Semiconductor light-emitting device
View Patent ↗A semiconductor light-emitting device having: a light-emitting portion formed on a semiconductor substrate, the light-emitting portion having an n-type clad layer, an active layer and a p-type clad layer; an As-based contact layer formed on the light-emitting portion, the contact layer being doped with a p-type dopant of 1×10 19 /cm 3 or more; a current spreading layer formed on the contact layer, the current spreading layer being formed of a transparent conductive film of a metal oxide material; and a buffer layer formed between the contact layer and the p-type clad layer or formed being inserted inside of the p-type clad layer. The buffer layer is of an undoped group III/V semiconductor, and the group III/V semiconductor is of a group V element having P (phosphorus) as a main component thereof.
1. A semiconductor light-emitting device, comprising:
a light-emitting portion formed on a semiconductor substrate, the light-emitting portion comprising an n-type clad layer, an active layer and a p-type clad layer;
an As-based contact layer formed on the light-emitting portion, the contact layer being doped with a p-type dopant of 1×10 19 /cm 3 or more;
a current spreading layer formed on the contact layer, the current spreading layer comprising a transparent conductive film of a metal oxide material; and
a buffer layer formed between the contact layer and the p-type clad layer or formed being inserted inside of the p-type clad layer,
wherein the buffer layer comprises an undoped group III/V semiconductor, and
the group III/V semiconductor comprises a group V element comprising P (phosphorus) as a main component thereof.
2. The semiconductor light-emitting device according to claim 1 , wherein:
the buffer layer is lattice-matched to the semiconductor substrate.
3. The semiconductor light-emitting device according to claim 1 , wherein:
an Al composition of the buffer layer is smaller than the p-type clad layer.
4. The semiconductor light-emitting device according to claim 1 , further comprising:
an undoped layer formed between the active layer and the p-type clad layer.
5. The semiconductor light-emitting device according to claim 1 , wherein:
the buffer layer comprises a C-concentration of 1×10 17 atoms/cm 3 or less.
6. The semiconductor light-emitting device according to claim 1 , further comprising:
an undoped layer formed between the n-type clad layer and the active layer.
7. The semiconductor light-emitting device according to claim 1 , further comprising:
an n-type low-doped layer formed between the n-type clad layer and the active layer,
wherein the n-type low-doped layer comprises a lower carrier density than the n-type clad layer.
8. The semiconductor light-emitting device according to claim 1 , wherein:
the current spreading layer comprises an ITO (indium tin oxide).
9. The semiconductor light-emitting device according to claim 1 , wherein:
the current spreading layer comprises a thickness in a range of ±30% of d calculated by: d=A×λ P /(4×n) where A is a constant of 1 or 3, λ P is an emission wavelength (nm) and n is a refractive index.
10. The semiconductor light-emitting device according to claim 1 , wherein:
the contact layer comprises Zn as a main dopant thereof,
the contact layer comprises a carrier concentration of 1×10 19 /cm 3 or more, and
the contact layer comprises Al X Ga 1-X As where 0≦X≦0.4.
11. The semiconductor light-emitting device according to claim 1 , wherein:
the p-type clad layer comprises Mg as a dopant thereof, and
the n-type clad layer, the active layer and the p-type clad layer comprise (Al X Ga 1-X ) Y In 1-Y P where 0≦X≦1 and 0.4≦Y≦0.6.
12. The semiconductor light-emitting device according to claim 1 , further comprising:
a light reflecting layer formed between the semiconductor substrate and the n-type clad layer,
wherein the light reflecting layer comprises a semiconductor multilayer comprising 15 pairs or more of two semiconductor layers that are different in refractive index.
13. The semiconductor light-emitting device according to claim 1 , wherein:
the current spreading layer comprises a carrier concentration of 8×10 20 /cm 3 or more.
14. The semiconductor light-emitting device according to claim 1 , wherein:
the active layer comprises a multiquantum well structure or strained multiquantum well structure.
