8.5.4 Fabrication and Characterization of MEMS Based Optical Hydrogen Sensors

Abstract

This paper presents the fabrication and characterization of MEMS based optical type hydrogen sensors using transparent 3C-SiC membrane and photovoltaic effect.3C-SiC membrane was fabricated by anisotropic etching.Gasochromic material of Pd was deposited by sputter on the 3C-SiC membrane for gas sensing layer.Pd and WO 3 changes to transparency by exposure to hydrogen and the variations of light intensity generate the photovoltaic of P-N junction between N-type 3C-SiC and P-type Si.Photovoltaic increased with increase of hydrogen concentration.Pd/WO 3 shows almost 2 times faster response and recovery toward hydrogen compared with Pd.However, low response factor is shown at Pd/WO 3 by low penetration ratio.