摘要
研制了一种采用CMOS工艺和表面牺牲层技术加工的微热板式低气压传感器.该微热板为四臂支撑悬空矩形板,其边长为75μm,支撑桥长为60μm,板下气隙高度为0.5μm.采用经典傅里叶传热理论分析了恒电流工作方式下气压对微热板瞬态和稳态热特性的影响,结果表明在低气压范围内微热板传热以支撑桥导热为主,气压较高时以气体导热为主,微热板加热功率随气压增加而减小;传感器的热响应时间为毫秒量级并随气压增加而减小.传感器采用恒电流工作方式时,测得其气压响应范围为1～105Pa,且加热功率与气压间关系的理论分析结果与实测值吻合得较好.
A low gas pressure sensor based on micro-hotplate（MHP） is designed and successfully fabricated by a standard CMOS process followed by surface micromacbing. The MHP has dimensions of 75μm× 75μm and is suspended by four microbridges which form a 0.5μm air gap below it. The bridges are 21μm wide and 60μm long. A transient heat transfer equation of MHP with a constant-current operation mode is established based on the classical Fourier＇s analysis and solved numerically using the fourth-order Runge-Kutta scheme. The results of the transient analysis are used to analyze steady-state heat transfer.Results show that thermal response time is on the level of milliseconds and decreases if gas pressure increases. Thermal loss through the bridges is the main factor in the low-pressure range, while gaseous heat conduction dominates in the high-pressure range. The fabricated sensor shows a measurement range from 1 to 10^5Pa. The measured relationship between the heating power and gas pressure is in agreement with theoretical results.
基金
国家自然科学基金资助项目(批准号:90207003
599955505)~~
关键词
微热板
气压传感器
微传感器
传热
恒电流
micro-hotplate
gas pressure sensor
microsensor
heat transfer
constant current
