Polyimide based GaAs micromachined millimeter wave structures

Abstract

This paper presents the manufacturing of high-performance millimeter wave lumped elements on polyimide membranes obtained by micromachining of semi-insulating GaAs. The microwave performances of the devices are compared with those obtained for similar structures manufactured on SiO2/Si3N4/SiO2 membranes on silicon micromachined substrates, as well as with the performances of similar devices manufactured on bulk GaAs and high-resistivity silicon. S parameter analysis and the computed lumped equivalent circuit emphasize the substantial decrease in the parasitic capacitances and, as a result, the outstanding improvement in the resonant frequency of membrane supported inductors. Comparative analysis of roughness and planarity of both types of micromachined structures was also performed. Polyimide membranes manufactured on GaAs substrate have proved to be a very good support for millimeter wave circuit elements, both from mechanical as well as electrical points of view.

Micromachined filters for 38 and 77 GHz supported on thin membranes

“…For the manufacture of the three-layer SiO 2 /Si 3 N 4 /SiO 2 membranes, conventional technological processes have been used [8].…”

“…In recent years, European groups have also reported significant results on micromachined microwave circuit elements supported on dielectric membranes [6][7][8][9][10]. In addition, passive devices on polyimide membranes have also been reported [10,11].…”

“…In recent years, European groups have also reported significant results on micromachined microwave circuit elements supported on dielectric membranes [6][7][8][9][10]. In addition, passive devices on polyimide membranes have also been reported [10,11]. A semi-insulating GaAs semiconductor membrane, as a support for microwave circuits, represents an interesting solution due to the possibility of passive element integration with active elements manufactured on the same substrate.…”

Millimeter-wave Micromachined Filter Design by Artificial Neural Network Modeling Technique

“…Micromachined structures [7][8][9][10] show their advantages like less radiation loss and ohmic loss compared to the conventional planar structures. The three-layer membrane (SiO 2 /Si 3 N 4 /SiO 2 ), obtained by micromachining of high resistivity <100> oriented silicon, is the key element in this technology.…”

“…In this paper, we designed the micromachined bandpass filters on GaAs substrate with membrane [8][9][10]. The electromagnetic simulation shows less than 1 dB insertion loss and acceptable stop band rejection.…”