Abstract: The invention provides highly transparent single crystalline AlN layers as device substrates for light emitting diodes in order to improve the output and operational degradation of light emitting devices. The highly transparent single crystalline AlN layers have a refractive index in the a-axis direction in the range of 2.250 to 2.400 and an absorption coefficient less than or equal to 15 cm-1 at a wavelength of 265 nm. The invention also provides a method for growing highly transparent single crystalline AlN layers, the method including the steps of maintaining the amount of Al contained in wall deposits formed in a flow channel of a reactor at a level lower than or equal to 30% of the total amount of aluminum fed into the reactor, and maintaining the wall temperature in the flow channel at less than or equal to 1200° C.

Abstract: An apparatus for manufacturing a group III nitride single crystal including: a reaction vessel including a reaction area, wherein in the reaction area, a group III source gas and a nitrogen source gas are reacted such that a group III nitride crystal is grown on a substrate; a susceptor arranged in the reaction area and supporting the substrate; a group III source gas supply nozzle supplying the group III source gas to the reaction area; and a nitrogen source gas supply nozzle supplying the nitrogen source gas to the reaction area, wherein the nitrogen source gas supply nozzle is configured to supply the nitrogen source gas and at least one halogen-based gas selected from the group consisting of a hydrogen halide gas and a halogen gas to the reaction area.

Abstract: A silicon-doped n-type aluminum nitride monocrystalline substrate wherein, at a photoluminescence measurement at 23° C., a ratio (I1/I2) between the emission spectrum intensity (I1) having a peak within 370 to 390 nm and the emission peak intensity (I2) of the band edge of aluminum nitride is 0.5 or less; a thickness is from 25 to 500 ?m; and a ratio (electron concentration/silicon concentration) between the electron concentration and the silicon concentration at 23° C. is from 0.0005 to 0.001.

Abstract: A vertical nitride semiconductor device includes an n-type aluminum nitride single-crystal substrate having an Si content of 3×1017 to 1×1020 cm?3 and a dislocation density of 106 cm?2 or less. An ohmic electrode layer is formed on an N-polarity side of the n-type aluminum nitride single-crystal substrate.

Abstract: A silicon-doped n-type aluminum nitride monocrystalline substrate wherein, at a photoluminescence measurement at 23° C., a ratio (I1/I2) between the emission spectrum intensity (I1) having a peak within 370 to 390 nm and the emission peak intensity (I2) of the band edge of aluminum nitride is 0.5 or less; a thickness is from 25 to 500 ?m; and a ratio (electron concentration/silicon concentration) between the electron concentration and the silicon concentration at 23° C. is from 0.0005 to 0.001.

Abstract: The method for manufacturing an aluminum-based group III nitride single crystal includes the step of supplying an aluminum halide gas and a nitrogen source gas onto a base substrate, such that a reaction of the aluminum halide gas and the nitrogen source gas is conducted on the base substrate, wherein the reaction of the aluminum halide gas and the nitrogen source gas is conducted under coexistence of a halogen-based gas such that a halogen-based gas ratio (H) represented by the following formula (1) is no less than 0.1 and less than 1.0: H=VH/(VH+VAl)??(1) (In the formula (1), VH represents a supply of the halogen-based gas; and VAl represents a supply of the aluminum halide gas); and a growth rate of the aluminum-based group III nitride single crystal is no less than 10 ?m/h.

Abstract: The present invention relates to a single-crystalline aluminum nitride wherein a carbon concentration is 1×1014 atoms/cm3 or more and less than 3×1017 atoms/cm3, a chlorine concentration is 1×1014 to 1×1017 atoms/cm3, and an absorption coefficient at 265 nm wavelength is 40 cm?1 or less.

Abstract: A vertical nitride semiconductor device includes an n-type aluminum nitride single-crystal substrate having an Si content of 3×1017 to 1×1020 cm?3 and a dislocation density of 106 cm?2 or less. An ohmic electrode layer is formed on an N-polarity side of the n-type aluminum nitride single-crystal substrate.

