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TT: Tiefe Temperaturen

TT 14: Wachstum und Transport in dünnen Filmen

TT 14.1: Hauptvortrag

Mittwoch, 29. März 2000, 14:30–15:00, H19

Imposed layer-by-layer growth of high temperature superconductors with pulsed laser interval deposition — •Dave H.A. Blank — Low Temperature Division, MESA+ Research Institute University of Twente, The Netherlands

In oxides electronics the control on an atomic level becomes a central issue. The interface in gate-oxides, electrical, and magnetic junctions has to be controlled with the utmost precision. In order to be able to create a crystal structure by depositing consecutive unit cell layers of different materials, a layer-by-layer growth mode is a prerequisite: nucleation of each next layer may only occur after the previous layer is completed. We introduced a growth method, based on a periodic sequence: very fast deposition of the amount of material needed to complete one monolayer followed by an interval in which no deposition takes place and the film can reorganize. This makes it possible to grow in a layer-by-layer fashion in a growth regime (temperature, pressure) where otherwise island formation would dominate the growth. We present the results obtained for homo- and hetero-epitaxial growth on SrTiO₃ as monitored by high-pressure RHEED. In addition, Monte Carlo simulations are used to support the applicability of interval deposition. Furthermore, this technique is used to grow superconducting superlattices as well as ferromagnetic junctions.