Deep ultraviolet light emitting device and method of manufacturing deep ultraviolet light emitting device

Abstract

A deep ultraviolet light emitting device includes: an electron block layer of a p-type AlGaN-based semiconductor material or a p-type AlN-based semiconductor material provided on a support substrate; an active layer of an AlGaN-based semiconductor material provided on the electron block layer; an n-type clad layer of an n-type AlGaN-based semiconductor material provided on the active layer; an n-type contact layer provided on a partial region of the n-type clad layer and made of an n-type semiconductor material containing gallium nitride (GaN); and an n-side electrode formed on the n-type contact layer. The n-type contact layer has a band gap smaller than that of the n-type clad layer.

What is claimed is: 
     
         1 . A deep ultraviolet light emitting device comprising:
 an electron block layer of a p-type AlGaN-based semiconductor material or a p-type AlN-based semiconductor material provided on a support substrate;   an active layer of an AlGaN-based semiconductor material provided on the electron block layer;   an n-type clad layer of an n-type AlGaN-based semiconductor material provided on the active layer;   an n-type contact layer provided on a partial region of the n-type clad layer and made of an n-type semiconductor material containing gallium nitride (GaN); and   an n-side electrode formed on the n-type contact layer, wherein   the n-type contact layer has a band gap smaller than that of the n-type clad layer.   
     
     
         2 . The deep ultraviolet light emitting device according to  claim 1 , wherein
 a content percentage of aluminum nitride (AlN) of the n-type contact layer is lower than that of the n-type clad layer.   
     
     
         3 . The deep ultraviolet light emitting device according to  claim 1 , wherein
 the n-type clad layer has a band gap larger than a wavelength of deep ultraviolet light emitted by the active layer, and   the n-type contact layer has a band gap smaller than the wavelength of deep ultraviolet light emitted by the active layer.   
     
     
         4 . The deep ultraviolet light emitting device according to  claim 1 , wherein
 the n-type clad layer has a band gap of 4.3 eV or larger.   
     
     
         5 . A method of manufacturing a deep ultraviolet light emitting device comprising:
 forming a stack body in which an n-type clad layer of an n-type AlGaN-based semiconductor material, an active layer of an AlGaN-based semiconductor material, and an electron block layer of a p-type AlGaN-based semiconductor material or a p-type AlN-based semiconductor material are stacked on a base substrate successively;   removing the base substrate from the stack body;   forming an n-type contact layer of an n-type semiconductor material that contains GaN on a partial region on the n-type clad layer exposed by removing the base substrate; and   forming an n-side electrode on the n-type contact layer, wherein   the n-type contact layer has a band gap smaller than that of the n-type clad layer.   
     
     
         6 . The method of manufacturing a deep ultraviolet light emitting device according to  claim 5 , wherein
 the forming an n-type contact layer includes:   forming a mask, avoiding the partial region on the n-type clad layer exposed by removing the base substrate;   forming the layer of an n-type semiconductor material on the mask; and   removing the mask to form an opening region on the n-type clad layer.   
     
     
         7 . The method of manufacturing a deep ultraviolet light emitting device according to  claim 5 , wherein
 the forming an n-type contact layer includes:   forming the layer of an n-type semiconductor material on the n-type clad layer exposed by removing the base substrate; and   removing a portion of the layer of an n-type semiconductor material to form an opening region on the n-type clad layer.   
     
     
         8 . The method of manufacturing a deep ultraviolet light emitting device according to  claim 5 , further comprising:
 forming a texture structure in an opening region on the n-type contact layer.   
     
     
         9 . The method of manufacturing a deep ultraviolet light emitting device according to  claim 5 , wherein
 the base substrate is removed from the stack body by a laser lift-off process.   
     
     
         10 . The method of manufacturing a deep ultraviolet light emitting device according to  claim 5 , wherein
 the forming the stack body includes forming a base layer that contains aluminum nitride (AlN) between the base substrate and the n-type clad layer, and   the removing the base substrate includes removing at least a portion of the base layer to expose the n-type clad layer.