一種基于兩塊可變形膜的新型接觸式電容壓力傳感器外文翻譯@中英文翻譯@外文文獻(xiàn)翻譯

1 一種基于兩塊可變形膜的新型接觸式電容壓力傳感器 焦語仲 光學(xué)技術(shù)微工藝國家重點(diǎn)實(shí)驗(yàn)室 中國科學(xué)院光電子研究所 中國成都 610209 E-mail: Phorittoyahoo.Com 摘要 :為了獲得更好的線性特征，我們?cè)O(shè)計(jì)了名為 DDTMCPS 的一種新型的具有一對(duì)可變形感應(yīng)膜的接觸式電容壓力傳感器。與現(xiàn)有的接觸式電容壓力傳感器相比較，新型傳感器具有更好的線性、大的線性工作范圍等特征。這樣一個(gè)裝置也有高靈敏度 ,和普通接觸式電容壓力傳感器所沒有的其它優(yōu)勢(shì)。在這種新型的傳感器中，第二片作為底部電極的膜在修改第一片 作為頂部電極的膜產(chǎn)生的偏差時(shí)起了很大作用，進(jìn)一步優(yōu)化了接觸式傳感器的性能。硅熔接技術(shù)被用于制造這種新型傳感器。 關(guān)鍵詞： TMCPS、 DDTMCPS、線性、靈敏度 中圖分類號(hào)： TP212 文獻(xiàn)標(biāo)識(shí)碼： A 文章編號(hào)： 167124776 （ 2003） 0820492204 1、引言 眾所周知，電容壓力傳感器具有高靈敏度 ,耐用的結(jié)構(gòu) ,對(duì)外環(huán)境影響低靈敏性和沒有溫度漂移。但是，電容值與兩電極之間的距離成反比關(guān)系導(dǎo)致了這個(gè)裝置較大的非線性度的缺點(diǎn)。為了改進(jìn)電容壓力傳感器的線性度，我們做出了很大努力。在那些嘗試 中 ,接觸式電容壓力傳感器是比較成功的設(shè)計(jì)，因?yàn)樗粌H能獲得好的線性度，而且有較大的電壓工作范圍和順利獲得了過載保護(hù) 15?；谝郧暗难芯亢蛯?duì)接觸式電容壓力傳感器深入理解 ,我們?cè)O(shè)計(jì)了這種基于一對(duì)可變形感應(yīng)膜的新型接觸式電容壓力傳感器。與現(xiàn)有的接觸式電容壓力傳感器相比較，新型傳感器具有更好的線性、大的線性工作范圍等特征。這樣一個(gè)裝置也有高靈敏度 ,和普通接觸式電容壓力傳感器所沒有的其它優(yōu)勢(shì)。 在這篇論文中 ,我們描述了這種新型接觸式電容壓力傳感器的結(jié)構(gòu)特征和本身特性，并且給出了新型裝置和傳統(tǒng)的接觸式電容 壓力傳感器的比較。 2、結(jié)構(gòu)特征 這種新型裝置在結(jié)構(gòu)上非常不同于常規(guī)的電容壓力傳感器 (NMCPS)和傳統(tǒng)的接觸2 式電容壓力傳感器 (TMCPS)。圖 1(a)、 (b)、 (c)分別給出了 NMCPS 、 TMCPS 和新型裝置的結(jié)構(gòu)示意圖。 NMCPS 的結(jié)構(gòu)與 TMCPS 的結(jié)構(gòu)很相似。他們的主要差異在于壓力敏感膜的工作狀態(tài)。在正常方式運(yùn)作中 ,感應(yīng)膜與底層保持一定的距離，然而，在接觸方式運(yùn)作中感應(yīng)膜允許與底層的薄絕緣層接觸。在 NMCPS 和 TMCPS 中，感應(yīng)膜由 p+硅或者其它導(dǎo)體制造出來，適用作上部電極。另一電極作為底部電極被置 于底層上。當(dāng)一對(duì)電極彼此接觸的時(shí)候，底部電極上需鋪一層薄絕緣層來阻止短路。在二電極之間有一個(gè)真空的洞。 NMCPS 和 TMCPS 所用的結(jié)構(gòu)上參數(shù)是膜的大小 a (和 b)（為圓形膜的半徑，在正方形或矩形膜的邊長(zhǎng)， a， b 分別代表矩形膜的邊長(zhǎng)和寬度），膜的厚度用 h表示，空穴的初始間隙為 g，并且絕緣層厚度為 t（對(duì)于 NMCPS 不重要）。新型裝置包括兩片分別作為頂部電極和底部電極的懸浮的膜，兩個(gè)與外界隔絕的密封諧振腔，一層服著于兩片膜之一上的絕緣層 ，如圖 1.所示。在 NMCPS 和 TMCPS 中，底部電極被固定在底層上，然而在 新裝置中，底部電極是隨著第二片膜的變形而活動(dòng)著的。在接觸以前，第一片膜象壓力載荷增長(zhǎng)那樣變形，但是第二片膜是靜止的。在接觸后第一片膜施力于第二片膜，導(dǎo)致了第二片膜的變形。新裝置的基本結(jié)構(gòu)參數(shù)有第一片膜的厚度 h1、第二片膜的厚度 h2、第一片膜的大小 a1（ b1）、第一個(gè)空穴的初始間隙 g1、第二個(gè)空穴的初始間隙 g2、絕緣層的厚度 t。所有這些參數(shù)都與機(jī)械特性無關(guān)，隨著必要條件的不同而變化。既然新的電容壓力傳感器需要兩片懸浮的膜來形成，我們可以把這樣一種新裝置命名為雙膜接觸式電容壓力傳感器，縮寫為 DDTMCPS。在以 下部分，我們會(huì)給出與 DDTMCPS 特性有關(guān)的模擬結(jié)論。 3 圖 1、 三種類型電容壓力傳感器的示意圖 3、 C2P 特性 圖 2 表明了有兩片用摻雜了很多硼的硅（ P+）制成的正方形膜、邊長(zhǎng) a1=a2=400 m、厚度 h1=h2=5 m 、兩電極 m間初始間隙 g1=5 m、絕緣層厚度 t=0.35 m的DDTMCPS 的 C2P 特性在標(biāo)準(zhǔn)區(qū)域超越了傳統(tǒng)接觸式。 圖 2、 DDTMCPS 和 TMCPS 在四個(gè)區(qū)域：標(biāo)準(zhǔn)區(qū)、過渡區(qū)、 線性區(qū)和飽和區(qū)的模擬 C2P 特性示意圖 a1 = a2 = a = 400m ， h1 = h2 = h =5m ， g1 = g = 5m 為了比較，圖中也給出了參數(shù)為 a= 400m ， h = 5m ， g = 5m ，和 t = 0. 35的正方形 P+膜構(gòu)成的 TMCPS 的 C2P 特性。和 TMCPS 一樣， DDTMCPS 的特性也有四個(gè)區(qū)域，即 標(biāo)準(zhǔn)區(qū)、過渡區(qū)、線性區(qū)和飽和區(qū)。當(dāng)壓力負(fù)荷小于 52Psi 時(shí)，第一片膜沒有接觸到第二片膜時(shí)，在這 個(gè)區(qū)內(nèi)的特性和 NMCPS 一樣。當(dāng)?shù)谝黄ら_始和第二片膜接觸時(shí)， C2P 曲線進(jìn)入過渡區(qū)。在短暫的過渡區(qū)之后，在裝置將正常運(yùn)作的地方，曲線顯示出了一片相當(dāng)大的線性區(qū)。當(dāng)線性區(qū)的靈敏度 4 （ d C/ d P） 大 幅度地減小時(shí)飽和區(qū)開始。與 TMCPS 的特性相比較， C2P 曲線清楚地給出了更大的線性區(qū)，而且盡管靈敏度有一定程度的降低，但線性區(qū)之上表現(xiàn)出了更好的線性度。 圖 3、給出了結(jié)構(gòu)參數(shù)如上的 DDTMCPS 和 TMCPS 的靈敏度曲線。