Nanowire LED structure and method for manufacturing the same

• US 9,117,990 B2
• Filed: 01/28/2014
• Issued: 08/25/2015
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: GLO Technologies LLC
• Original Assignee: Glo AB (Shoei Electronic Materials, Inc.)
• Inventors: Lowgren, Truls
• Primary Examiner(s): Tran, Tran
• Application Number:
  US14/166,308
• Publication Number:
  US 20140141555A1
• Time in Patent Office: 574 Days
• Field of Search: 438/22, 438/29
• US Class Current: 1/1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: Y10S 977/762 Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less

Abstract

A light emitting diode (LED) structure includes a plurality of devices arranged side by side on a support layer. Each device includes a first conductivity type semiconductor nanowire core and an enclosing second conductivity type semiconductor shell for forming a pn or pin junction that in operation provides an active region for light generation. A first electrode layer extends over the plurality of devices and is in electrical contact with at least a top portion of the devices to connect to the shell. The first electrode layer is at least partly air-bridged between the devices.

Claims

1. A method of manufacturing a nanowire light emitting diode (LED) structure, comprising:

providing a support layer;

providing a plurality of devices arranged side by side on the support layer, wherein each device comprises a first conductivity type semiconductor nanowire core and an enclosing second conductivity type semiconductor shell for forming a pn or pin junction that in operation provides an active region for light generation;

depositing a sacrificial layer that completely covers the devices in a non-active area and partially covers the devices in a LED area, leaving top portions of the devices in the LED area exposed; and

depositing a first electrode layer on the exposed top portions of the devices and over the support layer between the devices.

2. The method of claim 1, wherein the first conductivity type comprises n-type, the second conductivity type comprises p-type and the first electrode layer comprises a p-electrode layer.

3. The method of claim 2, further comprising depositing a second n-electrode layer which electrically connects to the n-type nanowire cores.

4. The method of claim 3, wherein the support layer comprise an n-type semiconductor buffer layer on a substrate, which buffer layer serves as n-contact and the n-electrode layer contacts the buffer layer.

5. The nanowire method of claim 3, wherein the support layer comprises at least one of a transparent layer, a reflective layer or a semiconductor substrate.

6. The method of claim 4, wherein each device comprises a core-shell nanowire containing the core, the shell and an active layer between the core and the shell.

7. The method of claim 6, further comprising a dielectric masking layer on the support layer such that the cores protrude from the buffer layer through openings in the masking layer, and the shells are located on the masking layer.

8. The method of claim 7, further comprising removing the sacrificial layer such that a first portion of the first electrode layer located on the sacrificial layer in the non-active area is removed and a second portion of the first electrode layer located on top of the nanowire shells forms an air-bridged p-electrode.

9. The method of claim 8, wherein the sacrificial layer comprises a photoresist.

10. The method of claim 4, wherein the buffer layer comprises at least one of gallium nitride or aluminum gallium nitride.

11. The method of claim 2, wherein the p-electrode comprises a transparent conductive oxide layer.

12. The method as claimed in claim 8, further comprising the step of temporary bonding a carrier to the side of the structure comprising the nanowires.

13. The method as claimed in claim 12, further comprising the step of etching one or more recesses in the substrate down to the buffer layer.

14. The method as claimed in claim 13, further comprising forming a mirror on the buffer layer in the at least one recess to render the LED structure top emitting.

15. The method as claimed in claim 14, further comprising filling the at least one recess over the mirror with a filler material and removing the structure from the carrier.

16. The method as claimed in claim 12, further comprising removing the substrate from the structure leaving the buffer layer exposed and applying a mirror to the buffer layer to render the LED structure top emitting.

17. The method as claimed in claim 16, further comprising attaching a carrier to the mirror.

18. The method as claimed in claim 8, further comprising attaching a carrier to the structure, the carrier having a mirror on one surface facing the buffer layer.