Thin-film design of amorphous hafnium oxide nanocomposites enabling strong interfacial resistive switching uniformity

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Hellenbrand, Markus  ORCID logo
Hongyi, Dou 
Hill, Megan 

A design concept of phase-separated amorphous nanocomposite thin films is presented which realizes interfacial resistive switching (RS) in hafnium-oxide-based devices. The films are formed by incorporating an average of 7% Ba into hafnium oxide during pulsed laser deposition at temperatures ≤400 °C. The added Ba prevents the films from crystallizing and leads to ∼20-nm-thin films consisting of an amorphous HfOx host matrix interspersed with ∼2-nmwide, ∼5-to-10-nm-pitch Ba-rich amorphous nanocolumns penetrating ∼2/3 through the films. This restricts the RS to an interfacial Schottky-like energy barrier whose magnitude is tuned by ionic migration under an applied electric field. Resulting devices achieve stable cycle-to-cycle, device-to-device, and sample-to-sample reproducibility with a measured switching endurance of ≥10⁴ cycles for a memory window ≥10 at switching voltages of ±2 V. Each device can be set to multiple intermediate resistance states, which enables synaptic spike-timing-dependent plasticity. The presented concept unlocks additional design variables for RS devices.

40 Engineering, 4016 Materials Engineering, 51 Physical Sciences
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Science Advances
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American Association for the Advancement of Science
European Commission Horizon 2020 (H2020) ERC (882929)
Cambridge Herchel Smith postdoctoral fellowship
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