Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS


This result comprises the design, fabrication and characterization of polysilicon cantilever array configurations, integrated with CMOS readout and control circuitry.

Several array configurations have been designed and fabricated: 4 and 8 cantilevers defined in common and separated nanoareas, and connecting the cantilever and a detection electrode to the readout circuit. In all cases, the length and distribution of metal line connection between the array of cantilever-driver transducers and the readout circuitry, have been optimised to minimize the interface parasitic capacitance.

The definition of the cantilever-driver arrays has been performed by UV lithography. As readout circuitry, a transimpedance configuration has been chosen in order to avoid the polarization nano-capacitor in the nano area and, consequently, minimize the distance between cantielevers into the array.

Two different strategies for readout through transimpedance circuits have been designed and fabricated:
- Direct connection from the components of the 4 cantilevers array to two independent readout transimpedance circuits (2 cantilevers to 1 circuit),
- Digitally controlled multiplexed connection from the components of the 8 cantilevers array to a single transimpedance circuit. Also in this second option, special care has been taken on minimizing the interface parasitic capacitances.

Simultaneous excitation and detection of two components of a 4 cantilevers array has been achieved. This has been possible by selecting and exciting two cantilevers connected to two independent readout circuits.

Potential applications of such an integrated array configuration are:
a) Multiple simultaneous detection of different species by specific fictionalisation of each component of the array.
b) Optimisation of detection performance by differential detection. One of the cantilevers of the array remains not functionalised and is used as a resonant frequency reference, which is only sensitive to all common mode variations (temperature, humidity, etc.).

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Reported by

Department of Electronic Engineering
Edifici Q. Escola Tècnica Superior d’Enginyeria
08193 Bellaterra (Barcelona)