N-type group III nitride semiconductor stacked layer structure
An n-type Group III nitride semiconductor stacked layer structure including a first n-type layer which includes a layer containing n-type impurity atoms at a high concentration and a layer containing n-type impurity atoms at a low concentration, a second n-type layer containing n-type impurity atoms at an average concentration smaller than that of the first n-type layer, the second n-type layer neighboring the layer containing n-type impurity atoms at a low concentration in the first n-type layer.
1. An n-type Group III nitride semiconductor stacked layer structure comprising a first n-type layer which includes layers containing n-type impurity atoms at a high concentration and layers containing n-type impurity atoms at a low concentration, and a second n-type layer containing n-type impurity atoms at an average concentration smaller than that of the first n-type layer, wherein the layers containing n-type impurity atoms at a high concentration and the layers containing n-type impurities at a low concentration alternately and periodically exist in the first n-type layer and the second n-type layer neighbors the layer containing n-type impurity atoms at a low concentration in the first n-type layer.
2. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein the second n-type layer has not been doped.
3. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein the second n-type layer forms a layer that is homogeneously doped with n-type impurity atoms.
4. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein the second n-type layer comprises a layer containing n-type impurity atoms at a high concentration and a layer containing n-type impurity atoms at a low concentration.
5. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the layers containing n-type impurity atoms at a high concentration and the layers containing n-type impurities at a low concentration alternately and periodically exist in the second n-type layer.
6. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the layer containing n-type impurity atoms at a high concentration in the second n-type layer has a concentration lower than that of the layer containing n-type impurity atoms at a high concentration in the first n-type layer.
7. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the layer containing n-type impurity atoms at a low concentration in the second n-type layer has a concentration lower than that of the layer containing n-type impurity atoms at a low concentration in the first n-type layer.
8. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein a ratio (thd/tld) of the thickness (thd) of the layer containing n-type impurity atoms at a high concentration to the thickness (tld) of the layer containing n-type impurity atoms at a low concentration in the second n-type layer is smaller than that in the first n-type layer.
9. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the thickness of the layer containing n-type impurity atoms at a high concentration in the second n-type layer is smaller than that in the first n-type layer.
10. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the thickness of the layer containing n-type impurity atoms at a low concentration in the second n-type layer is greater than that in the first n-type layer.
11. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein the layer containing n-type impurity atoms at a high concentration and the layer containing n-type impurity atoms at a low concentration in the second n-type layer have thicknesses which are 0.5 to 500 nm.
12. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein, in the second n-type layer, the thickness of the layer containing n-type impurity atoms at a low concentration is equal to the thickness of the layer containing n-type impurity atoms at a high concentration or is greater than the thickness of the layer containing n-type impurity atoms at a high concentration.
13. An n-type Group III nitride semiconductor stacked layer structure according to claim 5 , wherein, in the second n-type layer, the layer containing n-type impurity atoms at a high concentration and the layer containing n-type impurity atoms at a low concentration have a recurring periodic number of 2 to 20.
14. An n-type Group III nitride semiconductor stacked layer structure according to claim 4 , wherein, in the second n-type layer, the layer containing n-type impurity atoms at a low concentration has not been intentionally doped with n-type impurity atoms.
15. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein the thickness of the second n-type layer is 0.01 to 0.5 μm.
16. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein an average concentration of n-type impurity atoms in the second n-type layer is not larger than 1/2 of an average concentration of n-type impurity atoms in the first n-type layer.
17. An n-type Group III nitride semiconductor stacked layer structure according to claim 1 , wherein the n-type impurity atoms contained in the first n-type layer and/or the second n-type layer are any one kind of, or a combination of two or more kinds of, those selected from the group consisting of silicon (Si), germanium (Ge), sulfur (S), selenium (Se), tin (Sn) and tellurium (Te).
18. An n-type Group III nitride semiconductor stacked layer structure according to claim 17 , wherein the n-type impurity atoms are any one kind of, or a combination of two or more kinds of, those selected from the group consisting of silicon (Si), germanium (Ge) and tin (Sn).
19. A Group III nitride semiconductor light-emitting device having a light-emitting layer comprising a Group III nitride semiconductor on a substrate, and having an n-type Group III nitride semiconductor stacked layer structure, according to claim 1 , between the substrate and the light-emitting layer.
20. A lamp comprising a Group III nitride semiconductor light-emitting device according to claim 19 .
21. A lamp comprising a Group III nitride semiconductor light-emitting device according to claim 19 and a fluorescent material.
22. An electronic device incorporating a lamp according to claim 20 .
23. A machine incorporating an electronic device according to claim 22 .
24. A toy incorporating an electronic device according to claim 22 .