GOALI: To Understand Crystallization and Amorphization Dynamics in Phase-Change Memories by Linking Electro-Thermal Models, Electrical Experiments and TEM Characterization

目标：通过连接电热模型、电气实验和 TEM 表征来了解相变存储器中的结晶和非晶化动力学

• 批准号: 1710468
• 负责人: Helena Silva
• 金额: $ 45万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710468&HistoricalAwards=false
• 关键词: GOALI; Understand; Crystallization; Amorphization; Dynamics

Nontechnical description: Phase-change memory, an electronic memory concept that utilizes materials whose electrical resistance can be rapidly and repeatedly switched between high and low magnitudes, holds great promise for more efficient computation and data storage. This collaborative project between the University of Connecticut and IBM Watson Research Center combines computation, electrical characterization and microscopy to gain a better understanding of several phase-change materials phenomena that are critical for data storage devices. Results from this work can open new possibilities for future materials synthesis and electronic devices. This project supports the education and training of a diverse group of students in Electrical Engineering and Materials Science and Engineering, and also the broader community through several outreach programs. The students and post-doctoral researchers directly involved with the project benefit from access to state-of-the-art facilities and opportunities for first-hand contributions to fundamental studies with direct technological applications.Technical description: Large-scale use of phase-change memory has been hindered by the high power required to heat the nano-scale element above crystallization or melting (for melt-quench amorphization) and by limited reliability due to resistance drifts of the metastable phases, elemental segregation, and void formation upon extensive cycling. If these device characteristics can be improved, phase-change memory can be integrated on top of conventional silicon electronics as high capacity, non-volatile on-chip storage, leading to significant performance and energy improvements. This project focuses on the crystalline-amorphous transition, including the possibility of solid-state or electronic amorphization which can lead to lower power devices. In addition, it investigates correlations between electronic properties, such as resistance drifts, and changes in microstructure. Finally, the team is also addressing details of the lesser known cubic-hexagonal transition that is not typically used but may be advantageous in some cases. This work requires development of techniques for in-situ transmission electron microscopy experiments, suitable electrical characterization techniques and improved models that combined can provide a better understanding of phase transition dynamics across different time and temperature scales.

非技术描述：相变存储器是一种电子存储器概念，它利用的材料的电阻可以在高低量级之间快速反复切换，它对更有效的计算和数据存储有很大的希望。康涅狄格大学和IBM沃森研究中心之间的这个合作项目结合了计算、电表征和显微镜，以更好地了解对数据存储设备至关重要的几种相变材料现象。这项工作的结果可以为未来的材料合成和电子器件开辟新的可能性。该项目支持电气工程和材料科学与工程的不同学生群体的教育和培训，并通过几个外展计划支持更广泛的社区。直接参与该项目的学生和博士后研究人员将受益于使用最先进的设施，并有机会通过直接的技术应用为基础研究做出第一手贡献。技术描述：相变存储器的大规模使用一直受到以下因素的阻碍：在纳米级元件结晶或熔化以上加热所需的高功率（用于熔融-淬火非晶化），以及由于亚稳相的电阻漂移、元素偏析和广泛循环后形成的空洞而导致的可靠性有限。如果这些器件特性可以得到改善，相变存储器可以集成在传统硅电子器件之上，成为高容量、非易失性片上存储器，从而显著提高性能和能源。该项目侧重于晶体-非晶过渡，包括固态或电子非晶化的可能性，这可以导致低功率器件。此外，它还研究了电子特性（如电阻漂移）与微观结构变化之间的相关性。最后，该团队还讨论了鲜为人知的立方-六边形过渡的细节，这种过渡通常不使用，但在某些情况下可能是有利的。这项工作需要开发原位透射电子显微镜实验技术、合适的电表征技术和改进的模型，这些技术结合起来可以更好地理解不同时间和温度尺度的相变动力学。

项目成果

Reversible Phase Transformations during In-Situ Heating of Uncapped Ge2Sb2Te5 Films

无帽 Ge2Sb2Te5 薄膜原位加热过程中的可逆相变

• DOI: 10.1017/s1431927621008631
• 发表时间: 2021
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Ghosh, Chanchal;Singh, Manish;Kotula, Paul;Silva, Helena;Barry Carter, C.
• 通讯作者: Barry Carter, C.

Defect Imaging and Structure Evolution in GST Films During In-situ Heating

• DOI: 10.1017/s1431927620017961
• 发表时间: 2020-07
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: C. Ghosh;M. Singh;J. Watt;H. Silva;C. B. Carter

Modeling of void formation in phase change memory devices

相变存储器件中空隙形成的建模

• DOI: 10.1016/j.sse.2019.107684
• 发表时间: 2020
• 期刊: Solid-State Electronics
• 影响因子: 1.7
• 作者: Cywar, Adam;Woods, Zachary;Kim, SangBum;BrightSky, Matt;Sosa, Norma;Zhu, Yu;Kim, Hyeong Soo;Kim, Hyung Keun;Lam, Chung;Gokirmak, Ali
• 通讯作者: Gokirmak, Ali

Computational Analysis of Complex Amorphization/Crystallization Dynamics in Large Phase Change Memory Devices

大型相变存储器件中复杂非晶化/结晶动力学的计算分析

• 发表时间: 2019
• 期刊: Materials Research Society symposia proceedings
• 作者: Kashem, M. T.;Muneer, S.;Noor, N.;Scoggin, J.;Silva, H.;Gokirmak, A.
• 通讯作者: Gokirmak, A.

Direct Visualization of the Earliest Stages of Crystallization

• DOI: 10.1017/s1431927621000441
• 发表时间: 2021-05
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: M. Singh;C. Ghosh;B. Miller;C. B. Carter