EAGER: Room-Temperature Fabrication of Electroceramics

现代电子电路包含多种材料，但由于化学不兼容、致密化行为和/或热膨胀，在加工过程中将不同材料加热在一起是困难的。通常需要高温，但迫切需要创新的设计原则，允许在400°C的温度下用有机或半导体材料和银电极加工电陶瓷。室温制造方法可能是这样一种技术。不幸的是，许多电性能只有在随后加热后才能改善；因此，这一早期概念探索性研究资助(AGER)项目的目标是确定所涉及的致密化机制/动力学，从而开发具有有用电性能的室温可加工电容器氧化物，可应用于整个电陶瓷行业，以降低成本、能源消耗和随后的温室气体排放。这项研究直接支持了美国持续的竞争力，并支持了许多促进国家安全的商业防御应用。这项研究将通过几种方式与教育相结合，包括纳入陶瓷加工在线研究生课程。由于高温下的化学不相容以及烧结行为和热膨胀的差异，不同的材料很难共烧。由于缓慢的热激活扩散过程，致密化通常需要较高的温度。有可能通过在烧结过程中施加压力来增强驱动力；然而，迫切需要创新的设计原则，允许在400°C的温度下将电陶瓷组合物与有机或半导体结构和银电极共烧。室温制造方法可以是这样一种技术，但所涉及的物理原理尚未完全了解，其对功能陶瓷性能的影响也不是完全了解。该项目的目标将是利用原位电子显微镜研究来确定所涉及的致密化机制/动力学，从而对氧化物的室温致密化的机制和动力学有更全面的了解。利用这些信息，目标是开发相对介电常数高达~200，在射频范围内损耗正切为0.1的超低温可烧结电容器氧化物。该方法包括使用水溶液作为瞬时溶剂，通过中介的溶解-沉淀过程来实现陶瓷粉末的致密化。不幸的是，许多介电性能只有在消除应变、第二相、晶界和可能导致电子/离子运动的点缺陷后才会得到改善。这项研究的目标是开发在超低温下致密的陶瓷介质材料，并在不进行任何额外热处理的情况下展示微电子应用所需的性能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Modern electronic circuits contain many kinds of materials, but heating different materials together during processing is difficult due to incompatibilities in chemistry, densification behavior, and/or thermal expansion. High temperatures are typically required, but there is an urgent need for innovative design principles which would allow electroceramics to be processed with organic or semiconductive materials and silver electrodes at temperatures 400°C. The room-temperature fabrication method could be one such technology. Unfortunately, many electrical properties improve only after subsequent heating; thus, the goal of this EArly-concept Grant for Exploratory Research (EAGER) project is to determine the densification mechanisms/kinetics involved and thereby develop room-temperature processable capacitor oxides with useful electrical properties which can be applied throughout the electroceramics industry to lower costs, energy consumption, and consequent greenhouse gas emissions. This research directly supports the continued US competitiveness and supports many commercial defense applications promoting national security. The integration of this research with education will be achieved in several ways, including being included in a Ceramic Processing online graduate course.Co-firing different materials is difficult due to chemical incompatibility at high temperatures as well as differences in sintering behavior and thermal expansion. Due to the slow, thermally-activated diffusional processes, high temperatures are typically required for densification. It is possible to enhance the driving force by the application of pressure during sintering; however, there is an urgent need for innovative design principles which would allow electroceramic compositions to be co-fired with organic or semiconductive structures and silver electrodes at temperatures 400°C. The room-temperature fabrication method could be one such technology, but the physics involved are not yet completely understood, nor are its implications for the properties of functional ceramics. The goal of this project would be to use in situ transmission electron microscopy studies to determine the densification mechanisms/kinetics involved, and in so doing develop a fuller understanding of the mechanisms and kinetics of the room-temperature densification of oxides. With this information, the aim is to develop ultra-low-temperature sinterable capacitor oxides with relative permittivities up to ~200 and loss tangents 0.1 in the radio frequency range. The method involves the use of aqueous solutions as transient solvents to effect densification of ceramic powders via a mediated dissolution–precipitation process. Unfortunately, many dielectric properties improve only after annealing to remove strain, secondary phases, grain boundaries, and point defects which can lead to electron/ion motion. The goal of this research is to develop ceramic dielectric materials which densify at ultra-low temperatures and exhibit the requisite properties for microelectronic applications without any additional thermal processing.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.