Abstract: The method for manufacturing an aluminum-based group III nitride single crystal includes the step of supplying an aluminum halide gas and a nitrogen source gas onto a base substrate, such that a reaction of the aluminum halide gas and the nitrogen source gas is conducted on the base substrate, wherein the reaction of the aluminum halide gas and the nitrogen source gas is conducted under coexistence of a halogen-based gas such that a halogen-based gas ratio (H) represented by the following formula (1) is no less than 0.1 and less than 1.0: H=VH/I(VH+VAl)??(1) (In the formula (1), VH represents a supply of the halogen-based gas; and VAl represents a supply of the aluminum halide gas); and a growth rate of the aluminum-based group III nitride single crystal is no less than 10 ?m/h.

Abstract: A production method of aluminum based group III nitride single crystal includes a reaction step, wherein a halogenated gas and an aluminum contact at 300° C. or more to 700° C. or less, producing a mixed gas including an aluminum trihalide gas and an aluminum monohalide gas; a converting step, wherein the aluminum monohalide gas is converted to a solid by setting a temperature of the mixed gas equal to or higher than a temperature to which a solid aluminum trihalide deposit, and lower by 50° C. or more than a temperature to which halogenated gas and aluminum contact in the reaction step; a separation step, wherein the aluminum trihalide gas is removed; and a crystal growth step, wherein the aluminum trihalide gas is used for an aluminum based group III nitride single crystal raw material, keeping its temperature equal to or higher than a temperature of the converting step.

Abstract: The invention provides highly transparent single crystalline AlN layers as device substrates for light emitting diodes in order to improve the output and operational degradation of light emitting devices. The highly transparent single crystalline AlN layers have a refractive index in the a-axis direction in the range of 2.250 to 2.400 and an absorption coefficient less than or equal to 15 cm-1 at a wavelength of 265 nm. The invention also provides a method for growing highly transparent single crystalline A1N layers, the method including the steps of maintaining the amount of Al contained in wall deposits formed in a flow channel of a reactor at a level lower than or equal to 30% of the total amount of aluminum fed into the reactor, and maintaining the wall temperature in the flow channel at less than or equal to 1200° C.

Abstract: There is provided a method capable of obtaining an aluminum-based group III nitride crystal layer having a smooth surface and high crystallinity by employing only HVPE in which inexpensive raw materials can be used to reduce production costs and high-speed film formation is possible without employing MOVPE. To produce a group III nitride crystal by HVPE comprising the step of growing a group III nitride crystal layer by vapor-phase growth on a single crystal substrate by contacting the heated single crystal substrate with a raw material gas containing a group III halide and a compound having a nitrogen atom, the group III nitride crystal is grown by vapor-phase growth on the single crystal substrate heated at a temperature of 1,000° C. or more and less than 1,200° C. to form an intermediate layer and then, a group III nitride crystal is further grown by vapor-phase growth on the intermediate layer on the substrate heated at a temperature of 1,200° C. or higher.

Abstract: The present invention relates to a single-crystalline aluminum nitride wherein a carbon concentration is 1×1014 atoms/cm3 or more and less than 3×1017 atoms/cm3, a chlorine concentration is 1×1014 to 1×1017 atoms/cm3, and an absorption coefficient at 265 nm wavelength is 40 cm?1 or less.

Abstract: A production method of aluminum based group III nitride single crystal includes a reaction step, wherein a halogenated gas and an aluminum contact at 300° C. or more to 700° C. or less, producing a mixed gas including an aluminum trihalide gas and an aluminum monohalide gas; a converting step, wherein the aluminum monohalide gas is converted to a solid by setting a temperature of the mixed gas equal to or higher than a temperature to which a solid aluminum trihalide deposit, and lower by 50° C. or more than a temperature to which halogenated gas and aluminum contact in the reaction step; a separation step, wherein the aluminum trihalide gas is removed; and a crystal growth step, wherein the aluminum trihalide gas is used for an aluminum based group III nitride single crystal raw material, keeping its temperature equal to or higher than a temperature of the converting step.

