Semiconductor light emitting element and method for fabricating the same

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.

1 - 14 . (canceled) 
     
     
         15 . 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;   wherein the metal layer has approximately the same area as the second principle surface, and   the distance between the active layer and the first principle surface is larger than the distance between the active layer and the second principle surface.   
     
     
         16 . The semiconductor light emitting element of  claim 15 , wherein:
 a first electrode being in contact with the first principle surface; and   a second electrode being in contact with the second principle surface.   
     
     
         17 . The semiconductor light emitting element of  claim 15 , wherein:
 the distance between the active layer and the bottom surface of the projections is larger than the distance between the active layer and the second principle surface.   
     
     
         18 . The semiconductor light emitting element of  claim 15 , wherein:
 0.5 λ/N≦L≦20 λ/N is satisfied where L is a distance between the nearest two 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.   
     
     
         19 . The semiconductor light emitting element of  claim 15 , wherein:
 0.5 λ/N≦L≦4 λ/N is satisfied where L is a distance between the nearest two 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.