Single crystal silicon sensor with additional layer and method of producing the same

• US 7,138,694 B2
• Filed: 03/02/2004
• Issued: 11/21/2006
• Est. Priority Date: 03/02/2004
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Nunan, Thomas Kieran, Brosnihan, Timothy J.
• Primary Examiner(s): SMITH, BRADLEY
• Application Number:
  US10/791,638
• Publication Number:
  US 20050196933A1
• Time in Patent Office: 994 Days
• Field of Search: 257/415, 257/419, 257/E29.324
• US Class Current: 257/419
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A SOI-based MEMS device has a base layer, a device layer, and an insulator layer between the base layer and the device layer. The device also has a deposited layer having a portion that is spaced from the device layer. The device layer is between the insulator layer and the deposited layer.

Claims

1. A SOI-based MEMS device comprising:

a base layer;

a device layer;

an insulator layer between the base layer and the device layer; and

a deposited layer having a portion that is spaced from the device layer;

the device layer being between the insulator layer and the deposited layer,

the device layer having structure, the deposited layer forming a cap to seal the structure,

wherein the deposited layer includes germanium.

2. The MEMS device as defined by claim 1 further including an anchor extending from the deposited layer to contact the device layer.

3. The MEMS device as defined by claim 1 wherein the device layer includes circuitry.

4. The MEMS device as defined by claim 3 wherein the deposited layer includes a material having a deposition temperature, the circuitry being capable of operating after being subjected to the deposition temperature.

5. The MEMS device as defined by claim 1 wherein an air space separates the device layer from the deposited layer.

6. The MEMS device as defined by claim 5 wherein the device layer has a top surface with given material formed thereon, the air space separating the given material from the deposited layer.

7. A MEMS inertial sensor comprising:

a single crystal silicon layer having a top surface, the single crystal silicon layer also having sensing structure and a second component; and

a deposited additional layer adjacent to the top surface of the single crystal silicon layer, the deposited additional layer having a portion that is spaced from the top surface, the deposited additional layer being conductive to serve as an interconnect for the sensing structure on the single crystal silicon layer, the deposited additional layer electrically connecting the sensing structure with the second component

wherein the sensing structure includes a movable member spaced from the deposited additional layer by an air space.

8. The MEMS inertial sensor as defined by claim 7 wherein the deposited additional layer has a portion that is contacts the top surface.

9. The MEMS inertial sensor as defined by claim 7 wherein the single crystal silicon layer is a part of a silicon-on-insulator wafer, the sensor further including a base layer and an insulator layer separating the base layer and the single crystal silicon layer.

10. The MEMS inertial sensor as defined by claim 7 wherein the single crystal silicon layer is a bulk silicon wafer.

11. The MEMS inertial sensor as defined by claim 7 wherein at least an air space separates the top surface from the deposited additional layer.

12. The MEMS inertial sensor as defined by claim 7 wherein the second component includes circuitry, the deposited additional layer electrically connecting the sensing structure with the circuitry.

13. A SOI-based MEMS device comprising:

a base layer;

a device layer;

an insulator layer between the base layer and the device layer; and

a deposited layer having a portion that is spaced from the device layer;

the device layer being between the insulator layer and the deposited layer,

the device layer having structure, the deposited layer forming a cap to seal the structure,

wherein an air space separates the device layer from the deposited layer,

further wherein the device layer has a top surface with given material formed thereon, the air space separating the given material from the deposited layer.

14. The MEMS device as defined by claim 13 further including an anchor extending from the deposited layer to contact the device layer.

15. The MEMS device as defined by claim 13 wherein the device layer includes circuitry.

16. The MEMS device as defined by claim 15 wherein the deposited layer includes a material having a deposition temperature, the circuitry being capable of operating after being subjected to the deposition temperature.

17. The MEMS device as defined by claim 13 wherein the deposited layer includes germanium.