Monolithic integrated spreading-resistance silicon flow sensor

Abstract

A simple integrated flow sensor, with silicon spreading-resistance (SR) as the temperature-sensing element, has been designed and fabricated by a standard IC process. The operation of this spreading-resistance silicon flow (SRSF) sensor is based on the transfer of heat from a heated chip to a flowing fluid. The temperature difference on the chip is a measure of the flow velocity. Measurements are given for velocities up to about 4 m s-1 for air at room temperature, and higher sensor output is obtained for a higher temperature difference between the chip and flow. The SRSF sensor shows good prospects in applications involving velocity and direction sensitivities, and has great potential for flows of temperature higher than the intrinsic temperature of silicon ( ≈ 150°C) because the SR can sense higher temperature than conventional device structures.