超薄氧化铝层的电场调制效应

研究了基于高k介质材料的阻变存储器的写入/擦除 (SET/RESET) 特性和物理机制.研究发现基于NbAlO材料的阻变存储器SET/RESET电压具有较大波动性, 通过结构优化, 在Al2O3/NbAlO/Al2O3纳米薄片堆垛结构器件中获得高度稳定性的可重复的阻变特性.基于电场调制效应, 提出了一种统一的电阻开关模型去模拟阻变存储器的SET/RESET行为, 并探讨了单层阻变薄膜的阻变存储器中由导电单元形成和湮灭的巨大随机性引起的阻变特性分布.当在NbAlO基阻变存储器中嵌入超薄Al2O3膜后, 阻变存储器的SET/RESET电压稳定性将显著提升, 其原因在于采用堆垛结构的阻变器件中各介质层中的电场重新分布并精确可控, 因此导电细丝的导通/断裂通过电场调制作用稳定均匀地在发生在具有高电场的薄缓冲层介质层中.

Study on the electric field modulation effect of ultrathin alumina layer

The characteristics and mechanism of set/reset process in high-k based resistive random-access memory devices were studied.A great fluctuation in set/reset voltages was observed in the NbAlO single-layer RRAMdevices.However, it shows highly uniform and reproducible switching cycles in Al2O3/NbAlO/Al2O3 nanolaminate stack structures.Based on the electric-filed modulating effect, we proposed a unified resistive switching model to simulate the set and reset operations, and the switch parameters dispersion due to the great randomness of the conductive spots formation or annihilation was discussed for a single-layer RRAM.When an ultra-thin Al2O3 films was embedded in NbAlO-based RRAMdevices, there is an obvious improvement in the stabilization of the set/reset switching voltages.It can be explained that the electric-field distribution is rearranged and locally controlled in the stack structure, therefore the conductive filament bridges and ruptures appear in the thin buffer layer.