Environmentally rugged, wide dynamic range microstructure airflow sensor

Abstract

A silicon microstructure airflow sensor has been developed with a wide dynamic operating range and ruggedness for long-life operation in harsh environments. Platinum metallization is used for the airflow sensor because of its resistance to corrosion. Processing of thin-film platinum has been developed to achieve a high, stable value of the platinum temperature coefficient of resistance (TCR). The sensor design can be adjusted for sensitivity or range depending upon the application requirements. The airflow sensors were subjected to accelerated life testing to demonstrate the ability to maintain electrical stability and physical integrity in harsh environments. The life testing consisted of operation of the sensors with airflow in overpowered, high-temperature, and high-humidity conditions for extended periods. The sensors were also subjected to extended periods of time during which dust particles were added to the flow to simulate a dusty environment. The sensors performed well throughout the accelerated life testing with little change in output characteristics.