A deep submicron CMOS process compatible suspending high-Q inductor

A novel high-Q on-chip inductor structure called suspending inductor is dev eloped to improve the characteristics of the conventional on-chip spiral in ductor. The suspending inductor employs the air gap [1] and is supported by a set of novel metal pillars to suppress the capacitance from the metal la yer to the substrate. The measured maximum quality factor of the suspending inductor is improved from 4.8 to 6.3 in comparison to the conventional spi ral inductor. Furthermore, the frequency at maximum quality factor is raise d from 1.5-2 GHz.