The multi-university Industry/University Cooperative Research Center for Dielectric Studies at Pennsylvania State University and the University of Missouri aims to broaden the scope of the Center to complementary technological areas, which will drive the center towards long-term sufficiency. The Centers mission is to play a leadership role in the development of next-generation electronic components through the creation of new materials, new processing methods, high frequency device modeling, measurements, interfacial characterization, and prototyping highly integrated devices. New research thrust areas in microwave metamaterials and electrolytic capacitors will be developed.
Outcomes: Researchers at the I/UCRC Center for Dielectric Studies have made a number of important contributions to multilayer ceramic capacitor devices over the period of this grant. Impact: BaTiO3 is a high permittivity material that is the most important dielectric used in all passive components that dominate the circuit boards in all electrical systems. To give some idea of the number of BaTiO3-based devices manufactured per year, it is about 3 x 1012 components. In a smart phone, there are about 300 to 500 devices, and for every integrated circuit (chip), there may be 30 to 50 multilayer capacitors. The CDS work enabled manufacturers to increase volumetric efficiency by two orders of magnitude over the 10 years of the Center. Explanation: The major contributions to this advance are due to three pure and applied studies in the CDS: Understanding of critical dopant chemistries that limit the migration of oxygen vacancies under an electrical bias when under operation. This made the materials more robust to failure through this mechanism and thereby enabled grain sizes and thickness to be reduced. Introduced fast-firing as a method to control the electrode interface chemistry and roughness. All the major manufacturers in the world for high capacitance devices adopted this CDS innovation. It revolutionized the manufacturers' procedures for multlayer capacitor BaTiO3-based devices. Figures (a) and (b) show the electrode roughness for a conventionally processed capacitor device and a fast-fired device. A new theory and equation that enables manufacturers to predict wear-out and failure rates more effectively was introduced. Figures (c) and (d) compare data modeled with the old and new CDS model. Without going into details, the data points for failure are much more systematically represented with thte new equation from CDS (see reference). New quality control methods were introduced based on a method known as thermal stimulated depolarization current. High reliability systems, such as cardiac defibrillation, use a screening test developed by CDS to testmultilayer components before packaging into systems, which enhances their ultimate reliability. Ref: "Improved reliability predictions in high permittivity dielectric oxide capacitors under high dc electric fields with oxygen vacancy induced electromigration," C.A. Randall, C. A., R. Maier, R., W. Qu, K. Kobayashi, K. Morita, Y. Mizuno, N. Inoue, T.Oguni, J. Appl. Phys. 113(1), 014101 (2013).
