A method and apparatus for producing AlN whiskers includes reduced incorporation of metal particles, an AlN whisker body, AlN whiskers, a resin molded body, and a method for producing the resin molded body. The method for producing AlN whiskers includes heating an Al-containing material in a material accommodation unit to thereby generate Al gas; and introducing the Al gas into a reaction chamber through a communication portion while introducing nitrogen gas into the reaction chamber through a gas inlet port, to thereby grow AlN whiskers on the surface of an Al.sub.2O.sub.3 substrate placed in the reaction chamber.

A method and apparatus for producing AlN whiskers includes reduced incorporation of metal particles, an AlN whisker body, AlN whiskers, a resin molded body, and a method for producing the resin molded body. The method for producing AlN whiskers includes heating an Al-containing material in a material accommodation unit to thereby generate Al gas; and introducing the Al gas into a reaction chamber through a communication portion while introducing nitrogen gas into the reaction chamber through a gas inlet port, to thereby grow AlN whiskers on the surface of an Al.sub.2O.sub.3 substrate placed in the reaction chamber.

A boron nitride layer and a method of fabricating the same are provided. The boron nitride layer includes a boron nitride compound and has a dielectric constant of about 2.5 or less at an operating frequency of 100 kHz.

A boron nitride layer and a method of fabricating the same are provided. The boron nitride layer includes a boron nitride compound and has a dielectric constant of about 2.5 or less at an operating frequency of 100 kHz.

There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient α is approximately expressed by equation (1) in a wavelength range of at least 1 μm or more and 3.3 μm or less: α=n Kλ.sup.a (1) (wherein, λ(μm) is a wavelength, α(cm.sup.−1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm.sup.−3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.5×10.sup.−19≤K≤6.0×10.sup.−19, a=3).

There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient α is approximately expressed by equation (1) in a wavelength range of at least 1 μm or more and 3.3 μm or less: α=n Kλ.sup.a (1) (wherein, λ(μm) is a wavelength, α(cm.sup.−1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm.sup.−3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.5×10.sup.−19≤K≤6.0×10.sup.−19, a=3).

A sputtering target for a gallium nitride thin film, which has a low oxygen content, a high density and a low resistivity. A gallium nitride powder having powder physical properties of a low oxygen content and a high bulk density is used and hot pressing is conducted at high temperature in high vacuum to prepare a gallium nitride sintered body having a low oxygen content, a high density and a low resistivity.

A sputtering target for a gallium nitride thin film, which has a low oxygen content, a high density and a low resistivity. A gallium nitride powder having powder physical properties of a low oxygen content and a high bulk density is used and hot pressing is conducted at high temperature in high vacuum to prepare a gallium nitride sintered body having a low oxygen content, a high density and a low resistivity.

A substrate 10 contains a first layer L1 and a second layer L2 that are stacked on one another, the first layer L1 contains crystalline AlN and an additive element, the second layer L2 contains crystalline α-alumina, the additive element is at least one selected from the group consisting of rare earth elements, alkaline earth elements, and alkali metal elements, the thickness of the first layer L1 is 5 to 600 nm, RC(002) is a rocking curve of diffracted X-rays originating from a (002) plane of AlN, RC(002) is measured by an ω-scan of the surface S.sub.L1 of the first layer L1, the half width of RC(002) is 0° to 0.4°, RC(100) is a rocking curve of diffracted X-rays originating from a (100) plane of AlN, RC(100) is measured by a ϕ-scan of the surface S.sub.L1 of the first layer L1, and the half width of RC(100) is 0° to 0.8°.

There is provided a nitride crystal substrate having a main surface and formed of group-III nitride crystal, wherein N.sub.IR/N.sub.Elec, satisfies formula (1) below, which is a ratio of a carrier concentration N.sub.IR at a center of the main surface relative to a carrier concentration N.sub.Elec: 0.5≤N.sub.IR/N.sub.Elec≤1.5 . . . (1) where N.sub.IR is the carrier concentration on the main surface side of the nitride crystal substrate obtained based on a reflectance of the main surface measured by a reflection type Fourier transform infrared spectroscopy, and N.sub.Elec is the carrier concentration in the nitride crystal substrate obtained based on a specific resistance of the nitride crystal substrate and a mobility of the nitride crystal substrate measured by an eddy current method.