Epi-poly etch stop for out of plane spacer defined electrode

• US 10,173,887 B2
• Filed: 10/12/2016
• Issued: 01/08/2019
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Graham, Andrew, Yama, Gary, O'Brien, Gary
• Primary Examiner(s): Gupta, Raj R
• Application Number:
  US15/291,374
• Publication Number:
  US 20170297896A1
• Time in Patent Office: 818 Days
• CPC Class Codes: B81B 2201/0271 Resonators; ultrasonic resonators
• 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 2203/04 Electrodes
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• 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 1/00095 Interconnects
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: B81C 1/00166 Electrodes
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: B81C 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• CPC Class Codes: B81C 2201/0177 Epitaxy, i.e. homo-epitaxy, hetero-epitaxy, GaAs-epitaxy
• CPC Class Codes: B81C 2203/0136 Growing or depositing of a covering layer

Abstract

A device with an out-of-plane electrode includes 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.

Claims

1. 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 permanent spacer.

2. The device of claim 1, 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.

3. The device of claim 2, 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, the etch stop horizontally spacing the buried oxide layer portion from an etched portion.