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

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。在现代电容器的发展中，长期可靠性往往受到电容材料内部电化学过程的限制，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，可靠性成为保持产量和确保电气系统寿命的关键问题。本研究旨在利用独特的表征技术来了解电容器材料中材料失效的统计性质，以识别器件内最终发展到限制组件寿命的局部缺陷。该研究项目是Kemet公司（Greenville， SC）和宾夕法尼亚州立大学（Penn State University）之间的合作，Kemet公司在生产商业多层陶瓷电容器方面拥有丰富的经验，宾夕法尼亚州立大学在电容器材料研究方面有着悠久的历史，并拥有了解材料降解物理起源所必需的分析工具。除了提供一种新的实验方法来评估和理解降解和失效，该计划将促进更多的大学-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：本研究项目侧重于batio3基多层陶瓷电容器中的材料降解现象，具体目的是了解介电层厚度降至亚微米时降解的缩放规律。一般认为，在直流偏压下，BaTiO3中绝缘电阻的损失（泄漏电流的增加）与氧空位的迁移有关。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、层厚度和铺设、加工温度和PO2，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，对于每一种工艺，当介电层厚度减小到1毫米以下时，都会遇到显着的缩放问题，需要对其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泄漏电流的位置。在聚焦离子束系统中原位应用这些方法，从电容器的弱点中提取样品以进行更详细的电气和结构分析。统计方法的应用和建模，以更好地理解从微观起源的一个装置的总泄漏的开始。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，层数将达到数百层。

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.