表面微機(jī)械微小量程壓力傳感器采用多晶硅薄膜等有內(nèi)應(yīng)力的敏感膜片時(shí),應(yīng)力往往會(huì)
使膜片的力學(xué)靈敏度大大下降,無法滿足微量程測(cè)量的要求。波紋膜片可以消除或減小應(yīng)力來提高靈敏度,但是其波紋結(jié)構(gòu)本身又會(huì)造成力學(xué)靈敏度下降,從而部分抵消了應(yīng)力消除的效果。提出一種新型深盆腔膜片結(jié)構(gòu),在消除應(yīng)力的同時(shí)實(shí)現(xiàn)了比平膜片還高的力學(xué)靈敏度,可以提高微壓傳感器和微麥克風(fēng)的靈敏度。采用解析和有限元兩種方法相結(jié)合的方法,對(duì)該種膜片進(jìn)行了分析和研究。對(duì)比平膜和波紋膜結(jié)構(gòu),顯示了深盆腔膜在力學(xué)靈敏度方面的顯著提高。
關(guān)鍵詞:壓力膜片;微機(jī)械傳感器;力學(xué)靈敏度;薄膜殘余應(yīng)力
Abstract :When thin - film with residual stress used for sensitive diaphragm of micromachined low - range pressure sensors ,mechanical sensitivity of the diapgragm is ,more often than not ,much lowered due to the stress. Currently ,corru2 gated diaphragm is used for stress release ,thereby ,improving the mechanical sensitivity. However ,corrugated diaphragm
itself is with a stiffened structure compared with conventional flat diaphragm that renders a lower mechanical sensitivity. Therefore ,There is a trade off when a corrugated diaphragm employed for pre - stressed diaphragm. A novel deep cavity - shaped diaphragm is proposed in this paper. The structure is capable of simultaneously releasing the stress and decreasing
mechanical stiffness. Analysis and finite element method (FEM) are combined to study the mechanical principles of the di2 aphragm. The results show that the proposed deep cavity - shaped structure is with much improved mechanical sensitivity , compared with conventional flat diaphragm and corrugated diaphragm.
Key Words :Pressure - sensitive Diaphragm;Micromachined Sensors ;Mechanical Sensitivity ;Residual Stress of Thin - film