Modeling, design, fabrication and demonstration of multilayered ferromagnetic polymer-dielectric composites for ultra-thin high-denisty power inductors

Abstract

The emerging need for smart and wearable electronic systems are driving new electronics technology paradigms in miniaturization, functionality and cost.The operating voltages and power levels for devices in these systems are becoming increasingly varied with increased diversity of devices to serve these heterogeneous functions. Power convertor technologies are incorporated into various parts of these systems to step-up or step-down battery voltages and currents to address these diverse needs. Hence, multiple power converters, each requiring several passive components, are used to create stable power-supplies. This is placing significant challenges in ultra-miniaturized and ultra-efficient power management technologies. A typical power convertor consists of magnetic components such as inductors perform the basic energy storage and delivery functions from the source to the load. These power components are still at microscale in lithography and milliscale in component size. They occupy a large volume fraction of the power circuitry. Power convertors therefore, are a major bottleneck to system miniaturization. There is, thus, a need for ultra-miniaturized and high-performance power inductors for scaling down such power convertors. The critical parameters governing the size and performance of power inductors are its inductance density and power handling capability. These parameters are limited by the magnetic properties of the present inductor core materials. A new approach to inductor cores that achieves the best magnetic properties and yet allows integration of power inductors into ultra-thin substrates to meet the emerging needs for performance and size is therefore required. The objective of this research is to model, design and synthesize a novel multilayered ferromagnetic-polymer composite structure for inductor cores with high permeability and saturation magnetization.The multilayered composite structure consists of thin magnetic layers interspersed with ultra-thin polymers. A fabrication approach to integrate the composite structure in inductor devices is also demonstrated.