Semiconductor light-emitting element and method for manufacturing same
A semiconductor light-emitting element according to an embodiment has a light emission peak wavelength not less than 380 nm and not more than 425 nm. The semiconductor light-emitting element includes a stacked structure including a reflective layer, a substrate provided on the reflective layer, and a semiconductor layer provided on the substrate. An uneven structure is provided in a surface of the substrate on the semiconductor layer side. The semiconductor layer includes a buffer layer made of aluminum nitride and having a thickness not less than 10 nm and not more than 100 nm. The buffer layer includes oxygen; and 0.01≤O 8nm /O 3nm ≤0.5 is satisfied, where O 3nm (at %) is the oxygen concentration at a depth of 3 nm of the buffer layer, and O 8nm (at %) is the oxygen concentration at a depth of 8 nm of the buffer layer.
1. A semiconductor light-emitting element having a light emission peak wavelength not less than 380 nm and not more than 425 nm,
the semiconductor light-emitting element comprising:
a stacked structure including
a reflective layer,
a substrate provided on the reflective layer, and
a semiconductor layer provided on the substrate,
the substrate having an uneven structure provided in a surface of the substrate on the semiconductor layer side,
the semiconductor layer including
a buffer layer made of aluminum nitride and having a thickness not less than 10 nm and not more than 100 nm, and
a semiconductor sub-layer positioned on the buffer layer,
the buffer layer including oxygen, a concentration of oxygen in the buffer layer being at 20 at % or less,
0.01≤O 8nm /O 3nm ≤0.5 being satisfied, O 3nm (at %) being an oxygen concentration at a depth of 3 nm from a boundary positioned between the buffer layer and the semiconductor sub-layer, O 8nm (at %) being an oxygen concentration at a depth of 8 nm from the boundary.
2. The semiconductor light-emitting element according to claim 1 , wherein the substrate is a sapphire substrate.
3. The semiconductor light-emitting element according to claim 1 , wherein
the semiconductor sub-layer is of an n-type, and
at least a portion of the semiconductor sub-layer is an AlGaN layer.
4. The semiconductor light-emitting element according to claim 1 , wherein
the semiconductor layer includes an active layer positioned on the buffer layer, and
at least a portion of the active layer is a stacked structure of an InAlGaN layer and an AlGaN layer.
5. The semiconductor light-emitting element according to claim 4 , wherein
the semiconductor layer further includes a relaxation layer provided between the buffer layer and the active layer, and
the relaxation layer includes at least one of In or Al.
6. The semiconductor light-emitting element according to claim 5 , wherein
the relaxation layer includes
an InAlGaN layer, or
a superlattice structure having an InAlGaN layer and an AlGaN layer provided alternately.
7. The semiconductor light-emitting element according to claim 1 , wherein a width at half maximum of a (0002) plane in an X-ray diffraction measurement of the buffer layer is 350 arcsec or less.
8. The semiconductor light-emitting element according to claim 1 , wherein the light emission peak wavelength is not less than 400 nm and not more than 420 nm.
9. A method for manufacturing the semiconductor light-emitting element according to claim 1 , comprising forming the buffer layer by sputtering.
10. The method for manufacturing the semiconductor light-emitting element according to claim 9 , wherein the sputtering is performed in a vacuum of 1×10 −4 Pa or less with a temperature of the substrate set to be not less than 400° C. and not more than 800° C.
11. The method for manufacturing the semiconductor light-emitting element according to claim 9 , wherein heat treatment of the buffer layer is performed in an inert gas atmosphere at not less than 1200° C. and not more than 1800° C. after the forming of the buffer layer.
12. The semiconductor light-emitting element according to claim 1 , wherein
the substrate is a sapphire substrate,
the semiconductor layer further includes
a relaxation layer positioned on the semiconductor sub-layer, the relaxation layer including at least one of In or Al, and
an active layer positioned on the relaxation layer, at least a portion of the active layer being a stacked structure of an InAlGaN layer and an AlGaN layer,
the semiconductor sub-layer is of an n-type, and
at least a portion of the semiconductor sub-layer is an AlGaN layer.
13. The semiconductor light-emitting element according to claim 12 , wherein
the relaxation layer includes
an InAlGaN layer, or
a superlattice structure having an InAlGaN layer and an AlGaN layer provided alternately.
14. The semiconductor light-emitting element according to claim 13 , wherein a width at half maximum of a (0002) plane in an X-ray diffraction measurement of the buffer layer is 350 arcsec or less.
15. The semiconductor light-emitting element according to claim 14 , wherein the light emission peak wavelength is not less than 400 nm and not more than 420 nm.
16. The semiconductor light-emitting element according to claim 12 , wherein the light emission peak wavelength is not less than 400 nm and not more than 420 nm.