Thickness effect on 1 GHz permeability of (CoFeB)-(SiO/sub 2/) films with high electrical resistivity

Highly resistive (CoFeB)-(SiO/sub 2/) films for magnetic core of 1 GHz driving inductor were deposited on glass substrates by synchronous dual-rf magnetron sputtering. Permeability characteristics In the range of a few GHz were investigated. The thickness effect on the reciprocal of the loss factors of tan /spl delta/ (/spl mu//sub r/'//spl mu//sub r/") were investigated at 1 GHz. The film exhibited the maximum value of /spl mu//sub r/'//spl mu//sub r/" of 5.7 for film thickness d=0.1 /spl mu/m, with relative permeability of 120-150 and resonance frequency f/sub r/=1.6-1.9 GHz. The result shows good potential for magnetic core of 1 GHz driving inductor.