Micromechanical component with different doping types so that one type is anodized into porous silicon

• US 6,803,637 B2
• Filed: 10/28/2002
• Issued: 10/12/2004
• Est. Priority Date: 11/03/2000
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Benzel, Hubert, Artmann, Hans, Weber, Heribert, Schaefer, Frank
• Primary Examiner(s): Tran, Minhloan
• Assistant Examiner(s): Dickey, Thomas L
• Application Number:
  US10/169,464
• Publication Number:
  US 20030116813A1
• Time in Patent Office: 715 Days
• Field of Search: 257/414-419, 257/420, 257/E21.216, 257/E29.082, 257/E29.324, 257/3, 257/619, 438/50-53, 735/143.2, 735/143.5, 216/2, 216/56
• US Class Current: 257/414
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/036 Micropumps
• CPC Class Codes: B81C 1/00595 Control etch selectivity
• CPC Class Codes: B81C 2201/0114 Electrochemical etching, anodic oxidation
• CPC Class Codes: B81C 2201/0115 Porous silicon
• CPC Class Codes: B81C 2201/0136 by doping limited material regions
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer

Abstract

A micromechanical component having a substrate made from a substrate material having a first doping type, a micromechanical functional structure provided in the substrate and a cover layer to at least partially cover the micromechanical functional structure. The micromechanical functional structure has zones made from the substrate material having a second doping type, the zones being at least partially surrounded by a cavity, and the cover layer has a porous layer made from the substrate material.

Claims

1. A micromechanical component comprising:

a substrate made from a first substrate material having a first doping type, the substrate including a micromechanical functional structure; and

a cover layer at least partially covering the micromechanical functional structure;

wherein the micromechanical functional structure includes at least one zone made from a second substrate material having a second doping type, the at least one zone is at least partially surrounded by a cavity, and the cover layer includes a porous layer made from the substrate material.

2. The micromechanical component of claim 1, wherein at least one of the at least one zone includes a supporting zone for supporting the porous layer.

3. The micromechanical component of claim 1, wherein at least one of the at least one zone is one of completely detached from surroundings and resiliently connected to the substrate.

4. The micromechanical component of claim 1, wherein the substrate includes at least one trench partially filled with a doping material having the second doping type and at least partially filled with a filler.

5. The micromechanical component of claim 1, wherein the first and second substrate materials include silicon.

6. The micromechanical component of claim 1, wherein the zones of the substrate are situated at different depths of the substrate.

7. The micromechanical component of claim 1, wherein the cavity includes a vacuum.

8. The micromechanical component of claim 1, further comprising:

a scaling layer to seal pores of the porous layer.

9. The micromechanical component of claim 8, wherein the sealing layer includes an oxide layer formed on the porous layer.

10. The micromechanical component of claim 8, further comprising:

a detection device for piezoresistively detecting a flow rate, the detection device being on the sealing layer.

11. The micromechanical component of claim 8, further comprising:

two check valve devices having different dimensions, each of the check valve devices situated above a respective one of transfer openings, the porous layer with the sealing layer being operable as a pump diaphragm.

12. The micromechanical component of claim 8, wherein a predetermined atmosphere is set by the sealing layer.

13. The micromechanical component of claim 8, further comprising:

at least one piezoresistive resistor arranged on the sealing layer above the porous layer.

14. The micromechanical component of claim 1, wherein the cavity includes a flow channel connected to at least two back openings.

15. The micromechanical component of claim 14, wherein the at least two back openings are connected by respective transfer openings, and each of the respective transfer openings are formed in the zone.

16. The micromechanical component of claim 15, further comprising:

a check valve device in the flow channel and above a corresponding one of the respective transfer openings within the flow channel, the check valve device including at least one of the zones.

17. The micromechanical component of claim 1, wherein the cavity includes a circular inner flow channel and a concentric outer flow channel connected by radial ports in a separation zone made from the second substrate material, the inner flow channel is interrupted by a bar, a back inlet opening is arranged on one side of the bar, a first back outlet opening is arranged on an other side of the bar, and a second back outlet opening is arranged in the outer flow channel, so that a medium flowing through the back inlet opening may be separated in accordance with a mass of the medium by a centrifugal force through the first and second back outlet openings.