Semiconductor device and method for manufacturing the same

Abstract

A light emitting layer made of a group III-V nitride semiconductor is formed between a first semiconductor layer made of an n-type group III-V nitride semiconductor and a second semiconductor layer made of a p-type group III-V nitride semiconductor. In side portions of the second semiconductor layer, oxidized regions are formed through the oxidization of the second semiconductor layer itself so as to be spaced apart from each other in the direction parallel to the plane of the light emitting layer. A p-side electrode is formed across the entire upper surface of the second semiconductor layer including the oxidized regions, and an n-side electrode is formed on one surface of the first semiconductor layer that is away from the second semiconductor layer.

1 . A semiconductor device, comprising a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type, including an active region, wherein at least one of the first semiconductor layer and the second semiconductor layer includes oxidized regions, which are spaced apart from each other in a direction parallel to a plane of the active region and are obtained through oxidization of the at least one of the first semiconductor layer and the second semiconductor layer itself.  
     
     
         2 . The semiconductor device of  claim 1 , further comprising: 
 a first ohmic electrode formed on the second semiconductor layer; and    a second ohmic electrode formed on one side of the first semiconductor layer that is away from the second semiconductor layer.    
     
     
         3 . The semiconductor device of  claim 2 , wherein a conductive substrate is provided between the first semiconductor layer and the second ohmic electrode.  
     
     
         4 . The semiconductor device of  claim 3 , wherein the conductive substrate is made of silicon carbide, silicon, gallium arsenide, gallium phosphide, indium phosphide, zinc oxide or a metal.  
     
     
         5 . The semiconductor device of  claim 1 , wherein the first semiconductor layer and the second semiconductor layer are formed in this order on an insulative substrate, the semiconductor device further comprising: 
 a first ohmic electrode formed on the second semiconductor layer; and    a second ohmic electrode formed on an exposed portion of one surface of the first semiconductor layer that is closer to the second semiconductor layer.    
     
     
         6 . The semiconductor device of  claim 5 , wherein the insulative substrate is made of sapphire, magnesium oxide or lithium gallium aluminum oxide (LiGa x Al 1-x O 2  (where 0≦x≦1)).  
     
     
         7 . The semiconductor device of  claim 1 , wherein the oxidized regions are formed so as to include the active region.  
     
     
         8 . The semiconductor device of  claim 1 , wherein at least one of the first semiconductor layer and the second semiconductor layer includes a current constriction section formed by removing side portions of the at least one of the first semiconductor layer and the second semiconductor layer.  
     
     
         9 . The semiconductor device of  claim 8 , wherein a ridge portion to be a waveguide is formed in an upper portion of the current constriction section.  
     
     
         10 . The semiconductor device of  claim 1 , wherein an insulating film is formed on the oxidized regions.  
     
     
         11 . The semiconductor device of  claim 10 , wherein the insulating film is made of silicon oxide or silicon nitride.  
     
     
         12 . The semiconductor device of  claim 1 , wherein the first semiconductor layer and the second semiconductor layer are made of a compound semiconductor containing nitrogen.  
     
     
         13 . A method for manufacturing a semiconductor device, comprising: 
 a first step of forming a first semiconductor layer of a first conductivity type;    a second step of forming a second semiconductor layer of a second conductivity type on the first semiconductor layer, thereby forming an active region between the first semiconductor layer and the second semiconductor layer, and    a third step of selectively oxidizing at least the second semiconductor layer, thereby forming, at least in the second semiconductor layer, oxidized regions spaced apart from each other in a direction parallel to a plane of the active region.    
     
     
         14 . The method for manufacturing a semiconductor device of  claim 13 , wherein the third step includes a step of selectively covering an upper surface of the second semiconductor layer by a mask film made of a material that is less likely to be oxidized than the second semiconductor layer.  
     
     
         15 . The method for manufacturing a semiconductor device of  claim 14 , further comprising, after the third step, a fourth step of forming an ohmic electrode on the second semiconductor layer after removing the mask film.  
     
     
         16 . The method for manufacturing a semiconductor device of  claim 13 , further comprising, after the third step: 
 a fourth step of forming a first ohmic electrode on the second semiconductor layer; and    a fifth step of forming a second ohmic electrode on one surface of the first semiconductor layer that is away from the active region.    
     
