LED lamps

• US 8,604,508 B2
• Filed: 08/08/2012
• Issued: 12/10/2013
• Est. Priority Date: 11/19/1997
• Status: Expired due to Fees

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Salam, Hassan P. A.
• Primary Examiner(s): STARK, JARRETT J
• Application Number:
  US13/570,022
• Publication Number:
  US 20120305978A1
• Time in Patent Office: 489 Days
• Field of Search: 257/91, 257/94, 257/95, 257/96, 257/99, 257/E33.062
• US Class Current: 257/99
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A high power LED lamp has a GaN chip placed over an AlGaInP chip. A reflector is placed between the two chips. Each of the chips has trenches diverting light for output. The chip pair can be arranged to produce white light having a spectral distribution in the red to blue region that is close to that of daylight. Also, the chip pair can be used to provide an RGB lamp or a red-amber-green traffic lamp. The active regions of both chips can be less than 50 microns away from a heat sink.

Claims

1. A light-emitting device, comprising:

a substrate;

a semiconductor structure having a top face, comprising a lower semiconductor layer connected to the substrate, an upper semiconductor layer connected to the lower semiconductor layer, and an active region between the lower semiconductor layer and the upper semiconductor layer for generating light;

a region through the upper semiconductor layer and the active layer, and having an inclined sidewall exposing the upper semiconductor layer and the active layer, and a floor exposing the lower semiconductor layer;

an insulator on the inclined sidewall of the region; and

a conductor on the insulator and the exposed lower semiconductor layer, wherein the inclined sidewall forms an obtuse angle with the top face.

2. The light-emitting device according to claim 1, wherein the obtuse angle is between 95 and 130 degrees.

3. The light-emitting device according to claim 1, wherein the insulator comprises a transparent dielectric.

4. The light-emitting device according to claim 1, wherein the region comprises a plurality of cavities.

5. The light-emitting device according to claim 1, wherein the region comprises an elongated trench and the conductor comprises an elongated metallic conductor.

6. The light-emitting device according to claim 1, wherein the lower semiconductor layer under the conductor has a thickness greater than 5% of a total thickness of the lower semiconductor layer.

7. The light-emitting device according to claim 1, wherein the region extends from the top face into the semiconductor structure by more than 50% of a thickness of the semiconductor structure.

8. The light-emitting device according to claim 1, wherein the substrate is transparent to light generated in the semiconductor structure.

9. The light-emitting device according to claim 1, wherein the substrate comprises a non-semiconductor material.

10. The light-emitting device according to claim 1, wherein the semiconductor structure is grown on the substrate.

11. The light-emitting device according to claim 1, further comprising a transparent cover material covering the semiconductor structure and having a refractive index of at least 15% less than that of the semiconductor structure.

12. The light-emitting device according to claim 1, further comprising a heat sink connected to the substrate.

13. The light-emitting device according to claim 12, wherein the heat sink comprises aluminum.

14. The light-emitting device according to claim 12, further comprising a translucent medium between the semiconductor structure and the heat sink, wherein the semiconductor structure is between the substrate and the translucent medium.

15. The light-emitting device according to claim 1, wherein the conductor comprises a material selected from the group consisting of gold and aluminum.

16. The light-emitting device according to claim 1, further comprising a top metallic conductor formed on the upper semiconductor layer.

17. The light-emitting device according to claim 1, wherein the light-emitting device is an LED chip.

18. The light-emitting device according to claim 17, wherein the LED chip has a size greater than 1 mm², and the input power rating of the chip exceeds 150 milliwatts.

19. The light-emitting device according to claim 1, wherein the light-emitting device generates incoherent light.

20. The light-emitting device according to claim 1, wherein the region comprises a trench, and wherein the trench reaches the substrate.

21. A light-emitting device, comprising:

a substrate;

a semiconductor structure having a top face, comprising a lower semiconductor layer connected to the substrate, an upper semiconductor layer connected to the lower semiconductor layer, and an active region between the lower semiconductor layer and the upper semiconductor layer for generating light;

a region through the upper semiconductor layer and the active layer, and having an inclined sidewall exposing the upper semiconductor layer and the active layer, and a floor exposing the lower semiconductor layer;

an insulator on the inclined sidewall of the region;

a conductor on the insulator and the exposed lower semiconductor layer;

a heat sink connected to the substrate; and

a translucent medium between the semiconductor structure and the heat sink, wherein the semiconductor structure is between the substrate and the translucent medium.