Cab-nanoelectronics

Nanoelectronics Micromechanical actuators and oscillators

 

The scope of this project is to produce micromanipulators, broadband low-frequency oscillators and extremely-high-frequency resonators, which are devices of broad applicability.

The precise manipulation of small objects is becoming more and more relevant for appliances used in data storage, micro assembly, sample manipulation in optical and electron microscopes, cell manipulation, routing fluids through microchannels, and manipulation of beam paths by micro mirrors. A general micromanipulation/positioning platform is being developed, consisting of grippers attached to a 6 degree-of-freedom (translation along 3 perpendicular axes and pitch, yaw and roll rotations) MEMS actuator composed of micromachined silicon in-plane, out-of-plane and torsional flexures combined with in-plane and out-of-plane electrostatic comb-drives.

Regarding broadband oscillators, such devices will be integrated into an energy harvesting circuit, in which a PZT conversion layer is subjected to mechanical bending originating from ambient vibrations in the Hz-kHz. For that matter, both piezoelectric and respective electrical contact materials are deposited and patterned atop the flexures of an out-of-plane microactuator. Requirements for such actuator are that displacements must be as large as possible (>10 µm) and its response should be as broad as possible in the ambient vibration frequency spectrum. A simple resonator is not the ideal device for that, as it only picks up a relatively narrow bandwidth, at and around its resonance frequency. A more convenient bistable, buckled oscillator that can oscillate between its two stable points with virtually no elastic restoring forces is being investigated. Design variations for obtaining generators capable of scavenging energy from 2D and 3D vibration spectra are being pursued as well.

Another type of actuators to be developed include micro- and nanoelectromechanical resonators, applied here to ultrasensitive mass, media and chemical detection through frequency shifting and damping analysis, in which appropriate coatings, inclusion of microchannels and innovative materials such as graphene are explored. Main efforts are currently in the size downscaling of conventional surface out-of-plane and bulk in-plane micromachined devices operating in the GHz range with consequent improvement in sensitivity. Sensor monitoring at such high frequencies is to be accomplished by UHF scanning laser vibrometry and integrated low-noise magnetoresistive systems.