A z-axis differential capacitive SOI accelerometer with vertical comb electrodes

Tsuchiya, Toshiyuki; Funabashi, Hirofumi

doi:10.1016/j.sna.2004.05.008

Cited by 62 publications

(38 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, compared with the sensitivity of Z-axis reported in the previously published works, i.e. 1.14 (Tsuchiya and Funabashi 2004) and 1.3 fF/g (Hamaguchi et al 2007), the Z-axis sensitivity of the presented accelerometer has been greatly improved. The nonlinearity, which is defined as the ratio of the maximum deviation from the best fit line to the full scale output, is measured as 0.5% for the inplane accelerometer, and 2.3% for the out-of-plane accelerometer.…”

Section: Testingmentioning

confidence: 66%

“…To realize differential capacitive sensing scheme in Z-axis, in C A and C B , the moving electrodes are lower than the stationary electrodes, while in C C and C D , the moving electrodes are higher. Different from the designs by Tsuchiya and Funabashi (2004) and Hamaguchi et al (2007), the vertical comb electrodes of the presented accelerometer have even gaps (d 0 ) between the moving and stationary fingers, which helps minimize zero-g offset when modulation voltage is applied to the capacitors.…”

Section: Design and Simulationmentioning

confidence: 99%

“…7. The needle-like residue in the vertical electrodes may have been caused in the following process: the sidewall formed by the first DRIE is quickly passivated at the beginning of the second DRIE; these passivation reagents may act as the mask for second DRIE, which causes the formation of needle-shaped residue (Tsuchiya and Funabashi 2004). To remove the needle-like residue, one more cycle of isotropic etching is added after second DRIE.…”

Section: Fabricationmentioning

confidence: 99%

“…Hsu et al (2010) fabricated a silicon-onglass (SOG) three-axis accelerometer, in which the authors integrated in-plane and out-of-plane accelerometers into a single sensing structure to achieve small size, and made the unbalanced proof mass as the outer frame of the in-plane accelerometers to enhance the output of Z-axis sensing. Vertical comb electrodes, which are composed of high and low comb fingers, were utilized to detect Z-axis acceleration on SOI wafer with differential capacitive scheme by Tsuchiya and Funabashi (2004) and Hamaguchi et al (2007). But in their three-axis accelerometers, both the out-of-plane and in-plane motions were detected by the same group of vertical comb electrodes, so the sensitivity must be decoupled for each of the three axes, and consequently the capacitive sensitivities for all the three axes were reduced.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A three-axis SOI accelerometer sensing with both in-plane and vertical comb electrodes

et al. 2011

View full text Add to dashboard Cite

A three-axis capacitive accelerometer based on silicon-on-insulator is designed and fabricated. In the accelerometer, totally eight groups of capacitors are compactly arranged around an octagonal proof mass. The four groups of capacitors along orthogonal direction with in-plane comb electrodes detect XY acceleration, while the other four groups of capacitors along diagonal direction with vertical comb electrodes detect Z acceleration. Measurements of in-plane and vertical motion by the respective in-plane and vertical comb electrodes enable direct detection for all the three axes with differential capacitive sensing scheme. For the fabricated accelerometer in the size of 4 9 4 mm 2 , the capacitance sensitivities of in-plane and outof-plane accelerometers are 145.3 and 9.1 fF/g, respectively.

show abstract

Section: Testingmentioning

confidence: 66%

Section: Design and Simulationmentioning

confidence: 99%

Section: Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A three-axis SOI accelerometer sensing with both in-plane and vertical comb electrodes

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Various sensing mechanisms like capacitive (Yazdi and Najafi 2000;Rudolf et al 1990;Farahani et al 2009;Bernstein et al 1999;Rödjegård et al 2005;Lee et al 2005;Tsuchiya and Funabashi 2004;Francis et al 2000;Lötters et al 1997Lötters et al , 1998Wang et al 2007), piezoresistive (Kal et al 2006;Ravi Sankar et al 2009a;Engesser et al 2009), piezoelectric (Tsai et al 2009), tunnelling (Liu et al 1998), etc. are used to convert input acceleration into an equivalent electrical quantity.…”

Section: Introductionmentioning

confidence: 99%

Coupled effects of gold electroplating and electrochemical discharge machining processes on the performance improvement of a capacitive accelerometer

2011

View full text Add to dashboard Cite

Coupled effects of an electroplated gold layer and damper holes drilled by Electro Chemical Discharge Machining (ECDM) process on the performance improvement of a quad beam capacitive accelerometer is presented in this paper. A simple quad beam-proof mass configuration with its beams located symmetrically at the centre of all the edges of the proof mass and connected to an outer supporting frame is considered in the present study. For a fixed damping ratio, prime-axis sensitivity of the sensor is increased by the damper holes whereas an electroplated gold layer improves the prime-axis sensitivity, cross-axis sensitivity, and Brownian Noise Equivalent Acceleration (BNEA). Moreover, the increased weight of the proof mass due to an electroplated gold layer further reduces the damping of the device which in turn helps to increase the prime-axis sensitivity more. A new figure of merit called Performance Factor (PF), defined as the ratio of the product of the primeaxis sensitivity and resonant frequency to the cross-axis sensitivity at a fixed damping ratio of 0.7 is used as a quantitative index to evaluate the performance improvement caused by the coupled effects of gold electroplating and ECDM processes. Simulation results show that for a device with damper holes of 8 lm diameter and electroplated gold layer of dimensions 3,000 lm 9 3,000 lm 9 20 lm, the prime-axis sensitivity is increased by more than 500 times, rotational cross-axis sensitivity and BNEA are reduced by around 10 and 30%, respectively and the PF is improved by around 482 times at a fixed damping ratio of 0.7.

show abstract

Capacitive Microsensors for Biomedical Applications

Tsoukalas¹,

Chatzandroulis²,

Goustouridis³

2006

Encyclopedia of Medical Devices and Instrumentation

View full text Add to dashboard Cite

The use of reliable, high performance miniature sensors in the medical field is of growing importance for patient health monitoring. Batch sensor fabrication, as this has been introduced by Integrated Circuit (IC) manufacturing, is an efficient way to produce silicon sensors with desirable characteristics. Since microsensors combine small size with electrical and mechanical principles of operation they constitute together with microactuators what is usually called Microelectromechanical Systems (MEMS). These components are mainly made from silicon and other related materials to explore existing know‐how and infrastructure of silicon technology. All of the above factors have allowed for fast growth of the microsensor field during the last years. This article focuses on physical microsensors used in the medical field that are based on the capacitive approach.

show abstract

A z-axis differential capacitive SOI accelerometer with vertical comb electrodes

Cited by 62 publications

References 3 publications

A three-axis SOI accelerometer sensing with both in-plane and vertical comb electrodes

A three-axis SOI accelerometer sensing with both in-plane and vertical comb electrodes

Coupled effects of gold electroplating and electrochemical discharge machining processes on the performance improvement of a capacitive accelerometer

Capacitive Microsensors for Biomedical Applications

Contact Info

Product

Resources

About