從圖形我們可以觀察到在接觸前 DDTMCPS 和 TMCPS 有相同的靈敏度。接觸之后靈敏度值不同。 TMCPS具有較高的靈敏度。然而與 DDTMCPS 的林靈敏度曲線比較，我們發(fā)現(xiàn) TMCPS 的靈敏度曲線表現(xiàn)出了靈敏度在過渡區(qū)中（之后）快速取得較高數(shù)值這樣一種趨勢(shì)，通過一段平滑的靈敏度區(qū)后，靈敏度以更快地速度下降。 DDTMCPS 的靈敏度曲線表明了一段更大的平滑靈敏度區(qū)。當(dāng)壓力負(fù)載接近飽和區(qū)時(shí)靈敏度值下降緩慢，這使新裝置能表現(xiàn)出更好的線性度和更大的工作范圍。在圖中，出現(xiàn)一些波紋。這主要是由于數(shù)字化處理錯(cuò)誤導(dǎo)致地。文章中的所有數(shù)據(jù)都來自于使用有限元分析法程序， ANSYS 軟件。它還能進(jìn)行更多的計(jì)算細(xì)節(jié)。 圖 3、 如上同樣大小的膜的靈敏度的比較 圖 4、表明了上述 DDTMCPS 在應(yīng)用范圍從 70Psi 到 120Psi 之外的線性最小平方適合曲線。工作范圍的有效靈敏度，合適直線的斜率是 0.0144 p F/ Psi， 非線性 度被定義為： 公式中： Cmax 是從適合直線特性的最大變量； Cmax 和 Cmin 分別表示工作范圍中電容的最大值和最小值。在圖 4、中，新裝置的非線性度是 0.78%。 5 圖 4、 上述的 DDTMCPS 在工作范圍從 70Psi到 120Psi中線性 最小平方合適曲線，其斜率為 0.0144PF/Psi，非線性度為 0.78% 這種新裝置的工作范圍和非線性度、靈敏度間有著緊密的關(guān)系。圖 5、表明了大小如上所述的 DDTMCPS和 TMCPS的非線性度和壓力工作范圍間的關(guān)系。對(duì)于 DDTMCPS來說，隨著工作范圍地增加，非線性度增加，然而對(duì)于 TMCPS 來說，非線性度首先緩慢減小，然后象 DDTMCPS 的變化趨勢(shì)那樣增加。盡管 DDTMCPS 的工作范圍的大小和非線性度往往小于普通的 TMCPS，尤其當(dāng)工作范圍在 5060Psi之間時(shí)。當(dāng)工作范圍被選定在 50Psi時(shí)，這種裝置能達(dá)到 0.723%的非線性度， 這遠(yuǎn)小于當(dāng) TMCPS也工作在 50Psi時(shí)的 1.45%的非線性度。對(duì)于指定的非線性度， DDTMCPS 能實(shí)現(xiàn)比 TMCPS 有更大的工作范圍。 圖 5、 如上述大小的 DDTMCPS 和 TMCPS 的 非線性度和線性工作范圍之間的關(guān)系 4、結(jié)論 這篇文章所陳述的涉及到我的一個(gè)設(shè)計(jì) 一種新型的接觸式電容壓力傳感器。6 DDTMCP 已經(jīng)表明了這種傳感器的結(jié)構(gòu)特點(diǎn)。 DDTMCPS 主要的優(yōu)點(diǎn)是更好的線性度和更大的工作范圍。除此之外如果兩種傳感器有相同的膜參數(shù)，則 DDTMCPS 的靈敏度要較小于 TMCPS， DDTMCPS 幾乎擁有 TMCPS 所有的優(yōu)點(diǎn)。第二片作為底部電極的膜在修改第一片作為頂部電極的膜產(chǎn)生的偏差時(shí)起了很大作用，進(jìn)一步優(yōu)化了接觸式傳感器的性能。第二片膜的合適的厚度對(duì)獲得更好的性能至關(guān)重要。所有的數(shù)據(jù)都來源于有限元分析軟件， ANSYS。根據(jù) DDTMCPS 的結(jié)構(gòu)特征，硅熔接技術(shù)將成為制作 DDTMCPS 的一個(gè)好方法是有希望的。 參考文獻(xiàn) 1 KO W H , WANG Q , WANG Y. Touch mode capacitive pressure sensors for industrial application A . IEEE Int Workshop on Solid State Sensor and Actuator , Technical Digest C . Hilton HeadIsland , 1996. 24422481 2 WANG Q , KO W H. Si2to2Si fusion bonded touch mode capacitive pressure sensors J . Mechatronics 1998 , 8 , 4672484. 3 WANG Q. Touch mode capacitive pressure sensors and interface circuits D . PH D Thesis , Case Western Reserve University , January 1998. 4 KO W H , WANG Q. Touch mode capacitive pressure sensors J . Sensors and Actuators A , 1999 ,75 , 2422251. 5 GUO S W, GUO J , KO W H. A monolithically integrated surface micromachined touch mode capacitive pressure sensor J . Sensor and Actuators , 2000 ,80 , 2242232 7 A new touch mode capacitive pressure sensor with two deformable diaphragms JIAO Yu zhong ( State Key Lab of Optical Technologies for Microfabrication , Institute of Optics and Electronics ,Chinese Academy of Sciences , Chengdu 610209 , China) E-mail : Phorittoyahoo. Com Abstract : To achieve the characteristics of better linearity , a new type of touch mode capacitive pressure sensor named as DDTMCPS is devised , which has a pair of deformable sensing diaphragms. Compared to present touch mode capacitive pressure sensors , the new sensor is characterized by better linearity , and large linear operation range. Such a device also has high sensitivity , and other advantages of normal touch