Semiconductor light emitting element and method for fabricating the same

• US 7,763,903 B2
• Filed: 09/16/2005
• Issued: 07/27/2010
• Est. Priority Date: 06/28/2004
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Orita, Kenji
• Primary Examiner(s): Monbleau; Davienne
• Assistant Examiner(s): Rodela; Eduardo A
• Application Number:
  US11/227,428
• Publication Number:
  US 20060060868A1
• Time in Patent Office: 1,775 Days
• Field of Search: 257/79, 257/98, 257/99, 257/E33.001, 257/E33.062, 257/E33.065, 257/E33.066, 257/E33.075
• US Class Current: 257/98
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

Projections/depressions forming a two-dimensional periodic structure are formed in a surface of a semiconductor multilayer film opposing the principal surface thereof, while a metal electrode with a high reflectivity is formed on the other surface. By using the diffracting effect of the two-dimensional periodic structure, the efficiency of light extraction from the surface formed with the projections/depressions can be improved. By reflecting light emitted toward the metal electrode to the surface formed with the projections/depressions by using the metal electrode with the high reflectivity, the foregoing effect achieved by the two-dimensional periodic structure can be multiplied.

Claims

1. A semiconductor light emitting element for emitting light, comprising:

a metal layer;

multiple group-III nitride semiconductor layers located on the metal layer and having an active layer, a first principle surface with projections and a second principle surface facing the metal layer and located under the first principle surface;

a first electrode being in contact with the first principle surface; and

a second electrode being in contact with the second principle surface,

wherein the metal layer has approximately the same area as the second principle surface, and

0.5λ

/N≦

L≦

4λ

/N is satisfied where L is a distance between the nearest two projections of the projections, λ

is a wavelength of emitted light from the active layer, and N is a refractive index of the group-III nitride semiconductor comprising the projections.

2. The semiconductor light emitting element of claim 1, wherein

a n-type group-III nitride semiconductor layer is provided in an upper part of the multiple group-III nitride semiconductor layers, and

the first principle surface is the upper surface of the n-type group-III nitride semiconductor layer.

3. The semiconductor light emitting element of claim 1, wherein the projections are formed in the uppermost region of the multiple group-III nitride semiconductor layers.

4. The semiconductor light emitting element of claim 1, wherein the thickness of the metal layer is equal to or more than 10 μ

m.

5. The semiconductor light emitting element of claim 1,

wherein the projections do not penetrate the active layer.

6. The semiconductor light emitting element of claim 1,

wherein the light is extracted through the first principal surface.

7. The semiconductor light emitting element of claim 1,

wherein the semiconductor light emitting element does not include a growth substrate used for growing the multiple group-III nitride semiconductor layers.