XTEM/SAED and SNMS study of film/substrate reactions in Bi2Sr2CaCu2Oy films on Si(100) with Si3N4 buffer layer

✍ Scribed by Dietrich Hesse; Volker Klocke; Andreas Pfau; Gernot Güntherodt; Uwe Breuer; Wolfgang Albrecht; Hans Kurz

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 873 KB
• Volume: 185-189
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)91185-7

✦ Synopsis

We have performed cross-sectional TEM/SAED and SNMS studies of film/substrate interactions in Bi2Sr2CaCu20 v ("2212") films on Si(lO0) substrates using Au, SiO 2, and Si3N 4 buffer layers. The 2212 "films were prepared by electron beam evaporation of stoichiometric targets in O 2 of 2x10 -4 mbar and post-annealed in air at 800•850 oc. SNMS depth profiles indicated Si3N 4 layers to be most effective of the buffers studied; they enabled us to grow c-axis oriented 2212 films. These, however, were not superconductive. XTEM and SAED revealed a strong attack on the Si3N 4 buffer layer by solid state reactions resulting in a severe roughness of the initially plane interface. The induced roughness of the interface obviously is responsible for the observed deviations (up to 20 o) of the c-axis of the 2212 grains from the substrate normal, which in turn lead to weak links. The latter then probably inhibit superconductivity.