mode capacitive pressure sensor. In the case of such a novel sensor , the second diaphragm served as bottom electrode plays great roles in modifying the deflection of the first diaphragm served as top electrode , furthermore optimizing the performance of touch mode sensors. Silicon fusion bonding technology is advised to fabricate the novel device. Key words : TMCPS ； DDTMCPS ； linearity ； sensitivity CLC number : TP212 Document code : A Article ID : 167124776( 2003) 07/ 0820492204 1 Introduction Capacitive pressure sensors are known to have high sensitivity , robust structure , low sensitivity to outer environment effects and no turn on temperature drift . However ,large nonlinearity is the drawback of such devices due to the inverse relation between capacitance and spacing between two electrodes. Much effort has been made to improve the linearity of capacitive pressure sensors. Among those attempts ,touch mode capacitive pressure sensor is a more successful design for in that not only good linearity is gotten , but also large operating pressure range , and large overload protection are achieved15 . On the basis of the previous study and the deep understanding of touch mode capacitive 8 pressure sensor , a new type of touch mode capacitive pressure sensor that has a pair of deformable sensing diaphragms is devised.Compared with present ones , the new sensor has the characteristics of better linearity , and larger linear operation range. Such a device also has high sensitivity and other advantages of normal touch mode capacitive pressure sensor. In this paper , the structural features are presented and the characteristics of the novel touch mode capacitive pressure sensor is simulated , and necessary contrast s between the novel device and conventional touch mode capacitive pressure sensor are also given. 2 Structural features The novel device differs greatly from normal mode capacitive pressure sensor (NMCPS) and conventional touch mode capacitive pressure sensor ( TMCPS) in the configuration. Fig. 1 (a) , (b) , (c) give the schematic views of the configurations of NMCPS , TMCPS and the novel device , respectively. The structure of NMCPS is quite similar to that of TMCPS. Their main difference lies in the working state of the pressure sensitive diaphragm. In the normal mode operation , the diaphragm is kept at a distance away from the substrate , while , in the touch mode operation , the diaphragm is allowed to contact the substrate with a thin insulating layer. In NMCPS and TMCPS , the sensing diaphragm made from p + silicon or other conductors , is served as upper electrode. The other electrode in terms of bottom electrode is situated on the substrate. A thin insulating layer is needed to deposit on the bottom electrode to stop short circuiting when the pair of electrodes contacts each other. There is a vacuum cavity between the two electrodes. The used structural parameters of NMCPS and TMCPS are diaphragm size a ( and b) ( radius for circular diaphragm , edge length for square or rectangular diaphragm, where