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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 28: Focus Session: (Multi-)Ferroic States IV
KFM 28.5: Talk
Thursday, March 21, 2024, 16:45–17:05, EMH 225
Conduction mechanisms in Al1−xScxN-based thin-film ferroelectric capacitors — •Vinay Lulla1, Georg Schönweger2,3, Simon Fichtner2,3, Hermann Kohlstedt1,4, and Adrian Petraru1 — 1Chair of Nanoelectronics, Institute of Electrical and Information Engineering, Faculty of Engineering, Kiel University, Kaiserstraße 2, D-24143 Kiel, Germany — 2Chair of Microsystems and Technology Transfer, Institute of Material Science, Faculty of Engineering, Kiel University, Kaiserstraße 2, D-24143 Kiel, Germany — 3Fraunhofer Institute of Silicon Technology, Fraunhoferstraße 1, 25524 Itzehoe, Germany — 4Kiel NanoSurface and Interface Science KiNSIS, Kiel University, Christian-Albrechts-Platz 4, D-24118 Kiel, Germany
Current Al1−xScxN based devices are limited by the high electric switching fields that require to operate the capacitors in a regime where the breakdown is highly likely, i.e., close to 4 MV/cm. In this work, ferroelectric capacitors with the layer sequence Pt/Al1−xScxN/Pt have been investigated. The electrodes and the Al1−xScxN were deposited by DC sputtering and pulsed DC sputtering, respectively. These devices exhibit high leakage currents, especially for films thinner than 100 nm. In order to understand the transport mechanisms, the electric field dependence and temperature dependence (300 K - 77 K) of the leakage currents were investigated. The experiments showed that Richardson-Schottky conduction is likely to dominate the transport in high electric field regime (4 MV/cm), while domain wall conduction and Poole-Frenkel were valid mechanisms in the low-field regime (2 MV/cm).
Keywords: Ferroelectric; Scandium; Thin-film; Conductivity; Memory