Stability of silicon microfabricated pull-in voltage references

Micromechanical structures have been designed, fabricated in silicon and tested for use as on-chip voltage reference. Applications are in electrical metrology and in integrated silicon microsystems. Microbeams of 100 /spl mu/m length, 3 /spl mu/m width and 11 /spl mu/m thickness are electrostatically actuated with a very reproducible pull-in voltage at 9.1 V. Devices demonstrated an initial drift of -12 mV over 10 days and stabilised with a 500 /spl mu/V uncertainty. The temperature coefficient is 1.2 mV/K and the overall noise level is at 100 /spl mu/V (analytical value).