High-Quality Factor Ni-Zn Ferrite Planar Inductor

Ferrite and air-core planar inductor arrays were fabricated on 4 inch Si wafer to characterize inductor performance. Three micron thick Ni
_0.5
Zn
_0.5
Fe
₂
O
₄
film was deposited by a low temperature electrophoresis ferrite deposition process. All ferrite inductors in the array showed 35% higher inductance (
L
) and 130% higher quality factor (
Q
) than air-core inductor. The maximum
Q
of ferrite inductor was found to be 53 at 2 MHz. The superimposed DC current and the rated power were measured to be about 3 A and 15 W, respectively, for a 5% drop in
L
. The fabricated ferrite inductor has a higher current capability than the air-core inductor. In addition, the power efficiency of the buck DC-DC converter was predicted to be 94.3% at 1.93 W.