A resonant pressure micro sensor with a stress isolation layer

This paper presents a resonant pressure micro sensor with a stress isolation layer. This sensor consisted of a glass cap for hermetic package, an SOI layer as sensing elements and a glass base for stress isolation. These three layers were mounted through a three-stack anodic bonding process. The effectiveness of stress isolation was validated by both finite element analysis and experimental characterizations. Experimental results confirm the high performances of the developed sensors, including high linearity of 0.9999, high sensitivities of -25 Hz/kPa and low temperature compensation errors of 0.005% FS. In addition, the hysteresis errors of temperature and pressure are 0.1 ppm FS/C and 40 ppm respectively, which exhibited overwhelming advantages in comparison to non-stress-isolation counterparts (about 2 ppm FS/degrees C and 1616 ppm).