The property of silicon micro-capacitive accelerometer is analyzed and discussed by establishing the model of the sensor,to lay a basis for optimization design of sensor system structure. Discussed issues include the ...The property of silicon micro-capacitive accelerometer is analyzed and discussed by establishing the model of the sensor,to lay a basis for optimization design of sensor system structure. Discussed issues include the static modeling and dynamic behavior of the two commonly used structures,i.e., double-cantilever supported and four-beam supported structures, and also the measurement range of these devices.展开更多
A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting comb...A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting combs. The sensing method of changing capacitance area is used in the design,which depresses the requirement of the DRIE process, and de- creases electronic noise by increasing sensing voltage to improve the resolution. The parameters and characteristics of the biaxial microaccelerometer are discussed with the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is equal to zero. The testing devices based on the slide-film damping effect are fabricated, and the testing quality factor is 514, which shows that the designed structure can improve the resolution and proves the feasibility of the designed process.展开更多
We analyze the effects of possible noise sources on a fence structure micromachined capacitive accelerometer system by modeling and simulation to improve its performance. Simulation results show that a mismatch betwee...We analyze the effects of possible noise sources on a fence structure micromachined capacitive accelerometer system by modeling and simulation to improve its performance. Simulation results show that a mismatch between the two initial sensing capacitors of the accelerometer or a mismatch between the two capacitance-voltage conversion circuits has a great effect on the output noise floor. When there is a serious mismatch, the noise induced by a sinusoidal carrier is the major noise source. When there is no or only a slight mismatch, the differential capacitance-voltage conversion circuits become the main noise source. The simulation results were validated by experiments and some effective approaches are proposed to improve the system resolution.展开更多
The comb capacitances fabricated by deep reactive ion etching （RIE） process have high aspect ratio which is usually smaller than 30 ： 1 for the complicated process factors, and the combs are usually not parallel du...The comb capacitances fabricated by deep reactive ion etching （RIE） process have high aspect ratio which is usually smaller than 30 ： 1 for the complicated process factors, and the combs are usually not parallel due to the well-known micro-loading effect and other process factors, which restricts the increase of the seismic mass by increasing the thickness of comb to reduce the thermal mechanical noise and the decrease of the gap of the comb capacitances for increasing the sensitive capacitance to reduce the electrical noise. Aiming at the disadvantage of the deep RIE, a novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances is developed. One part of sensing of inertial signal of the micro-accelerometer is by the grid strip capacitances whose overlapping area is variable and which do not have the non-parallel plate＇s effect caused by the deep RIE process. Another part is by the sensing gap alterable capacitances whose gap between combs can be reduced by the actuators. The designed initial gap of the alterable comb capacitances is relatively large to depress the effect of the maximum aspect ratio （30 ： 1） of deep RIE process. The initial gap of the capacitance of the actuator is smaller than the one of the comb capacitances. The difference between the two gaps is the initial gap of the sensitive capacitor. The designed structure depresses greatly the requirement of deep RIE process. The effects of non-parallel combs on the accelerometer are also analyzed. The characteristics of the micro-accelerometer are discussed by field emission microscopy （FEM） tool ANSYS. The tested devices based on slide-film damping effect are fabricated, and the tested quality factor is 514, which shows that grid strip capacitance design can partly improve the resolution and also prove the feasibility of the designed silicon-glass anodically bonding process.展开更多
A novel MEMS inertial sensor with enhanced sensing capacitors is developed. The designed fabricated process of the sensor is a deep RIE process, which can increase the mass of the seismic to reduce the mechanical nois...A novel MEMS inertial sensor with enhanced sensing capacitors is developed. The designed fabricated process of the sensor is a deep RIE process, which can increase the mass of the seismic to reduce the mechanical noise, and the designed capacitance sensing method is changing the capacitance area, which can reduce the air damping between the sensing capacitor plates and reduce the requirement for the DRIE process precision, and reduce the electronic noise by increasing the sensing voltage to improve the resolution. The design and simulation are also verified by using the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is approximately equal to zero. Finally, the fabricated process based on silicon-glass bonding and the preliminary test results of the device for testing grid capacitors and the novel inertial sensor are presented. The testing quality factor of the testing device based on the slide-film damping effect is 514, which shows that the enhanced capacitors can reduce mechanical noise. The preliminary testing result of the sensitivity is 0.492pf/g.展开更多
文摘The property of silicon micro-capacitive accelerometer is analyzed and discussed by establishing the model of the sensor,to lay a basis for optimization design of sensor system structure. Discussed issues include the static modeling and dynamic behavior of the two commonly used structures,i.e., double-cantilever supported and four-beam supported structures, and also the measurement range of these devices.
