Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 3: Oxide Semiconductors for Novel Devices (Focussed Session): Session I

DS 3.11: Talk

Monday, March 12, 2018, 12:15–12:30, E 020

Ferro- and antiferroelectricity in oxygen defficient hafnia and zirconia — •Konstantin Z. Rushchanskii, Stefan Blügel, and Marjana Ležaić — Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

Conventional perovskite ferroelectrics as materials for ferroelectric RAM (FeRAM) suffer from poor CMOS-compatibility and limited scalability. In this sense, the discovery of ferroelectricity in Si:HfO₂ thin films [1] opens new prospectives for HfO₂-based materials because they are CMOS-compatible, and the robust ferroelectric behavior scales down to a film thickness below 10 nm. Recent discovery of ferroelectricity in undoped HfO₂ [2] emphasizes the importance of oxygen deficiency for the desired ferroelectric properties and the quest for a better microscopic understanding.

We present results of our Density Functional Theory combined with an evolutionary algorithm [3] based study of metastable structures in Hf-O and Zr-O solid solutions. We will show suboxides of HfO₂ and ZrO₂, which simultaneously possess a resistive switching capability and (anti)ferroelectricity, i.e. both properties originate from the same structures. We will discuss a possible origin of the ferro-antiferroelectric crossover, observed in Hf_xZr_1−xO₂ thin films [4].

We acknowledge the support by DFG via SFB 917 "Nanoswitches".

[1] T. Böscke et al, Appl. Phys. Lett. 99, 102903 (2011); [2] P. Polakowski, J. Müller, Appl. Phys. Lett. 106, 232905 (2015); [3] http://uspex.stonybrook.edu; [4] J. Müller et al, Nano Lett. 12, 4318 (2012).