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DS: Fachverband Dünne Schichten

DS 56: Focussed Session: Resistive Effects II

DS 56.3: Vortrag

Freitag, 11. März 2016, 10:45–11:00, H11

Metastable states of HfO₂ suboxides and resistive switching — •Konstantin Z. Rushchanskii, Stefan Blügel, and Marjana Ležaić — Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Resistive random access memories (RRAM) are considered the next generation of memory devices, which combine the operation speed of volatile DRAM and the nonvolatile ability of flash technology in one device with good scalability. Materials used for RRAM should be compatible with silicon technology. One of these materials is hafnia (HfO₂), thin films of which have valence change memory properties. With the aim of shining light on the filamentary initial state of the memory cell after electroforming we will present results of a study of the Hf-O system combining an evolutionary-algorithm [1] for structure prediction with density functional theory. The main focus is given to suboxides in close vicinity of the HfO₂ ground state, in order to search for possible metastable structures in oxygen deficient conditions. We find metastable crystalline structures, which could occur in the electroforming process and allow for a reversible resistive switching. The obtained structures favor ionic conductivity of oxygen. We characterise electronic and vibrational properties of these phases in order to compare them with experimental data.

We acknowledge financial support by the Helmholtz Young Investigators Group Programme VH-NG-409 and by the DFG through the SFB917 (Nanoswitches).

[1] http://uspex.stonybrook.edu