Gallium nitride based compound semiconductor light-emitting device having high emission efficiency and method of manufacturing the same
The present invention provides a gallium nitride based compound semiconductor light-emitting device having high light emission efficiency and a low driving voltage Vf. The gallium nitride based compound semiconductor light-emitting device includes a p-type semiconductor layer, and a transparent conductive oxide film that includes dopants and is formed on the p-type semiconductor layer. A dopant concentration at an interface between the p-type semiconductor layer and the transparent conductive oxide film is higher than the bulk dopant concentration of the transparent conductive oxide film. Therefore, the contact resistance between the p-type semiconductor layer and the transparent conductive oxide film is reduced.
1. A gallium nitride based compound semiconductor light-emitting device including:
a gallium nitride based compound semiconductor device including a p-type semiconductor layer; and
a transparent conductive oxide film that includes dopants and is formed on the p-type semiconductor layer,
wherein a dopant concentration at an interface between the p-type semiconductor layer and the transparent conductive oxide film is higher than a bulk dopant concentration of the transparent conductive oxide film, and
wherein the dopant concentration of the transparent conductive oxide film is 15 at % or more in the region that is 2 nm or less away from the interface and the dopant concentration is 5 to 10 at % in the region that is 2 nm or more away from the interface.
2. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein an uneven surface is formed on at least a portion of the p-type semiconductor layer.
3. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein the dopant concentration of the transparent conductive oxide film is the highest at the interface between the transparent conductive oxide film and the p-type semiconductor layer.
4. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein a highly doped region having a dopant concentration that is higher than that of the transparent conductive oxide film is provided between the p-type semiconductor layer and the transparent conductive oxide film.
5. The gallium nitride based compound semiconductor light-emitting device according to claim 4 ,
wherein the highly doped region is formed of any one of a dopant, a dopant oxide, and a transparent conductive material having a dopant concentration that is higher than that of the transparent conductive oxide film.
6. The gallium nitride based compound semiconductor light-emitting device according to claim 4 ,
wherein the highly doped region is formed of any one of Sn, SnO 2 , and ITO(In 2 O 3 —SnO 2 ) having a Sn concentration that is higher than that of the transparent conductive oxide film.
7. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein the transparent conductive oxide film is formed of at least one of ITO(In 2 O 3 —SnO 2 ), AZO(ZnO—Al 2 O 3 ), IZO(In 2 O 3 —ZnO), and GZO(ZnO—GeO 2 ).
8. The gallium nitride based compound semiconductor light-emitting device according to claim 7 ,
wherein the transparent conductive oxide film contains at least ITO(In 2 O 3 —SnO 2 ).
9. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein the thickness of the transparent conductive oxide film is in the range of 35 nm to 10000 nm (10 μm).
10. The gallium nitride based compound semiconductor light-emitting device according to claim 1 ,
wherein the thickness of the transparent conductive oxide film is in the range of 100 nm to 1000 nm (1 μm).
11. A lamp including the gallium nitride based compound semiconductor light-emitting device according to claim 1 .