Semiconductor light emitting element and semiconductor light emitting device
View Patent ↗A semiconductor light emitting element, includes: a laminated structure body including an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer; a p-side electrode provided in contact with the p-type semiconductor layer; an n-side electrode provided in contact with the n-type semiconductor layer; a highly reflective insulating layer provided in contact with the n-type semiconductor layer and having a higher reflectance than a reflectance of the n-side electrode; and an upper metal layer provided on at least a part of the n-side electrode and on at least a part of the highly reflective insulating layer and electrically connected to the n-side electrode. An area of a region of the n-side electrode in contact with the n-type semiconductor layer is smaller than an area of a region of the highly reflective insulating layer sandwiched between the n-type semiconductor layer and the upper metal layer.
1. A semiconductor light emitting element, comprising:
a laminated structure body including an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer provided between the n-type semiconductor layer and the p-type semiconductor layer;
a p-side electrode provided in contact with the p-type semiconductor layer;
an n-side electrode provided in contact with the n-type semiconductor layer, a reflectance of the n-side electrode being lower than a reflectance of the p-side electrode;
a highly reflective insulating layer provided in contact with the n-type semiconductor layer and having a higher reflectance to light emitted from the light emitting layer than a reflectance of the n-side electrode to the light, the highly reflective insulating layer and the n-side electrode not covering each other; and
an upper metal layer electrically connected to the n-side electrode, at least a part of the n-side electrode and at least a part of the highly reflective insulating layer being disposed between the upper metal layer and the n-type semiconductor layer, and a part of the upper metal layer being in direct contact with the n-type semiconductor layer,
an area of a region of the n-side electrode in contact with the n-type semiconductor layer being smaller than an area of a region of the highly reflective insulating layer sandwiched between the n-type semiconductor layer and the upper metal layer, and
the upper metal layer completely covering the n-side electrode and the highly reflective insulating layer.
2. The element according to claim 1 , wherein
the laminated structure body further includes a substrate made of sapphire and provided on a side of a second main surface opposite to the first main surface.
3. The element according to claim 2 , wherein
the laminated structure body is formed on the substrate via a single-crystal aluminum nitride layer.
4. The element according to claim 3 , wherein
the aluminum nitride layer has a first portion and a second portion, the first portion is provided between the substrate and a second portion, the first portion has a carbon concentration relatively higher than a carbon concentration in the second portion.
5. The element according to claim 1 , wherein the upper metal layer includes a first layer and a second layer, the first layer being disposed between the second layer and the n-type semiconductor layer.
6. The element according to claim 5 , wherein a reflectance of the first layer to the light is higher than a reflectance of the second layer to the light.
7. The element according to claim 5 , wherein the first layer includes at least one of Ag or Al, and the second layer includes Au.
8. The element according to claim 1 , wherein
the n-side electrode includes a transparent conductive film provided on a side of the n-type semiconductor layer and having translucency to the light.
9. The element according to claim 8 , wherein
the transparent conductive film has ohmic property to the n-type semiconductor layer.
10. The element according to claim 1 , wherein
an area of a region of the n-side electrode facing the upper metal layer is smaller than the area of the region of the highly reflective insulating layer sandwiched between the n-type semiconductor layer and the upper metal layer.
11. The element according to claim 1 , wherein
the n-type semiconductor layer is exposed in an exposed region on a side of a first main surface of the laminated structure body, a part of the p-type semiconductor layer being removed in the exposed region,
the n-side electrode and the highly reflective insulating layer are provided in contact with the exposed n-type semiconductor layer,
the p-side electrode is provided in contact with the p-type semiconductor layer on a side of the first main surface, and
at least a part of the n-side electrode is provided closer to a side of the p-side electrode than the highly reflective insulating layer in a plane parallel to the first main surface.
12. The element according to claim 1 , wherein
a peak wavelength of the light is not less than 370 nanometers and not more than 400 nanometers.
13. The element according to claim 1 , wherein
the upper metal layer includes a layer provided on a side of the laminated structure body and including at least one of aluminum, an aluminum alloy, rhodium, and a rhodium alloy.
14. The element according to claim 1 , wherein
the n-side electrode has ohmic property to the n-type semiconductor layer.
15. The element according to claim 1 , wherein
the n-side electrode includes at least one of silver and a silver alloy.
16. The element according to claim 1 , wherein
the p-side electrode includes at least one of silver and a silver alloy.
