Light-emitting device
A light-emitting device includes a first nitride semiconductor structure; a stress relief structure on the first nitride semiconductor structure including a plurality of narrow band gap layers and a plurality of wide band gap layers alternately stacked, wherein one of the plurality of wide band gap layers includes a plurality of wide band gap sub-layers and one of the plurality of wide band gap sub-layers includes aluminum; an active structure on the stress relief structure including a plurality of quantum well layers and a plurality of barrier layers alternately stacked, wherein one of the plurality of barrier layers includes a plurality of barrier sub-layers and one of the plurality of barrier sub-layers includes aluminum, an aluminum composition of the wide band gap sub-layer is greater than or equal to that of the barrier sub-layer, and an average aluminum composition of the wide band gap layer is greater than that of the barrier layer; and an electron blocking structure on the active structure.
1 . A semiconductor device, comprising:
a n-type nitride semiconductor structure;
a stress relief structure on the n-type nitride semiconductor structure comprising a plurality of narrow band gap layers and a plurality of wide band gap layers alternately stacked, wherein one of the plurality of wide band gap layers comprises a first wide band gap sub-layer and a second wide band sub-layer;
an active structure on the stress relief structure and comprising a plurality of quantum well layers and a plurality of barrier layers alternately stacked, wherein one of the plurality of barrier layers comprises a first barrier sub-layer and a second barrier sub-layer;
an electron blocking structure on the active structure; and
a p-type nitride semiconductor structure on the electron blocking structure;
wherein the first wide band gap sub-layer has a first band gap, the second wide band gap sub-layer has a second band gap, one of the plurality of narrow band gap layers has a third band gap, the first barrier sub-layer has a fourth band gap, and the first band gap is greater than the fourth band gap; and
wherein both of the first band gap and the second band gap are greater than the third band gap.
2 . The semiconductor device according to claim 1 , wherein the first wide band gap sub-layer or the second wide band gap sub-layer comprises Al x Ga (1-x) N, where 0<x<1.
3 . The semiconductor device according to claim 2 , wherein the first wide band gap sub-layer comprises GaN, and the second wide band gap sub-layer comprises Al x Ga (1-x) N, where 0<x<1.
4 . The semiconductor device according to claim 3 , wherein x≤0.05.
5 . The semiconductor device according to claim 3 , wherein the first wide band gap sub-layer or the second wide band gap sub-layer directly contacts the one of the plurality of narrow band gap sub-layers.
6 . The semiconductor device according to claim 1 , wherein the second barrier sub-layer comprises a fifth band gap, both of the fourth band gap and the fifth band gap are greater than a band gap of one of the plurality of quantum well layers.
7 . The semiconductor device according to claim 6 , wherein the fourth band gap is greater than the fifth band gap.
8 . The semiconductor device according to claim 1 , wherein the second barrier sub-layer comprises GaN, and the first barrier sub-layer comprises Al s8 Ga (1-s8) N, where 0<s8<1.
9 . The semiconductor device according to claim 7 , wherein the one of the plurality of barrier layers further comprises a third barrier sub-layer, the third barrier sub-layer comprises GaN.
10 . The semiconductor device according to claim 9 , wherein the first barrier sub-layer is between the second barrier sub-layer and the third barrier sub-layer.
11 . The semiconductor device according to claim 1 , wherein the first wide band gap sub-layer comprises a first thickness, the first barrier sub-layer comprises a second thickness, and a first thickness ratio defined by the first thickness to a thickness of the one of the plurality of wide band gap layers is greater than a second thickness ratio defined by the second thickness to another thickness of one of the plurality of barrier layers.
12 . The semiconductor device according to claim 1 , wherein the one of the plurality of narrow band gap layers comprises In t5 Ga (1-t5) N, where 0<t5≤0.1, and one of the plurality of quantuell layers comprises In t7 Ga (1-17) N, where 0.1<t7<0.15.
13 . The semiconductor device according to claim 1 , wherein the one of the plurality of barrier layers further comprises a capping layer directly contacting one of the plurality of quantum well layers.
14 . The semiconductor device according to claim 13 , wherein the capping layer comprises GaN.
15 . The semiconductor device according to claim 1 , wherein the first wide band gap sub-layer comprises a first aluminum composition, the second wide band gap sub-layer comprises a second aluminum composition, the first barrier sub-layer comprises a third aluminum composition, the second barrier sub-layer comprises a fourth aluminum composition, and one of the first aluminum composition and the second aluminum composition is greater than one of the third aluminum composition and the fourth aluminum composition.
16 . The semiconductor device according to claim 1 , wherein the first wide band gap sub-layer comprises a first thickness, the second wide band gap sub-layer comprises a second thickness, the one of the plurality of wide band gap layers comprises a third wide band gap sub- layer comprising a third thickness, a sum of thickness of the first thickness and the second thickness is greater than the third thickness.
17 . The semiconductor device according to claim 1 , wherein the one of the plurality of wide band gap layers comprises a first average aluminum composition, the one of the plurality of barrier layers comprises a second average aluminum composition, and the first average aluminum composition is greater than the second average aluminum composition.
18 . The semiconductor device according to claim 17 , wherein the electron blocking structure comprises a third average aluminum composition, and the third average aluminum composition is greater than the first average aluminum composition.
19 . The semiconductor device according to claim 1 , wherein the plurality of barrier layers further comprises a final barrier layer closest to the electron blocking structure, and the final barrier layer comprises Al s9 In 9 Ga (1-19) N, where 0<s9<1, 0<t9<1.
20 . The semiconductor device according to claim 1 , wherein 0.002<t9<0.02.