Light emitting diode and method of manufacturing the same

Abstract

A light emitting diode and a method of manufacturing the light emitting diode are provided. The light emitting diode includes an n-type semiconductor layer, an inclined type superlattice thin film layer, an active layer, and a p-type semiconductor layer. The n-type semiconductor layer is disposed on a substrate. The inclined type superlattice thin film layer is disposed on the n-type semiconductor layer and includes a plurality of thin film pairs in which InGaN thin films and GaN thin films are sequentially stacked. The active layer having a quantum well structure is disposed on the inclined type superlattice thin film layer. The p-type semiconductor layer is disposed on the active layer. Composition ratio of Indium (In) included in the InGaN thin film is increased as getting closer to the active layer. Thus, internal residual strain is reduced, and quantum confinement effect is enhanced, and internal quantum efficiency is increased.

What is claimed is: 
     
         1 . A light emitting diode, comprising:
 an n-type semiconductor layer disposed on a substrate;   an inclined type superlattice thin film layer disposed on the n-type semiconductor layer, and including a plurality of thin film pairs in which InGaN thin films and GaN thin films are sequentially stacked;   an active layer having a quantum well structure disposed on the inclined type superlattice thin film layer; and   a p-type semiconductor layer disposed on the active layer,   wherein composition ratio of indium (In) included in the InGaN thin film is increased as getting closer to the active layer.   
     
     
         2 . The light emitting diode of  claim 1 , wherein the inclined type superlattice thin film layer has a structure in which the thin film pairs of 2 to 100 are disposed. 
     
     
         3 . The light emitting diode of  claim 1 , wherein the inclined type superlattice thin film layer reduces band bending generated by a lattice mismatch in the quantum well structure of the active layer. 
     
     
         4 . The light emitting diode of  claim 1 , wherein the n-type semiconductor layer and the p-type semiconductor layer comprise an n-type GaN layer and a p-type GaN layer, respectively. 
     
     
         5 . The light emitting diode of  claim 1 , further comprising a GaN layer interposed between the inclined type superlattice thin film layer and the active layer. 
     
     
         6 . A method of manufacturing a light emitting diode, comprising:
 forming an n-type semiconductor layer on a substrate;   forming an inclined type superlattice thin film layer including a plurality of thin film pairs in which InGaN thin films and GaN thin films are sequentially stacked on the n-type semiconductor layer;   forming an active layer having a quantum well structure on the inclined type superlattice thin film layer; and   forming a p-type semiconductor layer on the active layer,   wherein composition ratio of indium (In) included in the InGaN thin film is increased as getting closer to the active layer.   
     
     
         7 . The method of  claim 6 , wherein forming of the inclined type superlattice thin film layer comprises:
 a first step of forming the InGaN thin film; and   a second step of removing indium included in an upper portion of the InGaN thin film to form the thin film pairs in which the InGaN thin films and the GaN thin films are sequentially stacked,   wherein the first step and the second step are alternately performed repeatedly a plurality of times.   
     
     
         8 . The method of  claim 7 , wherein the first step is performed under nitrogen atmosphere using a metal organic chemical vapor deposition (MOCVD) method. 
     
     
         9 . The method of  claim 7 , wherein the second step comprises supplying hydrogen (H 2 ) on an upper portion of the InGaN thin film and removing indium (In) included in the upper portion of the InGaN thin film. 
     
     
         10 . The method of  claim 9 , wherein the hydrogen is supplied for 25 seconds to 30 seconds at a speed in a range of 8,000 sccm to 8,500 sccm. 
     
     
         11 . The method of  claim 7 , wherein the inclined type superlattice thin film layer is formed by alternately performing the first step and the second step repeatedly 2 to 100 times. 
     
     
         12 . The method of  claim 7 , wherein after the first step and the second step are alternately performed, the steps are performed at a temperature lower than the temperature of previous steps during repeatedly performing of the first step and the second step. 
     
     
         13 . The method of  claim 12 , wherein during repeatedly performing of the first step and the second step, the steps are performed at a temperature lower than the temperature of previous steps by 5° C. 
     
     
         14 . The method of  claim 6 , wherein before forming of the active layer of the quantum well structure on the inclined type superlattice thin film layer, further comprising forming a GaN layer on the inclined type superlattice thin film layer.