忆阻器中量子点接触结构的可控构建和精准调控

In memristor, quantum point contacts (QPCs) with room temperature quantum conductance (QC) effect, can be constructed, and they hold promise for integrating higher density, larger capacity information storage with high efficient multi-valued logic information processing. However, the controllability and thermal stability of QPCs are now very poor, which seriously restricts their applications. In view of this issue, this project comprehensively considers ion species of migration, device architectures and operation modes of QC. By analyzing the electrochemical and thermodynamics processes associated with the evolution of QPCs including the ion formation energy, migration barrier and diffusion coefficient and understanding the physical process of atomic reconstruction. Then, the dielectric microstructure and the device architecture will be optimized so as to control the growth position of the QPCs, which along with the choice of optimal ion species and operation mode would push to achieve the atom-by-atom evolution of QPCs. Ultimately, we aim to realize the stable and controllable QC, in which the relationship between QC and modulated variables will be quantified, and a versatile scheme for controllable construction and precise modulation of QPCs will be proposed. Finally, the feasibility of using controllable QC as multi-state memory and multi-valued logic gates will be demonstrated. The studies aforementioned will provide a new idea for solving von Neumann bottleneck problem and developing new functional nanodevices in the more than moore.

在忆阻器中构建具有室温量子电导效应的量子点接触结构有望在单一器件中实现更高密度、更大容量的信息存储和高效多值逻辑信息处理。然而，当前构建的量子点接触结构可控性和热稳定性差，严重制约其应用。针对这一问题，本项目综合考虑迁移离子类型、器件结构和量子电导调控方式，通过对量子点接触结构演化过程中离子的电化学和热动力学过程包括原子形成能、迁移势垒和扩散系数进行全面分析，对原子重构的物理过程进行深入理解，优化介质层微结构和器件构型以控制量子点接触结构的生长位置，选择最优离子类型和调控方式以实现逐个原子操纵的量子点接触结构演化，最终达到量子电导的稳定可控，得到量子电导与调控变量之间的定量关系，建立一种可控构建和精准调控量子点接触结构的通用方案，演示其作为多态存储和多值逻辑运算的可行性。本项目的成功实施将为解决冯·诺依曼瓶颈问题及后摩尔时代下发展新型功能纳米器件提供新思路。

在忆阻器中构建具有室温量子电导效应的量子点接触结构有望在单一器件中实现更高密度、更大容量的信息存储和高效多值逻辑信息处理。然而，当前构建的量子点接触结构可控性和热稳定性差，严重制约其应用。针对这一问题，本项目通过综合考虑迁移离子类型，原子电沉积和自发扩散之间的竞争以及器件电流反馈对局域原子重排的影响，深入理解原子重排的物理本质以及它对原子点接触结构的电输运行为的影响，利用氧离子的高活化能、ITO的储氧特性、单界面离子调控以及HfOx的高κ特性和简单相图，设计了非对称的Pt/HfOx/ITO器件，通过电场精准控制本地氧离子在欠氧的纳米尺寸HfOx和ITO单界面上迁移以及电化学反应过程，成功构建了具有较好鲁棒性的Hf原子点接触结构，该原子点接触结构能够被精准调控而获得在一定温度和时间范围内稳定可控的量子化电导态（>7000 s，300 K；>1000 s，400 K；>500次操作过程中，电导偏差小于0.5G0），这些量子电导以0.5G0为单位从0.5G0到16G0（32个量子电导态），最后，利用这些量子电导态演示了用于高效信息处理的三值逻辑完备集。这部分工作提出了构建任意量子电导态的的通用方案，即通过精准控制Reset能量输入能够在物理可重构的三明治结构体系Pt/HfOx/ITO中按需构建原子点接触结构。这项工作为获得多值存储与逻辑器件、设计具有其它功能的量子点接触器件提供了一个很好的平台。