基于跃迁理论的阻变存储器载流子输运特性的研究

Due to the advantages of the simple structure, high speed, low power and easy 3D integration, resistive random-access memory (RRAM) will be one of the potential techniques for the high-density non-volatile memory of the next generation. However, the development and practical application of RRAM is seriously hindered by the unclear resistance transformation mechanism. By establishing the charge carrier mobility model of RRAM, this project, will demonstrate the influence of the electric field, temperature, concentration and microstructure of the material on ion migration. The charge carrier diffusion model, relating to the concentration, is set up by introducing hopping transport and modifying conventional semiconductor drift-diffusion equations and continuity equations. The real density of state of RRAM is extracted by setting up the current relaxation model of RRAM with time. The microcosmic physical mechanism of RRAM can be explained by combining the charge carrier characteristics with the real density of state of RRAM. The successful implementation of this project will create a new research method for charge carrier transport characteristics of RRAM and hence provides theoretical guidance for the development of RRAM device models.

阻变存储器具有结构简单、高速、低功耗、易于3D集成等优势，是下一代高 密度非易失性存储器的潜在技术之一。然而，阻变机制的不清晰严重阻碍和制约了RRAM的快速发展和实用化。本项目提出一种应用跃迁理论研究RRAM载流子输运特性的理论方法，从物理层面上解释RRAM的微观物理机制。本项目通过建立RRAM载流子迁移率模型，阐明电场、温度、浓度、材料的微观特性等对载流子迁移率的影响；引入跃迁方法并通过修正传统半导体漂移扩散方程和连续性方程，建立与浓度相关的载流子扩散模型；建立RRAM器件随时间变化的电流弛豫模型，获得器件真实的状态密度函数，并结合载流子的输运特性剖析RRAM的微观物理机制。该项目的成功实施将开创一种新的RRAM载流子输运特性的研究方法，为RRAM器件模型的开发提供理论指导。

阻变存储器具有结构简单、高速、低功耗、易于3D集成等优势，是下一代高 密度非易失性存储器的潜在技术之一。然而，阻变机制的不清晰严重阻碍和制约了RRAM的快速发展和实用化。我们基于跃迁理论并结合第一性原理计算、蒙特卡洛方法，研究了氧化物基的阻变存储器(RRAM)中载流子的传输机理；通过把宏观的I-V特性与阻变材料的微观特性结合起来，建立了一种理论模型来识别载流子的输运通道以及分析阻变参数离散性方法；建立了RRAM中载流子传输的扩散模型、迁移率模型以及电流弛豫模型，获得了RRAM器件中真实的状态密度函数。通过本课题的研究，在国际著名刊物上发表了15篇论文以及申请了四项中国发明专利（其中1项已获得授权）。