Wavelength-converted semiconductor light emitting device

• US 8,445,929 B2
• Filed: 03/15/2010
• Issued: 05/21/2013
• Est. Priority Date: 03/14/2005
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Inventors: Krames, Michael R., Mueller, Gerd O.
• Primary Examiner(s): Lee, Eugene
• Assistant Examiner(s): ULLAH, ELIAS
• Application Number:
  US12/723,720
• Publication Number:
  US 20100200886A1
• Time in Patent Office: 1,163 Days
• Field of Search: 257/98, 257/E33.061, 257/E33.067
• US Class Current: 257/98
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/5454 nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2237/02 Aspects relating to interlayers, e.g. used to join ceramic articles with other articles by heating
• CPC Class Codes: C04B 2237/06 Oxidic interlayers
• CPC Class Codes: C04B 2237/064 based on alumina or aluminates
• CPC Class Codes: C04B 2237/068 based on refractory oxides, e.g. zirconia
• CPC Class Codes: C04B 2237/08 Non-oxidic interlayers
• CPC Class Codes: C04B 2237/083 Carbide interlayers, e.g. silicon carbide interlayers
• CPC Class Codes: C04B 2237/10 Glass interlayers, e.g. frit or flux
• CPC Class Codes: C04B 2237/12 Metallic interlayers
• CPC Class Codes: C04B 2237/30 Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/36 Non-oxidic
• CPC Class Codes: C04B 2237/365 Silicon carbide
• CPC Class Codes: C04B 2237/366 Aluminium nitride
• CPC Class Codes: C04B 2237/368 Silicon nitride
• CPC Class Codes: C04B 2237/52 : Pre-treatment of the joining surfaces, e.g. cleaning, machining
• CPC Class Codes: C04B 2237/525 : by heating
• CPC Class Codes: C04B 2237/704 : of one or more of the ceramic layers or articles
• CPC Class Codes: C04B 2237/708 : of one or more of the interlayers
• CPC Class Codes: C04B 2237/76 : Forming laminates or joined articles comprising at least one member in the form other than a sheet or disc, e.g. two tubes or a tube and a sheet or disc
• CPC Class Codes: C04B 35/44 : based on aluminates
• CPC Class Codes: C04B 35/495 : based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
• CPC Class Codes: C04B 35/6268 : characterised by the applied pressure or type of atmosphere, e.g. in vacuum, hydrogen or a specific oxygen pressure
• CPC Class Codes: C04B 35/62805 : Oxide ceramics
• CPC Class Codes: C04B 35/62807 : Silica or silicates
• CPC Class Codes: C04B 35/62813 : Alumina or aluminates
• CPC Class Codes: C04B 35/645 : Pressure sintering
• CPC Class Codes: C04B 37/001 : directly with other burned ceramic articles
• CPC Class Codes: C04B 37/005 : consisting of glass or ceramic material
• CPC Class Codes: C04B 37/006 : consisting of metals or metal salts
• CPC Class Codes: C04B 37/008 : by means of an interlayer consisting of an organic adhesive, e.g. phenol resin or pitch
• CPC Class Codes: C04B 37/026 : consisting of metals or metal salts
• CPC Class Codes: H01L 2224/0554 : External layer
• CPC Class Codes: H01L 2224/0555 : Shape
• CPC Class Codes: H01L 2224/0556 : Disposition
• CPC Class Codes: H01L 2224/05568 : the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 : Single external layer
• CPC Class Codes: H01L 2224/05599 : Material
• CPC Class Codes: H01L 2224/14 : of a plurality of bump connectors
• 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 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• 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 33/08 : 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 33/501 : characterised by the materials, e.g. binder

Abstract

Embodiments of the invention include a light emitting structure comprising a light emitting layer. A first luminescent material comprising a phosphor is disposed in a path of light emitted by the light emitting layer. A second luminescent material comprising a semiconductor is also disposed in a path of light emitted by the light emitting layer. The second luminescent material is configured to absorb light emitted by the light emitting layer and emit light of a different wavelength. In some embodiments, one of the first and second luminescent materials may be bonded to the semiconductor structure.

