Microelectromechanical Systems Anonymous | 4.25.2009 | Defined Project (updated on 4.26.2009) | Print Preview
In this project we aim to work on the design and fabrication of various MEMS devices. As a part of our project we, in particular, investigated a micromachined-gas sensor. The reliability of the membrane structure for micromachined-gas sensors is one of the main concerns in MEMS technology. The major source of this problem is the stress on the membrane. We found that the use of SiO2/Si3N4/SiO2 stacked layers with optimized dimensions reduces the stress on the membrane, and hence improves the reliability. We also use electro-thermal simulations with finite element analysis (FEA) to model the structural properties of the membrane in order to reduce the stress. The appropriate selection of materials and dimensions yields maximum active area temperature of 530°C at the center of the membrane with a polysilicon heater element, less than 5 V supply voltage, 40 mW of power consumption, membrane edge temperature of 177°C and acceptable mechanical stress of 0.097 GPa. Upon realizing the structure with the modeled parameters, micromachined-gas sensors could respond to many industry/environment application demands.