a , b denote the edge length and width of a rectangular diaphragm , respectively) , diaphragm thickness h , initial gap of cavity g and insulator depth t ( unimportant for NMCPS) . The new device consist s of two suspended diaphragms which serve as the upper and bottom electrodes , respectively , two hermetical sealed cavities , one isolation layer attached on one of the two diaphragms , as shown in Fig. 1 ( c) . In NMCPS and TMCPS , the bottom electrode is fixed on the substrate , while in the novel device the bottom electrode is 9 movable , following the deformation of the second diaphragm. Before touch the first diaphragm deforms as the load pressure increases , but the second diaphragm is stationary. After touching the first diaphragm pressing on the second diaphragm , and result s in the deformation of the second diaphragm. The essential structural parameters of the new device are the thickness of the first diaphragm h1 , the thickness of the second diaphragm h2 , the first diaphragm size a1 ( b1 ) , the second diaphragm size a2 ( b2) , the initial gap of the first cavity g1 , the initial gap of the second cavity g2 , the isolation layer thickness t . All these parameters are independent mechanical qualities , and are changeable with the difference of requirements. Since double suspended diaphragms are needed to form the new capacitive pressure sensor , we can name such a device as double diap hragm touch mode capacitive pressure sensor , for short , DDTMCPS. In the following part , the Fig. 1 Schematic views of three types of capacitive pressure sensors simulated results relative to the characteristics of DDTMCPS are given. 3 C2P characteristics Fig. 2 shows the C2P characteristics covering normal and touch mode regions of DDTMCPS that has two similar square diaphragms made f rom heavily boron doped silicon (p + ) with side length a1 = a2 =400m , thickness h1 = h2 = 5m , initial gap 10 between two electrodes g1 = 5m , insulator t = 0. 35m. Fig. 2 The simulated C2P characteristics of DDTMCPS and TMCPS with four regions :normal , transition ,linear and saturation regions , a1 = a2 = a = 400m , h1 = h2 = h =5m , g1 = g = 5m For contrast , the C2P characteristics of TMCPS having a square p + diaphragm with the parameters a= 400m , h = 5m , g = 5m , and t = 0. 35m is also shown in the figure. Like TMCPS , the characteristic of DDTMCPS has four regions , namely normal , transition , linear and saturation regions. When load pressure is less than 52 Psi , the first diaghragm doesnt touch the second diaphragm , and the characteristic in this region is the same as that of NMCPS.When the first diaphragm comes into contact with the second diaphragm , the C2P curve enters transition region. After a short transition region , the curve reveals a comparatively large linear region where the device should operate in applications. The saturation region begins when the sensitivity (d C/ d P) is reduced significantly from that of the linear region. Compared with the characteristic of TMCPS , the C2P curve clearly