Semiconductor light emitting device

Abstract

According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer, a light emitting layer, a bonding pad, a narrow wire electrode and a first insulating layer. The light emitting layer is provided between the first semiconductor layer and the second semiconductor layer and is in contact with the first semiconductor layer. The narrow wire electrode includes a first portion and a second portion. The first portion is provided on a surface of the first semiconductor layer not in contact with the light emitting layer and is in ohmic contact with the first semiconductor layer. The second portion is provided on the surface and located between the first portion and the bonding pad. The narrow wire electrode is electrically connected to the bonding pad. The first insulating layer is provided between the second portion and the first semiconductor layer.

1 . A semiconductor light emitting device, comprising:
 a first semiconductor layer of a first conductivity type, wherein the first semiconductor layer includes a first surface that is a light extract surface and a second surface, which is opposite to the first surface;   a second semiconductor layer of a second conductivity type;   a light emitting layer provided between the second surface of the first semiconductor layer and the second semiconductor layer and in contact with the second surface of the first semiconductor layer;   a bonding pad;   a narrow wire electrode including a first portion and a second portion,
 the first portion being in direct contact with the second surface of the first semiconductor layer, wherein the first portion is not in contact with the light emitting layer, 
 the second portion being provided on the second surface of the first semiconductor and located between the first portion and the bonding pad, the narrow wire electrode being electrically connected to the bonding pad; and 
   a first insulating layer provided between the second portion of the narrow wire electrode and the second surface of the first semiconductor layer.   
     
     
         2 . The device according to  claim 1 , further comprising:
 a metal layer;   a second electrode provided on a first part of the metal layer and electrically connected to the metal layer; and   a second insulating layer provided on a second part of the metal layer,   wherein the second semiconductor layer is placed on the second electrode.   
     
     
         3 . The device according to  claim 2 , wherein the narrow wire electrode is placed on the second insulating layer. 
     
     
         4 . The device according to  claim 1 , wherein
 the narrow wire electrode further includes a third portion not overlapping the first semiconductor layer as projected on a plane parallel to the surface, and   the bonding pad is placed on the third portion of the narrow wire electrode.   
     
     
         5 . The device according to  claim 1 , wherein a distance (in micrometers) between the bonding pad and an end of the first insulating layer on opposite side from the bonding pad is 35 times or more of square root of a thickness (in micrometers) of the first semiconductor layer. 
     
     
         6 . The device according to  claim 5 , wherein the distance is half or less of a length of the narrow wire electrode. 
     
     
         7 . The device according to  claim 5 , wherein a width of the narrow wire electrode is half or less of the distance. 
     
     
         8 . The device according to  claim 2 , wherein the second electrode is reflective to a light emitted from the light emitting layer. 
     
     
         9 . The device according to  claim 1 , wherein the first portion of the narrow wire electrode is spaced from the first insulating layer. 
     
     
         10 . The device according to  claim 1 , further comprising:
 a substrate electrically connected to the second semiconductor layer,   wherein the light emitting layer is placed between the substrate and the first semiconductor layer, and   wherein the second semiconductor layer is placed between the light emitting layer and the substrate.   
     
     
         11 . The device according to  claim 10 , wherein the substrate is connected to the second semiconductor layer. 
     
     
         12 . The device according to  claim 1 , wherein in a light emitted from the light emitting layer, a proportion of the light passing through the first semiconductor layer and emitted outside is larger than a proportion of the light passing through the second semiconductor layer and emitted outside. 
     
     
         13 . The device according to  claim 1 , wherein the first insulating layer is transmissive to a light emitted from the light emitting layer. 
     
     
         14 . The device according to  claim 1 , wherein the first semiconductor layer has a thickness of 0.5 micrometers or more and 6 micrometers or less. 
     
     
         15 . The device according to  claim 1 , wherein the narrow wire electrode includes Al. 
     
     
         16 . The device according to  claim 1 , wherein the bonding pad includes Al. 
     
     
         17 . The device according to  claim 1 , wherein the first semiconductor layer includes an unevenness portion provided at the first surface. 
     
     
         18 . The device according to  claim 1 , wherein the narrow wire electrode includes an outer edge portion along an outer edge of the first semiconductor layer and an inside portion inside the outer edge portion. 
     
     
         19 . The device according to  claim 1 , wherein
 the first conductivity type is n-type, and   the second conductivity type is p-type.   
     
     
         20 . The device according to  claim 19 , wherein the first semiconductor layer, the second semiconductor layer, and the light emitting layer include a nitride semiconductor. 
     
     
         21 . The device according to  claim 1 , wherein the narrow wire electrode extends along an outer edge of the first semiconductor layer, and
 wherein the first portion of the narrow wire electrode extends along the outer edge of the first semiconductor layer.   
     
     
         22 . The device according to  claim 21 , wherein the second portion of the narrow wire electrode extends along the outer edge of the first semiconductor layer. 
     
     
         23 . The device according to  claim 1 , wherein the first insulating layer includes:
 a first insulating region provided between the second portion of the narrow wire electrode and the first semiconductor layer; and   a second insulating region provided between the bonding pad and the first semiconductor layer,   wherein a width of the first insulating region in the second direction is less a width of the second insulating region.   
     
     
         24 . The device according to  claim 1 , wherein the first insulating layer includes a first insulating region provided between the second portion of the narrow wire electrode and the first semiconductor layer, and
 wherein the first insulating region extends along a first direction from the bonding pad toward the first portion of the narrow wire electrode.   
     
     
         25 . The device according to  claim 1 , wherein the first insulating layer includes SiO 2 . 
     
     
         26 . The device according to  claim 1 , wherein:
 the second surface of the first semiconductor layer includes a first region and a second region;   the first region contacts the light emitting layer;   the second region contacts the first portion of the narrow wire electrode; and   the first region and the second region form a step.