Enhanced Silicon Microresonator Oscillators

Lead Research Organisation: University of Cambridge
Department Name: Engineering


The 2 billion quartz resonator industry is on the verge of major change, as a result of an emerging disruptive technology that will replace quartz crystals in electronic devices / the integrated silicon resonator. SiTime Inc., founded by MEMS pioneer Kurt Peterson, has just begun manufacturing silicon resonators that are directly integratable with integrated circuit technologies, enabling mechanical oscillators to be fabricated on the same wafer as electrical circuits. These devices are just coming to market and the technology is still immature / offering substantial avenues for further development. In particular there is a major outstanding issue with silicon microresonator technology, which this proposal seeks to address viz. the net electrical impedance (or motional impedance) that these silicon resonators present to interfacing circuits is currently too large. One reason for this problem is the 'air-gap' actuators and sensors that are currently used to interface to the devices. We have developed and patented a novel internal actuation technique using pn-junctions that can be adapted for efficient electrical interfacing to silicon microresonators. This technique combined with a piezoresistive sensing mechanism, promises to significantly reduce the motional impedance for silicon-based devices as well provide a route towards full monolithic integration with CMOS technologies.


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Ransley J (2008) Silicon depletion layer actuators in Applied Physics Letters