非破坏性读出的铁电基互补逻辑机制研究及器件制作

The ferroelectric oxides based memory and logic devices have many advantages such as low power consumption, high density, non-volatility, and ease of writing, but the complex and destructive readout process greatly limits its application. Therefore, this project will study a non-destructive readout ferroelectric-based complementary logic device. The nanocrack induced at the domain boundary by the domain switching can be reversibly switched through electric field. The states of the crack are associated with the surrounding polarization states, which offers a new route for non-destructive readout. Specially, when two cracks located at two separated zones are manipulated by in-plane electric field, the complementary switching of cracks can be observed, which resembles the property of CMOS inverter. This project will study the physics mechanism of complementary switching and construct novel complementary logics based on the PMN-PT/MnPt heterostructure. Firstly, the structure of the device will be designed and optimized according to the electric field distribution simulated by the finite element software. Then the morphological characterization and electrical measurement of the complementary switching will be performed and further the logic devices including AND, OR, NOT and NAND will be constructed. The piezoelectric force microscopy is used to study the internal correlation between the crack states and domain switching. At last, a quantitative/semi-quantitative physical model will be established. It is believed that this project will offer a new route for the research of ferroelectric devices.

基于铁电氧化物实现的存储或逻辑器件具有低功耗、高密度、非易失和易于写入等诸多优点，但复杂且“破坏性”的读出过程极大地限制了它的应用，因此本项目拟研究一种非破坏性读出的铁电基互补逻辑器件。由铁电畴翻转在畴边界处诱导产生的纳米裂纹，能够在电场作用下可逆地开闭，且裂纹的开闭状态取决于周围铁电畴的极化状态，当裂纹扩展至在铁电表面生长的薄膜后，铁电极化状态就可以通过薄膜内电流通路的开闭来反映，从而实现非破坏性读出。特别地，在相互分离的两个薄膜区域间施加面内电场进行调控时，两个区域内的裂纹翻转会呈现出类似于CMOS反相器的互补特点，即一条裂纹闭合时另一条裂纹会打开。本项目拟基于PMN-PT/MnPt异质结，采用面内电场调控裂纹的互补翻转，构建新型的互补逻辑器件，并深入探究裂纹开闭与铁电畴翻转之间的物理机制。相信本项目将为铁电器件的研究提供新的方法和思路。

铁电纳米裂纹器件可以通过裂纹的开闭状态反应铁电体的极化状态，是一种非破坏性读出的铁电电子器件。该器件展现出的非易失翻转特性以及互补翻转特性，使得可以在同一器件结构内集成存储和逻辑功能，用于存算一体化研究。本项目基于铁电纳米裂纹构建非破坏性读出的铁电存算一体化器件。研究内容包括：（1）实验上观测纳米裂纹的互补翻转特性，并揭示其互补特性产生的内在原因；（2）纳米裂纹器件的互补翻转特性的电学性能表征；（3）缩放特性研究；（4）利用互补翻转特性构建基本逻辑功能；（5）探究纳米裂纹翻转的内在物理机制。.本项目基于（001）PMN-PT/MnPt异质结，揭示了铁电畴翻转诱导纳米裂纹开闭的物理机制，研究了纳米裂纹的互补翻转特性，解释了其产生的内在机理，并利用该互补翻转特性构建了逻辑器件，实验上实现了与、或和非等基本逻辑功能，同时给出了实现复杂逻辑功能的思路和方法，另外，纳米尺寸器件的测试结果表明随着尺寸缩放，翻转特性依然具有很好的稳定性，其翻转电压会降低。.与传统CMOS逻辑器件相比，铁电纳米裂纹逻辑器件的互补特性是自发形成的，不需要通过复杂的离子注入等工艺形成互补特性。并且，实现相同的逻辑功能时，铁电纳米裂纹器件使用的器件数目更少。本项目的研究成果表明，铁电纳米裂纹器件可用于构建互补逻辑功能，不仅为铁电电子器件的开发提供了新的思路和方案，同时在发展存算一体化器件方面具有很大的潜力。