Semiconductor light emitting device including a window layer and a light-directing structure

Abstract

A device comprises a window layer and a light-directing structure comprising a porous semiconductor layer formed in an n-type region. The device comprises a semiconductor structure, disposed between the window layer and the light-directing structure, comprising a light emitting layer. An opening is formed in the semiconductor structure. A first metal layer is in direct contact with the light-directing structure. A dielectric layer is disposed over the first metal layer and in the opening. A second metal layer is disposed over the dielectric layer. A transparent conductive oxide is disposed between the p-type region and the window layer and in direct contact with the p-type region. A first hole is formed in the dielectric layer, wherein the first hole exposes the transparent conductive oxide such that the second metal layer is in direct contact with the transparent conductive oxide through the first hole.

What is being claimed is: 
     
         1 . A device comprising:
 a window layer;   a light-directing structure comprising a porous semiconductor layer formed in an n-type region, the light-directing structure configured to direct light toward the window layer;   a semiconductor structure, disposed between the window layer and the light-directing structure, comprising a light emitting layer disposed between the n-type region and a p-type region;   an opening formed in the semiconductor structure;   a first metal layer in direct contact with the light-directing structure;   a dielectric layer disposed over the first metal layer and in the opening;   a second metal layer disposed over the dielectric layer;   a transparent conductive oxide disposed between the p-type region and the window layer and in direct contact with the p-type region; and   a first hole formed in the dielectric layer, wherein the first hole exposes the transparent conductive oxide such that the second metal layer is in direct contact with the transparent conductive oxide through the first hole.   
     
     
         2 . The device of  claim 1  further comprising a second hole formed in the dielectric layer, wherein the second hole exposes the first metal layer such that the first metal layer is in direct contact with the second metal layer through the second hole. 
     
     
         3 . The device of  claim 2  wherein the second metal layer comprises:
 a first portion that is in contact with the transparent conductive oxide and forms an anode; and 
 a second portion that is in contact with the first metal layer and forms a cathode. 
 
     
     
         4 . The device of  claim 1  wherein the transparent conductive oxide is one of indium tin oxide, zinc oxide, and ruthenium oxide. 
     
     
         5 . The device of  claim 1  wherein a combined thickness of all layers disposed between the p-type region and the window layer is less than 2 μm. 
     
     
         6 . The device of  claim 1  wherein the second metal layer is disposed in direct contact with the transparent conductive oxide in the opening etched through the semiconductor structure to expose the transparent conductive oxide. 
     
     
         7 . The device of  claim 1  further comprising an additional transparent bonding layer disposed between the transparent conductive oxide and the window layer. 
     
     
         8 . The device of  claim 7  further comprising a wavelength converting material disposed in the additional transparent bonding layer. 
     
     
         9 . The device of  claim 7  wherein an interface between the additional transparent bonding layer and the transparent conductive oxide is adapted to scatter light. 
     
     
         10 . The device of  claim 7  wherein the additional transparent bonding layer is one of a transparent conductive oxide, a non-conducting glass material, a dielectric material, silicon nitride, ITO, soda-lime glass, borosilicate glass, an organic material, benzocyclobutene, spin-on glass, and silicone. 
     
     
         11 . The device of  claim 1  wherein a bond between the window layer and the p-type region is substantially free of organic material. 
     
     
         12 . The device of  claim 1  wherein the window layer is one of an optical filter, sapphire, and glass. 
     
     
         13 . The device of  claim 1  wherein the window layer comprises a wavelength converting material configured to absorb light emitted by the light emitting layer and emit light of a different wavelength. 
     
     
         14 . The device of  claim 1  wherein the window layer comprises a ceramic phosphor. 
     
     
         15 . The device of  claim 1  wherein the light emitting layer is a III-nitride layer. 
     
     
         16 . The device of  claim 1  wherein the semiconductor structure is disposed on at least two sides of the opening.