Group-III nitride compound semiconductor light-emitting device, method of manufacturing group-III nitride compound semiconductor light-emitting device, and lamp
A group-III nitride compound semiconductor light-emitting device, a method of manufacturing the group-III nitride compound semiconductor light-emitting device, and a lamp. The method includes the steps of: forming an intermediate layer ( 12 ) made of a group-III nitride compound on a substrate ( 11 ) by activating and reacting gas including a group-V element with a metal material in plasma; and sequentially forming an n-type semiconductor layer ( 14 ), a light-emitting layer ( 15 ), and a p-type semiconductor layer ( 16 ) each made of a group-III nitride compound semiconductor on the intermediate layer ( 12 ). Nitrogen is used as the group-V element, and the thickness of the intermediate layer ( 12 ) is in the range of 20 to 80 nm.
1. A group-III nitride compound semiconductor light-emitting device comprising:
a substrate;
an intermediate layer that is made of a group-III nitride compound, covers an entire upper surface of the substrate, has substantially uniform thickness, and is formed on the substrate by activating and reacting gas including a group-V element with a metal material in plasma; and
an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer that are made of group-III nitride compound semiconductors and are sequentially formed on the intermediate layer,
wherein nitrogen is used as the group-V element, and
a thickness of the intermediate layer is in the range of 20 to 80 nm,
wherein the intermediate layer has high crystallinity wherein a half width of an XRC spectrum of the (0002) plane of an undoped GaN layer is less than 150 arcsec, and a half width of an XRC spectrum of the (10-10) plane is less than 350 arcsec.
2. The group-III nitride compound semiconductor light-emitting device according to claim 1 ,
wherein the intermediate layer has a composition including Al.
3. The group-III nitride compound semiconductor light-emitting device according to claim 2 ,
wherein the intermediate layer is formed of AlN.
4. The group-III nitride compound semiconductor light-emitting device according to claim 1 ,
wherein the intermediate layer is formed so as to cover 90% or more of a front surface of the substrate.
5. The group-III nitride compound semiconductor light-emitting device according to claim 1 ,
wherein the intermediate layer is composed of an aggregate of columnar crystals.
6. The group-III nitride compound semiconductor light-emitting device according to claim 5 ,
wherein, in the intermediate layer, the average of the widths of grains of the columnar crystals in the range of 1 to 100 nm.
7. The group-III nitride compound semiconductor light-emitting device according to claim 5 ,
wherein, in the intermediate layer, the average of the widths of grains of the columnar crystals is in the range of 2 to 70 nm.
8. The group-III nitride compound semiconductor light-emitting device according to claim 1 ,
wherein the intermediate layer has a hexagonal close-packed structure.
9. The group-III nitride compound semiconductor light-emitting device according to claim 1 ,
wherein an underlying layer included in the n-type semiconductor layer is formed on the intermediate layer.
10. The group-III nitride compound semiconductor light-emitting device according to claim 9 ,
wherein the underlying layer is formed of a GaN-based compound semiconductor.
11. The group-III nitride compound semiconductor light-emitting device according to claim 10 ,
wherein the underlying layer is formed of GaN.
12. The group-III nitride compound semiconductor light-emitting device according to claim 10 ,
wherein the underlying layer is formed of AlGaN.