Large area YBa sub(2)Cu sub(3)O sub(7) and Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) thin films for microwave and electronic applications

This paper reviews recent work at DuPont to develop high performance Tl sub(2 )Ba sub(2)CaCu sub(2)O sub(8) and YBa sub(2)Cu sub(3)O sub(7) thin films for microwave and electronic device applications. The YBa sub(2)Cu sub(3)O sub(7) thin films are produced by off-axis magnetron sputtering onto radiatively heated substrates and have surface roughness levels of less than 1 nm over 2 in. diameter wafers as determined by atomic force microscopy. Double-sided Tl sub(2)Ba sub(2 )CaCu sub(2)O sub(8) films are produced on 3 in. diameter CeO sub(2) buffered sapphire substrates with excellent uniformity of structural and electrical properties. These films have low microwave surface resistance up to high microwave power levels. We also report on the establishment of a Six Sigma manufacturing capability for Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) films. These films are used to fabricate a compact high performance eight-pole bandpass filter operating at 1.85 GHz and 80 K. copyright 2001 Elsevier Science B.V. All rights reserved.