IP Library Granted Patent US 11,127,887
Granted Patent B2
US 11,127,887 · App. 15/750,144 · Granted Sep 21, 2021

Semiconductor light emitting device with reflective side coating

Inventors: Hisashi Masui (San Jose, CA); Oleg B. Shchekin (San Francisco, CA); Ken Shimizu (Sunnyvale, CA); Lex Kosowsky (San Jose, CA); Ken Davis (Raleigh, NC)
Assignee: Lumileds LLC
H01L33/46H01L33/0095H01L33/20H01L33/486H01L33/505H01L33/56H01L2933/0025H01L2933/0058
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Quick Facts
Patent No.
US 11,127,887
App. No.
15/750,144
Granted
Sep 21, 2021
Kind
B2
Abstract

A semiconductor light emitting device ( 100;200;300;400,400 B, 400 C; 500;600;700 ) may have a reflective side coating ( 120;220;320;420;520;620;720 ) disposed on a sidewall ( 118;215;315;415,435;515 ) of a semiconductor light emitting device structure. Such a device may be fabricated by dicing a semiconductor structure to separate a semiconductor light emitting device structure and then forming a reflective side coating ( 120;220;320;420;520;620;720 ) on a sidewall ( 118;215;315;415,435;515 ) of the separated semiconductor light emitting device structure.

Claims (30)

1. A light emitting structure comprising:

a semiconductor light emitting device having a top emitting surface connected to an opposite bottom surface by sloped sidewalls that are at a non-perpendicular angle with respect to the top emitting surface;

a reflecting thin-film coating disposed in direct contact with and conforming to the sloped sidewalls of the semiconductor light emitting device, the reflecting thin-film coating having a thickness that is at least 1 micron and no greater than 50 microns.

2. The light emitting structure of claim 1 , the reflecting thin-film coating including at least 20 layers and no more than 80 layers.

3. The light emitting structure of claim 1 , the semiconductor light emitting device including a growth substrate and a light emitting diode (LED) that is formed on the growth substrate, and the reflecting thin-film coating covering one or more sides of the growth substrate while leaving a top surface of the growth substrate exposed.

4. The light emitting structure of claim 1 , the reflecting thin-film coating comprising a plurality of layers arranged to form a Bragg reflector, each layer of the plurality of layers having a same thickness between 100 nm and 10 microns.

5. The light emitting structure of claim 1 , the reflecting thin-film coating being disposed in direct contact with at least part of the opposite bottom surface of the semiconductor light emitting device.

6. The light emitting structure of claim 1 , further comprising a wavelength converting layer disposed on the top emitting surface of the semiconductor light emitting device and comprising second sloped sidewalls, the reflecting thin-film coating disposed on and in direct contact with second sloped sidewalls of the wavelength converting element.

7. The light emitting structure of claim 1 , the semiconductor light emitting device comprising:

a die; and

a transparent layer in direct contact with and on a side of the die and conforming and in direct contact with the sloped sidewalls on which the thin-film reflective coating is disposed.

8. The light emitting structure of claim 7 , the transparent layer including a porous material having a refractive index that varies to perform an optical function on light emitted from the die.

9. The light emitting structure of claim 7 , the transparent layer having a variable thickness along a direction perpendicular to the top emitting surface of the semiconductor light emitting device.

10. A light emitting structure comprising:

a semiconductor light emitting device comprising:

a die with a first top emitting surface connected to an opposite first bottom surface by first sidewalls;

a wavelength conversion layer having a second top emitting surface connected to an opposite second bottom surface by second sidewalls, the opposite second bottom surface disposed on and in direct contact with the first top emitting surface of the die, the second top emitting surface having a different area than the first top emitting surface of the die;

a reflecting thin-film coating disposed in direct contact with and conforming to the first sidewalls of the die and the second sidewalls of the wavelength conversion layer, the reflecting thin-film coating having a thickness that is at least 1 micron and no greater than 50 microns.

11. A method comprising:

dicing a semiconductor structure to form a plurality of semiconductor light emitting devices, each of the semiconductor light emitting devices respectively including a sidewall; and

forming, on each of the semiconductor light emitting devices, a reflecting thin-film coating on and in direct contact with the sidewall of the semiconductor light emitting device, the reflecting thin-film coating having a thickness that is at least 1 micron and no greater than 50 microns.

12. The method of claim 11 , wherein the reflecting thin-film coating includes at least 20 layers and no more than 80 layers.

13. The method of claim 11 , the forming the thin-film coating comprising forming by atomic layer deposition.

14. The method of claim 11 , further comprising forming the semiconductor light emitting device by forming a light emitting diode (LED) on a growth substrate, the reflecting thin-film coating being formed to cover one or more sides of the growth substrate while leaving a top surface of the growth substrate exposed.

15. The method of claim 11 , further comprising prior to said forming, depositing a transparent material such that the transparent material forms the sidewall, the sidewall forming an angle with a light emitting layer of the semiconductor light emitting device less than 90°.

16. The method of claim 11 , further comprising texturing a top surface of the semiconductor light emitting device.

17. The method of claim 11 , the reflecting thin-film coating operating as partial reflector.

18. The method of claim 11 , the reflecting thin-film coating comprising a plurality of layers arranged to form a Bragg reflector, each layer of the plurality of layers having a same thickness between 100 nm and 10 microns.

19. The method of claim 11 , further comprising forming, in the reflecting thin-film coating, a layer of porous material.

20. The light emitting device according to claim 1 , wherein the top emitting surface of the semiconductor light emitting device is flush with the reflecting thin-film coating at all edges of the semiconductor light emitting device.

Assignments (5)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 10, 2025
From: LUMILEDS LLC
To: LUMILEDS SINGAPORE PTE. LTD.
Reel/Frame 071888/0086 →
RELEASE OF SECURITY INTEREST Recorded Jan 29, 2025
From: SOUND POINT AGENCY LLC
To: LUMILEDS LLC; LUMILEDS HOLDING B.V.
Reel/Frame 070046/0001 →
SECURITY INTEREST Recorded Jan 5, 2023
From: LUMILEDS LLC; LUMILEDS HOLDING B.V.
To: SOUND POINT AGENCY LLC
Reel/Frame 062299/0338 →
PATENT SECURITY AGREEMENT Recorded Dec 9, 2022
From: LUMILEDS, LLC
To: DEUTSCHE BANK AG NEW YORK BRANCH
Reel/Frame 062114/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 5, 2020
From: MASUI, HISASHI; SHCHEKIN, OLEG B.; SHIMIZU, KEN; KOSOWSKY, LEX; DAVIS, KEN
To: LUMILEDS LLC
Reel/Frame 052030/0149 →
Continuity (2)
Provisional Application 62200490 · Aug 3, 2015
Related Publication 20180226543A1 · Aug 9, 2018