HIGH-CURRENT DENSITIES AND ASSOCIATED FAILURE MECHANISMS IN LONG NARROW TL2BA2CACU2O8 LINES

The use of high temperature superconducting thin films in chip-to-chip interconnects requires the fabrication of long, narrow lines capable of carrying high current density on large area films. The capability o f Tl2Ba2CaCu2O8 thin films and patterning technology were studied for 0.65 mu m-thick films prepared on 2- and 3-inch diameter LaAlO3 wafers . For 15, 12, and 10 mu m wide lines 1.8-2.0 m in length, critical cur rent density J(c) at 80 K in excess of 1,4 MA/cm(2) was achieved. Line s of length 70 cm and widths of 4 and 7 mu m yielded J(c) at 80 K of 1 .10 and 0.94 MA/cm(2) respectively. Patterning of long, continuous lin es 2 mu m in width was difficult, but one such line 33.8 cm in length achieved a J(c) of 1.2 MA/cm2 at 70 K and another a J(c) of 0.42 MA/cm (2) at 80 K. Line failure at high current density occurred through two mechanisms. Localized melting at high current density resulted in sma ll localized line discontinuities. A second mechanism, postulated to b e arcing, was characterized by melting and disfiguration over line len gths of up to several centimeters.