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Uncovering the atomic origins of thin film ferroelectricity

揭示薄膜铁电性的原子起源

基本信息

批准号：
2004897
负责人：
BC Regan
金额：
$ 46.82万
依托单位：
University of California-Los Angeles
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004897&HistoricalAwards=false
关键词：
Uncovering atomic origins thin film

项目摘要

Non-technical Summary Memory is a key specification in consumer electronics like laptop computers and cell phones. For instance, a hard disk drive stores information as a series of “1”s and “0”s that are physically realized as tiny magnets. Instead of the magnetic materials in hard disk drives, new “ferroelectric” materials might form the basis of next-generation digital storage. In this project the research team uses advanced electron microscopy to probe the relationships between physical structure (where the atoms are) and electronic structure (how they respond to electric fields) in these new materials at the atomic level. Graduate and undergraduate students sponsored by this award will perform microelectronic device fabrication and testing, and become proficient at electron microscopy. These skillsets are directly applicable in the semiconductor industry. Students are being trained not only at the home institution of UCLA, but also at the minority-serving institutions of Norfolk State University and Fort Lewis College via a collaboration with the Partnership for Education and the Advancement of Quantum and nanoSystems (PEAQS), which is part of the NSF-funded Partnership for Research and Education in Materials (PREM).Technical SummaryHafnia (HfO2), when prepared in a very specific, non-equilibrium crystalline state, can exhibit ferroelectricity. Materials such as hafnia specifically are already commonplace in microprocessors, and underlie the emerging technologies of ferroelectric field effect transistors (FeFETs) and ferroelectric random access memory (FRAM). The team fabricates nanoscale, electron-transparent ferroelectric hafnia devices, and cycles the hafnia thermally and electrically in situ. These stimuli bring the hafnia, which is amorphous as deposited, through its various crystalline phases. Imaging the hafnia in each phase with electron beam-induced current (EBIC) imaging and electron energy loss spectroscopy (EELS), the team produces near-atomic resolution structural, electronic, and temperature maps. Correlating these maps with transport data acquired simultaneously provides a complete picture of these live, switchable devices. In particular, differential measurements of electronic properties, both before and after thermal and electrical cycling, enable the team to directly address such open problems as the origin and stability of the ferroelectric phase. Developing techniques for measuring the electrical and thermal properties of such materials contributes to the rational design of compact, low-power, and robust memory elements.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.

非技术性总结内存是笔记本电脑和手机等消费电子产品的关键规格。例如，硬盘驱动器将信息存储为一系列“1”和“0”，这些“1”和“0”在物理上被实现为微小的磁体。新的“铁电”材料可能取代硬盘驱动器中的磁性材料，成为下一代数字存储的基础。在这个项目中，研究小组使用先进的电子显微镜在原子水平上探测这些新材料的物理结构（原子所在的位置）和电子结构（它们如何对电场做出反应）之间的关系。由该奖项赞助的研究生和本科生将进行微电子器件制造和测试，并精通电子显微镜。这些技能直接适用于半导体行业。学生们不仅在加州大学洛杉矶分校的家乡机构接受培训，而且还在诺福克州立大学和刘易斯堡学院的少数民族服务机构通过与教育伙伴关系和量子和纳米系统的进步（PEAQS）合作进行培训，PEAQS是NSF资助的材料研究和教育伙伴关系（PREM）的一部分。非平衡结晶状态，可表现出铁电性。具体地，诸如氧化物的材料已经在微处理器中是常见的，并且是铁电场效应晶体管（FeFET）和铁电随机存取存储器（弗拉姆）的新兴技术的基础。该团队制造了纳米级的电子透明铁电氧化物器件，并在原位对氧化物进行热循环和电循环。这些刺激使沉积时为无定形的氧化铌通过其各种结晶相。利用电子束感应电流（EBIC）成像和电子能量损失谱（EELS）对每个阶段的纳米粒子进行成像，该团队产生了近原子分辨率的结构，电子和温度图。将这些地图与同时获取的交通数据相关联，可以提供这些实时可切换设备的完整图像。特别是，在热和电循环之前和之后的电子特性的差分测量，使团队能够直接解决铁电相的起源和稳定性等开放性问题。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Mapping Charge Recombination and the Effect of Point-Defect Insertion in GaAs Nanowire Heterojunctions

GaAs 纳米线异质结中电荷复合的映射和点缺陷插入的影响

DOI：
10.1103/physrevapplied.16.044030
发表时间：
2021
期刊：
Physical Review Applied
影响因子：
4.6
作者：
Zutter, Brian T.;Kim, Hyunseok;Hubbard, William A.;Ren, Dingkun;Mecklenburg, Matthew;Huffaker, Diana;Regan, B.C.
通讯作者：
Regan, B.C.

Imaging Dielectric Breakdown in Valence Change Memory