Thermally excited silicon oxide bridge resonators in CMOS technology

The authors report the design and fabrication of thermally excited silicon oxide bridge resonators realized by two different industrial CMOS processes combined with subsequent micromachining. They characterized the devices by measuring resonance frequencies, vibration amplitudes, and mode shapes using a Mach-Zehnder interferometer. They tested the on-chip detection of vibrations using polysilicon piezoresistors. They investigated the acoustic transmitting and receiving efficiencies of the bridge resonators in air for possible application as ultrasound transducers for proximity sensing.