Ferromagnetic Thin Films for Loss Reduction in On-Chip Transmission Lines

Microstrip transmission lines fabricated on standard silicon wafers are shown to benefit from the incorporation of thin ferromagnetic Ni-Fe films when compared to control devices without Ni-Fe. At 1 GHz, inductance and quality factor of the microstrip lines are enhanced by factors of 6 and 3, respectively, while the characteristic impedance of a 20 mum wide line is increased by 85%. For constant characteristic impedance, a 200 nm thick Ni-Fe film reduces attenuation from 1.6 to 0.7 dB/cm at 500 MHz