Electronic Synapses Enabled by an Epitaxial SrTiO3‐δ / Hf0.5Zr0.5O2 Ferroelectric Field‐Effect Memristor Integrated on Silicon

• Published in: Advanced functional materials 2024-02, Vol.34 (8), p.n/a
• Main Authors: Siannas, Nikitas, Zacharaki, Christina, Tsipas, Polychronis, Kim, Dong Jik, Hamouda, Wassim, Istrate, Cosmin, Pintilie, Lucian, Schmidbauer, Martin, Dubourdieu, Catherine, Dimoulas, Athanasios
• Format: Article
• Language: English
• Subjects: artificial synapses; Data processing; epitaxial HZO; Epitaxy; ferroelectric field effect memristors; Ferroelectric materials; Ferroelectricity; Low voltage; Memory devices; Memristors; molecular beam epitaxy; neuromorphic computing; Silicon; Strontium titanates; Synapses
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202311767

Synapses play a vital role in information processing, learning, and memory formation in the brain. By emulating the behavior of biological synapses, electronic synaptic devices hold the promise of enabling high‐performance, energy‐efficient, and scalable neuromorphic computing. Ferroelectric memristive devices integrate the characteristics of both ferroelectric and memristive materials and present a far‐reaching potential as artificial synapses. Here, it is reported on a new ferroelectric device on silicon, a field‐effect memristor, consisting of an epitaxial ultrathin ferroelectric Hf0.5Zr0.5O2 film sandwiched between an epitaxial highly doped oxide semiconductor SrTiO3‐δ and a top metal. Upon a low voltage of less than 2 V, the field‐effect modulation in the semiconductor enables to access multiple states. The device works in a large time domain ranging from milliseconds down to tens of nanoseconds. By gradually switching the polarization by identical pulses, the ferroelectric diode devices can dynamically adjust the synaptic strength to mimic short‐ and long‐term memory plasticity. Ionic contributions due to redox processes in the oxide semiconductor beneficially influence the device operation and retention. The integration of thin Hf0.5Zr0.5O2 ferroelectric and SrTiO3‐δ semiconductor films in a field effect memristor on silicon, breaks new grounds for the development of ferroelectric artificial electronic synapses. By dynamically adjusting their synaptic strength to mimic short‐ and long‐term memory plasticity, such devices can emulate the behavior of biological synapses enabling high‐performance, energy‐efficient, and scalable circuits that are key to the development of next‐generation neuromorphic computers.