Light-emitting semiconductor device using group III nitride compound

Abstract

An emission layer ( 5 ) for a light source device is formed to have a multi-layer structure, doped with an acceptor and a donor impurity. The multi-layer structure may include a quantum well (QW) structure or a multi quantum well (MQW) structure ( 50 ). With such a structure, a peak wavelength of the light source can be controlled, because the distances between atoms of the acceptor and the donor impurities are widened. Several arrangements can be made by, e.g., altering the thickness of each composite layer of the multi-layer structure, altering their composition ratio, forming undoped layer 5 between the impurity doped layers, and so forth. Further, luminous intensity of ultra violet color can be improved, because doping the donor impurity and the acceptor impurity realizes a donor-acceptor emission mechanism and abundant carriers. Several arrangements can be made by, e.g., optimizing the materials of the composite layers, optimizing their composition ratios, optimizing their lattice constants, and so forth to further enhance the luminous intensity of the light source.

What is claimed:  
     
         1 . A method for producing a group III nitride compound semiconductor light-emitting device comprising steps of; 
 producing an emission layer comprising a multi quantum structure (MQW) with well layers and barrier layers, and    doping at least one of donor impurity and acceptor impurity into at least one of said well layers and barrier layers in a producing process of said multi quantum structure.    
     
     
         2 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 1 , further comprising a double-hetero junction structure in which said emission layer is sandwiched between adjacent layers.  
     
     
         3 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 1 , wherein said donor impurity is selected from the group comprising silicon (Si), germanium (Ge), tellurium (Te), and sulfur.  
     
     
         4 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 1 , wherein said multi quantum well structure (MQW) comprises alternating Al X2 Ga Y2 In 1−X2−Y2 N barrier layers and Al X2 Ga y1 In 1−X1−Y1 N well layers, where 0≦x1≦1, 0≦x2≦1, 0<y1≦1, 0≦y2≦1, 0≦x1+y1≦1, and 0≦x2+y2≦1.  
     
     
         5 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 4 , wherein said composition ratios are designed to match a lattice constant of said barrier layer with a lattice constant of said well layer.  
     
     
         6 . A method for producing a, group III nitride compound semiconductor light-emitting device according to  claim 4 , wherein said well layer is from 50 Å to 200 Å in thickness.  
     
     
         7 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 4 , wherein said barrier layer is from 50 Å to 200 Å in thickness.  
     
     
         8 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 1 , wherein said multi quantum well structure (MQW) comprises alternating Al X2 Ga 1−X2 N burrier layers and Al X1 Ga 1−X1 N well layers, where 0≦x1≦1, 0≦x2≦1, and x1≦x2.  
     
     
         9 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 8 , wherein said well layer is doped with a donor impurity.  
     
     
         10 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 4 , wherein said donor impurity is silicon (Si).  
     
     
         11 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 8 , wherein said emission layer is sandwiched between a p-layer comprising acceptor doped Al x3 Ga 1−x3 N with p-type conduction where x1≦x3 and an n-layer of a donor doped Al x4 Ga 1−x4 N with n-type conduction where x1≦x4.  
     
     
         12 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 11 , wherein said acceptor impurity doped into said player is magnesium (Mg) and said donor impurity doped into said n-layer is silicon (Si).  
     
     
         13 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 8 , wherein said multi quantum well structure (MQW) comprises Ga x1 In 1−x1 N well layers and Ga y1 In 1−y1 N barrier layers, a band gap of said barrier layers being wider than a band gap of said well layers, where 0≦x1≦1, 0≦y1≦1.  
     
     
         14 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 13 , wherein said barrier layers comprise gallium nitride (GaN).  
     
     
         15 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 13 , wherein said donor impurity is silicon (Si).  
     
     
         16 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 13 , wherein said well is doped with an impurity concentration ranging from 1×10 17 /cm 3  to 5×10 18 /cm 3 .  
     
     
         17 . A method for producing a group III nitride compound semiconductor light-emitting device comprising steps of: 
 producing an emission layer comprising a multi quantum well structure (MQW) with well layers and barrier layers, and    doping donor impurity alternately into said well layers and said barrier layers in a producing process of said multi quantum well structure.    
     
     
         18 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , further comprising a step of: producing a double-hetero junction structure in which said emission layer is sandwiched between adjacent layers.  
     
     
         19 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 18 , wherein said emission layer comprises aluminum gallium indium nitride satisfying the formula Al x Ga y In 1−x−y N, inclusive of x=0, y=0, and x=y=0.  
     
     
         20 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein an undoped layer is formed between said layer doped with said acceptor impurity and said layer doped with said donor impurity.  
     
     
         21 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 20 , said undoped layer having a thickness of from 50 Å to 500 Å.  
     
     
         22 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said acceptor impurity and said donor impurity are distributed into said emission layer by one of modulation doping and δ doping.  
     
     
         23 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said layer doped with said acceptor impurity and said layer doped with said donor impurity are each from wherein said layer doped with said acceptor impurity and said layer doped with said donor impurity are each from 50 Å to 500 Å in thickness.  
     
     
         24 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said emission layer is doped with a concentration of magnesium (Mg) ranging from 1×10 19 /cm 3  to 1×10 19 /cm 3  to 1×10 21 /cm 3  and exhibits p-type conduction.  
     
