Results on the reliability of silicon micromachined structures for semiconductor gas sensors

Thin film semiconductor gas sensors fabricated on thermally isolated silico n substrates have been proposed as good alternative to thick film devices t hat are on the market as they show low power consumption. However, for thei r industrial success, it is necessary to assess good yield and high reliabi lity for maintaining the functionality of the device during a long period o f time. In this paper, a set of thermomechanical tests has been applied to gas sensors based on silicon micromachined structures with dielectric membr anes. The aim of the tests is to determine the survivability of the devices under aggressive conditions of use. The tests have been carried out on two specific structures, a single Si3N4 membrane; and the same device that als o includes a silicon plug below the sensor active area. Results are compare d as a tool for improving the structure in the future. (C) 2001 Elsevier Sc ience B.V. All rights reserved.