Design and evaluation of a highly robust MEMS Pirani vacuum gauge based on porous silicon thermal insulation layer

Abstract

Vacuum gauges based on Micro-Electro-Mechanical System (MEMS) technology have the advantages of small size, high reliability and low cost, so they are widely used in semiconductor, chemical, laboratory and aerospace fields. In this paper, a high-reliability MEMS Pirani vacuum gauge based on a porous silicon thermal insulation layer is designed and fabricated, and good measurement accuracy is achieved in the vacuum range of 0.01~105 Pa. The developed porous silicon support material developed achieves a porosity of 68% and a thermal conductivity of 3~4 W/(m • K), and the surface morphology of the porous silicon is smooth, which is compatible with standard semiconductor processes such as metal electron beam evaporation. The proposed MEMS Pirani vacuum gauge containing no suspended film structure has good mechanical stability and is not affected by violent gas convection shock and mechanical vibration.