     
         25 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said acceptor impurity is selected from the group comprising cadmium (Cd), zinc (Zn), beryllium (Be), and calcium (Ca).  
     
     
         26 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said donor impurity is selected from the group comprising silicon (Si), germanium (Ge), tellurium (Te), and sulfur (S).  
     
     
         27 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 17 , wherein said layer doped with said acceptor layer comprises aluminum gallium indium nitride satisfying the formula Al x Ga y In 1−x−y N, inclusive of x=0, y=0, and x=y=0, and wherein said layer doped with said donor impurity comprises aluminum gallium indium nitride with a varied composition ratio of said formula.  
     
     
         28 . A method for producing a group III nitride compound semiconductor light-emitting device comprising steps of: 
 producing an emission layer comprising a quantum well (QW) structure having at least one well layer, and    doping both an acceptor impurity and a donor impurity into said quantum well structure in a producing process of said quantum well structure.    
     
     
         29 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer is doped with both an acceptor impurity and a donor impurity.  
     
     
         30 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer and a barrier layer of said emission layer are doped with both an acceptor impurity and a donor impurity.  
     
     
         31 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said emission layer is an active layer comprising a zinc (Zn) and silicon (Si) doped indium aluminum gallium nitride (InAlGaN) compound.  
     
     
         32 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 29 , wherein said quantum well (QW) structure comprises a barrier layer comprising an indium aluminum gallium nitride (InAlGaN) compound, having composition ratios different from said well layer.  
     
     
         33 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 32 , wherein said composition ratios are designed to match a lattice constant of said barrier layer with a lattice constant of said well layer.  
     
     
         34 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said quantum well (QW) structure comprises said well layer sandwiched between barrier layers, said barrier layer being doped with an acceptor impurity.  
     
     
         35 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer is from 50 Å to 200 Å in thickness.  
     
     
         36 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 32 , wherein said barrier layer is from 50 Å to 200 Å in thickness.  
     
     
         37 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said emission layer having a quantum well (QW) structure comprises alternating Al x2 Ga 1−2 N barrier layers and Al x1 Ga 1−x1 N well layers, where 0≦x1≦1, 0≦x2≦1, and x1≦x2.  
     
     
         38 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 37 , wherein said well layer is doped with both an acceptor impurity and a donor impurity.  
     
     
         39 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 37 , wherein said well layer and said barrier layer are doped with both an acceptor impurity and a donor impurity.  
     
     
         40 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 37 , wherein said quantum well (QW) structure comprises a multi quantum well (MQW) having a plurality of well layers, a first selected one of said well layers being doped with said acceptor impurity and a second selected one of said well layers being doped with said donor impurity, the first and second selected well layers being adjacent to each other.  
     
     
         41 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 37 , wherein said well layer is doped with said acceptor impurity and said barrier layer is doped with said donor impurity.  
     
     
         42 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein said well layer is doped with said donor impurity and said barrier layer is doped with said acceptor impurity.  
     
     
         43 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein said acceptor impurity is zinc (Zn) and said donor impurity is silicon (Si).  
     
     
         44 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 37 , wherein said emission layer is sandwiched between a p-layer comprising acceptor doped Al x3 Ga 1−x3 N with p-type conduction where x1≦x3 and an n-layer of a donor doped A x4 Ga 1−x4 N with n-type conduction where x1≦x4.  
     
     
         45 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 44 , wherein said acceptor impurity doped into said player is magnesium (Mg) and said donor impurity doped into said n-layer is silicon (Si).  
     
     
         46 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said quantum well (QW) structure comprises an Al x1 Ga y1 In 1−x1−y1 N well and an Al x2 Ga y2 In 1−x2−y2 N barrier, a band gap of said barrier being wider than a band gap of said well, said well being doped with one of a donor impurity and an acceptor impurity.  
     
     
         47 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said quantum well (QW) structure comprises an Al x1 Ga y1 In 1−x1−y1 N well and an Al x2 Ga y2 In 1−x2−y2 N barrier, a band gap of said barrier being wider than a band gap of said well, and said barrier being doped with one of a donor impurity and an acceptor impurity.  
     
     
         48 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein said barrier comprises gallium nitride (GaN).  
     
     
         49 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein said donor impurity is one of silicon (Si), tellurium (Te), sulfur (S), and selenium (Se) and said acceptor impurity is one of magnesium (Mg) and zinc (Zn).  
     
     
         50 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein said well is doped with an impurity concentration ranging from 1×10 17 /cm 3  to 5×10 18 /cm 3 .  
     
     
         51 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 41 , wherein a lattice constant of said well matches a lattice constant of said barrier.  
     
     
         52 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer and said barrier layer are doped with both an acceptor impurity and a donor impurity.  
     
     
         53 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said quantum well (QW) structure comprises a multi quantum well (MQW) having a plurality of well layers, a first selected one of said well layers being doped with said acceptor impurity and a second selected one of said well layers being doped with said donor impurity, the first and second selected well layers being adjacent to each other.  
     
     
         54 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer is doped with said acceptor impurity and said barrier layer is doped with said donor impurity.  
     
     
         55 . A method for producing a group III nitride compound semiconductor light-emitting device according to  claim 28 , wherein said well layer is doped with said donor impurity and said barrier layer is doped with said acceptor impurity.