P-AlGAN LAYER AND GROUP III NITRIDE SEMICONDUCTOR LIGHT EMITTING DEVICE

Abstract

A p-AlGaN layer doped with magnesium is provided that includes an aluminum composition ratio x of 0.2 or more and less than 0.5 and a carrier concentration of 2.5×10 17 /cm 3 or more. A Group III nitride semiconductor light emitting device including the p-Al x Ga 1-x N layer is also provided.

What is claimed is: 
     
         1 . A p-AlGaN layer doped with magnesium, the p-AlGaN layer having an aluminum composition ratio x of 0.2 or more and less than 0.5 and a carrier concentration of 2.5×10 17 /cm 3  or more. 
     
     
         2 . The p-AlGaN layer doped with magnesium according to  claim 1 , which is manufactured by a process comprising the steps of:
 a first step of supplying a Group V source gas at a Group V source gas flow rate B 1  (0<B 1 ) and supplying a gas containing magnesium at a Mg-containing gas flow rate C 1  (0<C 1 ) while supplying a Group III source gas at a Group III source gas flow rate A 3  (0<A 3 ); and   a second step of supplying a Group V source gas at a Group V source gas flow rate B 2  (0<B 2 ) and supplying a gas containing magnesium at a Mg-containing gas flow rate C 2  (0<C 2 ) while supplying a Group III source gas at a Group III source gas flow rate A 2  (0<A 2 ),   wherein the first step and the second step are performed to form the p-Al x Ga 1-x N layer, and   the Group III source gas flow rate A 3  is a flow rate which allows only initial growth nuclei of the p-Al x Ga 1-x N layer to grow and satisfies A 3 ≦0.5A 2 .   
     
     
         3 . The p-AlGaN layer doped with magnesium according to  claim 2 , wherein the first step and the second step are repeated a plurality of times to form the p-Al x Ga 1-x N layer. 
     
     
         4 . The p-AlGaN layer doped with magnesium according to  claim 1 , wherein the aluminum composition ratio x is 0.2 or more and less than 0.3 and the carrier concentration is 5×10 17 /cm 3  or more. 
     
     
         5 . The p-AlGaN layer doped with magnesium according to  claim 1 , wherein the aluminum composition ratio x is 0.3 or more and less than 0.4 and the carrier concentration is 3.5×10 17 /cm 3  or more. 
     
     
         6 . The p-AlGaN layer doped with magnesium according to  claim 1 , wherein the aluminum composition ratio x is 0.4 or more and less than 0.5 and the carrier concentration is 2.5×10 17 /cm 3  or more. 
     
     
         7 . A Group III nitride semiconductor light emitting device comprising the p-Al x Ga 1-x N layer according to  claim 1 . 
     
     
         8 . A Group III nitride semiconductor light emitting device comprising the p-Al x Ga 1-x N layer according to  claim 4 . 
     
     
         9 . A Group III nitride semiconductor light emitting device comprising the p-Al x Ga 1-x N layer according to  claim 5 . 
     
     
         10 . A Group III nitride semiconductor light emitting device comprising the p-Al x Ga 1-x N layer according to  claim 6 .