[18p-E102-1~13] 12.7 Biomedical Engineering and Biochips

△ [18p-E102-13] Highly sensitive MEMS surface stress gas sensor by optimizing geometric parameters

〇Ryusei Sogame¹, Takato Sakagami¹, Yong-Joon Choi¹, Toshihiko Noda¹, Kazuaki Sawada¹, Kazuhiro Takahashi¹ (1.Toyohashi Univ.)

Keywords:Fabry-Perot interface, Surface stress sensor, Volatile organic compounds(VOCs)

We developed an optical interferometric MEMS surface stress sensor composed of freestanding submicron-thick membrane with microcavity for sub-ppm EtOH gas detection. When the EtOH gas molecules are adsorbed to the gas sensitive poly methyl methacrylate (PMMA) layer, the PMMA film shrinks and the film deforms in the sinking direction. In surface stress measurement, thinner film thickness is expected to improve stress sensitivity. However, as the thickness of the sensitive film increased, the surface stress increased, with the highest sensitivity at a film thickness of 190 nm. As a result, the fabricated sensor succeeded in detecting a quarter of the amount of EtOH of the previously reported sensor.