The fabrication of oxidized porous silicon membrane and its application to RF module

An oxidized porous silicon (OPS) membrane has been formed by anodization, thermal oxidation, and wet etching of a silicon wafer. Since the thick OPS layer is hetero silicon-dioxide, ethylene diamine pyrocatechol (EDP) does not etch it and so the self-etch-stop becomes possible. Passive RF elements, including coplanar waveguides, MIM capacitors, and spiral inductors, have been fabricated on this membrane and we have measured their performances. Using the design library of passive elements on OPS and OPS membranes, we have developed a low noise amplifier (LNA) for 2 GHz applications. The key idea of this LNA is based on the Friis equation and an input matching block was implemented on a locally formed nearly lossless OPS membrane to minimize the noise figure (NF). The inductively degenerated single-stage LNA showed 14 dB gain, 1.35 dB NF, and 5 dB IIP3 at 24 mW power dissipation.