An integrated CMOS polysilicon coil-based micro-Pirani gauge with high heat transfer efficiency

Abstract

A micro-Pirani gauge with a heat transfer efficiency of 99% to the ambient has been fabricated in 1.2 /spl mu/m CMOS technology. Device operation is based on the heat transfer from an active current-heated polysilicon coil to the ambient which includes a passive coil. The active coil temperature and hence, resistance, is modulated by the pressure or thermal conductivity of the surrounding gas. The device has a peak sensitivity of 400 mV/torr and its power ranges from 27 /spl mu/W at vacuum to 2 mW at 1 atm. Design and fabrication details of the structure are presented along with simulation and measurement results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>