Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Resputtering effects on the stoichiometry of YBa2Cu3Ox thin films (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 390-395 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Energetic particle bombardment of the substrate during deposition will under certain process conditions adversely affect the properties of YBa2Cu3Ox thin films. Films were grown by dc magnetron sputtering from stoichiometric compound targets in a planar geometry. An increased oxygen fraction in the sputtering gas entailed a drastic decrease in the film deposition rate. Etching of the substrates was observed in pure oxygen plasmas for pressures below 2 Pa. For the whole range of sputtering gas mixtures, the film composition deteriorated if too low total pressures were used; that is, even if pure argon was used as working gas. Copper deficiency was observed under these conditions and attributed to resputtering of the growing film by energetic particles. This conclusion was supported by the copper deficiency observed in films grown at negative substrate bias, i.e., during ion bombardment from argon plasmas. The origin of various energetic particles during normal sputtering is discussed. We concluded that oxygen neutrals were responsible for the resputtering. At elevated substrate temperatures the film composition was more sensitive to resputtering than at low temperatures. If the energetic oxygen particles were thermalized, stoichiometric films were grown at temperatures up to at least 760 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347727
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Reduction of surface particles on YBa2Cu3O7−∂ thin films through the use of nonstoichiometric sputtering targets and N2O in the sputtering gas (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 6388-6393 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High quality YBa2Cu3O7−∂ (YBCO) thin films that combine good electrical properties and smooth surfaces without particles are important for many future applications. Today most films with good electrical properties have secondary phases in the form of copper-rich surface particles and small Y2O3 inclusions in the film. This work investigates how the surface particle coverage and superconducting properties of dc-magnetron sputtered thin films change as a function of target stoichiometry and the use of Ar:O2 or Ar:O2:N2O as sputtering gases. In an attempt to eliminate the copper-rich surface particles, sputtering was performed using targets deficient in copper (by up to 28%). However, only a small reduction in the number of the surface particles was achieved with an Ar:O2 sputtering gas mixture and little change in the superconducting properties was found. No new secondary phases could be detected. When nitrous oxide (N2O) was added to the sputtering gas, the superconducting properties deteriorated and Ba2CuO3 precipitates formed. To compensate for the usual Y2O3 formation in YBCO, yttrium-rich targets were also investigated. A significant reduction in the number of copper-rich surface particles was achieved when an Ar:O2 sputtering gas mixture was used and an yttrium-rich phase (possibly Y2BaCuO5) was detected. By incorporating N2O in the sputtering gas, the formation of copper-rich surface particles and the precipitates of the yttrium-rich phase was avoided and hence smooth films were deposited. No deterioration of the superconducting properties was observed in this case. It is concluded that the use of yttrium-rich targets and N2O in the sputtering gas may be a reliable way to achieve smooth films without surface particles and with satisfactory superconducting properties. It appears that the excess yttrium in the target compensates for the usual formation of Y2O3 inclusions and the N2O is needed to avoid barium desorption. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Target presputtering effects on stoichiometry and deposition rate of Y-Ba-Cu-O thin films grown by dc magnetron sputtering (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 1907-1909 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Y-Ba-Cu-O thin films have been grown from stoichiometric compound targets using dc magnetron sputtering. Initially, the film composition was strongly off-stoichiometric and the deposition rate very low. However, after extensive presputtering, stoichiometric films, with respect to the metal content, were deposited at a rate of 2–2.5 A(ring)/s. The long presputtering time (20–30 h) needed is due to a slowly changing oxygen content on the target surface. This is caused not only by preferential sputtering effects, but also by bulk diffusion in the target. The presputtering time is significantly decreased if the target is annealed in an argon atmosphere prior to use. Oxygen adsorbed on the target surface during venting of the chamber will also affect the process significantly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99740
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The dc magnetron sputter deposition process of YBa"2Cu"3O"x thin films
    Amsterdam : Elsevier
    Physica C: Superconductivity and its applications 162-164 (1989), S. 599-600 
    Details
    ISSN: 0921-4534
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0921-4534(89)91166-0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Temperature and magnetic field variations in the resistance, cos conductance, and effective capacitance of small Josephson junctions
    Amsterdam : Elsevier
    Solid State Communications 26 (1978), S. 953-956 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(78)91260-7
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A low noise SIS array receiver for radioastronomical applications in the 35–50 GHz band (1983)
    Springer
    International journal of infrared and millimeter waves 4 (1983), S. 847-858 
    Details
    ISSN: 1572-9559
    Keywords: Low noise ; receiver ; mm-wave cryogenic mixer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Arrays of six superconducting tunnel junctions have been used in a heterodyne receiver over the frequency range 35–50 GHz. The mixer array and a 3.7–4.2 GHz parametric amplifier used as the if amplifier are immersed in liquid helium and operated at 2 K. The high if allows single sideband operation with a system noise temperature varying rather smoothly from 220 K at 35 GHz to 140 K at 50 GHz. Mixer noise temperatures between 11 and 21 K were measured over the band indicating that the use of arrays to enhance the dynamic range does not seriously affect the mixer noise performance in this frequency range. The receiver is used for radio astronomical observations in the Onsala 20 m telescope in Sweden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01009311
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...