GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Thursday, January 25, 2018

11:00 AM
in GTMI 401

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Teng Sun

"Modeling, Design, Fabrication and Characterization of High-Density Inductors with Advanced Magnetic Composites"

Committee Members:

Prof. Rao Tummala, Advisor, MSE

Prof. Hamid Garmestani, MSE

Prof. Dong Qin, MSE

Prof. Eric Vogel, MSE

Dr. Raj Pulugurtha, ECE

Abstract:

Inductors are critical power components in power converters. Their large size is, however, a major bottleneck for power module integration and efficient power management. High-density and miniaturized inductors can help migrate the power converters close to the processor. This can lead to lower losses, more efficient and granular power delivery. However, traditional magnetic materials that are used to fabricate inductors cannot achieve very high power densities or current-handling. Magnetic flake-composite materials provide unique opportunities to address these challenges by enhancing permeability, reducing core losses, miniaturizing and integrating inductors close to the processor load.

The primary objective of this research is to model, design and demonstrate high-performance power inductors with inductance densities of 10 nH/mm² for 100 nH inductors, with 5 milliohm DC resistance, and current-handling of 1 A/mm² for 10 A inductors . This requires major advances in magnetic materials with permeabilities of ~140, loss tangent of 0.1 at 5 MHz and saturation magnetization (Ms ) of 1 Tesla as well as specific inductor designs, materials, and  innovative substrate-embedding processes and characterizations.

Two-dimensional magnetic flakes provide multiple degrees of freedom to achieve high in-plane permeability with large X-Y dimensions and low eddy current losses from small Z dimensions. By synthesizing them as polymer composites, adequate thickness can be achieved for high current-handling. Advanced materials with 2D magnetic flakes will be designed to achieve high in-plane permeability, low losses from their plate-like morphology and high field-anisotropy. These materials are processed to achieve adequate thicknesses for current-handling. Such advanced materials are then integrated into inductors with innovative designs for achieving high inductance density with low DC resistance and high current-handling, with smaller footprints and lower thicknesses. Innovative material processing is developed to integrate such inductors with ultra-high performance into thin substrates.