Light-emitting gallium nitride-based compound semiconductor device

Abstract

A light-emitting gallium nitride-based compound semiconductor device of a double-heterostructure. The double-heterostructure includes a light-emitting layer formed of a low-resistivity In x Ga 1-x N (0<x<1) compound semiconductor doped with p-type and/or n-type impurity. A first clad layer is joined to one surface of the light-emitting layer and formed of an n-type gallium nitride-based compound semiconductor having a composition different from the light-emitting layer. A second clad layer is joined to another surface of the light-emitting layer and formed of a low-resistivity, p-type gallium nitride-based compound semiconductor having a composition different from the light-emitting layer.

What is claimed is:  
     
         1 . A light-emitting gallium nitride-based compound semiconductor device having a double-heterostructure comprising: 
 a light-emitting layer having first and second major surfaces and formed of a low-resistivity In x Ga 1-x N, where 0<x<1, compound semiconductor doped with an impurity;    a first clad layer joined to said first major surface of said light-emitting layer and formed of an n-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer; and    a second clad layer joined to said second major surface of said light-emitting layer and formed of a low-resistivity, p-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer.    
     
     
         2 . The device according to  claim 1 , wherein said compound semiconductor of said light-emitting layer is of p-type, doped with a p-type impurity.  
     
     
         3 . The device according to  claim 2 , wherein said p-type impurity comprises a Group II element.  
     
     
         4 . The device according to  claim 1 , wherein said compound semiconductor of said light-emitting layer is of n-type, doped with at least a p-conductivity type impurity.  
     
     
         5 . The device according to  claim 3 , wherein said impurity doped in said compound semiconductor of said light-emitting layer comprises a p-type impurity including a Group II element and an n-type impurity including a Group IV or VI element.  
     
     
         6 . The device according to  claim 1 , wherein said compound semiconductor of said light-emitting layer is of n-type, does with an n-type impurity.  
     
     
         7 . The device according to  claim 6 , wherein said n-type impurity comprises a Group IV or VI element.  
     
     
         8 . The device according to  claim 1 , wherein said compound semiconductor or said first clad layer is represented by the formula: Ga y Al 1-y N, where 0≦y≦1.  
     
     
         9 . The device according to  claim 1 , wherein said compound semiconductor of said second clad layer is represented by the formula: Ga z Al 1-z N, where 0≦z≦1.  
     
     
         10 . The device according to  claim 1 , wherein said light-emitting layer has a thickness of 10 Å to 0.5 μm.  
     
     
         11 . The device according to  claim 1 , wherein said double-heterostructure has an n-type GaN contact layer joined to said first clad layer, and a p-type GaN contact layer joined to said second clad layer.  
     
     
         12 . The device according to  claim 1 , wherein 0<x<0.5.  
     
     
         13 . A light-emitting gallium nitride-based compound semiconductor device having a double-heterostructure comprising: 
 a light-emitting layer having first and second major surfaces and formed of a low-resistivity In x Ga 1-x N, where 0<x<1, compound semiconductor doped with a p-type impurity;    a first clad layer joined to said first major surface of said light-emitting layer and formed of an n-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer; and    a second clad layer joined to said second major surface of said light-emitting layer and formed of a low-resistivity, p-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer.    
     
     
         14 . The device according to  claim 13 , wherein said p-type impurity doped in said compound semiconductor of said light-emitting layer comprises at least one element selected from the group consisting of cadmium, zinc, beryllium, magnesium, calcium, strontium, and barium.  
     
     
         15 . The device according to  claim 13 , wherein said compound semiconductor of said first clad layer is represented by a formula: Ga y Al 1-y N, where 0≦y≦1.  
     
     
         16 . The device according to  claim 13 , wherein said compound semiconductor of said second clad layer is represented by a formula: Ga z Al 1-z N, where 0≦z≦1.  
     
     
         17 . The device according to  claim 13 , wherein said light-emitting layer has a thickness of 10 Å to 0.5 μm.  
     
     
         18 . The device according to  claim 13 , wherein said p-type impurity doped in said compound semiconductor of said light-emitting layer comprises zinc, and a concentration of the zinc is 1×10 17  to 1×10 21 /cm 3 .  
     
     
         19 . The device according to  claim 13 , wherein said p-type impurity doped in said compound semiconductor of said second clad layer comprises magnesium, and a concentration of the magnesium is 1×10 18  to 1×10 21 /cm 3 .  
     
     
         20 . The device according to  claim 13 , wherein said second clad layer has a thickness of 0.05 μm to 1.5 μm.  
     
     
         21 . The device according to  claim 13 , wherein said double-heterostructure is provided on a substrate through a buffer layer.  
     