     
         17 . The method for manufacturing a semiconductor device of  claim 16 , wherein the fourth step includes: 
 a step of forming an insulating film on the second semiconductor layer including the oxidized regions;    a step of forming a resist pattern having an opening corresponding to a portion of the insulating film above the second semiconductor layer, and then etching the insulating film while using the formed resist pattern as a mask, thereby transferring an opening pattern onto the insulating film; and    a step of depositing a metal film on the second semiconductor layer including the resist pattern, and lifting off the resist pattern, thereby forming the first ohmic electrode from the metal film.    
     
     
         18 . The method for manufacturing a semiconductor device of  claim 17 , wherein the insulating film is made of silicon oxide or silicon nitride.  
     
     
         19 . The method for manufacturing a semiconductor device of  claim 13 , further comprising, after the third step: 
 a fourth step of forming a first ohmic electrode on the second semiconductor layer; and    a fifth step of selectively removing the active region and the second semiconductor layer, thereby forming an exposed region of the first semiconductor layer, and forming a second ohmic electrode on the formed exposed region.    
     
     
         20 . The method for manufacturing a semiconductor device of  claim 19 , wherein the fourth step includes: 
 a step of forming an insulating film on the second semiconductor layer including the oxidized regions;    a step of forming a resist pattern having an opening corresponding to a portion of the insulating film above the second semiconductor layer, and then etching the insulating film while using the formed resist pattern as a mask, thereby transferring an opening pattern onto the insulating film; and    a step of depositing a metal film on the second semiconductor layer including the resist pattern, and lifting off the resist pattern, thereby forming the first ohmic electrode from the metal film.    
     
     
         21 . The method for manufacturing a semiconductor device of  claim 20 , wherein the insulating film is made of silicon oxide or silicon nitride.  
     
     
         22 . The method for manufacturing a semiconductor device of  claim 13 , wherein: 
 in the first step, the first semiconductor layer is formed on a substrate; and    the method further comprises, after the third step, a step of separating the substrate from the first semiconductor layer.    
     
     
         23 . The method for manufacturing a semiconductor device of  claim 22 , wherein the substrate is made of sapphire, silicon carbide, silicon, gallium arsenide, gallium phosphide, indium phosphide, magnesium oxide, zinc oxide or lithium gallium aluminum oxide (LiGa x Al 1-x O 2  (where 0≦x≦1)).  
     
     
         24 . The method for manufacturing a semiconductor device of  claim 22 , wherein the substrate separation step includes a step of bonding a support substrate for supporting the second semiconductor layer to an upper surface of the second semiconductor layer.  
     
     
         25 . The method for manufacturing a semiconductor device of  claim 24 , further comprising, after the substrate separation step, a step of forming an ohmic electrode on the support substrate.  
     
     
         26 . The method for manufacturing a semiconductor device of  claim 24 , wherein the support substrate is made of silicon, gallium arsenide, gallium phosphide, indium phosphide or a metal.  
     
     
         27 . The method for manufacturing a semiconductor device of  claim 22 , wherein the substrate separation step is performed by a polishing method.  
     
     
         28 . The method for manufacturing a semiconductor device of  claim 22 , wherein: 
 the substrate is made of a material whose forbidden band width is larger than that of the first semiconductor layer;    the substrate separation step includes a step of irradiating the first semiconductor layer with irradiation light from one surface of the substrate that is away from the first semiconductor layer; and    an energy of the irradiation light is smaller than the forbidden band width of the substrate and larger than that of the first semiconductor layer.    
     
     
         29 . The method for manufacturing a semiconductor device of  claim 28 , wherein the irradiation light is laser light that oscillates in a pulsed manner.  
     
     
         30 . The method for manufacturing a semiconductor device of  claim 28 , wherein the irradiation light is an emission line of a mercury lamp.  
     
     
         31 . The method for manufacturing a semiconductor device of  claim 28 , wherein the substrate separation step includes a step of heating the substrate.  
     
     
         32 . The method for manufacturing a semiconductor device of  claim 28 , wherein in the substrate separation step, the irradiation light is radiated so as to scan a surface of the substrate.  
     
