Electrically induced stimuli for MEMS self-test

Abstract

A major problem for applying self-test techniques to MEMS is the multi-domain nature of the sensing parts that require special test equipment for stimuli generation. In this work we describe, for three different types of MEMS that work in different energy domains, how the required nonelectrical test stimuli can be induced onchip by means of electrical signals. This provides the basis for adding BIST strategies for MEMS parts embedded in the coming generation of integrated systems. The first case corresponds to an accelerometer as a review of a classical example. The last two cases correspond to piezoresistive and infrared sensors that we use in innovative applications under development in our Laboratory, and for which the self-test methods are new to our knowledge. The last case is also illustrated as a complete application that corresponds to an infrared imager. The on-chip test signal generation proposed requires only slight modifications and allows production test of the imager with a standard test equipment, without the need of special infrared sources and the associated optical equipment. The test function can also be activated off-line in the field for validation and maintenance purposes.