HK1099054A - Nitride crystal, nitride crystal substrate, epilayer-containing nitride crystal substrate, semiconductor device and method of manufacturing the same - Google Patents

Description

Nitride crystal, nitride crystal substrate containing epitaxial layer, semiconductor device, and method for manufacturing the same

Technical Field

The present invention relates to a nitride crystal, a nitride crystal substrate containing an epitaxial layer, a semiconductor device, and methods for producing the same, and particularly to a nitride crystal that can be preferably used as a substrate for growing an epitaxial crystal when producing a semiconductor device.

Background

As is well known, various devices using nitride semiconductor crystals have been produced in recent years, and as a typical example of these semiconductor devices, nitride semiconductor light emitting devices have been produced.

Generally, in a process of manufacturing a nitride semiconductor device, a plurality of nitride semiconductor layers are epitaxially grown on a substrate. The crystal quality of the epitaxially grown nitride semiconductor layer is affected by the state of the surface layer of the substrate for epitaxial growth, and this quality affects the performance of the semiconductor device including the nitride semiconductor layer. Therefore, in the case where a nitride semiconductor crystal is used as the substrate of the above-described kind, it is desirable that at least one main surface of the substrate providing the base for epitaxial growth has a smooth form without distortion.

More specifically, the main surface of the nitride semiconductor substrate for epitaxial growth is generally subjected to smoothing treatment and distortion removal treatment. Among various compound semiconductors, a gallium-nitride-based semiconductor is relatively hard, and therefore, the surface smoothing treatment thereof is not easy, and the distortion removal treatment after the smoothing treatment is not easy.

Japanese patent laid-open No. 2004-311575 discloses a polishing method for polishing the surface of a gallium nitride substrate using soft particles and hard particles as polishing compounds. U.S. Pat. No. 6,596,079 discloses a method of forming a substrate surface in which a substrate is produced from an (algainn) N bulk (bulk) crystal grown on an (algainn) N seed crystal by vapor phase epitaxy, more specifically a method of forming a substrate surface having an RMS (root mean square) surface roughness of 1nm or less and having no surface damage due to CMP (chemical-mechanical polishing) or etching performed on the substrate surface subjected to mechanical polishing. U.S. patent specification No. 6,488,767 discloses Al having an RMS surface roughness of 0.15nm obtained by CMP treatment_xGa_yIn_zAnd N (0 < y ≦ 1, and x + y + z ═ 1) substrate. The treating agent for the CMP contains Al₂O₃Particles of SiO₂Particles, a pH control agent and an oxidizing agent. According to japanese patent laid-open No. 2001-322899, the processing-affected layer is removed by dry etching to finish (finish) the substrate surface after the GaN substrate is polished.

As described above, in the related art, CMP treatment or dry etching is performed after mechanically polishing a GaN crystal, so as to remove a processing-affected layer formed by mechanical polishing and form a GaN substrate having a finished substrate surface. However, the process rate of the CMP process is low, and causes problems in cost and productivity. In addition, dry etching causes a problem of surface roughness.

The finishing method of a Si substrate using CMP and the polishing agent used for the method are not suitable for a hard nitride semiconductor substrate, and the removal rate of the surface layer is reduced. In particular, GaN is chemically suitable and relatively resistant to wet etching, and thus CMP processing is not easy. Although the dry etching can remove the nitride semiconductor surface, it has no leveling effect on the surface in the horizontal direction, and therefore the surface smoothing effect cannot be achieved.

In order to epitaxially grow a compound semiconductor layer having good crystal quality on the substrate surface, it is necessary to use a substrate surface having good crystal quality and less processing damage and less distortion as described above. However, the crystal quality of the surface layer required on the substrate surface is unclear.