17. The element according to claim 1 , wherein
the p-side electrode includes a silver contained film in contact with the p-type semiconductor layer and a platinum contained film stacked with the silver contained film.
18. The element according to claim 1 , wherein
the upper metal layer is connected to a connection member.
19. The element according to claim 1 , wherein
the highly reflective insulating layer includes a plurality of dielectric films alternatively laminated and having a different refractive index from each other.
20. The element according to claim 1 , wherein
the highly reflective insulating layer includes at least one of oxide, nitride, or acid nitride of at least one of silicon (Si), aluminum (Al), zirconium (Zr), titanium (Ti), niobium (Nb), tantalum (Ta), magnesium (Ma), hafnium (Hf), cerium (Ce), and zinc (Zn).
21. The element according to claim 1 , wherein
the highly reflective insulating layer includes a silicon oxide contained film and a titanium oxide contained film.
22. The element according to claim 1 , wherein the highly reflective insulating layer contacts the n-side electrode.
23. The element according to claim 1 , wherein
the highly reflective insulating layer is apart from the n-side electrode, and
the part of the upper metal layer is in direct contact with the n-type semiconductor layer between the highly reflective insulating layer and the n-side electrode.
24. A semiconductor light emitting device comprising:
a semiconductor light emitting element; and
a mounting component, the semiconductor light emitting element being mounted on the mounting component,
the semiconductor light emitting element including:
a laminated structure body including an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer provided between the n-type semiconductor layer and the p-type semiconductor layer;
a p-side electrode provided in contact with the p-type semiconductor layer;
an n-side electrode provided in contact with the n-type semiconductor layer, a reflectance of the n-side electrode being lower than a reflectance of the p-side electrode;
a highly reflective insulating layer provided in contact with the n-type semiconductor layer and having a higher reflectance to light emitted from the light emitting layer than a reflectance of the n-side electrode to the light, the highly reflective insulating layer and the n-side electrode not covering each other; and
an upper metal layer electrically connected to the n-side electrode, at least a part of the n-side electrodes and at least a part of the highly reflective insulating layer being disposed between the upper metal layer and the n-type semiconductor layer, and a part of the upper metal layer being in direct contact with the n-type semiconductor layer,
an area of a region of the n-side electrode in contact with the n-type semiconductor layer being smaller than an area of a region of the highly reflective insulating layer sandwiched between the n-type semiconductor layer and the upper metal layer,
the n-type semiconductor layer being exposed in an exposed region on a side of a first main surface of the laminated structure body, a part of the p-type semiconductor layer being removed in the exposed region,
the n-side electrode and the highly reflective insulating layer being provided in contact with the exposed n-type semiconductor layer,
the p-side electrode being provided in contact with the p-type semiconductor layer on a side of the first main surface of the laminated structure body, the n-side electrode being provided on the first main surface of the laminated structure body,
the mounting component including a plurality of mounting electrodes,
the first main surface of the laminated structure body and the mounting electrodes of the mounting component being disposed to face each other,
the upper metal layer being electrically connected to one of the mounting electrodes, and the p-side electrode being electrically connected to another one of the mounting electrodes, and
the upper metal layer completely covering the n-side electrode and the highly reflective insulating layer.
25. The device according to claim 24 , wherein the upper metal layer includes a first layer and a second layer, the first layer being disposed between the second layer and the n-type semiconductor layer.
26. The device according to claim 25 , wherein a reflectance of the first layer to the light is higher than a reflectance of the second layer to the light.
27. The device according to claim 25 , wherein the first layer includes at least one of Ag or Al, and the second layer includes Au.
28. The device according to claim 25 , further comprising:
a connecting member electrically connecting the upper metal layer and the one of the mounting electrodes,
the second layer having at least one of
an adhesion to the connecting member higher than an adhesion of the first layer to the connecting member,
a resistance against diffusion of elements included in the connecting member higher than a resistance of the first layer against diffusion of the elements included in the connecting member, or
a resistance against increase in temperature higher than a resistance of the second layer against increase in temperature.
29. The device according to claim 24 , further comprising:
a wavelength conversion layer absorbing the light and emitting light having a wavelength different from a wavelength of the light.
30. The device according to claim 24 , wherein the highly reflective insulating layer contacts the n-side electrode.
31. The device according to claim 24 , wherein
the highly reflective insulating layer is apart from the n-side electrode and
the part of the upper metal layer is in direct contact with the n-type semiconductor layer between the highly reflective insulating layer and the n-side electrode.