科研之友
微信
新浪微博
Facebook
分享链接
摘要
A low temperature (<=200 degrees C) Ni alloy based microheater is fabricated here for MEMS based gas sensor platform using nanocrystalline metal oxide semiconductor (<=200 degrees C) appears to be necessary in some application like underground coal mines. The low temperature sensing allows the use of a relatively thin silicon membrane instead of zero Silicon SiO2/Si3N4 composite membrane resulting into temperature uniformity across the entire active area (2 mm*2 mm). Further, the use of the silicon membrane significantly reduces the reliability problem of suspended type microheaters (on SiO2/Si3N4 membranes) arising due to the thermal stress generated micro- cracks. As temperature uniformity is obtained across the entire active area due to the underlying silicon membrane, the interdigited sensing electrodes may be placed on the same layer as that of the microheater thus allowing a coplanar design. A novel nickel alloy having a high resistivity similar to 49*10(-8) Omega m and high yield stress similar to 680 MPa while maintaining the low thermal conductivity similar to 17.5 W/m/degrees C is presented here in this paper. Thermal electrical and thermal stress analyses were done using Intellisuite v8.2. A maximum temperature of similar to 200 degrees C with a distribution of +/-(2-3)% over the entire microheater membrane region has been achieved experimentally with 5 V excitation. The performance parameters of temperature distribution along the membrane and the temperature variation with power consumption were verified and were found within satisfactory error limit of +/- 5%. The heat transfers on the basis of thermodynamic equations have also been studied. The thermal distribution measured by IA thermovision is uniform across the membrane surface.
- 出版日期2011-8
