Group III nitride compound semiconductor stacked structure
An object of the present invention is to obtain a group III nitride compound semiconductor stacked structure where a group III nitride compound semiconductor layer having good crystallinity is stably stacked on a dissimilar substrate. The group III nitride compound semiconductor stacked structure of the present invention is a group III nitride compound semiconductor stacked structure comprising a substrate having provided thereon a first layer comprising a group III nitride compound semiconductor and a second layer being in contact with the first layer and comprising a group III nitride compound semiconductor, wherein the first layer contains a columnar crystal with a definite crystal interface and the columnar crystal density is from 1×10 3 to 1×10 5 crystals/μm 2 .
1. A group III nitride compound semiconductor stacked structure comprising a substrate having provided thereon a first layer comprising a group III nitride compound semiconductor and a second layer being in contact with the first layer and comprising a group III nitride compound semiconductor, wherein the first layer contains a columnar crystal with a definite crystal interface, which is a crystal grain having a distinct crystal interface and showing a hexagon-based cross-sectional shape in plan view, and the columnar crystal density is from 1×10 3 to 1×10 5 crystals/μm 2 .
2. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the first layer covers at least 90% of the substrate surface.
3. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the width of the columnar crystal with a definite crystal interface is from 1 to 50 nm.
4. The group III nitride compound semiconductor stacked structure according to claim 3 , wherein the width of the columnar crystal with a definite crystal interface is from 2 to 30 nm.
5. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the thickness of the first layer is from 10 to 500 nm.
6. The group III nitride compound semiconductor stacked structure according to claim 5 , wherein the thickness of the first layer is from 20 to 100 nm.
7. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the first layer is an Al-containing group III nitride compound semiconductor.
8. The group III nitride compound semiconductor stacked structure according to claim 7 , wherein the first layer comprises AlN.
9. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the second layer is AlGaN.
10. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the second layer is GaN.
11. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the group III nitride compound semiconductor forming the first layer and the group III nitride compound semiconductor forming the second layer are different materials.
12. The group III nitride compound semiconductor stacked structure according to claim 11 , wherein the first layer is AlN and the second layer is GaN.
13. The group III nitride compound semiconductor stacked structure according to claim 1 , wherein the substrate is composed of a material selected from the group consisting of sapphire, SiC, silicon, zinc oxide, magnesium oxide, manganese oxide, zirconium oxide, manganese zinc iron oxide, magnesium aluminum oxide, zirconium boride, gallium oxide, indium oxide, lithium gallium oxide, lithium aluminum oxide, neodymium gallium oxide, lanthanum strontium aluminum tantalum oxide, strontium titanium oxide, titanium oxide, hafnium, tungsten and molybdenum.
14. A group III nitride compound semiconductor light-emitting device comprising the group III nitride compound semiconductor stacked structure according to claim 1 .
15. A lamp comprising the group III nitride compound semiconductor light-emitting device according to claim 14 .
16. A method for producing a group III nitride compound semiconductor stacked structure, said stacked structure comprising a substrate having provided thereon a first layer comprising a group III nitride compound semiconductor and a second layer being in contact with the first layer and comprising a group III nitride compound semiconductor, wherein the first layer contains a columnar crystal with a definite crystal interface, which is a crystal grain having a distant crystal interface and showing a hexagon-based cross-sectional shape in plan view, and the columnar crystal density is from 1×10 3 to 1×10 5 crystals/μm 2 , said method comprising growing, on a substrate, a first layer comprising a columnar crystal of group III nitride compound semiconductor by activating a group III metal raw material and a nitrogen element-containing gas with a plasma to cause a reaction therebetween, and then growing a second layer being in contact with the first layer and comprising a group III nitride compound semiconductor.
17. The method for producing a group III nitride compound semiconductor stacked structure according to claim 16 , wherein the growth method of the second layer is MOCVD.
18. The method for producing a group III nitride compound semiconductor stacked structure according to claim 16 , wherein the growth method of the second layer is reactive sputtering.
19. The method for producing a group III nitride compound semiconductor stacked structure according to claim 16 , wherein the substrate temperature at the growth of the second layer is 900° C. or more.
20. The method for producing a group III nitride compound semiconductor stacked structure according to claim 16 , wherein the growth method of the first layer is at least one member selected from the group consisting of sputtering, PLD, PED and CVD.
21. The method for producing a group III nitride compound semiconductor stacked structure according to claim 20 , wherein the growth method of the first layer is sputtering.
22. The method for producing a group III nitride compound semiconductor stacked structure according to claim 21 , wherein the growth method of the first layer is reactive sputtering performed while flowing a nitrogen source in the reactor.
23. The method for producing a group III nitride compound semiconductor stacked structure according to claim 22 , wherein the growth method of the first layer is sputtering utilizing ammonia as the nitrogen source.
24. The method for producing a group III nitride compound semiconductor stacked structure according to claim 22 , wherein the growth method of the first layer is sputtering utilizing a nitrogen gas as the nitrogen source.
25. The method for producing a group III nitride compound semiconductor stacked structure according to claim 21 , wherein the growth method of the first layer is RF sputtering.
26. The method for producing a group III nitride compound semiconductor stacked structure according to claim 25 , wherein the growth method of the first layer is RF sputtering performed while moving the position of the magnet in the cathode.
27. The method for producing a group III nitride compound semiconductor stacked structure according to claim 21 , wherein the substrate temperature at the growth of the first layer is from 400 to 800° C.