Method of fabricating nitride-based semiconductor light-emitting device and nitride-based semiconductor light-emitting device

Abstract

A method of fabricating a nitride-based semiconductor light-emitting device capable of suppressing reduction of characteristics and a yield is obtained. This method of fabricating a nitride-based semiconductor light-emitting device comprises steps of forming a groove portion on a nitride-based semiconductor substrate by selectively removing a prescribed region of a second region of the nitride-based semiconductor substrate other than a first region corresponding to a light-emitting portion of a nitride-based semiconductor layer up to a prescribed depth and forming the nitride-based semiconductor layer having a different composition from the nitride-based semiconductor substrate on the first region and the groove portion of the nitride-based semiconductor substrate.

1 . A method of fabricating a nitride-based semiconductor light-emitting device, comprising steps of:
 forming a groove portion on a nitride-based semiconductor substrate by selectively removing a prescribed region of a second region of said nitride-based semiconductor substrate other than a first region corresponding to a light-emitting portion of a nitride-based semiconductor layer formed on said nitride-based semiconductor substrate up to a prescribed depth; and   forming said nitride-based semiconductor layer having a different composition from said nitride-based semiconductor substrate on said first region and said groove portion of said nitride-based semiconductor substrate.   
     
     
         2 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 said nitride-based semiconductor substrate includes a GaN substrate, and   said nitride-based semiconductor layer includes a layer containing Al, Ga and N.   
     
     
         3 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 2 , wherein
 said step of forming said nitride-based semiconductor layer on said nitride-based semiconductor substrate includes a step of forming said nitride-based semiconductor layer on the upper surface of said first region of said nitride-based semiconductor substrate and the bottom surface and the side surface of said groove portion, and   the Al composition ratio of a portion of said nitride-based semiconductor layer formed on the side surface of said groove portion is lower than the Al composition ratio of a portion of said nitride-based semiconductor layer formed on the upper surface of said first region.   
     
     
         4 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 3 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of forming said groove portion so that the opening width of said groove portion is gradually increased from the bottom surface toward the opening end of said groove portion.   
     
     
         5 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 said step of forming said nitride-based semiconductor layer on said nitride-based semiconductor substrate includes a step of forming said nitride-based semiconductor layer on the upper surface of said first region of said nitride-based semiconductor substrate and the bottom surface and the side surface of said groove portion, and   the thickness of a portion of said nitride-based semiconductor layer formed on the side surface of said groove portion is smaller than the thickness of a portion of said nitride-based semiconductor layer formed on the upper surface of said first region.   
     
     
         6 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 5 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of forming said groove portion so that the side surface of said groove portion is substantially perpendicular to the surface of said nitride-based semiconductor substrate.   
     
     
         7 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 5 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of forming said groove portion so that the opening width of said groove portion is gradually reduced from the bottom surface toward the opening end of said groove portion.   
     
     
         8 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of forming slender said groove portion extending in a prescribed direction on said nitride-based semiconductor substrate.   
     
     
         9 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (H and K are integers, and at least either H or K is nonzero).   
     
     
         10 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 9 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,0) plane.   
     
     
         11 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 9 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (L is a nonzero integer).   
     
     
         12 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 9 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of forming said groove portion extending along a [K,−H,H−K,0] direction on said nitride-based semiconductor substrate.   
     
     
         13 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 said step of forming said groove portion on said nitride-based semiconductor substrate includes a step of latticing slender said groove portions extending in a first direction and a second direction intersecting with said first direction on said nitride-based semiconductor substrate to enclose said first region.   
     
     
         14 . The method of fabricating a nitride-based semiconductor light-emitting device according to  claim 1 , wherein
 said nitride-based semiconductor layer includes a layer, formed on said first region and said second region of said nitride-based semiconductor substrate, of a nitride-based semiconductor having a different composition from said nitride-based semiconductor substrate and a light-emitting layer of a nitride-based semiconductor formed at least on said first region.   
     
     
         15 . A nitride-based semiconductor light-emitting device comprising:
 a nitride-based semiconductor substrate including a first region corresponding to a light-emitting portion and a second region arranged to be adjacent to said first region through a step portion having a prescribed height; and   a nitride-based semiconductor layer, formed on the upper surface of said first region of said nitride-based semiconductor substrate and the side surface of said step portion, having a different composition from said nitride-based semiconductor substrate, wherein   the thickness of a portion of said nitride-based semiconductor layer formed on the side surface of said step portion is smaller than the thickness of a portion of said nitride-based semiconductor layer formed on the upper surface of said first region.   
     
     
         16 . The nitride-based semiconductor light-emitting device according to  claim 15 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (H and K are integers, and at least either H or K is nonzero).   
     
     
         17 . The nitride-based semiconductor light-emitting device according to  claim 16 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,0) plane.   
     
     
         18 . The nitride-based semiconductor light-emitting device according to  claim 17 , wherein
 said step portion is so formed as to extend along a [K,−H,H−K,0] direction.   
     
     
         19 . The nitride-based semiconductor light-emitting device according to  claim 16 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (L is a nonzero integer).   
     
     
         20 . The nitride-based semiconductor light-emitting device according to  claim 15 , wherein
 said nitride-based semiconductor layer includes a layer, formed on said first region and said second region of said nitride-based semiconductor substrate, of a nitride-based semiconductor having a different composition from said nitride-based semiconductor substrate and a light-emitting layer of a nitride-based semiconductor formed at least on said first region.   
     
     
         21 . A nitride-based semiconductor light-emitting device comprising:
 a nitride-based semiconductor substrate including a first region corresponding to a light-emitting portion and a second region arranged to be adjacent to said first region through a step portion having a prescribed height; and   a nitride-based semiconductor layer, formed on the upper surface of said first region of said nitride-based semiconductor substrate and the side surface of said step portion, having a different composition from said nitride-based semiconductor substrate and containing Al, Ga and N, wherein   the Al composition ratio of a portion of said nitride-based semiconductor layer formed on the side surface of said step portion is lower than the Al composition ratio of a portion of said nitride-based semiconductor layer formed on the upper surface of said first region.   
     
     
         22 . The nitride-based semiconductor light-emitting device according to  claim 21 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (H and K are integers, and at least either H or K is nonzero).   
     
     
         23 . The nitride-based semiconductor light-emitting device according to  claim 22 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,0) plane.   
     
     
         24 . The nitride-based semiconductor light-emitting device according to  claim 22 , wherein
 the surface of said nitride-based semiconductor substrate has a (H,K,−H−K,L) plane (L is a nonzero integer).   
     
     
         25 . The nitride-based semiconductor light-emitting device according to  claim 24 , wherein
 said step portion is so formed as to extend along a [K,−H,H−K,0] direction.   
     
     
         26 . The nitride-based semiconductor light-emitting device according to  claim 21 , wherein
 said nitride-based semiconductor layer includes a layer, formed on said first region and said second region of said nitride-based semiconductor substrate, containing Al and Ga and a light-emitting layer of a nitride-based semiconductor formed at least on said first region.