Quality factor enhancement of an on-chip inductor through the slot-trace method

This study investigated a slot-trace method to enhance the quality factor of an on-chip inductor. To verify the effect of a slot-trace method with lowered trace loss, and to compare it with a method lowering the substrate loss, three on-chip inductors were implemented with a 0.35 μm COMS–MEMS process: a CMOS inductor, a COMS–MEMS inductor, and a COMS–MEMS inductor with a slot trace. The results show that the substrate loss mainly lowers the quality factor performance at frequencies above 2 GHz. Unlike substrate loss, trace loss influences the quality factor from low to high frequencies, and the trace loss should not be ignored. Moreover, the results show that the slot-trace method can improve the quality factor, making it useful in on-chip inductor design for the circuits of wireless communication system applications.