Systems and methods for operating a MEMS device based on sensed temperature gradients

Patent metadata

Field	Value
Publication number	US-11548780-B2
Application number	US-202117516245-A
Country	US
Kind code	B2
Filing date	Nov 1, 2021
Priority date	Aug 21, 2019
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

An exemplary microelectromechanical device includes a MEMS layer, portions of which respond to an external force in order to measure the external force. A substrate layer is located below the MEMS layer and an anchor couples the substrate layer and MEMS layer to each other. A plurality of temperature sensors are located within the substrate layer to identify a temperature gradient being experienced by the MEMS device. Compensation is performed or operations of the MEMS device are modified based on temperature gradient.

First claim

What is claimed is:

1. A microelectromechanical (MEMS) device, comprising:
a layer;
a plurality of temperature sensors located within the layer, comprising;
a first temperature sensor at a first location relative to a center point within the layer, wherein a first response of the first temperature sensor changes based on a temperature at the first location;
a second temperature sensor at a second location relative to the center point, wherein the second location is on a first common measurement axis on an opposite side of the center point from the first location, and wherein a second response of the second temperature sensor changes based on a temperature at the second location;
a third temperature sensor at a third location relative to the center point, wherein a third response of the third temperature sensor changes based on a temperature at the third location, and wherein a first output value is based on the first response and the third response; and
a fourth temperature sensor at a fourth location relative to the center point, wherein the fourth location is on a second common measurement axis on an opposite side of the center point from the third location, wherein a fourth response of the fourth temperature sensor changes based on a temperature at the fourth location, and wherein a second output value is based on the second response and the fourth response; and

processing circuitry configured to output a signal that corresponds to a vertical thermal gradient perpendicular to the layer based on a change in a difference between the first output value and the second output value in response to the vertical thermal gradient, and wherein the processing circuitry rejects a lateral thermal gradient within the layer in outputting the signal.

2. The MEMS device of claim 1 , wherein the layer comprises a first layer, further comprising at least one anchor and a second layer, wherein the at least one anchor couples the first layer to the second layer.

3. The MEMS device of claim 2 , wherein the at least one anchor is located vertically above the center point.

4. The MEMS device of claim 2 , wherein the at least one anchor comprises a plurality of anchors each located equidistant from the center point.

5. The MEMS device of claim 2 , further comprising a gap between the first layer and the second layer, wherein the at least one anchor is located within the gap.

6. The MEMS device of claim 2 , wherein a first anchor of the at least one anchor is in contact with the first layer at a first anchoring location, wherein the third temperature sensor of the plurality of temperature sensors is located below the first anchoring location, wherein a second anchor of the at least one anchor is in contact with the first layer at a second anchoring location, wherein the fourth temperature sensor of the plurality of temperature sensors is located below the second anchoring location, and wherein the first and the second temperature sensors of the plurality of temperature sensors are not located below the first or the second anchoring locations.

7. The MEMS device of claim 1 , wherein the layer comprises a first layer, further comprising a second layer, wherein the first layer comprises a first plane located within the first layer, wherein the second layer comprises a second plane located within the second layer, and wherein each of the plurality of temperature sensors is located within the first plane.

8. The MEMS device of claim 7 , wherein the first plane is parallel to the second plane.

9. The MEMS device of claim 1 , wherein the layer comprises a first layer, further comprising a second layer, wherein the second layer comprises a MEMS layer and the first layer comprises a CMOS layer.

10. The MEMS device of claim 1 , wherein the first common measurement axis and the second common measurement axis are orthogonal axes.

11. The MEMS device of claim 1 , wherein a respective output from one or more of the plurality of temperature sensors changes based on a strain induced on the one or more of the plurality of temperature sensors, and wherein, in response to the strain induced on the one or more of the plurality of temperature sensors, the signal is substantially unchanged.

12. The MEMS device of claim 11 , wherein the one or more of the plurality of temperature sensors comprise at least two temperature sensors, and wherein, in response to the strain induced on the one or more of the plurality of temperature sensors, the signal is substantially unchanged based on the two temperature sensors being equidistant from a center point within the layer.

13. The MEMS device of claim 1 , wherein a respective output from one or more of the plurality of temperature sensors changes based on a strain induced on the one or more of the plurality of temperature sensors, and wherein the signal changes in response to the strain induced on the one or more of the plurality of temperature sensors.

14. The MEMS device of claim 1 , wherein the plurality of temperature sensors comprises BJTs, MOSFETs, or thermistors.

15. The MEMS device of claim 1 , wherein the plurality of temperature sensors is configured in a Wheatstone bridge, and wherein the processing circuitry is coupled to the plurality of temperature sensors via the Wheatstone bridge.

16. The MEMS device of claim 1 , further comprising one or more switching elements to select a subset of the plurality of temperature sensors to reconfigure the signal to change in response to one of a thermal gradient perpendicular to the layer, a thermal gradient parallel to the layer, an induced strain, or a temperature value.

17. The MEMS device of claim 1 , wherein the MEMS device comprises an accelerometer, a gyroscope, a magnetometer, a barometer, a microphone, or an ultrasonic sensor.

18. The MEMS device of claim 1 , wherein the processing circuitry rejects any lateral thermal gradient within the layer based on a proportional response of the first output value and the second output value to the lateral thermal gradient.

19. The MEMS device of claim 1 , wherein the respective responses of the plurality of temperature sensors correspond to changes in current, voltage, or resistance.

20. A substrate of a microelectromechanical (MEMS) device, comprising:
a plurality of temperature sensors located within the substrate, comprising;
a first temperature sensor at a first location relative to a center point within the substrate, wherein a first response of the first temperature sensor changes based on a temperature at the first location;
a second temperature sensor at a second location relative to the center point, wherein the second location is on a first common measurement axis on an opposite side of the center point from the first location, and wherein a second response of the second temperature sensor changes based on a temperature at the second location;
a third temperature sensor at a third location relative to the center point, wherein a third response of the third temperature sensor changes based on a temperature at the third location, and wherein a first output value is based on the first response and the third response; and
a fourth temperature sensor at a fourth location relative to the center point, wherein the fourth location is on a second common measurement axis on an opposite side of the center point from the third location, wherein a fourth response of the fourth temperature sensor changes based on a temperature at the fourth location, and wherein a second output value is based on the second response and the fourth re

Assignees

• Invensense Inc

Inventors

• Dekoninck David
• Kumar Varun Subramaniam
• Thompson Matthew Julian
• Tsinker Vadim
• Jayaraman Logeeswaran Veerayah
• Nitzan Sarah
• Johari-Galle Houri
• Shin Jongwoo
• Jin Le

Classifications

• G01L19/04

  Means for compensating for effects of changes of temperature {, i.e. other than electric compensation} · CPC title

• B81B7/0087 Primary

  On-device systems and sensors for controlling, regulating or monitoring · CPC title

• G01L9/0072

  using variations in capacitance · CPC title

• G01K1/20

  Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature · CPC title

• B81B2201/0242

  Gyroscopes · CPC title