一种新型CMOS电容式绝对压力传感器设计.pdfVIP

第19 卷　第5 期 传 感 技 术 学 报 V ol. 19　No. 5 2006 年10 月 CHINESE JOURNAL OF SENSORS AND ACT UATORS Oct. 2006 Design of A Novel CMOS Capacitive Absolute Pressure Sensor * LI U N a, H UAN G Qing-an , QI N Ming (K ey Laboratory of MEMS of Ministry of E d ucation, Southeast Un iversity , N anj ing 210096, China) Abstract:A novel capacitive pressure sensor based on the post CMOS MEMS process is presented. The sensing part is a variable capacitor ith a conductor /dielectric/conductor structure. The top and bottom layers are poly-gate and n- ell Si in the CMOS process, respectively, hile the center layer is the gate SiO2 . After CMOS process, selectively etching bulk silicon, PN junction self etch-stop, and anodic bond- ing to the glass are used to get the microstructure. Compared ith the traditional capacitive pressure sen- sor, this structure has intrinsic larger initial capacitance value hich benefits the follo ing interface ci-r cuits and high sensitivity. A mechanical thermal model for the mult-i layers as used to analyse the sensor structure, hich as also simulated by ANSYS. After that, the capacitance change model as used to e- valuate the sensitivity of the device. For the 800 μm×800 μm square membrane, the sensitivity is obtained to be 46 fF /hPa and the initial capacitance is 1 104 pF. Then the capacitive interface circuit as also de- signed to detect the change of the sensor capacitance. Key words:CMOS;capacitive absolute pressure sensor;sensitivity;capacitive interface circuit EEACC:25 5D;25 0D CMOS * 刘　娜, 黄庆安 , 秦　明 (MEMS , 210096) CMOS MEMS . 　: //. CMOS n , .CMOS , 、pn MEMS ., , , ., , ANSYS , . 800 μm , 1 104 pF, 46 fF/hPa., . CMOS ;; : :TP212. 12