Beilliard Yann, Paquette François, Brousseau Frédéric, Ecoffey Serge, Alibart Fabien, Drouin Dominique
Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke J1K 0A5, Canada.
Laboratoire Nanotechnologies Nanosystèmes (LN2) - CNRS UMI-3463 - 3IT, CNRS, Sherbrooke J1K 0A5, Canada.
Nanotechnology. 2020 Oct 30;31(44):445205. doi: 10.1088/1361-6528/aba6b4. Epub 2020 Jul 16.
Non-volatile resistive switching devices are considered as prime candidates for next-generation memory applications operating at room temperature and above, such as resistive random-access memories or brain-inspired in-memory computing. However, their operability in cryogenic conditions remains to be mastered to adopt these devices as building blocks enabling large-scale quantum technologies via quantum-classical electronics co-integration. This study demonstrates multilevel switching at 1.5 K of AlO/TiO resistive memory devices fabricated with complementary metal-oxide-semiconducto-compatible processes and materials. The I-V characteristics exhibit a negative differential resistance (NDR) effect due to a Joule-heating-induced metal-insulator transition of the TiO conductive filament. Carrier transport analysis of all multilevel switching I-V curves show that while the insulating regime follows the space charge limited current (SCLC) model for all resistance states, the conduction in the metallic regime is dominated by SCLC and trap-assisted tunneling for low- and high-resistance states respectively. A non-monotonic conductance evolution is observed in the insulating regime, as opposed to the continuous and gradual conductance increase and decrease obtained in the metallic regime during the multilevel SET and RESET operations. Cryogenic transport analysis coupled to an analytical model accounting for the metal-insulator-transition-induced NDR effects and the resistance states of the device provide new insights on the conductive filament evolution dynamics and resistive switching mechanisms. Our findings suggest that the non-monotonic conductance evolution in the insulating regime is due to the combined effects of longitudinal and radial variations of the TiO conductive filament during the switching. This behavior results from the interplay between temperature- and field-dependent geometrical and physical characteristics of the filament.
非易失性电阻开关器件被认为是在室温及以上温度下运行的下一代存储器应用的主要候选者，例如电阻式随机存取存储器或受大脑启发的内存计算。然而，要将这些器件用作通过量子-经典电子学共集成实现大规模量子技术的构建模块，它们在低温条件下的可操作性仍有待掌握。本研究展示了采用互补金属氧化物半导体兼容工艺和材料制造的AlO/TiO电阻式存储器件在1.5 K时的多级开关特性。由于焦耳热诱导的TiO导电细丝的金属-绝缘体转变，其I-V特性呈现出负微分电阻（NDR）效应。对所有多级开关I-V曲线的载流子输运分析表明，虽然绝缘状态在所有电阻状态下均遵循空间电荷限制电流（SCLC）模型，但金属状态下的传导分别由SCLC和低电阻及高电阻状态下的陷阱辅助隧穿主导。在绝缘状态下观察到非单调的电导演化，这与多级SET和RESET操作期间在金属状态下获得的连续且逐渐的电导增加和减少相反。结合考虑金属-绝缘体转变诱导的NDR效应和器件电阻状态的分析模型进行的低温输运分析，为导电细丝的演化动力学和电阻开关机制提供了新的见解。我们的研究结果表明，绝缘状态下的非单调电导演化是由于开关过程中TiO导电细丝的纵向和径向变化的综合影响。这种行为是由细丝的温度和场依赖的几何和物理特性之间的相互作用导致的。
