Frequency dependence of relative permeability up to 9 GHz in Si/NiFe/FeCoB thin films was measured. In 200-nm-thick FeCoB thin film, μ′ reached about 70 and remained up to 3 GHz then decreased precipitously. Furthermore, μ″ indicated its resonance frequency fr at 6.4 GHz and produced prominent peak around the frequency. It was found that permeability characteristics increased loss term and lost its prompt responsivity when increasing thickness of FeCoB layer. Then a film with multilayer configuration was suggested in order to suppress the loss. The problems in multilayer configuration were solved and a multilayer film with fine soft magnetic properties was developed by insertion of Si/NiFe layers as intermediate layer. The multi-FeCoB-layer film with Si/NiFe intermediate layer indicated loss-suppressed permeability and good performance in permeablity at high frequency range.
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Physics and Astronomy (miscellaneous)