Media protected surface micromachined leverage beam pressure sensor

• Published in: Journal of micromechanics and microengineering 2001-11, Vol.11 (6), p.617-622
• Main Authors: Melvås, Patrik, Kälvesten, Edvard, Stemme, Göran
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diaphragms; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electronics; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lithography, masks and pattern transfer; Micro- and nanoelectromechanical devices (mems/nems); Microelectronic fabrication (materials and surfaces technology); Micromachining; Physics; Piezoelectric devices; Polysilicon; Pressure transducers; Resistors; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Strain rate
• ISSN: 0960-1317; 1361-6439; 1361-6439
• DOI: 10.1088/0960-1317/11/6/301

In this paper we present the first surface micromachined ultraminiaturized, highly sensitive, pressure sensor that utilizes a force-transducing beam and a 2 mum thick polysilicon pressure sensing diaphragm as an encapsulation layer for high media isolation of the sensing piezoresistor. A beam is attached to the diaphragm at one end and to the cavity at the other end. The pressure-induced diaphragm deflection is transduced to strain in the beam and sensed by a piezoresistive strain-gauge on the beam. The piezoresistor is thus well isolated from the sensing environment. The pressure sensing performance was measured to 0.9 muV V exp -1 mmHg exp -1 .