Significantly Enhanced Inductance and Quality Factor of GHz Integrated Magnetic Solenoid Inductors With FeGaB/<inline-formula> <tex-math notation="TeX">${\rm Al}_{2}{\rm O}_{3}$ </tex-math></inline-formula> Multilayer Films

Abstract

We report new high quality factor (Q) integrated GHz magnetic inductors based on solenoid structures with FeGaB/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">${\rm Al}_{2}{\rm O}_{3}$ </tex-math></inline-formula> multilayer films, which show significantly enhanced inductance and quality factor at GHz frequencies over their air core counterparts. These inductors show an excellent high-frequency performance with a wide operation frequency range 0.5–2.5 GHz, in which the inductance is flat and the peak quality factor can reach <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">${\sim}{\rm 20}$ </tex-math></inline-formula> . The inductance of the magnetic inductor shows <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">${&gt;}{100\%}$ </tex-math></inline-formula> enhancement compared with that of the same size air core inductor. These novel GHz inductors with high inductance and Q enhancement show great promise for applications in radio frequency integrated circuits.