Method for producing nitride semiconductor laminate, silicon semiconductor product, method for inspecting film quality and method for inspecting semiconductor growth device
There is provided a method for producing a nitride semiconductor laminate in which a thin film is homoepitaxially grown on a substrate comprising group III nitride semiconductor crystals, the method including: homoepitaxially growing a thin film on a substrate, using the substrate in which a dislocation density on its main surface is 5×10 6 pieces/cm 2 or less, a concentration of oxygen therein is less than 1×10 17 at·cm −3 , and a concentration of impurities therein other than n-type impurity is less than 1×10 17 at ·cm −3 ; and inspecting a film quality of the thin film formed on the substrate, wherein in the inspection of the film quality, the film quality of the thin film is inspected by detecting a deviation of an amount of reflected light at a predetermined wavenumber determined in a range of 1,600 cm −1 or more and 1,700 cm −1 or less in a reflection spectrum obtained by irradiating the thin film on the substrate with infrared light, from an amount of reflected light at the predetermined wavenumber determined according to a film thickness of the thin film, a carrier concentration of the substrate, and a carrier concentration of the thin film.
1. A method for inspecting a film quality for inspecting a film quality of a thin film in a nitride semiconductor laminate obtained by homoepitaxially growing a thin film on a substrate comprising crystals of a group III nitride semiconductor, which is a method for inspecting a film quality of a thin film by detecting a deviation of an amount of reflected light at a predetermined wavenumber determined in a range of 1,600 cm −1 or more and 1,700 cm −1 or less in a reflection spectrum obtained by irradiating the thin film on the substrate with infrared light,
from an amount of reflected light at the predetermined wavenumber determined according to a film thickness of the thin film, a carrier concentration of the substrate, and a carrier concentration of the thin film, using the substrate in which a dislocation density on its main surface is 5×10 6 pieces/cm 2 or less, a concentration of oxygen therein is less than 1×10 17 at ·cm −3 , and a concentration of impurities therein other than n-type impurity is less than 1×10 17 at ·cm −3 .
2. A nitride semiconductor laminate, comprising:
a substrate comprising group III nitride semiconductor crystals; and
a thin film homoepitaxially grown on the substrate,
wherein a dislocation density on a main surface of the substrate is 5×10 6 pieces/cm 2 or less, a concentration of oxygen in the substrate is less than 1×10 17 at ·cm −3 , and a concentration of impurities other than n-type impurity in the substrate is less than 1×10 17 at ·cm −3 , and
when taking into consideration of a deviation of an amount of reflected light at a predetermined wavenumber in a reflection spectrum obtained by irradiating the thin film on the substrate with infrared light, from an amount of reflected light at the predetermined wavenumber determined according to a film thickness of the thin film, a carrier concentration of the substrate, and a carrier concentration of the thin film, a maximum value of a degree of a deviation in a wavenumber range of 1,600 cm −1 or more and 1,700 cm −1 or less is larger than any of a maximum value of a degree of a deviation in a wavenumber range of 1,500 cm −1 or more and less than 1,600 cm −1 and a maximum value of a degree of a deviation in a wavenumber range of more than 1,700 cm −1 and 1,800 cm −1 or less.
3. The nitride semiconductor laminate according to claim 2 , wherein the maximum value of the degree of the deviation in the wavenumber range of 1,600 cm −1 or more and 1,700 cm −1 or less is 1% or more and 10% or less as a degree of a difference in intensity reflectance.
4. A nitride semiconductor laminate, comprising:
a substrate comprising group 111 nitride semiconductor crystals; and
a thin film homoepitaxially grown on the substrate,
wherein a dislocation density on a main surface of the substrate is 5×10 6 pieces/cm 2 or less, a concentration of oxygen in the substrate is less than 1×10 17 at ·cm −3 , and a concentration of impurities other than n-type impurity in the substrate is less than 1×10 17 at ·cm −3 , and
when taking into consideration of a deviation of an amount of reflected light at a predetermined wavenumber in a reflection spectrum obtained by irradiating the thin film on the substrate with infrared light, from an amount of reflected light at the predetermined wavenumber determined according to a film thickness of the thin film, a carrier concentration of the substrate, and a carrier concentration of the thin film, any of a maximum value of a degree of the deviation in a wavenumber range of 1,600 cm −1 or more and 1,700 cm −1 or less, a maximum value of a degree of a deviation in a wavenumber range of 1,500 cm −1 or more and less than 1,600 cm −1 and a maximum value of a degree of a deviation in a wavenumber range of more than 1,700 cm −1 and 1,800 cm −1 or less, is less than 1% as a degree of a difference in intensity reflectance.
5. The nitride semiconductor laminate according to claim 2 , wherein when the maximum value of the degree of the deviation in the wavenumber range of 1,600 cm −1 or more and 1,700 cm −1 or less is acquired at a plurality of positions on the main surface of the thin film, a maximum value is 1.5 times or less of a minimum value among the plurality of acquired maximum values.
6. The nitride semiconductor laminate according to claim 2 , wherein an absorption coefficient α in a wavelength range of at least 1 μm or more and 3.3 μm or less is approximated by equation (1) by a method of least squares, and
an error of the measured absorption coefficient at a wavelength of 2μ with respect to the absorption coefficient α obtained from the equation (1) is within ±0.1α,
where a wavelength is λ (μm), an absorption coefficient of the substrate at 27° C. is α (cm −1 ), a carrier concentration in the substrate is N e (cm −3 ), and K and a are constants.
7. The nitride semiconductor laminate according to claim 2 , wherein a crystal of the group III nitride semiconductor is a gallium nitride crystal.
8. The nitride semiconductor laminate according to claim 4 , wherein when the maximum value of the degree of the deviation in the wavenumber range of 1,600 cm −1 or more and 1,700 cm −1 or less is acquired at a plurality of positions on the main surface of the thin film, a maximum value is 1.5 times or less of a minimum value among the plurality of acquired maximum values.
9. The nitride semiconductor laminate according to claim 4 , wherein an absorption coefficient α in a wavelength range of at least 1 μm or more and 3.3 μm or less is approximated by equation (1) by a method of least squares, and
an error of the measured absorption coefficient at a wavelength of 2μ with respect to the absorption coefficient α obtained from the equation (1) is within ±0.1α,
where a wavelength is λ (μm), an absorption coefficient of the substrate at 27° C. is α (cm −1 ), a carrier concentration in the substrate is N e (cm −3 ), and K and a are constants.
10. The nitride semiconductor laminate according to claim 4 , wherein a crystal of the group III nitride semiconductor is a gallium nitride crystal.