GOALI: Electrical Degradation in Thin Layer BaTiO3: Microchemical Origins and Microstructural Control

GOALI：薄层 BaTiO3 中的电降解：微化学起源和微观结构控制

• 批准号: 0606352
• 负责人: Clive Randall
• 金额: --
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0606352&HistoricalAwards=false
• 关键词: GOALI; Electrical; Degradation; Thin; Layer

NON-TECHNICAL DESCRIPTION:Capacitors are in numerous electronic systems, ranging in application from medical, telecommunications, computational, consumer electronics, transportation, and military. In development of modern day capacitors, long-term reliability is often limited by electrochemical processes within the capacitive materials that ultimately lead to material and device failure. With continued miniaturization of devices and electronic components, reliability becomes a more critical issue in maintaining yields and insuring electrical system longevity. This research aims to understand the statistical nature of material failure in capacitor materials using unique characterization techniques to identify local defects within a device that ultimately evolve to limit the lifetime of the component. This research program is collaborative endeavor between Kemet Corporation (Greenville, SC), who has vast experience in producing commercial multilayer ceramic capacitors and Penn State University who has an established history of research in capacitor materials and the analytical tools necessary to understand the physical origins of material degradation. Beyond providing a new experimental methodology for assessing and understanding degradation and failure, the program will foster greater university-industrial interaction and provide students with a dual industrial/academic perspective on a scientifically rich and technologically significant materials science research program. TECHNICAL DESCRIPTION:This research program focuses on material degradation phenomena in BaTiO3-based multilayer ceramic capacitors, with the specific aim of understanding scaling laws for degradation as the dielectric layers are reduced to submicron thickness. Generally, it is agreed that the loss of insulation resistance (increase in leakage current) in BaTiO3 is associated with the migration of oxygen vacancies under a DC bias. The kinetics of this degradation process, however, are a function of many processing variables, including dielectric and electrode formulations, layer thicknesses and lay-down, processing temperatures and PO2, all of which affect the microstructure and distribution of dopants and point defects within the material. Moreover, for each of these processes there are significant scaling issues encountered as the dielectric layer thickness is reduced below 1 mm, which need to be quantitatively and statistically evaluated and scientifically understood. Utilizing electron probe techniques that are sensitive to voltage and current imaging, we identify locations of high leakage current in capacitive devices. Applying these methods in-situ within a focused ion beam system, samples are extracted from the weak points of capacitors for more detailed electrical and structural analysis. A statistical approach is applied and modeled to better understand the onset of total leakage of a device from its microscopic origins. This research is timely, given the fact that within the next ten years, multilayer capacitors based on barium titanate will reduce to thicknesses of the order of 0.2 micrometers, and with layers approaching the many hundreds.

非技术描述：电容器在许多电子系统中，应用范围从医疗，电信，计算，消费电子，运输和军事。 在现代电容器的开发中，长期可靠性通常受到电容材料内的电化学过程的限制，这些电化学过程最终导致材料和器件失效。随着设备和电子元件的不断小型化，可靠性在保持产量和确保电气系统寿命方面变得更加关键。本研究旨在了解电容器材料中材料失效的统计性质，使用独特的表征技术来识别器件中的局部缺陷，这些缺陷最终会限制组件的寿命。该研究计划是Kemet Corporation（Greenville，SC）和Penn州立大学之间的合作奋进，Kemet Corporation在生产商用多层陶瓷电容器方面拥有丰富的经验，Penn State University在电容器材料研究方面拥有悠久的历史，并拥有了解材料降解的物理起源所需的分析工具。 除了提供评估和理解退化和故障的新实验方法外，该计划还将促进更大的大学-工业互动，并为学生提供科学丰富和技术重要的材料科学研究计划的双重工业/学术视角。 技术描述：该研究计划的重点是钛酸钡基多层陶瓷电容器中的材料退化现象，其具体目的是了解介电层减少到亚微米厚度时退化的比例定律。 一般认为，BaTiO 3的绝缘电阻损失（漏电流增加）与直流偏压下氧空位的迁移有关。然而，这种降解过程的动力学是许多加工变量的函数，包括电介质和电极配方、层厚度和沉积、加工温度和PO 2，所有这些都会影响材料内掺杂剂和点缺陷的微观结构和分布。 此外，对于这些工艺中的每一个，当电介质层厚度减小到1 mm以下时，都会遇到显著的缩放问题，这需要进行定量和统计评估并科学地理解。利用对电压和电流成像敏感的电子探针技术，我们确定了电容器件中高漏电流的位置。 在聚焦离子束系统中原位应用这些方法，从电容器的弱点提取样品，以进行更详细的电气和结构分析。 应用统计方法并建模，以更好地了解器械从其微观来源开始的总泄漏。 这项研究是及时的，因为在未来十年内，基于钛酸钡的多层电容器的厚度将减少到0.2微米量级，并且层接近数百层。