APPLICATIONS OF THERMAL SILICON SENSORS ON MEMBRANES

Sensors fabricated on a thermally insulating thin inorganic membrane are described together with their applications. The device power consumption, level of response, response times and practical limitations are compared with theory. The use of the devices as sensors for pressure, flow rate and gas type is demonstrated. Pressures can be measured from about 10(-3) mbar to a few atmospheres; flow rates of at least 1 m s(-1) can be determined and a number of different gases can be identified. The sensor is normally operated in the temperature range 125-250 degrees C while consuming typically less than 10 mW of power with sensor response times of less than one second. The device is made using an inexpensive fabrication technique that is compatible with CMOS processing.