Microcoils for high frequency switching power supplies
Integrated inductors with soft magnetic core based on Powder MEMS technology
The Powder MEMS technology developed at Fraunhofer ISIT offers a wide range of possibilities in the fabrication of inductors and transformers with magnetic core on a substrate (e.g. silicon, FR4) for high frequency applications.
The soft magnetic powder is agglomerated by atomic layer deposition (ALD) in the cavities. This solidifies the soft magnetic particles (diameter 1-20µm) by means of a thin dielectric layer (50nm), so that the particles are electrically connected to each other only at the contact surfaces and consequently hardly allow eddy currents. Thus, these components offer great advantages in high frequency applications (switching power supplies with 1-100MHz). The manufacturing process allows operating temperatures of the inductors up to 400°C, enabling a new level of integration and the achievement of higher power densities in products such as a power supply in a chip or package.
Because of this back-end-of-line compatible method, there are great opportunities for integration solutions. Especially for high frequency switching power supplies (SMPS, POL converters), many advantages can be achieved from an electrical and thermal point of view through integration, thus achieving higher power densities in the power supplies of typical applications, such as smart homes, IoT, multimedia consumer market etc.