Semiconductor light emitting device and method for manufacturing same

Abstract

A semiconductor light emitting device, includes: a stacked structural unit including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting layer provided therebetween; and an electrode including a first and second metal layers, the first metal layer including silver or silver alloy and being provided on a side of the second semiconductor layer opposite to the light emitting layer, the second metal layer including at least one element selected from gold, platinum, palladium, rhodium, iridium, ruthenium, and osmium and being provided on a side of the first metal layer opposite to the second semiconductor layer. A concentration of the element in a region including an interface between the first and second semiconductor layers is higher than that of the element in a region of the first metal layer distal to the interface.

1 - 20 . (canceled) 
     
     
         21 . A semiconductor light emitting device, comprising:
 a stacked structural unit including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer including a nitride semiconductor, the second semiconductor layer including a nitride semiconductor; and   an electrode including a first metal layer and a second metal layer, the first metal layer including silver or silver alloy and being provided on a side of the second semiconductor layer opposite to the light emitting layer, the second metal layer including at least one element selected from gold, platinum, palladium, rhodium, iridium, ruthenium, and osmium and being provided on a side of the first metal layer opposite to the second semiconductor layer,   a concentration of the element in a region including an interface between the first metal layer and the second semiconductor layer being higher than a concentration of the element in a region of the first metal layer distal to the interface,   wherein an average particle diameter of silver in the first metal layer is not more than 0.3 micrometers.   
     
     
         22 . The device according to  claim 21 , wherein the first metal layer substantially does not include the element. 
     
     
         23 . The device according to  claim 21 , wherein the first metal layer is a single-layer film including silver. 
     
     
         24 . The device according to  claim 21 , wherein the second metal layer includes at least one selected from platinum, palladium, and an alloy including platinum and palladium. 
     
     
         25 . The device according to  claim 21 , wherein a peak wavelength of light emitted by the light emitting layer is not less than 370 nanometers and not more than 400 nanometers. 
     
     
         26 . The device according to  claim 21 , wherein the first semiconductor layer, the light emitting layer, and the second semiconductor layer are formed on a substrate made of sapphire via a buffer layer including monocrystalline Al x Ga 1-x N (0.8≦x≦1), the buffer layer including a high carbon concentration portion provided on the substrate side of the buffer layer, the high carbon concentration portion having a carbon concentration not less than 3×10 18  cm −3  and not more than 5×10 20  cm −3  and a thickness of not less than 3 nanometers and not more than 20 nanometers. 
     
     
         27 . The device according to  claim 21 , wherein
 a contact resistance between the second semiconductor layer and the electrode is not higher than 10×10 −4  Ωcm 2 .   
     
     
         28 . The device according to  claim 21 , wherein a thickness of the first electrode film is not less than 100 nanometers. 
     
     
         29 . A semiconductor light emitting device, comprising:
 a stacked structural unit including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer including a nitride semiconductor, the second semiconductor layer including a nitride semiconductor; and   an electrode including a first metal layer and a second metal layer, the first metal layer including silver or silver alloy and being provided on a side of the second semiconductor layer opposite to the light emitting layer, the second metal layer including at least one element selected from gold, platinum, palladium, rhodium, iridium, ruthenium, and osmium and being provided on a side of the first metal layer opposite to the second semiconductor layer,   the second semiconductor layer including an interface layer provided in contact with an interface between the second semiconductor layer and the first metal layer, the interface layer including silver,   wherein an average particle diameter of silver in the first metal layer is not more than 0.3 micrometers.   
     
     
         30 . The device according to  claim 29 , wherein a concentration of the element in a region including the interface between the first metal layer and the second semiconductor layer is higher than a concentration of the element in a region of the first metal layer distal to the interface. 
     
     
         31 . The device according to  claim 29 , wherein
 a contact resistance between the second semiconductor layer and the electrode is not higher than 10×10 −4  Ωcm 2 .   
     
     
         32 . The device according to  claim 29 , wherein a thickness of the first electrode film is not less than 100 nanometers.