Micromachined CMOS LNA and VCO by CMOS-compatible ICP deep trench technology

Selective removal of the silicon underneath the inductors in RF integrated circuits based on inductively coupled plasma (ICP) deep trench technology is demonstrated by a complementary metal-oxide-semiconductor (CMOS) 5-GHz low-noise amplifier (LNA) and a 4-GHz voltage-controlled oscillator (VCO). Design principles of a multistandard LNA with flat and low noise figures (NFs) within a specific frequency range are also presented. A 2-dB increase in peak gain (from 21 to 23 dB) and a 0.5-dB (from 2.28 to 1.78 dB) decrease in minimum NF are achieved in the LNA while a 3-dB suppression of phase noise is obtained in the VCO after the ICP backside dry etching. These results show that the CMOS-process-compatible backside ICP etching technique is very promising for system-on-a-chip applications.