The Sn/Pb eutectic alloy system is the most widely used joining material in the electronics industry. In this application, the solder acts as both an electrical and mechanical connection within and among the different packaging levels in an electronic device. Recent advances in packaging technologies, however, driven by the desire for miniaturization and increased circuit speed, result in severe operating conditions for the solder connection. In an effort to improve its mechanical integrity, metallic or intermetallic particles have been added to eutectic Sn/Pb solder, and termed composite solders. It was the goal of this study to investigate the growth and morphology of the two intermetallic phases (Cu6Sn5 and Cu3Sn) that form between a Cu substrate and Sn/Pb solder under different aging and annealing conditions.

Extreme environments pose major obstacles for electronics in the form of extremely wide temperature ranges and hazardous radiation. The most common mitigation procedures involve extensive shielding and temperature control or complete displacement from the environment with high costs in weight, power, volume, and performance. There has been a shift away from these solutions and towards distributed, in-environment electronic systems. However, for this methodology to be viable, the requirements of heavy radiation shielding and temperature control have to be lessened or eliminated. This work gained new understanding of the best practices in analog circuit design for extreme environments. Major accomplishments included the over-temperature -180 C to +120 C and radiation validation of the SiGe Remote Electronics Unit, a first of its kind, 16 channel, sensor interface for unshielded operation in the Lunar environment, the design of two wide-temperature (-180 C to +120 C), total-ionizing-dose hardened, wireline transceivers for the Lunar environment, the low-frequency-noise characterization of a second-generation BiCMOS process from 300 K down to 90 K, the explanation of the physical mechanisms behind the single-event transient response of cascode structures in a 45 nm, SOI, radio-frequency, CMOS technology, the analysis of the single-event transient response of differential structures in a 32 nm, SOI, RF, CMOS technology, and the prediction of scaling trends of single-event effects in SOI CMOS technologies.

The demands for advanced power sources with high energy efficiency, minimum environmental impact, and low cost have been the impetus for the development of a new generation of batteries and fuel cells. One of the key challenges in this effort is to develop and fabricate effective electrodes with desirable composition, microstructure and performance. This work focused on the design, fabrication, and characterization of nanostructured electrodes in an effort to minimize electrode polarization losses. Solid-state diffusion often limits the utilization and rate capability of electrode materials in a lithium-ion battery, especially at high charge/discharge rates. When the fluxes of Li+ insertion or extraction exceed the diffusion-limited rate of Li+ transport within the bulk phase of an electrode, concentration polarization occurs. Further, large volume changes associated with Li+ insertion or extraction could induce stresses in bulk electrodes, potentially leading to mechanical failure. Interconnected porous materials with high surface-to-volume ratio were designed to suppress the stress and promote mass transport. In this work, electrodes with these unique architectures for lithium ion batteries have been fabricated to improve the cycleability, rate capability and capacity retention. Cathodic interfacial polarization represents the predominant voltage loss in a low-temperature SOFC. For the first time, regular, homogeneous and bimodal porous MIEC electrodes were successfully fabricated using breath figure templating, which is self-assembly of the water droplets in polymer solution. The homogeneous macropores promoted rapid mass transport by decreasing the tortuosity. And mesoporous microstructure provided more surface areas for gas adsorption and more TPBs for the electrochemical reactions. Moreover, composite electrodes were developed with a modified sol-gel process for honeycomb SOFCs. The sol gel derived cathodes with fine grain size and large specific surface area, showed much lower interfacial polarization resistances than those prepared by other existing processing methods. Nanopetals of cerium hydroxycarbonate have been synthesized via a controlled hydrothermal process in a mixed water-ethanol medium. The formation of the cerium compound depends strongly on the composition of the precursors, and is attributed to the favored ethanol oxidation by Ce(IV) ions over Ce(IV) hydrolysis process. Raman studies showed that microflower CeO2 preferentially stabilizes O2 as a peroxide species on its surface for CO oxidation.