15. The semiconductor light-emitting device according to claim 1 , wherein:
the p-type clad layer and the buffer layer comprise a summed thickness of 1000 nm or more and 3000 nm or less, and
the p-type clad layer comprises a thickness of 200 nm or more and 600 nm or less.
16. The semiconductor light-emitting device according to claim 1 , wherein:
the contact layer comprises a thickness of 1 nm or more and 30 nm or less.
17. The semiconductor light-emitting device according to claim 1 , wherein:
the buffer layer comprises an AlInP or AlGaInP that is optically transparent to an emission wavelength.
18. The semiconductor light-emitting device according to claim 12 , wherein:
the light reflecting layer comprises a combination of (Al X Ga 1-X ) Y In 1-Y P where 0≦X≦1 and 0≦Y≦0.6 and Al X Ga 1-X As where 0≦X≦1.
19. The semiconductor light-emitting device according to claim 1 , further comprising:
a p-type low-doped layer formed between the active layer and the p-type clad layer,
wherein the p-type low-doped layer comprises a lower carrier density than the p-type clad layer.
20. The semiconductor light-emitting device according to claim 4 , wherein:
the undoped layer comprises a thickness of 100 nm or less.
21. The semiconductor light-emitting device according to claim 6 , wherein:
the undoped layer comprises a thickness of 100 nm or less.
22. The semiconductor light-emitting device according to claim 7 , wherein:
the n-type low-doped layer comprises a thickness of 100 nm or less.
23. The semiconductor light-emitting device according to claim 19 , wherein:
the p-type low-doped layer comprises a thickness of 100 nm or less.
24. The semiconductor light-emitting device according to claim 1 , further comprising:
a n-type buffer layer formed on the semiconductor substrate,
wherein the n-type buffer layer comprises a same material as the semiconductor substrate.
25. The semiconductor light-emitting device according to claim 1 , wherein:
the buffer layer comprises a lattice-mismatching ratio to a semiconductor layer formed thereunder, and
the lattice-mismatching ratio comprises an absolute value of 0.3% or less.
26. The semiconductor light-emitting device according to claim 1 , wherein:
the buffer layer comprises a GaP.
27. A semiconductor light-emitting device, comprising:
a light-emitting portion formed on a semiconductor substrate, the light-emitting portion comprising an n-type clad layer, an active layer and a p-type clad layer;
an As-based contact layer formed on the light-emitting portion, the contact layer being doped with a p-type dopant of 1×10 19 /cm 3 or more;
a current spreading layer formed on the contact layer, the current spreading layer comprising a transparent conductive film of a metal oxide material; and
a buffer layer formed between the contact layer and the p-type clad layer or formed being inserted inside of the p-type clad layer,
wherein the buffer layer comprises an undoped group III/V semiconductor,
the group III/V semiconductor comprises a group V element comprising P (phosphorus), and
the group III/V semiconductor comprises an H-concentration of 3×10 17 atoms/cm 3 or less.
28. The semiconductor light-emitting device according to claim 27 , wherein:
the buffer layer is lattice-matched to the semiconductor substrate, and
the buffer layer comprises the group III/V semiconductor with a higher resistivity than the p-type clad layer.
29. The semiconductor light-emitting device according to claim 27 , wherein:
an Al composition of the buffer layer is smaller than the p-type clad layer.
30. The semiconductor light-emitting device according to claim 27 , further comprising:
an undoped layer formed between the active layer and the p-type clad layer.
31. The semiconductor light-emitting device according to claim 27 , wherein:
the buffer layer comprises a C-concentration of 5×10 16 atoms/cm 3 or less.
32. The semiconductor light-emitting device according to claim 27 , further comprising:
an undoped layer formed between the n-type clad layer and the active layer.
33. The semiconductor light-emitting device according to claim 27 , further comprising:
an n-type low-doped layer formed between the n-type clad layer and the active layer,
wherein the n-type low-doped layer comprises a semiconductor comprising a n-type conductivity-determining impurity with a lower concentration than the n-type clad layer.
