Out-of-plane spacer defined electrode

• US 9,242,850 B2
• Filed: 03/18/2014
• Issued: 01/26/2016
• Est. Priority Date: 04/14/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Graham, Andrew B., Yama, Gary, O'Brien, Gary
• Primary Examiner(s): Tran, Tony
• Application Number:
  US14/217,956
• Publication Number:
  US 20140197713A1
• Time in Patent Office: 679 Days
• Field of Search: 438/584
• US Class Current: 1/1
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias

Abstract

In one embodiment, a method of forming an out-of-plane electrode includes providing an oxide layer above an upper surface of a device layer, providing a first cap layer portion above an upper surface of the oxide layer, etching a first electrode perimeter defining trench extending through the first cap layer portion and stopping at the oxide layer, depositing a first material portion within the first electrode perimeter defining trench, depositing a second cap layer portion above the first material portion, vapor releasing a portion of the oxide layer, depositing a third cap layer portion above the second cap layer portion, etching a second electrode perimeter defining trench extending through the second cap layer portion and the third cap layer portion, and depositing a second material portion within the second electrode perimeter defining trench, such that a spacer including the first material portion and the second material portion define out-of-plane electrode.

Claims

1. A device with an out-of-plane electrode comprising:

a device layer positioned above a handle layer;

a cap layer having a first cap layer portion above the device layer and spaced apart from an upper surface of the device layer; and

an out-of-plane electrode defined within the first cap layer portion by a spacer, the spacer having a lower nitride portion (i) terminating at a middle portion of the cap layer and (ii) extending within a lower portion of the cap layer toward a lower surface of the cap layer from the middle portion, and an upper oxide portion (i) terminating at the middle portion of the cap layer and (ii) extending within an upper portion of the cap layer toward an upper surface of the cap layer from the middle portion of the cap layer.

2. The device of claim 1, wherein the cap layer is an epitaxially deposited cap layer.

3. The device of claim 1, wherein the spacer comprises silicon nitride.

4. The device of claim 3, wherein the lower nitride portion comprises:

a laterally extending etch stop portion within the middle portion of the cap layer.

5. The device of claim 1, further comprising:

an oxide layer portion located between a second cap layer portion of the cap layer and the upper surface of the device layer; and

an etch stop extending downwardly from within the cap layer and defining a boundary of the oxide layer portion.

6. The device of claim 5, wherein the lower nitride portion comprises:

a laterally extending etch stop portion within the middle portion of the cap layer.

7. The device of claim 5, further comprising:

a buried oxide layer portion located between a lower surface of the device layer and an upper surface of a handle layer; and

an etch stop extending downwardly from the upper surface of the device layer and defining a boundary of the buried oxide layer portion.