Nitride semiconductor light-emitting element and light source including the nitride semiconductor light-emitting element
View Patent ↗A nitride semiconductor light-emitting element includes: n-side and p-side electrodes; n-type and p-type nitride semiconductor layers; and an active layer arranged between the n- and p-type nitride semiconductor layers. The p-type nitride semiconductor layer has a projection having a height of 30 nm to 50 nm. The projection is formed of a p-type nitride semiconductor including magnesium and silicon. The p-type nitride semiconductor has a silicon concentration of 1.0×10 17 cm −3 to 6.0×10 17 cm −3 . The projection projects from the active layer toward the p-side electrode. On a plan view of the nitride semiconductor light-emitting element, the p-side electrode overlaps with the projection. The projection includes a dislocation. The projection is surrounded with a flat surface which is formed of the p-type nitride semiconductor. And the projection has a higher dislocation density than the flat surface.
1. A nitride semiconductor light-emitting element comprising:
an n-side electrode;
a p-side electrode;
an n-type nitride semiconductor layer which is electrically connected to the n-side electrode;
a p-type nitride semiconductor layer having a principal surface that is either a non-polar plane or a semi-polar plane; and
an active layer which is arranged between the n- and p-type nitride semiconductor layers,
wherein the p-type nitride semiconductor layer has a projection having a height of not less than 30 nm and not more than 50 nm,
the projection is formed of a p-type nitride semiconductor including not only magnesium but also silicon,
the p-type nitride semiconductor has a silicon concentration of not less than 1.0×10 17 cm −3 and not more than 6.0×10 17 cm −3 ,
the projection projects from the active layer toward the p-side electrode,
on a plan view of the nitride semiconductor light-emitting element, the p-side electrode overlaps with the projection,
the projection includes a dislocation,
the projection is surrounded with a flat surface which is formed of the p-type nitride semiconductor, and
the projection has a higher dislocation density than the flat surface.
2. The nitride semiconductor light-emitting element of claim 1 , wherein the projection has a surface area of not less than 5.0×10 −7 cm 2 and not more than 3.8×10 −6 cm 2 .
3. The nitride semiconductor light-emitting element of claim 1 , wherein the dislocation density is not less than 1.0×10 5 cm −2 and not more than 1.0×10 7 cm −2 .
4. The nitride semiconductor light-emitting element of claim 1 , wherein the p-type nitride semiconductor has a magnesium concentration of not less than 5.0×10 19 cm −3 and not more than 5.0×10 20 cm −3 .
5. The nitride semiconductor light-emitting element of claim 1 , wherein the projection has a substantially square, substantially rectangular, substantially circular or substantially elliptical cross-sectional shape.
6. The nitride semiconductor light-emitting element of claim 3 , wherein on a plan view, a plurality of dislocations are dispersed, and
wherein the dislocations have a dispersion density of not less than 1.0×10 5 cm −2 and not more than 1.0×10 7 cm −2 .
7. The nitride semiconductor light-emitting element of claim 1 , wherein the flat surface has a thickness of not less than 26 nm and not more than 60 nm.
8. The nitride semiconductor light-emitting element of claim 1 , further comprising a p-type nitride semiconductor multilayer structure, wherein
the p-type nitride semiconductor multilayer structure comprises:
a p-type nitride semiconductor electron blocking layer; and
a p-type nitride semiconductor contact layer,
the p-type nitride semiconductor electron blocking layer is sandwiched between the active layer and p-type nitride semiconductor contact layer,
the p-type nitride semiconductor contact layer is sandwiched between the p-side electrode and the p-type nitride semiconductor electron blocking layer, and
the p-type nitride semiconductor electron blocking layer is the p-type nitride semiconductor layer.
9. The nitride semiconductor light-emitting element of claim 8 , wherein another p-type nitride semiconductor layer is sandwiched between the p-type nitride semiconductor electron blocking layer and the p-type nitride semiconductor contact layer.
10. The nitride semiconductor light-emitting element of claim 8 , wherein the p-type contact layer has a magnesium concentration of not less than 5.0×10 19 cm −3 and not more than 5.0×10 20 cm −3 , and
the p-type contact layer has a thickness of not less than 26 nm and not more than 60 nm.
11. The nitride semiconductor light-emitting element of claim 1 , wherein the p-type nitride semiconductor layer has an Si-doped layer which is located closer to the active layer,
the Si-doped layer has a thickness of not less than 10 nm and not more than 100 nm, and
the Si-doped layer has a silicon concentration of not less than 1.0×10 17 cm −3 and not more than 6.0×10 17 cm −3 .
12. The nitride semiconductor light-emitting element of claim 11 , wherein the p-type nitride semiconductor layer includes Al within a range of 100 nm as measured from an end of the p-type nitride semiconductor layer closer to the active layer.
13. A light source comprising:
the nitride semiconductor light-emitting element of claim 1 ; and
a wavelength converting section including a phosphor which converts the wavelength of light emitted from the nitride semiconductor light-emitting element.