Semiconductor light emitting device

Abstract

According to one embodiment, a semiconductor light emitting device includes a stacked structure body, first and second electrodes. The stacked structure body includes first and second semiconductor layers and a light emitting layer provided between the second and first semiconductor layers, and has first and second major surfaces. The first electrode has a first contact part coming into contact with the first semiconductor layer. The second electrode has a part coming into contact with the second semiconductor layer. A surface of the first semiconductor layer on a side of the first major surface has a first part having a part overlapping a contact surface with the first semiconductor layer and a second part having a part overlapping the second semiconductor layer. The second part has irregularity. A pitch of the irregularity is longer than a peak wavelength of emission light. The first part has smaller irregularity than the second part.

What is claimed is: 
     
         1 . A semiconductor light emitting device comprising:
 a stacked structure body including a first conductivity type first semiconductor layer, a second conductivity type second semiconductor layer facing a part of the first semiconductor layer, and a light emitting layer provided between the second semiconductor layer and the part of the first semiconductor layer, and having a first major surface on a side of the first semiconductor layer and a second major surface on a side of the second semiconductor layer;   a first electrode having a first contact part coming into contact with the first semiconductor layer on a side of the second major surface; and   a second electrode having a part coming into contact with the second semiconductor layer on the second major surface,   the first major surface having a first part and a second part, the first part having a part overlapping a contact surface with the first semiconductor layer in the first contact part when viewed in a stacking direction from the first semiconductor layer toward the second semiconductor layer, the second part having a part overlapping the second semiconductor layer when viewed in the stacking direction,   the second part having irregularity, the pitch of the irregularity being longer than a peak wavelength of emission light emitted from the light emitting layer, and   the first part having smaller irregularity than the second part.   
     
     
         2 . The device according to  claim 1 , wherein
 the pitch of the irregularity of the first part is shorter than the peak wavelength of the emission light.   
     
     
         3 . The device according to  claim 1 , wherein
 an outer edge of the first part when viewed in the stacking direction is located outside an outer edge of the contact surface when viewed in the stacking direction.   
     
     
         4 . The device according to  claim 3 , wherein
 reflectance to the emission light of the contact surface is lower than reflectance to the emission light of the surface facing the second semiconductor layer of the second electrode.   
     
     
         5 . The device according to  claim 1 , further comprising a dielectric layer that covers the first part. 
     
     
         6 . The device according to  claim 1 , wherein
 the stacked structure body has a recess part reaching the first semiconductor layer from the second major surface, and the first electrode comes into contact with the first semiconductor layer on a bottom surface of the recess part.   
     
     
         7 . The device according to  claim 1 , wherein
 the first semiconductor layer, the light emitting layer, and the second semiconductor layer include a nitride semiconductor.   
     
     
         8 . The device according to  claim 1 , wherein
 the peak wavelength of the emission light is 370 nanometers or more and 400 nanometers or less.   
     
     
         9 . The device according to  claim 1 , wherein
 the first electrode has a first bonding metal part, the first bonding metal part having a part being electrically connected to the first contact part, the first bonding metal part overlapping the second semiconductor layer when viewed in the stacking direction, and   further includes an insulating layer provided between the first bonding metal part and the second electrode between the first bonding metal part and the second semiconductor layer.   
     
     
         10 . The device according to  claim 1 , wherein
 the second electrode has a second contact part and a second bonding metal part, the second contact part coming into contact with the second semiconductor layer on the second major surface, the second bonding metal part having a part being electrically connected to the second contact part, the second bonding metal part overlapping the first electrode when viewed in the stacking direction, and   further includes an insulating layer provided between the second bonding metal part and the first electrode and between the second bonding metal part and the first semiconductor layer.   
     
     
         11 . The device according to  claim 10 , further comprising a support substrate,
 the support substrate being connected to the second bonding metal part.   
     
     
         12 . The device according to  claim 1 , wherein
 the first contact part and the first bonding metal part are provided integrally.   
     
     
         13 . The device according to  claim 12 , wherein
 the first contact part and the first bonding metal part are based on a material including aluminum.   
     
     
         14 . The device according to  claim 1 , further comprising: a plurality of the first electrodes,
 when viewed in the stacking direction, the plurality of the first electrodes being arranged in a matrix configuration.   
     
     
         15 . The device according to  claim 1 , wherein
 when viewed in the stacking direction, a shape of the first contact part and a shape of the first part are concentric, and   if a diameter in the shape of the first contact part is d and a thickness from the first contact part to the first part along the stacking direction of the stacking structure body is h, tan −1  (h/d)>30 degrees is satisfied.   
     
     
         16 . The device according to  claim 1 , wherein
 the irregularity of the second part is twice or more in length of the peak wavelength of the emission light.   
     
     
         17 . The device according to  claim 1 , wherein
 the irregularity of the second part is ten times or more in length of the peak wavelength of the emission light.   
     
     
         18 . The device according to  claim 1 , wherein
 a surface of the irregularity of the second part is a surface etched along the crystal surface orientation of the first semiconductor layer.   
     
     
         19 . The device according to  claim 1 , wherein
 the second electrode includes silver.   
     
     
         20 . The device according to  claim 1 , wherein
 a shape of a protrusion part in the irregularity of the second part is a hexagonal pyramid.