholar
  11. Golecki, I., Manasevit, H.M., Moudy, L.A., Yang, J.J., and Mee, J.E., 1983, Heteroepitaxial Si films on yttria-stabilized, cubic zirconia substrates, Appl. Phys. Lett., 42: 501.ADSCrossRefGoogle Scholar
  12. Grunthaner, F.J. and Grunthaner, P.J., 1986, Chemical and electronic structure of the SiO2/Si interface, Mater. Sci. Rep., 1: 65CrossRefGoogle Scholar
  13. Roas, B., Schultz L. and Endres, G., 1988, Epitaxial growth of YBa2Cu3O7 thin filmsby a laser evaporation process, Appl. Phys. Lett., 53: 1557.ADSCrossRefGoogle Scholar
  14. Schowalter, L.J., Fathauer, R.W., Goehner, R.P., Turner, L.G., DeBois, R.W., Hashimoto, S., Peng, J.L., Gibson, W.M. and Krusius, J.P., 1985, Epitaxial growth and characterization of CaF2onSi, J. Appl. Phys., 58: 302ADSCrossRefGoogle Scholar
  15. Wu, X.D., Inam, A., Hegde, M.S., Willkens, B., Chang, C.C., Hwang, D.M., Nazar, L., Venkatesan, T., Mirua, S., Matsubara, S., Miyasaka, Y., and Shohata, N., 1989, High critical currents in epitaxial YBa2Cu3O7, Appl.Phys. Lett., 54: 754.ADSCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1990

Authors and Affiliations

  • D. K. Fork
    • 1
    • 3
  • G. A. N. Connell
    • 1
  • D. B. Fenner
    • 1
    • 2
  • J. B. Boyce
    • 1
  • Julia M. Phillips
    • 4
  • T. H. Geballe
    • 3
  1. 1.Xerox Palo Alto Research CenterPalo AltoUSA
  2. 2.Physics Dept.Santa Clara UnivSanta ClaraUSA
  3. 3.Dept. of Appl. PhysStanford Univ.StanfordUSA
  4. 4.AT&T Bell LaboratoriesMurray HillUSA

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