In The prior art, distortion of The crystal surface layer is evaluated by cleaving The crystal and observing The cleaved plane with TEM (Transmission Electron microscope), as disclosed, for example, in S.S. park et al, "Free-Standing GaN microstructure by Hydride Vapor Phase epitope", Jpn, J.appl.Phys., The Japan Society of Applied Physics, volume 39, year 2000, month 11, pages L1141-L1142 and Yuttaka TAKAHAHI et al, "Transmission Electron microscope of surface Damage purification of filtration from thin polarization in a Polycrystalline nitride microstructure, The Academic Journal of The Ceramic Society of Japan, ceramics of Japan, Journal of The TEM microstructure of Japan, 19999, page 619 [ 1991 ], 1997 ]. Therefore, the distortion on the crystal surface layer is conventionally evaluated by a damage test for damaging the crystal, and therefore, problems arise in that correction cannot be performed even if the evaluation result is insufficient after the evaluation, and evaluation cannot be performed for the product itself. In the existing case, there is no index for nondestructively evaluating the crystallinity of the surface layer of the finished substrate surface, and therefore it is difficult to quantitatively determine the crystal quality of the surface layer.

Disclosure of Invention

An object of the present invention is to provide a nitride crystal, a nitride crystal substrate having a crystal surface layer which is evaluated directly and reliably without damaging the crystal, and which can therefore be used in a preferred manner as a substrate for epitaxial crystal growth in the production of semiconductor devices, and a nitride crystal substrate containing an epitaxial layer, a semiconductor device and a method for producing the same.

According to one aspect of the present invention, a nitride crystal is characterized by an interplanar spacing of any particular parallel lattice plane of the nitride crystal as defined by | d₁-d₂|/d₂The value of (A) represents a uniform distortion on the surface layer of the crystal equal to or lower than 2.1X 10^-3Wherein the plane spacing is obtained by X-ray diffraction measurement by changing the penetration depth of X-rays from the crystal surface while satisfying the X-ray diffraction condition of the specific parallel lattice plane, from the plane spacing d at the X-ray penetration depth of 0.3 μm₁And an in-plane distance d at an X-ray penetration depth of 5 μm₂Obtaining the | d₁-d₂|/d₂The value of (c).

According to another aspect of the present invention, a nitride crystal is characterized by having a diffraction intensity distribution diagram of | v |, on any specific parallel lattice plane of the nitride crystal₁-v₂An irregular distortion on a surface layer of the crystal represented by a value of | is equal to or lower than 150arcsec, wherein the diffraction intensity profile is obtained by X-ray diffraction measurement by varying a penetration depth of X-ray diffraction from a surface of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane, from a half-value width v of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of | is given.

According to the inventionIn still another aspect, a nitride crystal is characterized by | w on a rocking curve measured by varying a penetration depth of X-rays from a surface of the crystal with respect to X-ray diffraction of any specific parallel lattice plane of the nitride crystal₁-w₂A deviation in plane orientation of the specific parallel lattice plane expressed by a value of | is equal to or lower than 400arcsec where a half-value width w of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of | is given.

Preferably, the surface of the nitride crystal has a surface roughness Ry of 30nm or less. It is also preferable that the surface of the nitride crystal has a surface roughness Ry of 3nm or less.

Preferably, the surface of the nitride crystal is parallel to the C-plane of the wurtzite-type structure. It is also preferable that the surface of the nitride crystal has an off-angle of 0.05 ° to 15 ° with respect to the C-plane of the wurtzite-type structure.

A nitride crystal substrate formed of the above nitride crystal is preferable as a substrate of a semiconductor device. A nitride crystal substrate containing an epitaxial layer, which includes one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate, is also preferable as a substrate of a semiconductor device. The epitaxial layer is one or more semiconductor layers formed by epitaxial growth on at least one main surface side of the nitride crystal substrate.

According to still another aspect of the present invention, a semiconductor device is a nitride crystal substrate including the above nitride crystal substrate as a substrate, or a nitride crystal substrate containing an epitaxial layer. The semiconductor device of this aspect includes one or more semiconductor layers formed by epitaxial growth on at least one major surface side of the substrate.

