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MEMS Piezoresistive
Posted Feb 19, 2015, 5:33 p.m. EST MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Modeling Tools & Definitions, Parameters, Variables, & Functions, Results & Visualization, Studies & Solvers Version 5.0 2 Replies
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Hi team,
I hope you are ok, I am working on a simulation of a piezoresistive pressure sensor covered by a polymer layer, to understand the effect of the polymere on the performance of the sensor. First I am studying the piezoresistive model that COMSOL have on the web site (an amazing web site, I can say) and I have some questions, that I am sure that are very basics questions for you guys, but as I am a neophyte on COMSOL MEMS module I am having some issue on it. I hope you can help me.
1.- Running the Piezoresistive model that is available on the web page, I am studying every stop that the model follows. I can follow everything so far : however, on the PDF document of the model on page 6 said : "The model produces an output voltage of 52 mV, similar to the actual device output of 60 mV ". But, where I can obtain from the model the output of 52 mV with a pressure of 100 kPa?? I have been reading and I cant get it not from the Potential solution neither from the displacement one. Even I looked the Current and voltage solution and I cant find the voltage output of 53 mV described on the PDF document.
I would appreciate any clue on this, Iam pretty sure is something really easy that I am missing.
Thanks in advance.
Rogelio
I hope you are ok, I am working on a simulation of a piezoresistive pressure sensor covered by a polymer layer, to understand the effect of the polymere on the performance of the sensor. First I am studying the piezoresistive model that COMSOL have on the web site (an amazing web site, I can say) and I have some questions, that I am sure that are very basics questions for you guys, but as I am a neophyte on COMSOL MEMS module I am having some issue on it. I hope you can help me.
1.- Running the Piezoresistive model that is available on the web page, I am studying every stop that the model follows. I can follow everything so far : however, on the PDF document of the model on page 6 said : "The model produces an output voltage of 52 mV, similar to the actual device output of 60 mV ". But, where I can obtain from the model the output of 52 mV with a pressure of 100 kPa?? I have been reading and I cant get it not from the Potential solution neither from the displacement one. Even I looked the Current and voltage solution and I cant find the voltage output of 53 mV described on the PDF document.
I would appreciate any clue on this, Iam pretty sure is something really easy that I am missing.
Thanks in advance.
Rogelio
2 Replies Last Post Mar 12, 2015, 2:42 p.m. EDT
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Posted:
10 years ago
Go to the Result section.
Then derived values, choose Global Evaluation 2.
Evaluate it by implementing it on a table.
From that table you can get the desired output.
Then derived values, choose Global Evaluation 2.
Evaluate it by implementing it on a table.
From that table you can get the desired output.
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Posted:
10 years ago
Thanks Tamim,
I already did it!. Now , I have other questions, maybe you can help me.
I am working in the simulation of the effect of the packaging on the performance of a piezoresistive pressure sensor, basically I am adding a polymer protection layer to the upper surface of a piezoresistive pressure sensor and I am comparing the output of my sensor with and without the polymer layer. My model is working for the pressure sensor without parylene layer, and works as expected. However, for the addition of the polymer layer I have some questions which I hope you can help me.
1.- I am just adding to the upper surface of the pressure sensor the polymer layer (Parylene) which main properties are cited below, and then analyse the output with and without polymer layer. Does this is the right approach to model the effect of the polymer layer on the sensor? Anyone has experience in simulations of "sandwich style" deflective geometries?.
2.- The polymer layer is being modeled as linear elastic material as part of the piezoresistive MEMS module. Does this is correct? Or I would need to use a different approach to model the polymer layer?
The thickness of the MEMS diaphragm is 38 um and is made of Silicon. The thickness of the Polymer layer is 4 um and is Parylene.
Properties of the Polymer
Young modulus : 2.76e9 Pa
Poisson ratio : 0.4
The other big question here is to account the effect of the temperature on the piezoresistive effect. I am applying a uniform temperature to all my model, but I can not see any change in my output. Do you have any experience with the MEMS piezoresistive module?
I hope you can help me.
I already did it!. Now , I have other questions, maybe you can help me.
I am working in the simulation of the effect of the packaging on the performance of a piezoresistive pressure sensor, basically I am adding a polymer protection layer to the upper surface of a piezoresistive pressure sensor and I am comparing the output of my sensor with and without the polymer layer. My model is working for the pressure sensor without parylene layer, and works as expected. However, for the addition of the polymer layer I have some questions which I hope you can help me.
1.- I am just adding to the upper surface of the pressure sensor the polymer layer (Parylene) which main properties are cited below, and then analyse the output with and without polymer layer. Does this is the right approach to model the effect of the polymer layer on the sensor? Anyone has experience in simulations of "sandwich style" deflective geometries?.
2.- The polymer layer is being modeled as linear elastic material as part of the piezoresistive MEMS module. Does this is correct? Or I would need to use a different approach to model the polymer layer?
The thickness of the MEMS diaphragm is 38 um and is made of Silicon. The thickness of the Polymer layer is 4 um and is Parylene.
Properties of the Polymer
Young modulus : 2.76e9 Pa
Poisson ratio : 0.4
The other big question here is to account the effect of the temperature on the piezoresistive effect. I am applying a uniform temperature to all my model, but I can not see any change in my output. Do you have any experience with the MEMS piezoresistive module?
I hope you can help me.