Method for fabricating semiconductor device
First Claim
1. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
- (a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer below the second semiconductor layer and the step (b) includes irradiating the first semiconductor layer with the light beam through a back surface of the single-crystal substrate, wherein the step (b) includes performing a first-stage treatment for activating the p-type impurity in the first semiconductor layer and performing a second-stage treatment for varying a power density or energy of the light beam to separate the first semiconductor layer and the single-crystal substrate from each other.
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Accused Products
Abstract
A p-type InGaAlN layer, an InGaAlN active layer, and an n-type InGaAlN layer each having a composition represented by (AlxGa1-x)yIn1-yN (0≦x≦1, 0≦y≦1) are formed on a sapphire substrate. In the as-grown state, Mg is bonded to hydrogen atoms in the p-type InGaAlN layer. Then, the back surface of the sapphire substrate is irradiated with a laser beam in a nitrogen atmosphere. The resistance of the p-type InGaAlN layer is reduced by removing hydrogen therefrom with irradiation with a weak laser beam. During the irradiation with the laser beam, the diffusion of a dopant in a multilayer portion is suppressed such that a dopant profile retains sharpness. It is also possible to separate the sapphire substrate from the multilayer portion by subsequently using an intense laser beam for irradiation.
14 Citations
23 Claims
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1. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer below the second semiconductor layer and the step (b) includes irradiating the first semiconductor layer with the light beam through a back surface of the single-crystal substrate, wherein the step (b) includes performing a first-stage treatment for activating the p-type impurity in the first semiconductor layer and performing a second-stage treatment for varying a power density or energy of the light beam to separate the first semiconductor layer and the single-crystal substrate from each other. - View Dependent Claims (2)
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3. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer below the second semiconductor layer and the step (b) includes irradiating the first semiconductor layer with the light beam through a back surface of the single-crystal substrate, wherein the step (b) includes decomposing or denaturing the first semiconductor layer to form a conductor layer, the method further comprising, after the step (b), the step of;
forming an ohmic electrode composed of a conductor material on the conductor layer. - View Dependent Claims (4)
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5. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer below the second semiconductor layer and the step (b) includes irradiating the first semiconductor layer with the light beam through a back surface of the single-crystal substrate, said method further comprising, prior to the step (a), the step of;
forming, on the single-crystal substrate, a spacer layer having an optical band gap smaller than an optical band gap of the single-crystal substrate, wherein the step (a) includes forming the multilayer film on the spacer layer and the step (b) includes activating the p-type impurity in the first semiconductor layer and separating the spacer layer and the single-crystal substrate from each other.
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6. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer above the second semiconductor layer and the step (b) includes irradiating the first semiconductor layer with the light beam from above the first semiconductor layer. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the multilayer portion such that it further has an n-type third semiconductor layer opposing the second semiconductor layer with the first semiconductor layer interposed therebetween and having an optical band gap different from an optical band gap of the first semiconductor layer. - View Dependent Claims (14, 15, 16)
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17. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (b) is performed in an inert gas atmosphere or in an atmosphere under a reduced pressure.
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18. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the light beam used in activating the p-type impurity in the first semiconductor layer has an energy smaller than an optical band gap of the second semiconductor layer.
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19. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the single-crystal substrate is heated during the irradiation with the light beam, wherein a heating temperature in heating the single-crystal substrate is in the range of 400°
C. to 750°
C.
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20. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multi layer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the irradiation with the light beam is performed such that a luminous flux scans an entire surface of the single-crystal substrate.
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21. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes using Mg or Be as a dopant in forming the first semiconductor layer.
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22. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein the step (a) includes forming the first semiconductor layer in an atmosphere containing hydrogen.
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23. A method for fabricating a semiconductor device having a semiconductor layer formed by epitaxial growth from a single-crystal substrate, the method comprising the steps of:
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(a) forming a multilayer film having at least a first semiconductor layer composed of a group III-V compound doped with a p-type impurity and containing nitrogen and an n-type second semiconductor layer composed of a group III-V compound doped with an n-type impurity and containing nitrogen such that the single-crystal substrate is covered with the multilayer film; and
(b) irradiating the first semiconductor layer with a light beam to activate the p-type impurity in the first semiconductor layer, wherein a substrate selected from a sapphire substrate, an SiC substrate, an MgO substrate, an LiGaO2 substrate, an LiGaxAl1-xO2 (0≦
x≦
1) mixed crystal substrate, and an LiAlO2 substrate is used as the single-crystal substrate.
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Specification