Microelectromechanical systems in electrical metrology

Abstract

Microelectromechanical systems (MEMS) will have an important role in metrology. The essential features of a MEMS are (1) a piece of single crystal silicon forming a spring; (2) metallized surfaces of silicon structures that define an electrode geometry; (3) electrostatic forces between surfaces in a vacuum. With an electrostatic drive and readout such a system will dissipate very little power. In addition, compared to semiconducting devices, microelectromechanical components are large in size, and hence a low 1/f noise level is expected. We show that a MEMS can be used, in principle, to realize both a DC and an AC voltage reference, an AC/DC converter, a DC current reference, a low frequency voltage divider, a microwave and millimeter wave detector, etc. Unfortunately, existing MEMS technologies, where uncoated silicon structures form the electrodes, cannot be used due to trapped charges in silicon dioxide or on its surface. Thus, metallization of the surface is needed. We report preliminary results of our DC voltage reference showing a relative fluctuation level below 1 /spl mu/V/V.