Method for manufacturing a semiconductor device on GAN substrate having surface bidirectionally inclined toward <1-100> and <11-20> directions relative to {0001} crystal planes
View Patent ↗A semiconductor substrate encompasses a GaN substrate and a single-crystal layer formed of III-V nitride compound semiconductor epitaxially grown on the GaN substrate. The GaN substrate has a surface orientation defined by an absolute value of an off-angle of the surface from {0001} plane towards <1-100> direction lying in a range of 0.12 degree to 0.35 degree and by an absolute value of an off-angle of the surface from {0001} plane towards <11-20> direction lying in a range of 0.00 degree to 0.06 degree.
1. A method for growing a semiconductor substrate, comprising:
preparing a GaN substrate having a surface bidirectionally inclined from a {0001} crystal plane by two specified off-angles with respect to two crystal axis directions, respectively, such that an orientation of the surface is defined by a first absolute value of a first off-angle of the surface from the {0001} crystal plane towards <1-100> direction, the first absolute value is equal to or larger than 0.12 degree and equal to or smaller than 0.35 degree and by a second absolute value of a second off-angle of the surface from the {0001} crystal plane towards <11-20> direction, the second absolute value is larger than 0.00 degree and equal to or smaller than 0.06 degree; and
epitaxially growing a single-crystal layer of III-V nitride compound semiconductor on the surface of the GaN substrate.
2. The method of claim 1 , further comprising:
epitaxially growing a doped layer between the single-crystal layer and the GaN substrate so that the doped layer is doped with impurity atoms to a concentration of at least about 5×10 17 cm −3 and no greater than about 2×10 19 cm −3 .
3. The method of claim 2 , wherein the doped layer has a thickness of at least about 0.3 nm and no greater than about 200 nm.
4. The method of claim 2 , wherein the GaN substrate is an n-type GaN substrate, and the doped layer is doped with n-type impurity atoms as the impurity atoms.
5. The method of claim 1 , wherein the first absolute value lies in a range of 0.12 degree to 0.30 degree.
6. The method of claim 5 , wherein the first absolute value lies in a range of 0.14 degree to 0.28 degree.
7. A method for manufacturing a semiconductor light-emitting device, comprising:
preparing a GaN substrate having a surface bidirectionally inclined from a {0001} crystal plane by two specified off-angles with respect to two crystal axis directions, respectively, such that an orientation of the surface is defined by a first absolute value of a first off-angle of the surface from the {0001} crystal plane towards <1-100> direction, the first absolute value is equal to or larger than 0.12 degree and equal to or smaller than 0.35 degree and by a second absolute value of a second off-angle of the surface from the {0001} crystal plane towards <11-20> direction, the second absolute value is larger than 0.00 degree and equal to or smaller than 0.06 degree;
epitaxially growing a single-crystal layer of III-V nitride compound semiconductor on the surface of the GaN substrate; and
epitaxially growing a light-emitting layer of III-V nitride compound semiconductor on the single-crystal layer.
8. The method of claim 7 , wherein the GaN substrate is an n-type GaN substrate, and the single-crystal layer is an n-type III-V nitride compound semiconductor.
9. The method of claim 8 , further comprising:
epitaxially growing an n-type cladding layer of III-V nitride compound semiconductor between the single-crystal layer and the light-emitting layer; and
epitaxially growing a p-type cladding layer of III-V nitride compound semiconductor on the light-emitting layer.
10. The method of claim 9 , further comprising:
epitaxially growing an n-type light-guiding layer of III-V nitride compound semiconductor between the n-type cladding layer and the light-emitting layer; and
epitaxially growing a p-type light-guiding layer of III-V nitride compound semiconductor between the p-type cladding layer and the light-emitting layer.
11. The method of claim 7 , further comprising:
epitaxially growing a doped layer between the single-crystal layer and the GaN substrate so that the doped layer is doped with impurity atoms to a concentration of at least about 5×10 17 cm −3 and no greater than about 2×10 cm −3 .
12. The method of claim 11 , wherein the doped layer has a thickness of at least about 0.3 nm and no greater than about 200 nm.
13. The method of claim 11 , wherein the GaN substrate is an n-type GaN substrate, and the doped layer is doped with n-type impurity atoms as the impurity atoms.
14. The method of claim 7 , wherein the first absolute value lies in a range of 0.12 degree to 0.30 degree.
15. The method of claim 14 , wherein the first absolute value lies in a range of 0.14 degree to 0.28 degree.
16. A method for manufacturing a semiconductor device, comprising:
preparing a GaN substrate having a surface bidirectionally inclined from a {0001} crystal plane by two specified off-angles with respect to two crystal axis directions, respectively, such that an orientation of the surface is defined by a first absolute value of a first off-angle of the surface from the {0001} crystal plane towards <1-100> direction, the first absolute value is equal to or larger than 0.12 degree and equal to or smaller than 0.35 degree and by a second absolute value of a second off-angle of the surface from the {0001} crystal plane towards <11-20> direction, the second absolute value is larger than 0.00 degree and equal to or smaller than 0.06 degree; and
epitaxially growing a device-structure portion formed of III-V nitride compound semiconductor on the GaN substrate.
17. The method of claim 16 , wherein the device-structure portion comprises a light-emitting layer.
18. The method of claim 16 , wherein the GaN substrate is an n-type GaN substrate, and the epitaxially growing the device-structure portion comprises:
epitaxially growing an n-type drift layer of III-V nitride compound semiconductor on the n-type GaN substrate;
epitaxially growing a p-type base layer of III-V nitride compound semiconductor on the n-type drift layer; and
epitaxially growing an n-type emitter layer of III-V nitride compound semiconductor on the p-type base layer.
19. The method of claim 18 , wherein the n-type emitter layer has wider bandgap than the p-type base layer.
20. The method of claim 16 , wherein the epitaxially growing the device-structure portion comprises:
epitaxially growing a first single-crystal layer of III-V nitride compound semiconductor on the GaN substrate; and
epitaxially growing a second single-crystal layer of III-V nitride compound semiconductor on the first single-crystal layer, having wider bandgap than the first single-crystal layer.
21. The method of claim 16 , further comprising:
epitaxially growing a doped layer between the device-structure portion and the GaN substrate so that the doped layer is doped with impurity atoms to a concentration of at least about 5×10 17 cm −3 and no greater than about 2×10 19 cm −3 .
22. The method of claim 21 , wherein the doped layer has a thickness of at least about 0.3 nm and no greater than about 200 nm.