SILICON-BASED MASS AIRFLOW SENSOR

摘要

A mass airflow sensor is fabricated on a semiconductor substrate and which includes (1) a dielectric diaphragm, (2) p-etch-stopped silicon rim, (3) thin-film heating and temperature sensing elements, and (4) tapered chip edges. The dielectric diaphragm is formed with thin silicon oxide and silicon nitride in a sandwich structure and provides excellent thermal insulation for the sensing and heating elements of the sensor. The diaphragm dimensions, including thickness, are accurately controlled through the use of the heavily-p-doped silicon rim to help ensure uniform and reproducible sensor performance.