MEMS Devices and Methods of Manufacture Thereof

• US 20100301434A1
• Filed: 08/10/2010
• Published: 12/02/2010
• Est. Priority Date: 01/11/2008
• Status: Active Grant

• Current Assignee: Bernhard Winkler, Florian Schoen, Werner Weber, Wolfgang Raberg
• Original Assignee: Bernhard Winkler, Florian Schoen, Werner Weber, Wolfgang Raberg
• Inventors: Weber, Werner, Winkler, Bernhard, Schoen, Florian, Raberg, Wolfgang
• Granted Patent: US 8,198,690 B2
• Time in Patent Office: Days
• US Class Current: 257/418
• CPC Class Codes: B81B 2201/0271 Resonators; ultrasonic resonators
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: H10N 30/2041 Beam type
• CPC Class Codes: Y10S 977/732 Nanocantilever

Abstract

Micro-electromechanical system (MEMS) devices and methods of manufacture thereof are disclosed. In one embodiment, a MEMS device includes a first semiconductive material and at least one trench disposed in the first semiconductive material, the at least one trench having a sidewall. An insulating material layer is disposed over an upper portion of the sidewall of the at least one trench in the first semiconductive material and over a portion of a top surface of the first semiconductive material proximate the sidewall. A second semiconductive material or a conductive material is disposed within the at least one trench and at least over the insulating material layer disposed over the portion of the top surface of the first semiconductive material proximate the sidewall.

Claims

1. A micro-electromechanical system (MEMS) device, comprising:

a buried oxide layer disposed over a substrate;

a first semiconductive material disposed over the buried oxide layer;

at least one trench disposed in the first semiconductive material and the buried oxide layer, the at least one trench comprising a first sidewall and a second sidewall opposite the first sidewall;

an insulating material layer disposed over at least a portion of the first sidewall of the at least one trench, wherein the insulating material layer is not an air gap;

a second semiconductive material disposed within the at least one trench; and

a first gap disposed in an upper portion of the at least one trench, the first gap being disposed between the second semiconductive material and the second sidewall of the at least one trench in the first semiconductive material.

2. The MEMS device according to claim 1, wherein the first semiconductive material comprises single crystal silicon, wherein the second semiconductive material comprises polysilicon.

3. The MEMS device according to claim 1, wherein the first semiconductive material proximate the first gap comprises a moveable element comprising a resonator, an oscillating element, an actuator, a sensor, a switch, or an accelerometer.

4. The MEMS device according to claim 1, wherein the at least one trench comprises a first trench adjacent a first side of a portion of the first semiconductive material, and wherein the at least one trench further comprises a second trench adjacent a second side of the portion of the first semiconductive material, the second side being opposite the first side.

5. The MEMS device according to claim 4, further comprising:

a second gap disposed between the substrate and the second semiconductive material within a lower portion of the at least one trench; and

a third gap disposed between the substrate and the portion of first semiconductive material between the first trench and the second trench, wherein the portion of the first semiconductive material between the first trench and the second trench comprises a moveable element, and wherein the second semiconductive material on the first side and the second side of the moveable element within the first trench and the second trench, respectively, comprise electrodes.

6. The MEMS device according to claim 5, wherein the moveable element substantially comprises a shape of a rectangle, square, octagon, polygon, circle, ellipse, or fork in a top view of the MEMS device.

7. A micro-electromechanical system (MEMS) device, comprising:

a oxide layer disposed over a workpiece;

a first semiconductive material disposed over the oxide layer;

a first trench disposed in the first semiconductive material and the oxide layer, the trench comprising a first sidewall and a second sidewall opposite the first sidewall;

an insulating material layer disposed over the first semiconductive material, a first portion of the insulating material layer disposed over at least a portion of the first sidewall of the first trench, wherein the insulating material layer comprises an oxide or a nitride material;

a conductive material disposed within and over the first trench, the conductive material contacting the first portion of the insulating material layer; and

a first gap disposed in an upper portion of the first trench, the first gap being disposed between the conductive material and the second sidewall of the first trench.

