Y-Ba-Cu-O thin films on 3" sapphire wafers for microwave devices

Citation
R. Aidam et al., Y-Ba-Cu-O thin films on 3" sapphire wafers for microwave devices, IEEE APPL S, 11(1), 2001, pp. 357-360
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
ISSN journal
1051-8223 → ACNP
Volume
11
Issue
1
Year of publication
2001
Part
1
Pages
357 - 360
Database
ISI
SICI code
1051-8223(200103)11:1<357:YTFO3S>2.0.ZU;2-F
Abstract
Epitaxially grown large area YBCO films are essential for superconducting h igh frequency devices ag. microstrip filters for telecommunications. Theref ore, c-axis oriented, 250 to 500 nm thick YBCO films were simultaneously de posited by sputtering from hollow cylindrical targets on both sides of CeO2 buffered 3 " sapphire wafers. The lateral homogeneity was analyzed by mapp ing the surface resistance, R, at 145 GHz and 75K. Values of R, below 50m O mega were reached over the whole area The HF power handling capability was demonstrated by a break down field higher than 10 mT at 8.5 GHz and 77 K. In order to demonstrate the quality of our sputtered films with respect to large area high frequency applications, simple microstrip resonators were p atterned by UV photo lithography end wet chemical etching. At a circulating power of up to 1 W, very high unloaded quality factors, Q(0), of up to 320 00 at 4 GHz and 77 K were achieved Above 5 W, Q(0) decreased due to the fie ld dependence of R, The operation of complex structures was demonstrated by 3 pole and 7 pole bandpass filters operated at 77 K and 2 GHz and 6 GHz, r espectively. The filters, tuned by brass tuning elements, showed transmissi on losses of less than -0.3 dB and reflection losses of more than -17 dB.