Epi-Poly Etch Stop for Out of Plane Spacer Defined Electrode

Patent metadata

Field	Value
Publication number	US-2016137485-A1
Application number	US-201414201453-A
Country	US
Kind code	A1
Filing date	Mar 7, 2014
Priority date	Mar 15, 2013
Publication date	May 19, 2016
Grant date	—

Abstract

In one embodiment, a method of forming an out-of-plane electrode includes forming an oxide layer above an upper surface of a device layer, etching an etch stop perimeter defining trench extending through the oxide layer, forming a first cap layer portion on an upper surface of the oxide layer and within the etch stop perimeter defining trench, 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 deposited first material portion, and vapor releasing a portion of the oxide layer with the etch stop portion providing a lateral etch stop.

First claim

1 . A method of forming an out-of-plane electrode, comprising:
forming an oxide layer above an upper surface of a device layer; etching an etch stop perimeter defining trench extending through the oxide layer; forming a first cap layer portion on an upper surface of the oxide layer and within the etch stop perimeter defining trench; 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 deposited first material portion; and vapor releasing a portion of the oxide layer with the etch stop portion providing a lateral etch stop.

2 . The method of claim 1 , further comprising:
depositing a third cap layer portion above the second cap layer portion after vapor releasing the portion of the oxide layer; 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 a perimeter of an out-of-plane electrode.

3 . The method of claim 2 , further comprising:
depositing an etch stop layer portion on the deposited first material portion, wherein etching a second electrode perimeter defining trench comprises: etching a second electrode perimeter defining trench extending through the second cap layer portion and to the etch stop layer.

4 . The method of claim 2 , wherein the first cap layer portion, the second cap layer portion, and the third cap layer portion are deposited by an epitaxial deposition process.

5 . The method of claim 2 , wherein the first material portion and the second material portion comprise silicon nitride.

6 . The method of claim 2 , further comprising:
depositing an etch stop layer portion on the deposited first material portion, wherein etching a second electrode perimeter defining trench comprises: etching a second electrode perimeter defining trench extending through the second cap layer portion and to the etch stop layer.

7 . The method of claim 2 , further comprising;
etching vent holes through the first cap layer and the second cap layer, wherein vapor releasing a portion of the oxide layer comprises: vapor releasing a portion of the oxide layer through the vent holes.

8 . A device with an out-of-plane electrode comprising:
a device layer positioned above a handle layer; a first electrode defined within the device layer; a cap layer having a first cap layer portion spaced apart from an upper surface of the device layer by a gap, and having an etch stop perimeter defining portion defining a lateral edge of the gap; and an out-of-plane electrode defined within the first cap layer portion by a spacer.

9 . The device of claim 8 , wherein the spacer comprises:
a first silicon nitride portion extending upwardly from a lower surface of the cap layer; a second silicon nitride portion extending downwardly from an upper surface of the cap layer; and an etch stop portion located between the first silicon nitride portion and the second silicon nitride portion.

10 . The device of claim 9 , 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.

11 . A method of forming an out-of-plane electrode comprising:
providing an oxide layer above an upper surface of a device layer; etching an etch stop defining trench extending through the oxide layer; epitaxially depositing a first cap layer portion above an upper surface of the oxide layer and an etch stop cap layer portion within the etch stop defining trench; etching a first electrode perimeter defining trench extending through the first cap layer portion and stopping at the oxide layer; depositing a first insulating material portion within the first electrode perimeter defining trench; and performing an HF vapor etch release on a portion of the oxide layer with the etch stop cap layer portion providing a lateral etch stop.

12 . The method of claim 11 , further comprising:
epitaxially depositing a second cap layer portion above the deposited first material portion; epitaxially depositing a third cap layer portion above the second cap layer portion after performing the HF vapor etch release; etching a second electrode perimeter defining trench extending through the second cap layer portion and the third cap layer portion; and depositing a second insulating material portion within the second electrode perimeter defining trench, such that a spacer including the first material portion and the second material portion define a perimeter of an out-of-plane electrode.

13 . The method of claim 12 , further comprising:
depositing an etch stop layer portion on the deposited first insulating material portion, wherein etching a second electrode perimeter defining trench comprises: etching a second electrode perimeter defining trench extending through the second cap layer portion and to the etch stop layer.

14 . The method of claim 13 , wherein the first insulating material portion and the second insulating material portion comprise silicon nitride.

15 . The method of claim 13 , further comprising:
depositing an etch stop layer portion on the deposited first material portion, wherein etching a second electrode perimeter defining trench comprises: etching a second electrode perimeter defining trench extending through the second cap layer portion and to the etch stop layer.

16 . The method of claim 13 , further comprising;
etching vent holes through the first cap layer and the second cap layer, wherein performing an HF vapor etch release on a portion of the oxide layer comprises: performing an HF vapor etch release on a portion of the oxide layer through the vent holes.

Assignees

• Bosch Gmbh Robert

Inventors

• Graham Andrew
• Yama Gary
• O'Brien Gary

Classifications

• B81C2201/014

  by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal · CPC title

• B81B2203/04

  Electrodes · CPC title

• B81C2203/0136

  Growing or depositing of a covering layer · CPC title

• B81C2201/0177

  Epitaxy, i.e. homo-epitaxy, hetero-epitaxy, GaAs-epitaxy · CPC title

• B81B3/0021 Primary

  Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00) · CPC title