文摘A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting combs. The sensing method of changing capacitance area is used in the design,which depresses the requirement of the DRIE process, and de- creases electronic noise by increasing sensing voltage to improve the resolution. The parameters and characteristics of the biaxial microaccelerometer are discussed with the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is equal to zero. The testing devices based on the slide-film damping effect are fabricated, and the testing quality factor is 514, which shows that the designed structure can improve the resolution and proves the feasibility of the designed process.
基金Project (No. NCET-06-0514) supported by the Program for New Century Excellent Talents in University of China
文摘We analyze the effects of possible noise sources on a fence structure micromachined capacitive accelerometer system by modeling and simulation to improve its performance. Simulation results show that a mismatch between the two initial sensing capacitors of the accelerometer or a mismatch between the two capacitance-voltage conversion circuits has a great effect on the output noise floor. When there is a serious mismatch, the noise induced by a sinusoidal carrier is the major noise source. When there is no or only a slight mismatch, the differential capacitance-voltage conversion circuits become the main noise source. The simulation results were validated by experiments and some effective approaches are proposed to improve the system resolution.
基金supported by the National Natural Science Foundation of China (No. 60506015)the Zhejiang Provincial Natural ScienceFoundation of China (No.Y107105).
文摘The comb capacitances fabricated by deep reactive ion etching （RIE） process have high aspect ratio which is usually smaller than 30 ： 1 for the complicated process factors, and the combs are usually not parallel due to the well-known micro-loading effect and other process factors, which restricts the increase of the seismic mass by increasing the thickness of comb to reduce the thermal mechanical noise and the decrease of the gap of the comb capacitances for increasing the sensitive capacitance to reduce the electrical noise. Aiming at the disadvantage of the deep RIE, a novel capacitive micro-accelerometer with grid strip capacitances and sensing gap alterable capacitances is developed. One part of sensing of inertial signal of the micro-accelerometer is by the grid strip capacitances whose overlapping area is variable and which do not have the non-parallel plate＇s effect caused by the deep RIE process. Another part is by the sensing gap alterable capacitances whose gap between combs can be reduced by the actuators. The designed initial gap of the alterable comb capacitances is relatively large to depress the effect of the maximum aspect ratio （30 ： 1） of deep RIE process. The initial gap of the capacitance of the actuator is smaller than the one of the comb capacitances. The difference between the two gaps is the initial gap of the sensitive capacitor. The designed structure depresses greatly the requirement of deep RIE process. The effects of non-parallel combs on the accelerometer are also analyzed. The characteristics of the micro-accelerometer are discussed by field emission microscopy （FEM） tool ANSYS. The tested devices based on slide-film damping effect are fabricated, and the tested quality factor is 514, which shows that grid strip capacitance design can partly improve the resolution and also prove the feasibility of the designed silicon-glass anodically bonding process.
基金supported by the National Natural Science Foundation of China(No.60506015)the Zhejiang Provincial Natural Science Foundation of China(No.Y107105)
文摘A novel MEMS inertial sensor with enhanced sensing capacitors is developed. The designed fabricated process of the sensor is a deep RIE process, which can increase the mass of the seismic to reduce the mechanical noise, and the designed capacitance sensing method is changing the capacitance area, which can reduce the air damping between the sensing capacitor plates and reduce the requirement for the DRIE process precision, and reduce the electronic noise by increasing the sensing voltage to improve the resolution. The design and simulation are also verified by using the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is approximately equal to zero. Finally, the fabricated process based on silicon-glass bonding and the preliminary test results of the device for testing grid capacitors and the novel inertial sensor are presented. The testing quality factor of the testing device based on the slide-film damping effect is 514, which shows that the enhanced capacitors can reduce mechanical noise. The preliminary testing result of the sensitivity is 0.492pf/g.
