Center for Dielectric Studies (CDS)

The Pennsylvania State University

A National Science Foundation Industry/University Cooperative Research Center since 1983

An improved understanding of dielectric materials will lead to the development of advanced devices for electronic technology

Center Mission and Rationale

Research projects at the Center for Dielectric Studies (CDS) aim to improve the basic understanding of the synthesis, processing, and properties of dielectric materials and the electrode metallizations for electronic devices. These devices include: capacitors, microwave components, hybrid microcircuits, thermistors, packages, multichip modules, and thin-film dielectrics. CDS member companies are a mix of material suppliers, device manufacturers, and final users of electronic devices. Having a vertically integrated set of sponsors helps CDS to maintain focus on problems relevant to industry.

The overall CDS research program is almost equally funded by membership fees, State and Federal grants, and industry enhancement projects.

Research Program

The Center's research thrust areas are:

• Electrolytic Capacitors, including: studies considering development of a point-defect model to understand the electrolysis process and the impedance characteristics of anodized films; new electrical characterization methods to understand field limited properties. Thermally Stimulated Current has determined two Poole-Frenkel regions. High surface area powders and Gibb-Thompson defect concentrations at points of high curvature.
• Piezoelectric Materials and Devices, including: reliability issues in multilayer actuators, non-lead piezoelectric material development, development of high frequency ultrasound devices, new materials for high performance piezoelectric MEMS, high temperature piezoelectric materials for sensors and actuators, laser processing of piezoelectric and pyroelectric thin films. Aging effects.
• Integrated Components, including: ultra-low fire dielectrics for high frequency metamaterials and devices, thin film sensors, embedded capacitors and varistors, LTCC and cofiring issues.
• Multilayer Capacitors, including: reliability, compositions, electrode roughness and discontinuity, X5R, X8R, and COG materials. Base-metal and precious metal dielectrics. Novel characterization methods, and defect characterization and modeling.
• High Energy Density Dielectrics & Components, including: energy densities between 10 J/cc to 30 J/cc materials include high temperature capacitor materials for power electronics, antiferroelectrics, weakly coupled dielectrics, high permittivity linear dielectrics, glass capacitors. Reliability issues under high fields and temperature, including dynamic drive conditions, composite structure, glasses, and poliymer systems.
• Components for Hostile Environments: This is the least developed part of our program, but we are working on high temperature thermistors, piezoelectrics, dielectrics, and thermoelectrics. In the future, we aim to also consider electronic passive components and ceramic sensors in high field conditions.

Research programs with these thrusts are also designed with the following philosophies: Basic, Revolutionary, and Evolutionary:

• Basic Research: Enables our member companies to better understand the issues that control the properties and/or limit a material or device.
• Revolutionary Research: Considers disruptive science and engineering issues. This can be in the form of new materials, processes, or phenomena that would completely alter the state-of-the-art industry or offer new business opportunities.
• Evolutionary Research: Involves studies that are about 3-6 years out, and projects are based on roadmap trends.

Facilities

CDS is housed in the Pennsylvania State University's 70,000 square-foot Materials Research Laboratory, which is designed for the needs of interdisciplinary materials research. The laboratory maintains central facilities common to various types of research and is capable of conducting scanning electron microscopy, environmental scanning electron microscopy, transmission electron microscopy, state-of-the-art x-ray diffraction, thermal analysis, and wet chemical analysis. Missouri University of Science and Technology has complementary facilities

Processing and Synthesis
Powder synthesis and processing can be carried out with ball mills, vibration mills, and attritor mills, and a three-roll mill is available to mix pastes and inks. CDS's multilayer capabilities include tape casting, screen printing, and multilayer lamination. Firing of hybrids can be done in either an IR or resistance-heated belt furnace.

For processing research, CDS has a computer-controlled furnace room with controlled-atmosphere firing capabilities and a custom-designed, fast-fire furnace. CDS has made a rate-controlled sintering system for studying densification mechanisms in multilayer ceramics. A new automated furnace system for smart control of the binder burnout process is being constructed.

Measurements
CDS, both at Penn State University and Missouri University of Science and Technology , has collectively one of the most comprehensive electrical measurement facilities in the world for dielectric materials. Routine automated, multi-sample dielectric tests are carried out at temperatures ranging from that of liquid nitrogen to 200*C and for frequencies from 100 Hz to 10 MHz. CDS has written custom data analysis programs to extract dielectric properties from the electrical test data. CDS also designed high-temperature dielectric measuring equipment that operates at temperatures up to 1200*C. Specialized pulse power and breakdown characterization facilities exist for capacitors at the MST (Rolla) site.

Specialized microwave and RF spectrum analyzers available to CDS can measure up to 26 GHz, while a low frequency FFT dielectric spectrometer is capable of measuring to 1.0 milliHz. Multi-sample dielectric reliability tests are set up for computer-automated data collection.

Special Center Activities

At CDS, graduate students and postdoctoral researchers are active participants in the Center's basic and applied research programs. Three students have assisted in CDS research through the Women, Minority, and Disabled High School and Undergraduate Engineering Research Assistants program. To date, a total of 32 students have obtained Ph.D. degrees through the CDS program and 47 students have earned Master's degrees. Approximately 15 students and 12 faculty members currently participate in the Center's programs. Some students supported by fellowships elect to conduct research in the Center, which provides financial support for these research projects.

The Center holds symposia on topics of interest to its members, including such subjects as powder analysis methods, reliability of ceramic devices, improvement of multilayer capacitor reliability, multilayer ceramic reliability, and power electronics.

To provide broad technology transfer to its sponsors' technical staffs, CDS faculty are also available to conduct one-day seminars at participating company sites. In addition, CDS strongly encourages its member companies to send an R&D representative to spend time at the Center's lab and believes that this interaction is the most effective method of technology and knowledge transfer from academe to industry. The Center will provide logistical support for visits ranging from one week to one year.

Center Headquarters

Center for Dielectric Studies
Materials Research Laboratory
The Pennsylvania State University
University Park, PA 16802
Tel: (814) 863-1328
Fax: (814) 865-8126
Homepage: http://www.mri.psu.edu/Centers/cds

Center Director: Dr. Clive A. Randall
car4@psu.edu

Center Evaluator: Stephen McGregor
Tel: (814) 865-4883
Fax: (814) 865-0960
slm2@psu.edu