Claims

1. A device comprising:

a light emitting structure comprising a light emitting layer that emits first light;

a first luminescent material comprising a ceramic phosphor disposed in a path of light emitted by the light emitting layer; and

a second luminescent material comprising a luminescent semiconductor disposed in a path of light emitted by the light emitting layer, wherein the luminescent semiconductor is configured to absorb the first light and emit light of a different wavelength;

wherein the first luminescent material is disposed between the second luminescent material and the light emitting structure.

2. The device of claim 1 wherein the first luminescent material is bonded to the light emitting structure.

3. The device of claim 2 further comprising a bonding material disposed between the first luminescent material and the light emitting structure.

4. The device of claim 3 wherein the bonding material comprises one of nanoparticles, glass, high index glass, metal oxide, metal fluoride, aluminum oxide, lead oxide, and tungsten oxide.

5. The device of claim 1 wherein the second luminescent material comprises one of III-V material and II-VI material.

6. The device of claim 1 wherein the second luminescent material comprises one of nanoparticles and quantum dots.

7. The device of claim 1 wherein light emitted by the light emitting layer, light emitted by the ceramic phosphor, and light emitted by the luminescent semiconductor are different in color.

8. The device of claim 1 wherein the light emitting structure is mounted on a host substrate, the host substrate comprising one of copper, an alloy of copper, silicon, aluminum nitride, and diamond.

9. The device of claim 1 further comprising a reflector disposed on at least one of the light emitting structure, the first luminescent material, and the second luminescent material.

10. The device of claim 9 wherein the reflector comprises a distributed Bragg reflector.

11. The device of claim 1 wherein the light emitting structure includes a non-semiconductor substrate.

12. A device comprising:

a light emitting structure comprising a light emitting layer and a roughened or textured surface;

a first luminescent material comprising a ceramic phosphor disposed in a path of light emitted by the light emitting layer; and

a second luminescent material disposed in a path of light emitted by the light emitting layer;

wherein the ceramic phosphor is a rigid agglomerate of tightly packed individual phosphor particles that is free of binder material.

13. The device of claim 12 wherein the surface is roughened or textured by one of chemical mechanical polishing, dry etching, and photoelectrochemical etching.

14. The device of claim 12 wherein the light emitting layer comprises III-nitride material.

15. The device of claim 12 wherein at least one surface of the ceramic phosphor is roughened, textured, or shaped.

16. The device of claim 12 wherein the first luminescent material comprises one of (Lu_1-x-y-a-bY_xGd_y)₃(Al_1-zGa_z)₅O₁₂:

Ce_aPr_b wherein 0<

x<

1, 0 <

y<

1, 0<

z ≦

0.1, 0<

a ≦

0.2 and 0≦

b≦

0.1, Lu₃Al₅O₁₂;

Ce³⁺, Y₃Al₅O₁₂;

Ce³⁺, (Sr_1-x-yBa_xCa_y)_2-zSi_5-aAl_aN_{8 -a}O_a;

Eu_z²⁺ wherein 0≦

a <

5, 0<

x≦

1, 0≦

y ≦

1, and 0<

z≦

1, Sr₂Si₅N₈;

Eu²⁺, (Sr_1-a-bCa_bBa_c)Si_xN_yO_z;

Eu_a²⁺ (a =0.002-0.2, b =0.0-0.25, c =0.0-0.25, x =1.5-2.5, y =1.5-2.5, z =1.5-2.5), SrSi₂N₂O₂;

Eu²⁺;

(Sr_1-u-v-xMg_uCa_vBa_x)(Ga_2-y-zAl_yIn_zS₄);

Eu²⁺, SrGa₂S₄;

Eu²⁺;

Sr_1-xBa_xSiO₄;

Eu²⁺, (Ca_1-x,Sr_x)S;

Eu²⁺, CaS;

Eu²⁺ and SrS;

Eu²⁺.