Inductors have been used in RF circuits, such as voltage controlled oscillators, power amplifiers, mixers, etc. As the operating frequency of recent silicon RF IC's moves to the multi-GHz frequency range, it becomes difficult to achieve affordable Q-factors (>15) from on-chip inductors fabricated using conventional thin-film, planar IC processes.

Fully CMOS-compatible, highly-suspended spiral inductors have been designed and fabricated on standard silicon substrate (1~30§Ù¡¤cm in resistivity) by our surface micromachining technology. We have achieved a peak Q-factor of 70 at 6GHz with inductance of 1.38nH (at 1GHz). This work has demonstrated that the our MEMS inductors can be a viable technology option to meet the today's strong demands on high-Q on-chip inductors for multi-GHz silicon RF IC's.