Integrated Solenoid Inductors with Solid Ferrite Core

Abstract

Passive components such as inductors are essential components in many fields of electronics. This article focuses on the manufacturing of integrated inductors with a solid ferrite magnetic core. The use of the soft ferrite materials MnZn and NiZn enables the manufacturing of integrated inductors and transformers, which operate over a very wide frequency range, up to hundreds of MHz. The magnetic core is obtained via laser micromachining of low-cost and readily available commercial ferrite material. The proposed component is produced using microelectronic approaches such as PVD, electrolysis, and photolithography, and the chip placement of the thick ferrite magnetic circuit (20–200 µm) is reported. The main steps of microfabrication are described in detail, demonstrating the possibility of integrating solid ferrite cores into microtechnological processes. Simulated and measured values obtained for the produced component allow us to validate the presented approach.