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THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
GEORGIA INSTITUTE OF TECHNOLOGY
Under the provisions of the regulations for the degree
DOCTOR OF PHILOSOPHY
on Tuesday, December 4, 2018
1:00 PM
in MaRC 2011
will be held the
DISSERTATION PROPOSAL DEFENSE
for
Robert Grant Spurney
"Package-Integrated, Ultra-Thin, High-Density Capacitors for Integrated Voltage Regulation"
Committee Members:
Prof. Rao Tummala, Advisor, MSE
Prof. P.M. Raj, Florida International University
Prof. Preet Singh, MSE
Prof. Dong Qin, MSE
Prof. Meilin Liu, MSE
Abstract:
There is a prevalent and increasing need for voltage regulators that are integrated as close as possible to the active devices such as CPUs and GPUs. These integrated voltage regulators (IVRs) provide numerous performance benefits including higher efficiency, better transient performance, and increased functionality while miniaturizing the overall system size. However, passive components generally occupy the largest volume in power distribution networks (PDNs). Therefore, realizing high-density passive components in ultra-thin form-factors is the main bottleneck to enable highly miniaturized 3D IVRs. An approach that can create ultra-high surface area electrode materials, defect-free dielectrics, and stable electrode interfaces with low-cost integration processes on large-area substrates is required to comprehensively address the challenges of developing capacitors for IVRs.
High-density, printed thin-film tantalum capacitors can meet all these criteria. Tantalum as an electrode material can provide low resistivity and high surface area of >1,600 mm2/mm3 by using sintered metal nanoparticles to form the anode structure. A tantalum foil-based carrier used for printing and sintering Ta particulate electrode provides a unique way to reduce RC delay and improve the frequency stability of capacitance. Additionally, moderately high-permittivity Ta2O5 (r ~ 25) can be electrochemically grown directly on the nanoparticles to form a conformal, amorphous dielectric material with controllable thickness down to <3 nm. The combination of these properties provide some of the highest capacitance densities of any known capacitor material system, while maintaining low dielectric and conduction losses. The paraelectric dielectric Ta2O5 offers greater temperature and voltage stability compared to Barium Titanate (BaTiO3)-based ferroelectrics. The proposed capacitors in this work aim to improve upon current material approaches in capacitor technology by offering better density, ultra-thin form factor, and high-reliability in a package-integrated format. This work aims to provide a fundamental understanding of the interactions between the capacitor nanostructure and the properties that govern its electrical behavior while also demonstrating a novel technology that can be used in next-generation systems.
