Micro-Inductors and Transformers

Recently, many planar microdevices have been proposed, including planar bulk inductors, thin-film inductors, and thin-film transformers. In this paper, the high-frequency operation of thin-film microinductors and microtransformers prepared by photolithography techniques is investigated. Features such as the coil structure and resistivity, the structure and iron loss of the magnetic core, and the capacitance are examined in detail, and the main features of these thin-film microdevices are described. It is expected that the operation frequency of thin-film microinductors and microtransformers will be raised further by decreasing the iron loss and capacitance between the coil and the core.