Title :
The sputter deposition of cerium oxide thin films for superconducting electronics
Author :
Owens, J.M. ; Tarte, E.J. ; Berghuis, P. ; Somekh, R.E.
Author_Institution :
Dept. of Mater. Sci., Cambridge Univ., UK
fDate :
6/1/1995 12:00:00 AM
Abstract :
Thin films of cerium oxide (CeO/sub 2/) have been deposited by r.f. reactive sputter deposition on yttria-stabilised zirconia (YSZ) and on YBCO thin films on lanthanum aluminate (LaAlO/sub 3/) substrates. Subsequent growth of YBa/sub 2/Cu/sub 3/O/sub (7-x/) (YBCO) by high pressure d.c. sputtering has yielded superconducting transition temperatures (T/sub c/s) of 89-91 K for unpatterned YBCO films. CeO/sub 2/ thin films have been patterned and subsequent YBCO growth has been examined. Oxygenation levels were monitored between growth and patterning stages by X-ray diffraction (XRD). A YBCO track has been fabricated crossing steps in a CeO/sub 2/ buffer layer. A critical current density (J/sub c/) of 0.8/spl times/10 /sup 10/Am/sup -2/ at 77 K as compared with 1/spl times/10 /sup 10/Am/sup -2/ for a flat YBCO track on flat CeO/sub 2/ was measured. Crossover test structures were made, having T/sub c/s of 89-91 K for top and 80-90 K for the bottom YBCO electrodes. A 400 nm thickness of CeO/sub 2/ was sufficient to insulate two superconducting layers and found to have a resistivity of 2/spl times/10/sup 7/ /spl Omega/m at 77 K.<>
Keywords :
X-ray diffraction; barium compounds; cerium compounds; critical current density (superconductivity); high-temperature superconductors; sputter deposition; superconducting thin films; superconducting transition temperature; yttrium compounds; 400 nm; 77 K; CeO/sub 2/; CeO/sub 2/ buffer layer; LaAlO/sub 3/; LaAlO/sub 3/ substrates; RF reactive sputter deposition; X-ray diffraction; Y/sub 2/O/sub 3/-ZrO/sub 2/; YBa/sub 2/Cu/sub 3/O/sub 7/-CeO/sub 2/; critical current density; crossover test structures; high temperature superconductors; resistivity; superconducting transition temperature; thin films; yttria-stabilised zirconia; Cerium; Insulation life; Lanthanum; Monitoring; Sputtering; Superconducting films; Superconducting thin films; Superconducting transition temperature; X-ray diffraction; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