     
         33 . The method for manufacturing a semiconductor device of  claim 22 , wherein: 
 the first semiconductor layer is made of a plurality of semiconductor layers having different compositions;    the substrate is made of a material whose forbidden band width is larger than a forbidden band width of one of the plurality of semiconductor layers that has a smallest forbidden band width;    the substrate separation step includes a step of irradiating the first semiconductor layer with irradiation light from one surface of the substrate that is away from the first semiconductor layer; and    an energy of the irradiation light is smaller than the forbidden band width of the substrate and larger than the forbidden band width of one of the plurality of semiconductor layers that has the smallest forbidden band width.    
     
     
         34 . The method for manufacturing a semiconductor device of  claim 33 , wherein the irradiation light is laser light that oscillates in a pulsed manner.  
     
     
         35 . The method for manufacturing a semiconductor device of  claim 33 , wherein the irradiation light is an emission line of a mercury lamp.  
     
     
         36 . The method for manufacturing a semiconductor device of  claim 33 , wherein the substrate separation step includes a step of heating the substrate.  
     
     
         37 . The method for manufacturing a semiconductor device of  claim 33 , wherein in the substrate separation step, the irradiation light is radiated so as to scan a surface of the substrate.  
     
     
         38 . The method for manufacturing a semiconductor device of  claim 13 , further comprising, between the second step and the third step, a fourth step of etching at least the second semiconductor layer, thereby forming a current constriction section having a convex cross section at least in the second semiconductor layer.  
     
     
         39 . The method for manufacturing a semiconductor device of  claim 38 , wherein in the fourth step, the current constriction section is formed so as to reach the first semiconductor layer.  
     
     
         40 . The method for manufacturing a semiconductor device of  claim 38 , wherein in the fourth step, the current constriction section is formed so as not to reach the active region.  
     
     
         41 . The method for manufacturing a semiconductor device of  claim 38 , wherein the fourth step includes a step of forming a ridge portion to be a waveguide in an upper portion of the second semiconductor layer within the current constriction section.  
     
     
         42 . The method for manufacturing a semiconductor device of  claim 13 , wherein in the third step, the oxidization is performed in an atmosphere containing an oxygen gas or water vapor.  
     
     
         43 . The method for manufacturing a semiconductor device of  claim 13 , wherein the first semiconductor layer and the second semiconductor layer are deposited by using one of a metal organic chemical vapor deposition method, a molecular beam epitaxy method and a hydride vapor phase epitaxy method, or by using more than one of the methods in combination.  
     
     
         44 . The method for manufacturing a semiconductor device of  claim 13 , wherein the first semiconductor layer and the second semiconductor layer are made of a compound semiconductor containing nitrogen.  
     
     
         45 - 67 . (Cancelled)  
     
     
         68 . A method for manufacturing a semiconductor device, comprising: 
 a first step of forming a first semiconductor layer of a first conductivity type;    a second step of forming a portion of a second semiconductor layer of a second conductivity type on the first semiconductor layer, thereby forming an active region between the first semiconductor layer and the second semiconductor layer,    a third step of selectively oxidizing the first semiconductor layer, the active region and the portion of the second semiconductor layer, thereby forming oxidized regions spaced apart from each other in a direction parallel to a plane of the second semiconductor layer, in the first semiconductor layer, the active region and the portion of the second semiconductor layer; and    a fourth step of forming a rest of the second semiconductor layer on the portion of the second semiconductor layer including the oxidized regions.    
     
     
         69 . The method for manufacturing a semiconductor device of  claim 68 , wherein in the third step, the oxidization is performed in an atmosphere containing an oxygen gas or water vapor.  
     
     
         70 . The method for manufacturing a semiconductor device of  claim 68 , wherein the first semiconductor layer and the second semiconductor layer are deposited by using one of a metal organic chemical vapor deposition method, a molecular beam epitaxy method and a hydride vapor phase epitaxy method, or by using more than one of the methods in combination.  
     
     
         71 . The method for manufacturing a semiconductor device of  claim 68 , wherein the first semiconductor layer and the second semiconductor layer are made of a compound semiconductor containing nitrogen.