This work explores MEMS (Micro-ElectroMechanical Systems) potentialities to produce flexible AC voltage references through mechanical-electrical transduction that could be used for high precision electrical metrology and for applications in miniaturized instrumentation. AC voltage references ranging from 2 V to 90 V have been designed and fabricated using the same Epitaxial Silicon On Insulator (SOI) Surface Micromachining process that permits an accurate control of both dimensions and material properties. The measured MEMS AC voltage reference values have been found in a good agreement with the calculations performed with Coventor software. These test structures have been used to develop the read-out electronics to drive the MEMS and to design a second set of devices with improved characteristics. Deep Level Transient Spectroscopy measurements carried out on the new MEMS showed resonance frequencies of about a few kilohertz, which makes it possible to have AC voltage references working from about tens of kHz. Moreover, the stability of the MEMS out-put voltage at 100 kHz has been found very promising for the best samples where the relative deviation from the mean value over almost 12 h showed a standard deviation of 6.3 × 10-6, which is a very good result.

Key words

MEMS design
voltage reference
SOI process