Light emitting device and manufacturing method thereof

Abstract

Provided are a light emitting device and a manufacturing method thereof. The light emitting device comprises a first conductive semiconductor layer with a lower surface being uneven in height, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer on the active layer.

What is claimed is: 
     
         1 . A light emitting device, comprising:
 a substrate having a first surface and a second surface, wherein the first surface is flat surfaces and the second surface is uneven surfaces;   a first conductive semiconductor layer on the substrate and having an irregularly uneven lower surface facing the surfaces of the substrate;   a buffer layer and a semiconductor layer alternately interposed between the substrate and the first conductive semiconductor layer;   an active layer on the first conductive semiconductor layer; and   a second conductive semiconductor layer on the active layer,   wherein the buffer layer includes a first buffer layer and a second buffer layer, and   wherein the first buffer layer is only disposed on the flat surfaces of the first surface of the substrate.   
     
     
         2 . The light emitting device according to  claim 1 , wherein the semiconductor layer includes a first un-doped GaN (gallium-nitride) layer and a second un-doped GaN (gallium-nitride) layer. 
     
     
         3 . The light emitting device according to  claim 2 , wherein the first and the second buffer layers, the first and the second un-doped GaN (gallium-nitride) layers are alternately stacked on the substrate. 
     
     
         4 . The light emitting device according to  claim 3 , wherein the first un-doped GaN (gallium-nitride) layer is only formed on the first buffer layer. 
     
     
         5 . The light emitting device according to  claim 1 , wherein the first and the second buffer layers includes In (indium). 
     
     
         6 . The light emitting device according to  claim 1 , wherein the uneven surfaces of the second surface are formed between the flat surfaces of the first surface. 
     
     
         7 . The light emitting device according to  claim 1 , wherein the first surface of the substrate is higher than the second surface of the substrate. 
     
     
         8 . The light emitting device according to  claim 1 , wherein the semiconductor layer is a single layer and the single layer is an un-doped GaN layer. 
     
     
         9 . The light emitting device according to  claim 8 , wherein the first buffer layer, the second buffer layer and the un-doped GaN layer are alternately stacked on the substrate. 
     
     
         10 . The light emitting device according to  claim 1 , wherein the semiconductor layer includes an un-doped GaN (gallium-nitride) layer and an In-doped GaN (gallium-nitride) layer. 
     
     
         11 . The light emitting device according to  claim 10 , wherein the first and the second buffer layers, the un-doped GaN (gallium-nitride) layer and the In-doped GaN (gallium-nitride) layer are alternately stacked on the substrate. 
     
     
         12 . A light emitting device, comprising:
 a substrate having a first surface and a second surface, wherein the first surface is flat surfaces and the second surface is uneven surfaces;   a first conductive semiconductor layer on the substrate and having an irregularly uneven lower surface facing the upper surface of the substrate;   a buffer layer and a semiconductor layer alternately interposed between the substrate and the first conductive semiconductor layer;   an In—GaN semiconductor layer on the first conductive semiconductor layer;   an active layer on the In—GaN semiconductor layer; and   a second conductive semiconductor layer on the active layer,   wherein the buffer layer includes a first buffer layer and a second buffer layer, and   wherein the first buffer layer is only disposed on the flat surfaces of the first surface of the substrate.   
     
     
         13 . The light emitting device according to  claim 12 , wherein the semiconductor layer includes a first un-doped GaN (gallium-nitride) layer and a second un-doped GaN (gallium-nitride) layer. 
     
     
         14 . The light emitting device according to  claim 13 , wherein the first and the second buffer layers, the first and the second un-doped GaN (gallium-nitride) layers are alternately stacked on the substrate. 
     
     
         15 . The light emitting device according to  claim 13 , wherein the first un-doped GaN (gallium-nitride) layer is only formed on the first buffer layer. 
     
     
         16 . The light emitting device according to  claim 12 , wherein the uneven surfaces of the second surface are formed between the flat surfaces of the first surface. 
     
     
         17 . The light emitting device according to  claim 12 , wherein the first surface of the substrate is higher than the second surface of the substrate. 
     
     
         18 . The light emitting device according to  claim 12 , wherein the semiconductor layer is a single layer and the single layer is an un-doped GaN layer. 
     
     
         19 . The light emitting device according to  claim 18 , wherein the first buffer layer, the second buffer layer and the un-doped GaN layer are alternately stacked on the substrate. 
     
     
         20 . The light emitting device according to  claim 12 , wherein the semiconductor layer includes an un-doped GaN (gallium-nitride) layer and an In-doped GaN (gallium-nitride) layer.