A CMOS low noise amplifier with integrated front-side micromachined inductor

The paper presents the design and characterization of a low noise amplifier (LNA) in a 0.18 μm CMOS process with a novel micromachined integrated stacked inductor. The inductor is released from the silicon substrate by a low-cost CMOS compatible dry front-side micromachining process that enables higher inductor quality factor and self-resonance frequency. The post-processed micromachined inductor is used in the matching network of a single stage cascode 4 GHz LNA to improve its RF performance. This study compares performance of the fabricated LNA prior to and after post-processing of the inductor. The measurement results show a 0.5 dB improvement in the minimum noise figure and a 1 dB increase in gain, while good input matching is maintained. These results show that the novel low-cost CMOS compatible front-side dry micromachining process reported here significantly improves performance and is very promising for System-On-Chip (SOC) applications.