Fast ultra thin temperature silicon sensor

In this work a fast temperature sensor is studied for the application of aerospace field. The sensor has to detect, with a fast time response, in the order of the ms, the temperature rise of a MOSFET on to which it is placed, to avoid damaging the power circuit. The studied device is composed of an ultra-thin SOI thermodiode placed on a membrane and coupled to a micro-heater. The response time of the diode is measured while heating with an embedded micro-heater or with a power MOSFET on which the device is glued. It is found to be 20 ms when using the micro-heater and 106 s when using the power MOSFET. Numerical simulations were used to understand the device behaviour and the computed response time varies from 3.45 ms to 170 ms with the heater and 1.29 s with the power MOSFET. The difference with experimental measurements can be explained by the influence of the thermal model of the power MOSFET and the metal package.