Müller Moritz L, Strkalj Nives, Becker Maximilian T, Hill Megan O, Kim Ji Soo, Phuyal Dibya, Fairclough Simon M, Ducati Caterina, MacManus-Driscoll Judith L
Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, UK.
Center for Advanced Laser Techniques, Institute of Physics, Zagreb, 10000, Croatia.
Adv Sci (Weinh). 2025 Feb;12(8):e2409566. doi: 10.1002/advs.202409566. Epub 2025 Jan 9.
The discovery of ferroelectric phases in HfO-based films has reignited interest in ferroelectrics and their application in resistive switching (RS) devices. This study investigates the pivotal role of electrodes in facilitating the Schottky-to-Ohmic transition (SOT) observed in devices consisting of ultrathin epitaxial ferroelectric HfYO (YHO) films deposited on LaSrMnO-buffered Nb-doped SrTiO (NbSTO|LSMO) with Ti|Au top electrodes. These findings indicate combined filamentary RS and ferroelectric switching occurs in devices with designed electrodes, having an ON/OFF ratio of over 100 during about 10 cycles. Transport measurements of modified device stacks show no change in SOT when the ferroelectric YHO layer is replaced with an equivalent hafnia-based layer, HfZrO (HZO). However, incomplete SOT is observed for variations in the top electrode thickness or material, as well as LSMO electrode thickness. This underscores the importance of employing oxygen-reactive electrodes and a bottom electrode with reduced conductivity to stabilize SOT. These findings provide valuable insights for enhancing the performance of ferroelectric RS devices through integration with filamentary RS mechanism.
基于HfO的薄膜中铁电相的发现重新点燃了人们对铁电体及其在电阻开关（RS）器件中应用的兴趣。本研究调查了电极在促进由沉积在LaSrMnO缓冲的Nb掺杂SrTiO（NbSTO|LSMO）上的超薄外延铁电HfYO（YHO）薄膜与Ti|Au顶电极组成的器件中观察到的肖特基到欧姆转变（SOT）方面的关键作用。这些发现表明，在具有设计电极的器件中会发生丝状RS和铁电开关的组合，在大约10个周期内开/关比超过100。对改进的器件堆栈进行的输运测量表明，当铁电YHO层被等效的基于氧化铪的层HfZrO（HZO）取代时，SOT没有变化。然而，对于顶电极厚度或材料以及LSMO电极厚度的变化，观察到不完全的SOT。这强调了采用氧反应性电极和具有降低电导率的底部电极来稳定SOT的重要性。这些发现为通过与丝状RS机制集成来提高铁电RS器件的性能提供了有价值的见解。