34. The semiconductor light-emitting device according to claim 27 , wherein:
the current spreading layer comprises an ITO (indium tin oxide).
35. The semiconductor light-emitting device according to claim 27 , wherein:
the current spreading layer comprises a thickness in a range of ±30% of d calculated by: d=A×λ P /(4×n) where A is a constant of 1 or 3, λ P is an emission wavelength (nm) and n is a refractive index.
36. The semiconductor light-emitting device according to claim 27 , wherein:
the contact layer comprises Zn as a dopant thereof,
the contact layer comprises a carrier concentration of 1×10 19 /cm 3 or more, and
the contact layer comprises Al X Ga 1-X As where 0≦X≦0.4.
37. The semiconductor light-emitting device according to claim 27 , wherein:
the p-type clad layer comprises Mg as a dopant thereof, and
the n-type clad layer, the active layer and the p-type clad layer comprise (Al X Ga 1-X ) Y In 1-Y P where 0≦X≦1 and 0.4≦Y≦0.6.
38. The semiconductor light-emitting device according to claim 27 , further comprising:
a light reflecting layer formed between the semiconductor substrate and the n-type clad layer,
wherein the light reflecting layer comprises a semiconductor multilayer comprising 10 pairs or more of two semiconductor layers that are different in refractive index.
39. The semiconductor light-emitting device according to claim 27 , wherein:
the current spreading layer comprises a carrier concentration of 8×10 20 /cm 3 or more.
40. The semiconductor light-emitting device according to claim 27 , wherein:
the active layer comprises a multiquantum well structure or strained multiquantum well structure.
41. The semiconductor light-emitting device according to claim 27 , wherein:
the p-type clad layer and the buffer layer comprise a summed thickness of 1000 nm or more and 3000 nm or less, and
the p-type clad layer comprises a thickness of 200 nm or more and 1000 nm or less.
42. The semiconductor light-emitting device according to claim 27 , wherein:
the contact layer comprises a thickness of 1 nm or more and 30 nm or less.
43. The semiconductor light-emitting device according to claim 27 , wherein:
the buffer layer comprises an AlInP or AlGaInP that is optically transparent to an emission wavelength.
44. The semiconductor light-emitting device according to claim 38 , wherein:
the light reflecting layer comprises a combination of (Al X Ga 1-X ) Y In 1-Y P where 0≦X≦1 and 0≦Y≦0.6 and Al X Ga 1-X As where 0≦X≦1.
45. The semiconductor light-emitting device according to claim 27 , further comprising:
a p-type low-doped layer formed between the active layer and the p-type clad layer,
wherein the p-type low-doped layer comprises a semiconductor comprising a p-type conductivity-determining impurity with a lower concentration than the p-type clad layer.
46. The semiconductor light-emitting device according to claim 30 , wherein:
the undoped layer comprises a thickness of 100 nm or less.
47. The semiconductor light-emitting device according to claim 32 , wherein:
the undoped layer comprises a thickness of 100 nm or less.
48. The semiconductor light-emitting device according to claim 33 , wherein:
the n-type low-doped layer comprises a thickness of 100 nm or less.
49. The semiconductor light-emitting device according to claim 45 , wherein:
the p-type low-doped layer comprises a thickness of 100 nm or less.
50. The semiconductor light-emitting device according to claim 27 , further comprising:
a n-type buffer layer formed on the semiconductor substrate,
wherein the n-type buffer layer comprises a same material as the semiconductor substrate.
51. The semiconductor light-emitting device according to claim 27 , wherein:
the buffer layer comprises a lattice-mismatching ratio to a semiconductor layer formed thereunder, and
the lattice-mismatching ratio comprises an absolute value of 0.3% or less.
52. The semiconductor light-emitting device according to claim 27 , wherein:
the buffer layer comprises a GaP.