Light emitting diode

Abstract

In a light emitting diode, a light-emitting region is including an active layer provided between a first conductivity type cladding layer formed on the semiconductor substrate and a second conductivity type cladding layer. A transparent conductive film made of a metal oxide is located over the light-emitting region. A layer for preventing exfoliation of the transparent conductive film, the preventing layer being made of a compound semiconductor contains at least aluminum and is located between the light-emitting region and the transparent conductive film. The layer for preventing exfoliation of the transparent conductive film contains a conductivity type determination impurity in a concentration of 1×10 19 cm −3 or higher.

What is claimed is:  
     
         1 . A light emitting diode, comprising: 
 a semiconductor substrate;    a light-emitting region including an active layer provided between a first conductivity type cladding layer formed on the semiconductor substrate and a second conductivity type cladding layer;    a transparent conductive film made of a metal oxide and located over the light-emitting region;    a first electrode formed on the upper side of the transparent conductive film;    a second electrode formed on the whole or a part of the bottom of the semiconductor substrate; and    a layer for preventing exfoliation of the transparent conductive film, the preventing layer being made of a compound semiconductor containing at least aluminum and located between the light-emitting region and the transparent conductive film.    
     
     
         2 . The light emitting diode as defined in  claim 1 , wherein: 
 the preventing layer contains a conductivity type determination impurity at a concentration of 1×10 19  cm −3  or higher.    
     
     
         3 . The light emitting diode as defined in  claim 1 , wherein: 
 the preventing layer has a film thickness of 300 nm or less.    
     
     
         4 . The light emitting diode as defined in  claim 2 , wherein: 
 the preventing layer has a film thickness of 300 nm or less.    
     
     
         5 . The light emitting diode as defined in  claim 1 , wherein: 
 the transparent conductive film is made of indium tin oxide.    
     
     
         6 . The light emitting diode as defined in  claim 2 , wherein: 
 the transparent conductive film is made of indium tin oxide.    
     
     
         7 . The light emitting diode as defined in  claim 1 , wherein: 
 the preventing layer is made of an arsenic compound.    
     
     
         8 . The light emitting diode as defined in  claim 2 , wherein: 
 the preventing layer is made of an arsenic compound.    
     
     
         9 . The light emitting diode as defined in  claim 1 , wherein: 
 the light-emitting region is made of (Al X Ga 1−X ) Y In 1−Y P (0≦X≦1, 0≦Y≦1).    
     
     
         10 . The light emitting diode as defined in  claim 2 , wherein: 
 the light-emitting region is made of (Al X Ga 1−X ) Y In 1−Y P (0≦X≦1, 0≦Y≦1).    
     
     
         11 . The light emitting diode as defined in  claim 1 , wherein: 
 the preventing layer is an AlGaAs layer having a bandgap which is smaller than that of the active layer; and    the AlGaAs layer is made of Al X Ga 1−X As (0.01≦X≦0.43).    
     
     
         12 . The light emitting diode as defined in  claim 1 , wherein: 
 the AlGaAs layer has a carrier concentration of 1×10 19  cm −3  or higher.    
     
     
         13 . The light emitting diode as defined in  claim 11 , wherein: 
 the AlGaAs layer has a carrier concentration of 1×10 19  cm −3  or higher.    
     
     
         14 . The light emitting diode as defined in  claim 1 , wherein: 
 the AlGaAs layer is added with at least one of Zn, Be, and Mg.    
     
     
         15 . The light emitting diode as defined in  claim 11 , wherein: 
 the AlGaAs layer is added with at least one of Zn, Be, and Mg.    
     
     
         16 . The light emitting diode as defined in  claim 1 , wherein: 
 the AlGaAs layer is added with at least one of Zn, Be and Mg, and C; and    C is autodoped.    
     
     
         17 . The light emitting diode as defined in  claim 11 , wherein: 
 the AlGaAs layer is added with at least one of Zn, Be and Mg, and C; and    C is autodoped.    
     
     
         18 . The light emitting diode as defined in  claim 1 , wherein: 
 the AlGaAs layer is formed at a growth temperature of 600° C. or lower.    
     
     
         19 . The light emitting diode as defined in  claim 11 , wherein: 
 the AlGaAs layer is formed at a growth temperature of 600° C. or lower.    
     
     
         20 . The light emitting diode as defined in  claim 1 , wherein: 
 the AlGaAs layer is formed at a V/III ratio in raw materials of 50 or less at the time of growth.    
     
     
         21 . The light emitting diode as defined in  claim 11 , wherein: 
 the AlGaAs layer is formed at a V/III ratio in raw materials of 50 or less at the time of growth.    
     
     
         22 . The light emitting diode as defined in  claim 11 , wherein: 
 the transparent conductive film is made of indium tin oxide.    
     
     
         23 . The light emitting diode as defined in  claim 11 , wherein: 
 the light-emitting region is made of (Al X Ga 1−X ) Y In 1−Y P (0≦X≦1, 0≦Y≦1).