Fabrication method of light emitting diode incorporating substrate surface treatment by laser and light emitting diode fabricated thereby

Abstract

The present invention relates to a fabrication method of LEDs incorporating a step of surface-treating a substrate by a laser and an LED fabricated by such a fabrication method. The present invention can use a laser in order to implement finer surface treatment to an LED substrate over the prior art. As a result, the invention can improve the light extraction efficiency of an LED while protecting the substrate from chronic problems of the prior art such as stress or defects induced from chemical etching and/or physical polishing.

1 . A Light Emitting Diode (LED) comprising: 
 a sapphire substrate having a fine roughened structure formed in a first side thereof, the fine roughened structure being formed via laser illumination;    an n-doped semiconductor layer formed on the roughened first side of the substrate;    an active layer and a p-doped semiconductor layer formed in their order on the n-doped semiconductor layer to expose a partial area of the n-doped semiconductor layer;    a p-electrode formed on the p-doped semiconductor layer; and    an n-electrode formed on the exposed area of the n-doped semiconductor layer.    
   
   
       2 . The LED diode according to  claim 1 , wherein the sapphire substrate has a second side polished to reduce the thickness of the sapphire substrate and a fine roughened structure formed in a second side via laser illumination.  
   
   
       3 . The LED diode according to  claim 1 , wherein the sapphire substrate is replaced by one selected from the group consisting of a SiC substrate, an oxide substrate and a carbide substrate.  
   
   
       4 . A Light Emitting Diode (LED) comprising: 
 a sapphire substrate having a first side having a fine roughened structure formed therein and a second side having a fine roughened structure formed therein via laser illumination;    an n-doped semiconductor layer formed on the roughened first side of the sapphire substrate;    an active layer and a p-doped semiconductor layer formed in their order on the n-doped semiconductor layer to expose a partial area of the n-doped semiconductor layer;    a p-electrode formed on the p-electrode layer; and    an n-electrode formed on the exposed area of the n-doped semiconductor layer.    
   
   
       5 . The LED diode according to  claim 4 , wherein the fine roughened structure in the first side of the substrate is formed via laser illumination.  
   
   
       6 . The LED diode according to  claim 4 , wherein the sapphire substrate is replaced by one selected from the group consisting of a SiC substrate, an oxide substrate and a carbide substrate.