Design, fabrication, and characterization of a micromachined glass-blown spherical resonator with insitu integrated silicon electrodes and ALD tungsten interior coating

We propose a new approach for integration of electrodes as a part of the micro glass-blown spherical resonator fabrication process as well as an ALD metallization of the inner side of the spherical shell enabling electrostatic conduction. We use a 500μm thick silicon electrode whose electrostatic gap width, defined during the glass blowing process, is not limited by lithographic effect and enables sub-micron gap possibilities. In addition, we introduce a metallization technique based on ALD of tungsten on the inner side of the shell. 35:1 aspect ratio electrodes demonstrated to excite a 500μm radius spherical resonator with an operating frequency of 1.66MHz and a Q factor above 2700 in vacuum (0.4mT).