Deposition of Superconducting Thin Films on Amorphous and Artificially-Structured Substrates

该项目的目标是在非晶或多晶衬底上沉积出临界电流密度在77K下超过1*106A/cm2的高T_c稀土-钡-铜-氧超导体薄膜。这种能力将允许用超导体直接取代集成电路互连。目前多晶超导薄膜的临界电流密度极限(通常为103A/cm2)与晶界上的约瑟夫森结有关。为了克服这一限制，该项目旨在控制晶体的取向和质量，而不会引起外延生长。我们将评估两种完全不同的技术的潜力。在第一种方法中，将探索反应离子束辅助沉积对薄膜的氧含量和晶体取向的控制能力。在第二种方法中，将探索“图形外延”的可能性，即薄膜相对于人工结构的衬底定向。

The goal of this project is to deposit, on amorphous or polycrystalline substrates, thin films of high Tc, rare earth- barium-copper-oxygen superconductors with critical current densities exceeding 1*106 A/cm2 at 77k. This capability would permit the direct replacement of integrated circuit interconnects with superconductors. The present limits in critical current density for polycrystalline superconducting films (typically 103 A/cm2) are associated with Josephson junctions at grain boundaries. In an effort to overcome this limitation, this project is aimed at controlling crystalline orientation and quality without invoking epitaxial growth. The potential of two quite different techniques will be evaluated. In the first approach, the ability of reactive ion beam assisted deposition to control oxygen content and crystal orientation of films will be explored. In the second, the possibility of "grapho-epitaxy", where the film is oriented with respect to an artificially structured substrate, will be explored.