适于三维集成的阻变存储器选通管技术研究

To satisfy the future requirement of ultra-large data storage, development of three-dimensional (3D) storage technology is considered as the most effective solution. Resistive switching memory (RRAM) with outstanding memory performances, has a simple two-terminal structure for easy 3D integration, which is one of the strong candidates for future ultra-high density storage application. However, the lack of suitable selector technology is one of the main obstacles to realization of the RRAM 3D integration. For the key issue of RRAM 3D integration, this project will focus on the study of the nonlinear resistor and threshold switching device, which are two types of the potential selectors for bipolar RRAM crossbar array due to their bidirectional nonlinear I-V characteristics. To obtain satisfactory selector with large turn-on current density, high nonlinear factor, high stability and reliability, the two type of selectors will be systemically investigated and optimized from the materials, device structure, fabrication process and nonlinear I-V mechanisms. On this basis, the integration and characterization technologies of 1S1R (one selector one RRAM) cell structure will be developing to apply in the bipolar RRAM crossbar array. Finally, 3D RRAM integration technology will be developing based on the 1S1R cell structure and 3D RRAM crossbar array will be realized. Successful implementation of the project will provide important guidelines for the realization of the high-density 3D integration of bipolar RRAM and promote the development of the memory technology in our country.

发展三维存储技术是未来实现超高密度、超大容量数据存储的关键途径。高速、低功耗、非挥发性的阻变存储器(RRAM)，具有简单的两端器件结构易于三维集成，是未来超高密度存储技术的有力候选者之一。然而，缺乏合适的选通管(Selector)技术是RRAM实现三维集成的主要障碍之一。本项目针对这个关键问题，选取具有双向选通特性的非线性电阻和阈值转变器件为研究对象，从器件的材料、结构、制备和机制出发，阐明选通器件非线性I-V特性的物理根源，研制具有高导通电流密度、高非线性系数和高可靠性的选通管器件。以此为基础，开发适宜双极型RRAM交叉阵列选通功能的1S1R(one selector one RRAM)集成结构的制备工艺和测试表征技术，开发基于1S1R单元结构的三维RRAM交叉阵列的集成工艺，试制三维RRAM交叉阵列，为实现RRAM的三维集成奠定基础，从而推动我国存储器技术的发展。

发展三维存储技术是未来实现超高密度、超大容量数据存储的关键途径。高速、低功耗、非挥发性的阻变存储器(RRAM)，具有简单的两端器件结构易于三维集成，是未来超高密度存储技术的有力候选者之一。然而，缺乏合适的选通管（Selector）技术是RRAM实现三维集成的主要障碍之一。本项目按计划开展了具有双向选通特性的非线性电阻和阈值转变器件的研究，开发了适宜双极型RRAM交叉阵列选通功能的1S1R集成单元的制备工艺及测试表征技术，实现了多层的RRAM垂直交叉阵列。取得的代表性成果包括：1) 发展了界面势垒调控技术，提出了梯形能带的非线性电阻设计思路，获得了>103的选通比，小于1μA的工作电流的自选通器件，解决了RRAM三维垂直交叉阵列中选通层中的漏电通道，并开发了该器件的3D集成关键工艺，实现了4层的3D RRAM阵列；2) 阐明了阳离子基阈值转变器件的微观机制，提出了离子限域传输的导电通路尺寸、数量的调控思路，实现了驱动电流>1MA/cm2、选通比>108的阳离子基阈值转变器件，有效实现了双极性RRAM交叉阵列的漏电通道抑制；3) 进一步拓展了阳离子基阈值转变器件在类脑计算中的应用，基于该器件构建了神经元仿生单元，实现了神经元的积分-发射功能，为发展高密度类脑神经网络提供了硬件基础。在上述研究的基础上，项目组在Advanced Materials、Small、Nanoscale、IEEE Electron Device Letters等期刊上发表SCI论文13篇，在VLSI和SSDM微电子领域重要的国际会议上发表论文2篇，申请中国发明专利4项。