Embedded solenoid inductors for RE CMOS power amplifiers

The fabrication of a surface micromachined, epoxy-embedded, high-Q electroplated inductor, and the simultaneous integration of four of these devices with a foundry-fabricated CMOS RF power amplifier, is described. The embedded nature of these inductors allows conventional handling and packaging of inductor/chip systems without additional consideration for the inductor structure. A 6-turn inductor fabricated on silicon shows a peak Q-factor of 20.5 at 4.5 GHz and an inductance of 2.6nH. To demonstrate the technology, a power amplifier was implemented in a 0.24-mum CMOS foundry technology. Four inductors were integrated on the power amplifier. The resultant system demonstrated a gain of 6.7 dB at 0.8 GHz.