Metal Oksit İnce Filmlerin Gaz Sensörü Uygulamalarının Araştırılması

Abstract

This work covers such fabrication techniques; chemical (CVD) and physical vapor deposition (PVD), photolithography, plasma dry etching (ICP-RIE), anisotropic bulk silicon wet etching to develop michromachined metal oxide semiconductor based volatile organic compound (MOS-VOC) sensors and characterization of the fabricated devices. The integrated micro hot plate is fabricated on silicon substrate by using MEMS fabrication techniques. The hot plates in four different rezistor geometries, fabricated using nickel-chrome alloy and ITO as resistor material were thermally characterized. The metal oxide ZnO and SnO2 thin films which are sensitive to target gases were deposited by sputtering. The stuctures of the metal oxide thin films were investigeted by photoluminescence (PL) measuring system, x-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscope (SEM). Thermal properties of the sensors were investigated by thermal microscope. Developed SnO2 sensor response was investigated for 500ppm, 1000ppm, 2000ppm concentrations of methane and ammonia in four different operating temperatures. It is observed that the response of the sensor increases as the concentration of the target gases increases. The temperature dependent responsivity characteristics of the sensor to methane and ammonia target gases found to be unique for each gas. Additionally, ZnO sensor was investigated for its sensitivity to the unknown concentrations of the vapors of acetone, ethanol and isopropanol. The result were compatible with literature.