Uniform deposition of YBa sub 2 Cu sub 3 O sub 7 minus. delta. films over large areas using ion-beam sputtering

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.349822· OSTI ID:5096888

Lichtenwalner, D J; Soble, II, C N; Woolcott, Jr, R R ^[1]; Auciello, O ^[2]; Kingon, A I ^[3]

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1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina (USA)
2. Microelectronics Center of North Carolina, 3021 Cornwallis Road, Research Triangle Park, North Carolina 27709-2889 and Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina (USA)
3. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (USA)

Uniform films of YBaCuO have been deposited over 4-in.- (100-mm) diam, unheated Si wafers using ion-beam sputtering of a stoichiometric YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} target. Rutherford backscattering spectrometry reveals that within a 3-in. diam, the thickness variation is {plus minus}2.9%, and the compositional uniformity of Y, Ba, and Cu is {plus minus}0.9%, {plus minus}5.2%, and {plus minus}3.4%, respectively. The average film composition is Y{sub 1.03}Ba{sub 1.88}Cu{sub 3.09}O{sub 7{minus}{delta}}. Deposition onto unheated substrates virtually eliminates the problem of the low sticking coefficients of Ba and Cu, and is much simpler for film synthesis and processing. The observed difference from the 1:2:3 target composition is attributed mainly to angular differences in the sputtered-flux distribution of each element. These effects should be minimized by substrate rotation. In order to obtain useful superconducting films, a post-deposition anneal on a suitable substrate or buffer layer is required. Using a relatively low temperature ({similar to}810 {degree}C), low O{sub 2} pressure (1.2 Torr) post-anneal, we show that oriented, superconducting films can be obtained on single-crystal MgO and SrTiO{sub 3} substrates. Films annealed under these conditions on MgO are predominantly {ital c}-axis oriented, whereas those on SrTiO{sub 3} are predominantly {ital a}-axis oriented.

• OSTI ID: 5096888
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 70:11; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
BEAMS
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DEPOSITION
DIMENSIONS
ENERGY BEAM DEPOSITION
FILMS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
ION BEAMS
OXIDES
OXYGEN COMPOUNDS
SPUTTERING
SUPERCONDUCTING FILMS
SUPERCONDUCTORS
SURFACE COATING
THICKNESS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES