Methods of forming light emitting devices having current reducing structures

• US 8,163,577 B2
• Filed: 09/10/2010
• Issued: 04/24/2012
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Emerson, David Todd, Haberern, Kevin, Bergmann, Michael John, Slater, David B. Jr., Donofrio, Matthew, Edmond, John
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): Patton, Paul
• Application Number:
  US12/879,692
• Publication Number:
  US 20110008922A1
• Time in Patent Office: 592 Days
• Field of Search: 257/79, 438/22
• US Class Current: 438/22
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• 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 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/38 with a particular shape

Abstract

A light emitting device includes a p-type semiconductor layer, an n-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer. A non-transparent feature, such as a wire bond pad, is on the p-type semiconductor layer or on the n-type semiconductor layer opposite the p-type semiconductor layer, and a reduced conductivity region is in the p-type semiconductor layer or the n-type semiconductor layer and is aligned with the non-transparent feature. The reduced conductivity region may extend from a surface of the p-type semiconductor layer opposite the n-type semiconductor layer towards the active region and/or from a surface of the n-type semiconductor layer opposite the p-type semiconductor layer towards the active region.

Claims

1. A method of forming a light emitting device, comprising:

forming a p-type semiconductor layer, an n-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

forming a non-transparent feature on the n-type semiconductor layer opposite the p-type semiconductor layer; and

forming a reduced conductivity region in the p-type semiconductor layer, wherein edges of the reduced conductivity region are aligned with edges of the non-transparent feature, the reduced conductivity region extending from a surface of the p-type semiconductor layer opposite the n-type semiconductor layer towards the active region.

2. The method of claim 1, wherein forming a non-transparent feature on the n-type semiconductor layer comprises forming a wire bond pad, a current spreading finger and/or a passivation region on the n-type semiconductor layer.

3. The method of claim 1, wherein the reduced conductivity region extends from the surface of the p-type semiconductor layer to the active region.

4. The method of claim 1, wherein the reduced conductivity region extends from the surface of the p-type semiconductor layer into the active region.

5. The method of claim 1, wherein the reduced conductivity region extends from the surface of the p-type semiconductor layer through the active region.

6. The method of claim 1, wherein the reduced conductivity region extends through the active region.

7. The method of claim 1, wherein the active region comprises a Group III-nitride based active region.

8. The method of claim 1, wherein forming a reduced conductivity region comprises:

forming a mask layer on the surface of the p-type semiconductor layer, the mask layer having an opening corresponding to the bond pad region; and

implanting atoms into the p-type semiconductor layer through the opening in the mask layer.

9. A method of forming a light emitting device, comprising:

forming a p-type semiconductor layer, an n-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

forming a wire bond pad on the n-type semiconductor layer opposite the p-type semiconductor layer; and

forming a metal contact on a surface of the p-type semiconductor layer opposite the n-type semiconductor layer, wherein the metal contact forms an ohmic contact to the p-type semiconductor layer in a region other than a reduced conductivity area of the surface of the p-type semiconductor layer, wherein edges of the reduced conductivity area are aligned with edges of the wire bond pad.

10. The method of claim 9, further comprising forming a reduced conductivity region in the p-type semiconductor layer and aligned with the wire bond pad and the reduced conductivity area, the reduced conductivity region extending from the surface of the p-type semiconductor layer towards the active region.

11. The method of claim 9, further comprising forming a reduced conductivity region in the n-type semiconductor layer and aligned with the wire bond pad, the reduced conductivity region extending from a surface of the n-type semiconductor layer opposite the p-type semiconductor layer towards the active region.

12. The method of claim 9, further comprising forming a non-ohmic contact on the surface of the p-type semiconductor layer.

13. The method of claim 12, wherein the non-ohmic contact comprises a metal that does not form an ohmic contact with the p-type semiconductor layer.

14. A method of forming a light emitting device, comprising:

forming a p-type semiconductor layer, an n-type semiconductor layer, and an active region between the n-type semiconductor layer and the p-type semiconductor layer;

forming a wire bond pad on the n-type semiconductor layer opposite the p-type semiconductor layer;

forming a metal contact on a surface of the p-type semiconductor layer opposite the n-type semiconductor layer, wherein the metal contact forms on ohmic contact to the p-type semiconductor layer in a region other than a reduced conductivity area of the surface of the p-type semiconductor layer that is aligned with the wire bond pad; and

forming a reduced conductivity region in the n-type semiconductor layer and aligned with the wire bond pad, the reduced conductivity region extending from a surface of the n-type semiconductor layer opposite the p-type semiconductor layer towards the active region, wherein the non-ohmic contact comprises an insulator on the surface of the p-type semiconductor layer.