微机械悬臂梁中的机械噪声机制分析

Noise Mechanisms in Micromechanical Cantilever

本文采用能量统计分布方法研究微机械悬臂梁的噪声模型,对热机械噪声理论模型进行了拓展和修正,使之适用于低温和高频条件.研究了温度、压力和频率对热机械噪声、温漂噪声和吸附-脱附噪声的影响.根据研究结果对静态检测悬臂梁和动态频率响应悬臂梁传感器进行了具体分析.对于静态下工作的微机械悬臂梁,振幅的随机变化取决于热机械噪声.对于工作在谐振状态的微米尺度悬臂梁,在室温常压下热机械噪声是主要的噪声机制;当尺寸进一步缩小至纳米尺度时,表面效应变得显著,吸附-脱附噪声成为主要的噪声机制.基于对不同情况下噪声特性的分析,对微机械悬臂梁传感器的优化设计规则进行了探讨.

A modified model of thermal-mechanical noise is developed to make it adaptable to the micmmechanical cantilever in high frequency or low temperature, The influences of temperature, pressure and resonance frequency on thermal-mechanical noise, temperature-fluctuation noise and adsorption-desorption noise are investigated. In the static mode of micromechanical cantilever, the displacement resolution is determined by the thermal-mechanical noise. In the dynamic mode of micromechanical cantilever, the thermal-mechanical noise is main noise mechanism, and the frequency stability is dominated by adsorption-desorption noise while the size shrink to nano-scale, Present noise mechanism investigation is general and instructive in the design methodology of micromechanical cantilever.