LED with current injection confinement trench

• US 9,768,345 B2
• Filed: 12/20/2013
• Issued: 09/19/2017
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hu, Hsin-Hua, McGroddy, Kelly
• Primary Examiner(s): Dang, Trung Q
• Assistant Examiner(s): REDDINGTON, PATRICIA D
• Application Number:
  US14/137,847
• Publication Number:
  US 20150179876A1
• Time in Patent Office: 1,369 Days
• Field of Search: 257 13
• CPC Class Codes: H01L 2224/95 at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
• 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 2924/12044 OLED
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/405 Reflective 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

Abstract

A method and structure for forming an array of LED devices is disclosed. The LED devices in accordance with embodiments of the invention may include a confined current injection area, embedded mirror, or sidewall passivation layer, and any combination thereof.

Claims

1. An LED device comprising:

a p-n diode layer comprising;

a top surface with a maximum dimension of 3 to 20 μ

m,

a bottom surface comprising an interior bottom surface and a surrounding bottom surface;

external sidewalls extending between the top surface and the surrounding bottom surface;

a quantum well layer between an n-doped layer and a p-doped layer;

a confinement trench that extends from the bottom surface of the p-n diode layer through the quantum well layer and physically isolates an interior portion of the quantum well layer from a surrounding portion of the quantum well layer adjacent the external sidewalls, and the confinement trench physically isolates an interior bottom surface of the p-n diode layer from a surrounding bottom surface of the p-n diode layer adjacent the external sidewalls, wherein the surrounding bottom surface of the p-n diode completely surrounds the interior bottom surface of the p-n diode layer;

a bottom electrically conductive contact on and in electrical contact with the interior bottom surface of the p-n diode layer, wherein the bottom electrically conductive contact that is on and in electrical contact with the interior bottom surface of the p-n diode layer is not in electrical contact with the surrounding bottom surface of the p-n diode layer that completely surrounds the interior bottom surface of the p-n diode layer;

wherein the LED device is bonded to a bottom electrode of a subpixel within a display area of a display substrate, and the bottom electrically conductive contact is in electrical contact with the bottom electrode; and

a top electrode that is on and in electrical contact with the top surface, and the top electrode completely covers the top surface.

2. The LED device of claim 1, further comprising a mirror layer spanning along the interior bottom surface and along confinement trench sidewalls within the confinement trench.

3. The LED device of claim 2, wherein the mirror layer does not span along the external sidewalls of the p-n diode layer.

4. The LED device of claim 2, further comprising a passivation layer between the mirror layer and the confinement trench sidewalls.

5. The LED device of claim 4, wherein the passivation layer spans along the external sidewalls of the p-n diode layer.

6. The LED device of claim 4, further comprising an opening in the passivation layer on the interior bottom surface of the p-n diode layer.

7. The LED device of claim 6, wherein the mirror layer is formed within the opening of the passivation layer on the interior bottom surface of the p-n diode layer.

8. The LED device of claim 1, wherein a top surface area of the top surface of the p-n diode layer is larger than a surface area of the interior bottom surface of the p-n-diode layer surrounded by the confinement trench.

9. The LED device of claim 1, wherein the display substrate is incorporated within portable electronic device.