Semiconductor light-emitting diode
A semiconductor light-emitting diode 20 is provided with a silicon single crystal substrate 201 , an intervening layer 203 formed of a Group III nitride semiconductor and stacked on the silicon single crystal substrate 201 , and a light-emitting part ( 205, 206, 207 ) formed with a p-n-junction hetero-junction structure and stacked on the intervening layer 203 . The intervening layer 203 is formed of an aluminum-containing Group III nitride semiconductor. The intervening layer 203 and the light-emitting part ( 205, 206, 207 ) have interposed therebetween a superlattice structure 204 formed of a plurality of Group III nitride semiconductor layers that contain aluminum and have mutually different aluminum composition ratios. A DBR film formed of the superlattice structure 204 is enabled to excel in reflectance and enhance the light-emitting property.
1. A semiconductor light-emitting diode comprising:
a silicon single crystal substrate,
an intervening layer formed of an aluminum-containing Group III nitride semiconductor and stacked on the silicon single crystal substrate,
a light-emitting part formed with a p-n junction hetero junction structure and stacked on the intervening layer,
a superlattice structure interposed between the intervening layer and the light-emitting part and formed of a plurality of Group III nitride semiconductor layers that contain aluminum and have mutually different composition ratios of aluminum, and
an intermediate layer formed of an aluminum-containing Group III nitride semiconductor and interposed between the intervening layer and the superlattice structure,
wherein the intervening layer possesses an aluminum composition ratio of X 1 (0<X 1 ≦1),
the plurality of Group III nitride semiconductor layers of the superlattice structure possess aluminum composition ratios of X 2 and X 3 not exceeding X 1 and mutually differing to satisfy (0<X 2 <X 3 ≦X 1 ), and
the intermediate layer possesses an aluminum composition ratio of X 4 that is greater than X 2 and equal to or smaller than X 3 (0<X 2 <X 4 ≦X 3 ).
2. A semiconductor light-emitting diode according to claim 1 , wherein each of the intervening layer, and the plurality of Group III nitride semiconductor layers of the superlattice structure is formed of aluminum-gallium nitride.
3. A semiconductor light-emitting diode according to claim 2 , further comprising a gamma (γ) phase aluminum film interposed between the silicon single crystal substrate and the intervening layer.
4. A semiconductor light-emitting diode according to claim 1 , further comprising a gamma (γ) phase aluminum film interposed between the silicon single crystal substrate and the intervening layer.
5. A semiconductor light-emitting diode according to claim 1 , wherein each of the intervening layer, the plurality of Group III nitride semiconductor layers of the superlattice structure, and the intermediate layer is formed of aluminum-gallium nitride.
6. A semiconductor light-emitting diode according to claim 1 , wherein a thickness of a semiconductor layer of the plurality of semiconductor layers having an Al composition ratio X 3 is greater than a thickness of a semiconductor layer of the plurality of semiconductor layers having an Al composition ratio X 2 .