Semiconductor device

Abstract

A semiconductor device has an active layer, a first semiconductor layer of first conductive type, an overflow prevention layer disposed between the active layer and the first semiconductor layer, which is doped with impurities of first conductive type and which prevents overflow of electrons or holes, a second semiconductor layer of first conductive type disposed at least one of between the active layer and the overflow prevention layer and between the overflow prevention layer and the first semiconductor layer, and an impurity diffusion prevention layer disposed between the first semiconductor layer and the active layer, which has a band gap smaller than those of the overflow prevention layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.

1 - 18 . (canceled) 
     
     
         19 . A semiconductor device, comprising:
 an active layer which comprises a single or multiple quantum well structure having In x1 Ga 1-x1 N (0<x 1 ≦1) and a barrier layer having In x2 Ga 1-x2 N (0≦x 2 <1, x 1 >x 2 );   a first semiconductor layer which comprises GaN of first conductive type;   a Ga 1-y1 Al y1 N layer (0<y 1 ≦1) layer disposed between the active layer and the first semiconductor layer;   a second semiconductor layer which comprises GaN of the first conductive type, which is disposed either between the active layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer or between the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer and the first semiconductor layer; and   an In y2 Ga 1-y2 N (0<y 2 ≦1) layer disposed between the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer and the second semiconductor layer, which has a band gap smaller than those of the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.   
     
     
         20 . The semiconductor device according to  claim 19 ,
 wherein the second semiconductor layer is disposed between the active layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer; and   the In y2 Ga 1-y2 N (0<y 2 ≦1) layer is disposed between the second semiconductor layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer.   
     
     
         21 . The semiconductor device according to  claim 19 ,
 wherein a composition ratio of In in the In y2 Ga 1-y2 N (0<y 2 ≦1) layer is higher than those of the Ga 1-y1 Al y1 N layer (0<y 1 ≦1) layer, the first semiconductor layer and the second semiconductor layer.   
     
     
         22 . The semiconductor device according to  claim 19 ,
 wherein the active layer emits a light with a predetermined wavelength;   the first conductive type is p-type;   the first semiconductor layer is used as a p-type clad layer; and   the second semiconductor layer is used as a p-type guide layer.   
     
     
         23 . The semiconductor device according to  claim 22 , further comprising:
 an n-type guide layer disposed on a side of the active layer opposite from the p-type guide layer, which comprises GaN or In x3 Ga 1-x3 N (0<x 3 <1).   
     
     
         24 . A semiconductor device, comprising:
 an active layer which comprises a single or multiple quantum well structure having In x1 Ga 1-x1 N (0<x 1 ≦1) and a barrier layer having In x2 Ga 1-x2 N (0≦x 2 <1, x 1 >x 2 );   a first semiconductor layer which comprises GaN of first conductive type;   a Ga 1-y1 Al y1 N layer (0<y 1 ≦1) layer which comprises Ga 1-y1 Al y1 N (0<y 1 ≦1) disposed between the active layer and the first semiconductor layer;   a second semiconductor layer which comprises GaN of first conductive type disposed between the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer and the first semiconductor layer;   a third semiconductor layer which comprises In x3 Ga 1-x3 N (0≦x 3 <1, x 2 >x 3 ) of first conductive type disposed between the active layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer;   and   an In y2 Ga 1-y2 N (0<y 2 ≦1) layer disposed at least one of between the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer and the second semiconductor layer and between the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer and the third semiconductor layer, which has a band gap small than those of the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer, the first semiconductor layer, the second semiconductor layer and the third semiconductor layer.   
     
     
         25 . The semiconductor device according to  claim 24 ,
 wherein the In y2 Ga 1-y2 N (0<y 2 ≦1) layer is disposed between the second semiconductor layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer.   
     
     
         26 . The semiconductor device according to  claim 24 ,
 wherein the In y2 Ga 1-y2 N (0<y 2 ≦1) layer is disposed between the third semiconductor layer and the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer.   
     
     
         27 . The semiconductor device according to  claim 24 ,
 wherein a composition ratio of the In in the In y2 Ga 1-y2 N (0<y 2 ≦1) layer is higher than those of the Ga 1-y1 Al y1 N (0<y 1 ≦1) layer, the first semiconductor layer, the second semiconductor layer and the third semiconductor layer.   
     
     
         28 . The semiconductor device according to  claim 24 ,
 wherein the active layer emits a light with a predetermined wavelength;   the first conductive type is p-type;   the first semiconductor layer is used as a p-type clad layer; and   each of the second and third semiconductor-layers is used as a p-type guide layer.   
     
     
         29 . The semiconductor device according to  claim 28 , further comprising:
 an n-type guide layer disposed on a side of the active layer opposite from the p-type guide layer, which comprises GaN or In x4 Ga 1-x4 N (0<x 4 <1).