     
         22 . The device according to  claim 13 , wherein said double-heterostructure has an n-type GaN contact layer joined to said first clad layer, and a p-type GaN contact layer joined to said second clad layer.  
     
     
         23 . The device according to  claim 13 , wherein 0<x<0.5  
     
     
         24 . A light-emitting gallium nitride-based compound semiconductor device having a double-heterostructure comprising: 
 a light-emitting layer having first and second major surfaces and formed of a low-resistivity, n-type In x Ga 1-x N, where 0<x<1, compound semiconductor doped with at least a p-type impurity;    a first clad layer joined to said first major surface of said light-emitting layer and formed of an n-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer; and    a second clad layer joined to said second major surface and formed of a low-resistivity, p-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer.    
     
     
         25 . The device according to  claim 24 , wherein said compound semiconductor of said light-emitting layer has an electron carrier concentration of 1×10 17  to 5×10 21 /cm 3 .  
     
     
         26 . The device according to  claim 24 , wherein said compound semiconductor of said light-emitting layer is doped with not only said p-type impurity but also an n-type impurity.  
     
     
         27 . The device according to  claim 24 , wherein said p-type impurity doped in said compound semiconductor of said light-emitting layer comprises at least one element selected from the group consisting of cadmium, zinc, beryllium, magnesium, calcium, strontium, and barium.  
     
     
         28 . The device according to  claim 26 , wherein said n-type impurity doped in said compound semiconductor of said light-emitting layer comprises at least one element selected from the group consisting of silicon, germanium, and tin.  
     
     
         29 . The device according to  claim 24 , wherein said compound semiconductor of said first clad layer is represented by a formula: Ga y Al 1-y N, where 0≦y≦1.  
     
     
         30 . The device according to  claim 24 , wherein said compound semiconductor of said second clad layer is represented by a formula: Ga z Al 1-z N, where 0≦z≦1.  
     
     
         31 . The device according to  claim 26 , wherein said p-type impurity doped in said compound semiconductor of said light-emitting layer comprises zinc, and said n-type impurity comprises silicon.  
     
     
         32 . The device according to  claim 24 , wherein said double-heterostructure is provided on a substrate through a buffer layer.  
     
     
         33 . The device according to  claim 24 , wherein said double-heterostructure has an n-type GaN contact layer joined to said first clad layer, and a p-type GaN contact layer joined to said second clad layer.  
     
     
         34 . The device according to  claim 24 , wherein 0<x<0.5.  
     
     
         35 . A light-emitting gallium nitride-based compound semiconductor device having a double-heterostructure comprising 
 a light-emitting layer having first and second major surfaces and formed of a low-resistivity, n-type In x Ga 1-x N, where 0<x<1, compound semiconductor doped with an n-type impurity;    a first clad layer joined to said first major surface of said light-emitting layer and formed of an n-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer; and    a second clad layer joined to said second major surface of said light-emitting layer and formed so a low-resistivity, p-type gallium nitride-based compound semiconductor having a composition different from that of said compound semiconductor of said light-emitting layer.    
     
     
         36 . The device according to  claim 35 , wherein said n-type impurity doped in said compound semiconductor of said light-emitting layer comprises silicon or germanium.  
     
     
         37 . The device according to  claim 35 , wherein said n-type impurity doped in said compound semiconductor of said light-emitting layer comprises silicon, and a concentration of the silicon is 1×10 17  to 1×10 21 /cm 3 .  
     
     
         38 . The device according to  claim 35 , wherein said compound semiconductor of said first clad layer is represented by a formula: Ga y Al 1-y N, where 0≦y≦1.  
     
     
         39 . The device according to  claim 35 , wherein said compound semiconductor of said second clad layer is represented by a formula: Ga z Al 1-z N, where 0≦z≦1.  
     
     
         40 . The device according to  claim 35 , wherein said light-emitting layer has a thickness of 10 Å to 0.5 μm.  
     
     
         41 . The device according to  claim 35 , wherein said compound semiconductor of said second clad layer is doped with a p-type impurity comprising magnesium, and a concentration of the magnesium is 1×10 18  to 1×10 21 /cm 3 .  
     
     
         42 . The device according to  claim 35 , wherein said second clad layer has a thickness of 0.05 to 1.5 μm.  
     
     
         43 . A device according to  claim 35 , wherein said double-heterostructure is provided on a substrate through a buffer layer.  
     
     
         44 . The device according to  claim 35 , wherein said double-heterostructure has an n-type GaN contact layer joined to said first clad layer, and a p-type GaN con-tact layer joined to said second clad layer.  
     
     
         45 . The device according to  claim 35 , wherein 0<x<0.5.