Method for producing group III nitride semiconductor light emitting device, group III nitride semiconductor light emitting device, and lamp
Provided is a method for producing a group III nitride semiconductor light emitting device capable of producing a group III nitride semiconductor light emitting device with excellent light emitting properties with excellent productivity; a group III nitride semiconductor light emitting device; and a lamp. Provided is a method in which a buffer layer 12 composed of a group III nitride compound is laminated on a substrate 11 and then an n-type semiconductor layer 14 provided with an underlying layer 14 a , a light emitting layer 15 , and an p-type semiconductor layer 16 are sequentially laminated on the buffer layer 12 , and is a method in which the buffer layer 12 is formed so as to have a composition of Al X Ga 1-X N (0≦X<1) by activating, with plasma, and thereby reacting at least a metallic Ga source and a gas containing a group V element, and the underlying layer 14 is formed on the buffer layer 12.
1. A method for producing a group III nitride semiconductor light emitting device which is a method for producing a group III nitride semiconductor light emitting device, in which a buffer layer composed of a group III nitride compound is laminated on a substrate and then an n-type semiconductor layer provided with an underlying layer, a light emitting layer, and a p-type semiconductor layer are sequentially laminated on the buffer layer, the method comprising:
forming the buffer layer having a composition of Al x Ga 1-x N (0≦X<1) by activating, with plasma, and thereby reacting at least a metallic Ga source and a gas containing a group V element; and
forming the underlying layer on the buffer layer,
wherein the buffer layer is formed by a reactive sputtering method in which a gas containing a group V element is made to circulate inside a reactor.
2. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the underlying layer is formed by a metal organic chemical vapor deposition (MOCVD) method.
3. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the buffer layer is formed by a radio frequency (RF) sputtering method.
4. The method for producing a group III nitride semiconductor light emitting device according to claim 3 ,
wherein the buffer layer is formed by an RF sputtering method while moving a magnet of a cathode.
5. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the buffer layer is formed by a direct current (DC) sputtering method.
6. The method for producing a group III nitride semiconductor light emitting device according to claim 5 ,
wherein the buffer layer is formed by a pulsed DC sputtering method.
7. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the buffer layer is formed so as to cover at least 90% of a surface of the substrate.
8. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the buffer layer is formed by making a temperature of the substrate within a range of room temperature to 1,000° C.
9. The method for producing a group III nitride semiconductor light emitting device according to claim 8 ,
wherein the buffer layer is formed by making a temperature of the substrate within a range of 200 to 800° C.
10. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the group V element is nitrogen and a nitrogen gas fraction in the gas when forming the buffer layer is within a range of 20 to 100%.
11. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein the buffer layer is produced inside a chamber of a film forming apparatus under a condition of an ultimate vacuum degree of 1.0×10 −3 Pa or less.
12. The method for producing a group III nitride semiconductor light emitting device according to claim 11 ,
wherein the buffer layer is produced inside a chamber of a film forming apparatus under a condition of an ultimate vacuum degree of 3.5×10 −5 Pa or less.
13. The method for producing a group III nitride semiconductor light emitting device according to claim 11 ,
wherein the buffer layer is produced inside a chamber of a film forming apparatus under a condition of an ultimate vacuum degree of 6.0×10 −6 Pa or less.
14. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein a pressure inside a chamber of a film forming apparatus is not less than 0.3 Pa when forming the buffer layer.
15. The method for producing a group III nitride semiconductor light emitting device according to claim 1 ,
wherein a film formation rate is within a range of 0.01 nm/s to 10 nm/s when forming the buffer layer.
16. A group III nitride semiconductor light emitting device obtained by the method of claim 1 .