Dresden 2006 – scientific programme

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DF: Dielektrische Festkörper

DF 1: Internal Symposium “Integrated Electroceramic Functional Structures”

DF 1.6: Talk

Monday, March 27, 2006, 11:30–11:50, M{\"U}L Elch

Correlations between Microstructural Changes and Resistive Switching: An Approach by In-situ TEM Investigations — •Herbert Schroeder and Doo Seok Jeong — IEM / IFF and CNI, Forschungszentrum Jülich GmbH, Germany.

Among the material candidates for resistive non-volatile memories are functional oxides, e.g. ferroelectric and paraelectric oxide thin films. There are numerous experimental (leakage) current data published for each material class demonstrating the switchable memory effect but there is no agreement on the working mechanism. To a large extent this is due to the lack of microstructural information on the changes during formation and switching of the devices. If these effects are connected with microstructural changes these may be observable in a transmission electron microscope (TEM). Therefore, in this contribution we present a rather seldom used approach for a TEM experiment to observe the microstructure of a metal/insulator/metal (MIM) capacitor structure before and after (ex-situ) as well as during (in-situ) resistive switching due to an applied external voltage or current. We use a special TEM sample holder allowing controlled application of temperature (RT to 300^∘C) with a heating stage and of voltage (current) as a part of a 4-point resistance measurement set-up for ex- and in-situ experiments. This is combined with a special TEM sample preparation method, the so-called window-technique. Special electrode configurations have been designed to allow nearly undisturbed TEM observation of the switching insulator. Examples for first observations in a (Pt/amorphous TiO2 thin film/Pt) stack on the resistive switching will be presented.