Using an Insulator-Metal Transition to Overcome the Fundamental Limits of Non-Volatile Memory Based on Ferroelectric Field Effect Transistors

非技术：大数据时代给计算系统和网络带来了巨大的挑战。随着计算基础设施的发展以应对这些挑战，内存技术扮演着越来越重要的角色。预计到2025年，每年将产生超过100 Zeta字节的数据。因此，未来几代计算机将需要快速、节能、可靠和紧凑的高性能存储器。虽然现有的技术具有一些理想的特性，但它们严重缺乏其他特性。例如，基于氧化铪（一种最近发现的材料）的铁电场效应晶体管（fet）表现出非常有前途的特性。它们是持久的，即使在关闭时也能保留信息，具有纳秒级的切换速度，并且占用空间小。然而，这项技术的实际实现受到一些基本问题的阻碍，这些问题会损害可靠性并限制设备在低电压下的运行。提出的研究旨在通过将一种新的功能材料集成到铁电场效应管中来解决这一挑战。二氧化钒表现出绝缘体到金属的相变，允许它在绝缘和导电状态之间来回切换。这种特性将用于克服与现有材料相关的基本障碍，并使存储器技术的性能大大超过当前最先进的技术。该项目为参与的学生提供了一个自然的平台，使他们能够参与电气工程和材料科学交叉的跨学科研究。拓展工作将使本科生和高中生接触到现代电子产品，并扩大他们对该领域机会的经验和理解。技术：本研究项目旨在通过用绝缘体-金属相变氧化物VO2取代晶体管的传统硅沟道，克服从掺杂氧化铪铁电场效应晶体管非易失性存储器中写入和读取的基本设计折衷。将在该器件中设计的跨VO2相变的铁电态依赖突变电阻开关将有助于消除读写约束，并使存储单元能够在低电压下写入，而不会对读取裕度产生不利影响，同时也提高了可靠性。本研究的一个基本方面将集中于在受限的热预算下稳定掺杂氧化铪在VO2上的铁电相。此外，通过材料-器件协同设计方法，该项目将寻求实验证明一种基于铁电晶体管的存储器，该存储器可以在低写入电压和能量下工作，提供大的读取区别，并表现出大的耐用性和可靠性。将开发基于物理的模型和模拟，以捕获设备的操作以及说明其与阵列级操作的兼容性，以支持和指导实验工作。所提出的研究结果对实现通用存储器以支持和加速数据革命具有巨大的意义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical:The era of Big Data is creating enormous challenges to computing systems and networks. As the computing infrastructure evolves to meet these challenges, memory technology plays an increasingly important role. Over one hundred Zeta Bytes of data is expected to be generated annually by the year 2025. Future generations of computers will therefore need high performance memory that is fast, energy efficient, reliable, and compact. While existing technologies have some of the desired properties, they crucially lack others. For example, ferroelectric field effect transistors (FETs) based on hafnium oxide, a recently discovered material, exhibit very promising properties. They are persistent, retaining information even when turned off, have nanosecond switching speeds, and a small footprint. However, practical realization of this technology is impeded by fundamental issues which compromise reliability and constrain the operation of devices at low voltages. The proposed research aims at addressing this challenge by integrating a new functional material into ferroelectric FETs. Vanadium dioxide exhibits an insulator-to-metal phase transition, allowing it to be switched back and forth between an insulating and conductive states. This property will used to overcome the fundamental barriers associated with existing materials and enable a memory technology that significantly exceeds the performance of the current state-of-the-art. The project provides a natural platform for participating students to be involved in cross-disciplinary research at the intersection of electrical engineering and materials science. Outreach efforts will expose undergraduates and high school students to modern electronics, and broaden their experience and understanding of the opportunities in the area.Technical:This research project aims to overcome the fundamental design trade off involved in writing to, and reading from doped hafnium oxide ferroelectric field effect transistor-based non-volatile memory by replacing the conventional silicon channel of the transistor with an insulator-metal phase transition oxide, VO2. The ferroelectric state dependent abrupt resistance switching across the phase transition in VO2 that will be engineered in this device, will help de-convolute the read and write constraints, and enable the memory cell to be written at low voltages without adversely affecting the read margin, as well as also improve the reliability. A fundamental aspect of this research will focus on stabilizing the ferroelectric phase of doped hafnium oxide on the VO2 under a constrained thermal budget. Furthermore, through a materials-device co-design approach, the project will seek to experimentally demonstrate a ferroelectric transistor-based memory that can operate at a low write voltage and energy, provide large read distinguishability, and exhibit large endurance and reliability. Physics based models and simulations that capture the operation of the device as well as account for its compatibility with array level operation will be developed to support and guide the experimental effort. The results of the proposed research stand to have immense implications towards realizing a universal memory to support and accelerate the data revolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.