Micromachined on-chip high-aspect ratio air core solenoid inductor for multi-GHz applications

We present high aspect air-core solenoid inductors with 100 /spl mu/m and 200 /spl mu/m tall via structures on Pyrex wafer. The effect of various parameters such as different number of turns, via heights, pitch distance between turns on inductor's radio frequency (RF) characteristics have been studied. The highest Q factor we obtained from various solenoid inductors is 72.8 at 9.7 GHz, which was produced by a 3-turn inductor. The highest inductance we obtained was from a 20-turn inductor and it was from /spl sim/28 nH at peak Q frequency of 2 GHz 200 /spl mu/m tall via structures. This inductor occupies 0.75 mm/sup 2/ in area and hold a Q factor of 43 and a self-resonant frequency (SRF) of 5.1 GHz.