shows larger linear operation region , and over the linear region shows better linearity , though the sensitivity becomes somewhat lower. Fig. 3 gives the sensitivity curves of DDTMCPS and TMCPS both with the same structural parameters as above. From the figure , we observe DDTMCPS and TMCPS own the same sensitivity before touch. After touch , the sensitivity values differ. TMCPS has higher sensitivity. However comparing with the sensitivity curve of DDTMCPS , we find 11 that the sensitivity curve of TMCPS shows such a trend that sensitivity fast approaches to a higher value in (or after) transition region , through an even sensitivity region , sensitivity decreases at a higher speed. The sensitivity curve of DDTMCPS shows a larger even sensitivity region. The sensitivity value decreases slowly when load pressure approaches to the saturation region , which enables the new device to show a better linearity and a larger operation range. In the figure , some waves appear. This is mainly induced by the error of numerical computing. All the data in the article are derived using finite element method programme , ANSYS software. More detailed calculations are being made. Fig. 3 The comparison of sensitivities (dC/ d P) with the same diaphragm sizes as above Fig. 4 shows the linear least square fitting curve over the application range from 70 Psi to 120 Psi of DDTMCPS discussed above. The effective sensitivity of operation range , the slope of the fitting line is 0.0144 p F/ Psi ,the nonlinearity is defined as Where Cmax is the maximum deviation from a fitting line characteristic ； Cmax and Cmin are the maximum and minimum capacitances in the operation range , respectively. In Fig. 4 , the nonlinearity of the new device is 0. 78 %. 12 Fig. 4 The linear least square fitting curve over the operation range from 70 Psi to 120 Psi of DDTMCPS discussed above , with a slope of 0. 0144 PF/ Psi ,the nonlinearity is 0. 78 % There is a close relationship between the working range and the nonlinearity , sensitivity of such a device. Fig. 5 reveals the relation between nonlinearity a nd operation pressure range of DDTMCPS and TMCPS , both with the same sizes as above. For DDTMCPS , with the increase of operation range , the nonlinearity increases , while for TMCPS , the nonlinearity firstly decreases slowly , and then increases along the tendency of that of DDTMCPS. Despite the magnitude of operation range , the nonlinearity of DDTMCPS is always less than that of the normal TMCPS , especially when operation range is at 5060Psi. When operation range is selected to be 50 Psi ,the device can achieve a nonlinearity of 0. 723% ,which is much less than the nonlinearity of 1. 45 % of TMCPS when operation range is 50 Psi too. As for the specified nonlinearity , DDTMCPS can realize larger operation range than TMCPS. 13 Fig. 5 Relations between nonlinearity and linear operation range of DDTMCPS and TMCPS both with the same sizes as above 4 Conclusion The representation of the paper is related to a novel touch mode capacitive pressu