Computational investigation of van der Pauw structures for MEMS pressure sensors

Mian, Ahsan; Law, Jesse

doi:10.1016/j.commatsci.2010.06.008

Cited by 6 publications

(8 citation statements)

References 10 publications

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“…Models were solved and postprocessed for VDP angles of -30°to ?30°relative to the diaphragm axes. These results are consistent with the results for p-type silicon from the finite difference analysis, Mian and Law (2010). During the wafer processing steps required to produce this sensor, it is possible for misalignment to occur between the front and back masks.…”

Section: Angular Alignment Dependencesupporting

confidence: 89%

“…To get a true basis of comparison, a weighted average of the element stresses would have to be taken, where the weighting function captured the importance of the element position to the NRCD of the sensor. This has not been attempted, for our present purposes it is sufficient to compare the sensitivity of the 3D sensor to those 2D sensors that have already been analyzed and published in a reference (Mian and Law 2010). It is seen that the 3D sensitivity is comparable to that of the 2D sensors, acknowledging that in moving to the more complex 3D stress state we have lost the analytical stress basis for comparing the two.…”

Section: Pressure Sensitivity Of Vdpmentioning

confidence: 91%

“…Thus, only one VDP structure is able to perform temperature compensated pressure measurements. A detailed discussion on this observation is presented in our earlier publication (Mian and Law 2010). When fabricated on silicon, the sensor will have isotropic resistivity under unstressed condition and hence R 0 0 À R 0 90 ¼ R 0 due to rotational symmetry of a square sensor.…”

Section: Van Der Pauw Sensormentioning

confidence: 99%

“…5 where the 2D results are taken from reference (Mian and Law 2010). For the 2D uniaxial stress, r yy is assigned and r xx is zero.…”

Section: Pressure Sensitivity Of Vdpmentioning

confidence: 99%

“…The use of VDP as a piezoresistive sensing element in MEMS pressure sensor was discussed in reference (Mian and Law 2010) where two-dimensional finite difference and finite element modeling schemes were adopted to show a comparison between 1-D filament resistor and the VDP sensors. The VDP structure replaces a pair of 0/90 one-dimensional serpentine resistor, which at the same time can be very small.…”

Section: Introductionmentioning

confidence: 99%

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Geometric optimization of van der Pauw structure based MEMS pressure sensor

Mian

Law

2010

Microsyst Technol

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This paper characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to MEMS pressure sensing. The sensor to be studied is a fourterminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With MEMS devices being used in applications which continually necessitate smaller size, characterizing the effect of size and orientation of a VDP structure on the performance of a MEMS pressure sensor is important. In this paper, the effect of relative size and misalignment of the VDP sensor on the sensitivity is investigated using a coupled piezoresistive/stress finite element model. The mode is developed to simulate the full field stress over the deformed diaphragm in which the VDP is diffused. The change in resistivity of the VDP is then analyzed to predict the sensitivity of the VDP structure. Sensor size, position relative to the diaphragm, and angular misalignment of the VDP were varied to determine a theoretical result for the dependence of VDP output on those parameters. It is determined that the performance of the sensor is strongly dependent only on the longitudinal position of the sensor on the diaphragm, and is relatively tolerant of other errors in the manufacturing process such as transverse position, sensor depth, and orientation angle.

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Section: Angular Alignment Dependencesupporting

confidence: 89%

Section: Pressure Sensitivity Of Vdpmentioning

confidence: 91%

Section: Van Der Pauw Sensormentioning

confidence: 99%

“…5 where the 2D results are taken from reference (Mian and Law 2010). For the 2D uniaxial stress, r yy is assigned and r xx is zero.…”

Section: Pressure Sensitivity Of Vdpmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geometric optimization of van der Pauw structure based MEMS pressure sensor

Mian

Law

2010

Microsyst Technol

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Design, fabrication, and testing of VDP MEMS pressure sensors

2011

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In this paper, a four-terminal piezoresistive sensor commonly known as a van der Pauw (VDP) structure is presented for its application to MEMS pressure sensing. In a recent study, our team has determined the relation between the biaxial stress state and the piezoresistive response of a VDP structure by combining the VDP resistance equations with the equations governing silicon piezoresistivity and has proposed a new piezoresistive pressure sensor. It was observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. To check our theoretical findings, we fabricated several (100) silicon diaphragms with both the VDP sensors and filament resistor sensors on the same wafer so both the sensor elements have same doping concentration. Several diaphragms had VDP sensors of different sizes and orientations to find out their geometric effects on pressure sensitivity. The diaphragms were subjected to known pressures, and the pressure sensitivities of both types of sensors were measured using an in-house built calibration setup. It was found that the VDP devices had a linear response to pressure as expected, and were more sensitive than the resistor sensors. Also, the VDP sensors provided a number of additional advantages, such as its size independent sensitivity and simple fabrication steps due to its simple geometry.

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Effects of Electrical Current and External Stress on the Electromigration of Intermetallic Compounds Between the Flip-Chip Solder and Copper Substrate

Chen

Lee

et al. 2017

Journal of Elec Materi

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Computational investigation of van der Pauw structures for MEMS pressure sensors

Cited by 6 publications

References 10 publications

Geometric optimization of van der Pauw structure based MEMS pressure sensor

Geometric optimization of van der Pauw structure based MEMS pressure sensor

Design, fabrication, and testing of VDP MEMS pressure sensors

Effects of Electrical Current and External Stress on the Electromigration of Intermetallic Compounds Between the Flip-Chip Solder and Copper Substrate

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