S-Rum Inductors: 30-Fold Enhancement of Inductance by Controlled Electroplating Post Rolling

The demand on power inductors with high inductances (micro-Henries) and high current-carrying capacities to have small footprints for Internet-of-Things (IOT) and Cyber-Physical-System (CPS) applications poses design and fabrication challenges. 3D air-core microtube inductors fabricated with self-rolled-up membranes (S-RuM) can provide higher inductance densities than planar inductors, but are restricted by both high resistive losses, dependent on metal film thickness, and air-core limited magnetic core integration. This study proposes a post-rolling electroplating process for increased metal conductivity and core permeability for S-RuM inductors. S-RuM inductors with parallel-processed Au-shell and partial-plated permalloy core resulted in improvements of over 10x DC resistance (DCR) decrease and over 30x inductance boost. Such improvements are predicted to increase in magnitudes upon optimized shell and core-filling, offering the potential for scaling this technology for use in power electronics applications such as converters and filters with minimal power losses.