HfO_(2)/NiO_(x)/HfO_(2)堆栈的三电阻态开关特性与导电机制  

Tri-level resistive switching characteristics and conductive mechanism of HfO_(2)/NiO_(x)/HfO_(2) stacks

作　　者：陈涛 张涛 殷元祥 谢雨莎 邱晓燕[1,2] Chen Tao;Zhang Tao;Yin Yuan-Xiang;Xie Yu-Sha;Qiu Xiao-Yan(School of Physical Science and Technology,Southwest University,Chongqing 400715,China;Chongqing Key Laboratory of Micro&Nano Structure Optoelectronics,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学物理科学与技术学院,重庆400715 [2]西南大学,微纳结构光电子学重庆市重点实验室,重庆400715

出　　处：《物理学报》2023年第14期276-286,共11页Acta Physica Sinica

基　　金：重庆市自然科学基金(批准号:cstc2019jcyj-msxmX0451)资助的课题。

摘　　要：采用磁控溅射制备了沿<100>晶向择优生长的NiO_(x)薄膜,并与多晶HfO_(2)薄膜组装成HfO_(2)/NiO_(x)/HfO_(2)堆栈器件,研究其电阻开关特性和导电机制.微结构分析表明,NiO_(x)薄膜主要成分为NiO和Ni_(2)O_(3),薄膜整体富含氧空位.HfO_(2)/NiO_(x)/HfO_(2)堆栈器件初期呈现两电阻态的双极性电阻开关特性,高低电阻比约为10^(5);但中后期逐步演变为具有“两级置位过程”的三电阻态开关特性.器件循环耐受性大于3×10^(3)个周期,数据持久性接近10^(4)s.器件高低电阻态满足欧姆导电机制,而中间电阻态遵循空间电荷限制电流导电机制.NiO_(x)薄膜中的氧空位导电细丝和上层HfO_(2)薄膜中的空间电荷限制电流共同作用使得HfO_(2)/NiO_(x)/HfO_(2)堆栈器件表现出稳定的三电阻态开关特性,有望应用于多级非易失性存储器和类脑神经突触元件.With the extensive integration of portable computers and smartphones with"Internet of Things"technology,further miniaturization,high reading/writing speed and big storage capacity are required for the new-generation non-volatile memory devices.Compared with traditional charge memory and magnetoresistive memory,resistive random access memory(RRAM)based on transition metal oxides is one of the promising candidates due to its low power consumption,small footprint,high stack ability,fast switching speed and multilevel storage capacity.Inspired by the excellent resistive switching characteristics of NiO and HfO_(2),NiO_(x)films are deposited by magnetron sputtering on the Pt111 layer and the poly crystalline HfO_(2)film,respectively.Their microstructures,resistive switching characteristics and conductive mechanisms are studied.X-ray diffractometer data show the 111 preferred orientation for the NiO_(x)film deposited on the Pt111 layer but the(100)preferred one for the film deposited on the poly crystalline HfO_(2)layer.X-ray photoelectron depth profile of Ni 2p core level reveals that the NiO_(x)film is the mixture of oxygen-deficient NiO and Ni_(2)O_(3).NiO_(x)(111)films show bipolar resistive switching(RS)characteristics with a clockwise current-voltage(I-V)loop,but its ratio of the high resistance to the low resistance(R_H/R_L)is only~10,and its endurance is also poor.The NiO_(x)(200)/HfO_(2)stack exhibits bipolar RS characteristics with a counterclockwise I-V loop.The R_(H)/R_(L)is greater than 10^(4),the endurance is about 10^(4) cycles,and the retention time exceeds 10^(4) s.In the initial stage,the HfO_(2)/NiO_(x)(200)/Hf0_(2)stack shows similar bi-level RS characteristics to the NiO_(x)(200)/HfO_(2)stack.However,in the middle and the last stages,its I-V curves gradually evolve into tri-level RS characteristics with a"two-step Setting process"in the positive voltage region,showing potential applications in multilevel nonvolatile memory devices and brain-like neural synapses.Its I-V curves in the high and the lo

关 键 词：HfO_(2)/NiO_(x)/HfO_(2)堆栈 三电阻态 两级置位 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TP333[自动化与计算机技术—计算机系统结构]