Structure of micro-pirani sensor

摘要

A new structure of a vacuum meter with good designs of temperature compensation and stabilization, The structure comprises a floating plate made by a micro-machining technique and a thermal sensitive element installed on the floating plate, The floating plate has a number of suspending arms extending outward to supporting the floating plate in a cavity of a semiconductor substrate for good heat isolation. The area of the floating plate and the length and width of the suspending arm has a specific ratio for an optimized sensitivity. A dummy resistor for temperature compensation is composed by a serial connection of a constant resistor with almost zero temperature coefficient and the thermal sensitive elements in a specific ratio. The vacuum meter further overlap on a temperature-controlled thermoelectric cooling device and is covered by a thermal shield so that the temperatures on and circumferential to the floating plate can be maintained stably.