A Study of On-Chip Solenoid Inductors for High Frequency Applications

Abstract — Because many on-chip inductors were applied in high frequency circuits, the nearby components in the circuits may generate unnecessary magnetic fields. In addition, conventional on-chip inductors on silicon wafer have suffered low quality factors due to the substrate losses. In this paper, we developed a novel on-chip solenoid inductor to prevent influence of external magnetic fields generated by nearby components in RF circuits. Also, we designed the solenoid inductor on a glass substrate to reduce the substrate losses. These inductors with different geometries were investigated. The inductor has an inductance of 3.9 nH and the maximum quality factor ( maxQ) of 12.7. The self-resonant frequency and the operating frequency at maxQ are greater than 14.5 GHz and 6.6 GHz, respectively. Key Words — on-chip solenoid inductor, MMIC, quality factor, inductance, resistance, and self-resonant frequency