Abstract: This invention provides a self supporting substrate which consists of a n-type conductive aluminum nitride semiconductor crystal and is useful for manufacturing the vertical conductive type AlN semiconductor device. The n-type conductive aluminum nitride semiconductor crystal, by which the self supporting substrate is made up, contains Si atom at a concentration of 1×1018 to 5×1020 cm?3 is substantially free of halogen atoms and substantially does not absorb the light having the energy of not more than 5.9 eV. The self supporting substrate can be obtained by a method comprising the steps of forming an AlN crystal layer on a single crystal substrate such as a sapphire by the HVPE method, preheating the obtained substrate having the AlN crystal layer to a temperature of 1,200° C. or more, forming a second layer consisting of the n-type conductive aluminum nitride semiconductor crystal is formed on the AlN crystal layer in high rate by the HVPE method and separating the second layer from the obtained laminate.

Abstract: A method of producing a group III nitride such as aluminum nitride, comprising the step of reacting a group III halide gas such as aluminum trichloride gas with a nitrogen source gas such as ammonia gas in a growth chamber to grow a group III nitride on a substrate held in the growth chamber, wherein the method further comprises premixing together the group III halide gas and the nitrogen source gas to obtain a mixed gas and then introducing the mixed gas into the growth chamber without forming a deposit in the mixed gas substantially to be reacted each other. For the growth of a group III nitride such as an aluminum-based group III nitride by HVPE, there are provided a method of producing the group III nitride having as high quality as that obtained by the method of the prior art at a high yield and an apparatus used in the method.

Abstract: The present invention provides a self-supporting substrate obtained by the steps of: forming an Al-based group-III nitride thin-layer having a thickness in the range of 3-200 nm on a base substrate made of a single crystal of an inorganic substance which substantially does not decompose at 800° C. in an inert gas atmosphere and which does produce volatiles by decomposition when contacting with a reducing gas in a temperature range of 800-1600° C., for example sapphire; forming voids along the interface between the base substrate and the Al-based group-III nitride thin-layer of the obtained laminated substrate by thermally treating the laminated substrate in a temperature range of 800-1600° C. in a reducing gas atmosphere containing ammonia gas; forming a group-III nitride single crystal thick-layer on the Al-based group-III nitride thin-layer; and separating these formed layers.

Abstract: The present invention is a method for producing a laminated body, comprising the steps of: (1) preparing a base substrate having a surface formed of a single crystal which is different from the material constituting the Al-based group-III nitride single crystal layer to be formed; (2) forming an Al-based group-III nitride single crystal layer having a thickness of 10 nm to 1.5 ?m on the single crystal surface of the prepared base substrate; (3) forming on the Al-based group-III nitride single crystal layer a non-single crystal layer being 100 times or more thicker than the Al-based group-III nitride single crystal layer without breaking the previously-obtained Al-based group-III nitride single crystal layer; and (4) removing the base substrate.

Abstract: This invention provides a selfsupporting substrate which consists of a n-type conductive aluminum nitride semiconductor crystal and is useful for manufacturing the vertical conductive type AlN semiconductor device. The n-type conductive aluminum nitride semiconductor crystal, by which the selfsupporting substrate is made up, contains Si atom at a concentration of 1×1018 to 5×1020 cm?3, is substantially free from halogen atoms, and substantially does not absorb the light having the energy of not more than 5.9 eV. The selfsupporting substrate can be obtained by a method comprising the steps of forming an AlN crystal layer on a single crystal substrate such as a sapphire by the HVPE method, preheating the obtained substrate having the AlN crystal layer to a temperature of 1,200° C. or more, forming a second layer consisting of the n-type conductive aluminum nitride semiconductor crystal is formed on the AlN crystal layer in high rate by the HVPE method and separating the second layer from the obtained laminate.

Abstract: There is provided a method capable of obtaining an aluminum-based group III nitride crystal layer having a smooth surface and high crystallinity by employing only HVPE in which inexpensive raw materials can be used to reduce production costs and high-speed film formation is possible without employing MOVPE. To produce a group III nitride crystal by HVPE comprising the step of growing a group III nitride crystal layer by vapor-phase growth on a single crystal substrate by contacting the heated single crystal substrate with a raw material gas containing a group III halide and a compound having a nitrogen atom, the group III nitride crystal is grown by vapor-phase growth on the single crystal substrate heated at a temperature of 1,000° C. or more and less than 1,200° C. to form an intermediate layer and then, a group III nitride crystal is further grown by vapor-phase growth on the intermediate layer on the substrate heated at a temperature of 1,200° C. or higher.