A temperature all-silicon micro-sensor based on the thermo-optic effect

A new class of temperature silicon micro-sensors, based on an interferometric optical technique, is presented. The sensing element consists of a planar Fabry-Perot cavity defined on a silicon wafer by highly anisotropic reactive ion etching, and is therefore suitable for full integration with other standard opto- and micro-electronic devices. Preliminary temperature measurements have been performed with the temperature resolutions predicted by the theory. The limit performances, in terms of resolution, speed of operation and energy dissipation of this class of sensors are discussed in detail. In particular, a final temperature resolution of 0.064/spl deg/C is expected for a low loss interferometric cavity, with a settling time of 150 ns and a 0.2% readout error. An energy resolution as low as 30 nJ is also estimated.