Monolithic integration of mass sensing nano-cantilevers with CMOS circuitry

Miniaturization of cantilever dimensions will increase both the mass and spatial resolution of a resonating cantilever-based mass sensor, which monitors the mass change of the cantilever by measuring its resonant frequency shift. A fabrication method for nanometer-sized cantilevers with electrostatic excitation and integrated capacitive readout is introduced. The dynamic behavior of the nanometer-sized cantilever is characterized at atmospheric pressure using optical microscopy and in vacuum using scanning electron microscopy (SEM). A monolithic integration method for combining the nano-cantilevers with CMOS circuitry is described in detail. The circuitry is used to enhance the capacitive readout. The fabrication results, showing integrated nano-cantilevers with a CMOS analog amplification circuit, are presented along with preliminary electrical characterization of the device. (C) 2003 Elsevier Science B.V. All rights reserved.