According to still another aspect of the present invention, a semiconductor device is a nitride crystal substrate including the above nitride crystal substrate as a substrate, or a nitride crystal substrate containing an epitaxial layer. The semiconductor device of this aspect includes a light emitting element including three or more semiconductor layers formed by epitaxial growth on one of the main surface sides of the substrate, a first electrode formed on the other main surface side of the nitride crystal substrate or the nitride crystal substrate containing an epitaxial layer, and a second electrode formed over the outermost semiconductor layer among the plurality of semiconductor layers, and further includes a conductor carrying the light emitting element. In addition, the semiconductor device of this aspect is configured such that the substrate side of the light emitting element is a light emitting side, the outermost semiconductor layer side is a mount (mount) side, and the plurality of semiconductor layers include a p-type semiconductor layer, an n-type semiconductor layer, and a light emitting layer formed between these conductive semiconductor layers.

According to another aspect of the present invention, a method of manufacturing a semiconductor device is a method of manufacturing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer as a substrate, the nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method selects a nitride crystal as the nitride crystal substrate, the nitride crystal being configured such that: the interplanar spacing of any particular parallel lattice plane of the crystal is defined by | d₁-d₂|/d₂The value of (A) represents a uniform distortion on the surface layer of the crystal equal to or lower than 2.1X 10^-3Wherein the plane spacing is obtained by performing X-ray diffraction measurement by varying a penetration depth of X-rays from a surface of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane, from the plane spacing d at the X-ray penetration depth of 0.3 μm₁And said interplanar spacing d at an X-ray penetration depth of 5 μm₂Obtaining the | d₁-d₂|/d₂The value of (c). In addition, the semiconductor of this aspect is manufacturedThe method comprises the step of epitaxially growing one or more semiconductor layers on at least one major surface side of the substrate.

According to another aspect of the present invention, a method of manufacturing a semiconductor device is a method of manufacturing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer as a substrate, the nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method selects a nitride crystal as the nitride crystal substrate, the nitride crystal being configured such that: the diffraction intensity distribution diagram of any specific parallel lattice plane of the nitride crystal is expressed by | v₁-v₂An irregular distortion on a surface layer of the crystal represented by a value of | is equal to or lower than 150arcsec, wherein the diffraction intensity profile is obtained by X-ray diffraction measurement by varying a penetration depth of X-ray diffraction from a surface of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane, from a half-value width v of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of | is given. In addition, the method for producing a semiconductor of this aspect includes a step of epitaxially growing one or more semiconductor layers on at least one main surface side of the substrate.

According to another aspect of the present invention, a method of manufacturing a semiconductor device is a method of manufacturing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer as a substrate, the nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method selects a nitride crystal as the nitride crystal substrate, the nitride crystal being configured such that:on a rocking curve measured by varying the X-ray penetration depth from the surface of the nitride crystal with respect to X-ray diffraction of any particular parallel lattice plane of the nitride crystal, by | w₁-w₂A deviation in plane orientation of the specific parallel lattice plane expressed by a value of | is equal to or lower than 400arcsec where a half-value width w of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of | is given. In addition, the method for producing a semiconductor of this aspect includes a step of epitaxially growing one or more semiconductor layers on at least one main surface side of the substrate.

The present invention can provide a nitride crystal having a crystal surface layer which is evaluated directly and reliably without damaging the crystal, and thus it can be used in a preferable manner as a substrate for epitaxial crystal growth in producing a semiconductor device, and a nitride crystal substrate, a nitride crystal substrate containing an epitaxial layer, a semiconductor device, and methods for producing them.

The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a schematic sectional view showing a state of a crystal in a depth direction from a surface of the crystal.

FIG. 2 is a schematic view showing a measurement axis and a measurement angle of an X-ray diffraction method according to the present invention.

Fig. 3 schematically illustrates the relationship between the uniform distortion of the crystal lattice of a nitride crystal and the plane spacing of specific parallel lattice planes, shown on the diffraction profile of the X-ray diffraction method. In (a), uniform distortion of the crystal lattice is exemplified. In (b), the plane spacing of a particular parallel lattice plane is shown on the diffraction profile.

Fig. 4 schematically illustrates the relationship between the irregular distortion of the crystal lattice of the nitride crystal and the half-value width of the diffraction peak on the diffraction profile in the X-ray diffraction method. In (a), irregular distortion of the crystal lattice is exemplified. In (b), the half-value width of the diffraction peak on the diffraction profile is illustrated.

