Abstract.
Flat SiO2 / Si3N4 / SiO2 dielectric membranes have been produced on high resistivity silicon substrates. The membranes have been obtained by anisotropic etching using TMAH as etchant. The deposition process and the thickness of the dielectric layers have been chosen in order to obtain a slightly tensile "global" stress. The flatness of the membranes has been tested by three different techniques: Laser Scanning, AFM and Makyoh topography.
To demonstrate the effectiveness of the technological process, some coplanar waveguides have been produced both on membrane and high resistivity Si substrate. The electrical measurements have shown a satisfactory improvement in terms of device performances.