8. The MEMS device according to claim 7, wherein the first semiconductive material comprises single crystal silicon, and wherein the conductive material comprises W, Al, at least one liner, or combinations thereof.

9. The MEMS device according to claim 7, wherein the first semiconductive material proximate the first gap comprises a moveable element comprising a resonator, an oscillating element, an actuator, a sensor, a switch, or an accelerometer.

10. The MEMS device according to claim 7, wherein the first trench is adjacent a first side of a portion of the first semiconductive material, further comprising a second trench adjacent a second side of the portion of the first semiconductive material, the second side being opposite the first side.

11. The MEMS device according to claim 10, further comprising:

a second gap disposed between the substrate and the conductive material within a lower portion of the first trench; and

a third gap disposed between the substrate and the portion of first semiconductive material between the first trench and the second trench, wherein the portion of the first semiconductive material between the first trench and the second trench comprises a moveable element, and wherein the conductive material on the first side and the second side of the moveable element within the first trench and the second trench, respectively, comprise electrodes.

12. The MEMS device according to claim 11, wherein the moveable element substantially comprises a shape of a rectangle, square, octagon, polygon, circle, ellipse, or fork in a top view of the MEMS device.

13. The MEMS device according to claim 10, further comprising a release hole disposed within the portion of the first semiconductive material.

14. A method of manufacturing a micro-electromechanical system (MEMS) device, the method comprising:

providing a workpiece, the workpiece comprising a substrate, a buried oxide layer disposed over the substrate, and a first semiconductive material disposed over the buried oxide layer, the first semiconductive material having a top surface;

forming at least one trench in the first semiconductive material, exposing a top surface of the buried oxide layer at the bottom of the at least one trench, the at least one trench comprising a first sidewall and a second sidewall opposite the first sidewall;

forming an insulating material layer over the first and second sidewalls of the at least one trench, and the top surface of the buried oxide layer;

disposing a second semiconductive material or a conductive material over the insulating material layer;

removing portions of the second semiconductive material or the conductive material thereby leaving the second semiconductive material or the conductive material within the at least one trench; and

removing the insulating material layer from over the second sidewall of the at least one trench.

15. The method according to claim 14, wherein forming the insulating material layer comprises forming a conformal material.

16. The method according to claim 14, wherein removing the portions of the second semiconductive material or the conductive material comprises:

leaving an amount of the second semiconductive material or the conductive material having a first dimension over the first semiconductive material proximate the first sidewall; and

leaving an amount of the second semiconductive material or the conductive material having a second dimension over the first semiconductive material proximate the second sidewall, wherein the first dimension is larger than the second dimension.

17. The method according to claim 14, further comprising forming at least one release hole in the first insulating material proximate the second sidewall, and removing at least the buried oxide layer at least from beneath the first insulating material proximate the second sidewall, wherein removing the buried oxide layer further comprises removing at least a portion of the buried oxide layer from beneath the second semiconductive material or the conductive material in the at least one trench.

18. The method according to claim 17, wherein removing the buried oxide layer comprises forming a resonator or an oscillating element, further comprising forming an anchor proximate at least one end of the resonator or the oscillating element, above the resonator or the oscillating element, or below the resonator or the oscillating element.

19. The method according to claim 14, further comprising anisotropically etching the insulating material layer, after forming the insulating material layer, leaving an insulating material layer comprising a greater thickness over the first and second sidewalls of the at least one trench than over the top surface of the first semiconductive material and the top surface of the buried oxide layer.

20. The method according to claim 14, wherein forming the insulating material layer comprises using an anisotropic deposition process, leaving an insulating material layer comprising a greater thickness over the top surface of the first semiconductive material and the top surface of the buried oxide layer than over the first and second sidewalls of the at least one trench.