Integrated High Frequency RF Inductors with Nano/micro Patterned Ferromagnetic Cores

摘要

Integrated solenoid inductors with high operating frequency and low loss have been demonstrated by using nano-/micro- size granular Ni_(80)Fe_(20) cores. The Ni_(80)Fe_(20) films were deposited by electroplating on three types of seed layer, Cr, Ti, and Ti covered by TiN under a magnetic field ～ 80 mT to align the magnetization. The Ni_(80)Fe_(20) film on Ti seed layer exhibits a large amount mostly disconnected islands with maximum diameter < 1.6 μm. By using the granular Ni_(80)Fe_(20) layer as the magnetic core, the inductors show high operating frequency >6.5 GHz and high cut-off frequency >20 GHz. Systematically optimizing the device's geometrical parameters, a high inductance per area >0.20 μH/mm~2, and a high quality factor >4.5 have been reached.