Fig. 5 schematically illustrates the relationship between the plane orientation distortion of a specific parallel lattice plane of a nitride crystal and the half-value width on the rocking curve in the X-ray diffraction method. In (a), the deviation of the plane orientation of a specific parallel lattice plane is exemplified. In (b), the half-value width of the diffraction peak on the rocking curve is illustrated.

Fig. 6 is a schematic sectional view showing an example of a semiconductor device according to the present invention.

Detailed Description

The present invention employs an X-ray diffraction method, whereby direct evaluation of the crystallinity of the surface layer of the nitride crystal can be performed without damaging the crystal. The evaluation of the degree of crystallinity represents an evaluation or determination of the degree or level of the presence of crystal distortion, more specifically an evaluation of the degree or level of the presence of distortion of the crystal lattice and deviation of plane orientation of the crystal lattice plane. The distortion of the lattice can be particularly classified into a uniform distortion caused by a uniformly distorted lattice and an irregular distortion caused by an irregularly distorted lattice. The deviation in the plane orientation of the crystal lattice plane represents the magnitude of the deviation of the plane orientation of the crystal lattice plane of each crystal region from the average orientation of the plane orientations of the crystal lattice planes of the entire crystal lattice.

As shown in fig. 1, nitride crystal 1 has crystal surface layer 1a at a certain depth from crystal surface 1s, and this crystal surface layer 1a has uniform distortion, irregular distortion, and/or plane orientation deviation of crystal lattice, which is caused in crystal surface layer 1a by processing such as cutting, grinding, or polishing. Uniform distortion, irregular distortion and/or plane orientation deviation of crystal lattice may occur in the adjacent surface layer 1b adjacent to the crystal surface layer 1 a. Fig. 1 shows a case in which there is a deviation in the plane orientation of the crystal lattice. In addition, the crystal inner layer 1c located inside the adjacent surface layer 1b can be considered to have the original crystal structure of the crystal. The state and thickness of the crystalline surface layer 1a and the adjacent surface layer 1b depend on the manner and degree of grinding or polishing in the surface processing treatment.

In the above structure, the uniform distortion, the irregular distortion, and/or the plane direction deviation of the crystal lattice are evaluated in the depth direction from the crystal surface, so that the crystallinity of the crystal surface layer can be evaluated directly and reliably.

In the X-ray diffraction measurement for evaluating the crystallinity of the surface layer of the nitride crystal according to the present invention, the X-ray penetration depth from the crystal surface is changed while satisfying the X-ray diffraction conditions of any specific parallel lattice plane of the nitride crystal.

The diffraction conditions for any particular parallel lattice plane represent the conditions under which any given parallel lattice plane diffracts X-rays. Provided that the bragg angle is θ, the wavelength of the X-ray is λ and the plane spacing of the lattice planes is d, the X-ray is diffracted by the lattice planes satisfying the bragg condition (2dsin θ ═ n λ, where n is an integer).

The X-ray penetration depth represents the distance measured in the depth direction perpendicular to the crystal surface 1s and results in an intensity of the incident X-rays equal to 1/e, where e is the base of the natural logarithm. Referring to fig. 2, the linear absorption coefficient μ of X-rays of the crystal 1, the inclination angle χ of the crystal surface 1s, the X-ray incident angle ω with respect to the crystal surface 1s and the bragg angle θ in the crystal surface 1s determine the X-ray penetration depth T, which is expressed by equation (1). Φ represents the rotation angle of the crystal surface. The chi axis 21 exists on the plane formed by the incident X-rays 11 and the outgoing X-rays 12, the omega axis (2 theta axis) 22 is perpendicular to the plane formed by the incident X-rays 11 and the outgoing X-rays 12, and the phi axis 23 is perpendicular to the crystal surface 1 s.

Thus, the X-ray penetration depth T can be continuously varied by adjusting at least one of χ, ω, and Φ to satisfy the diffraction conditions for the particular lattice plane described above.

In order to continuously vary the X-ray penetration depth T to satisfy the diffraction condition of the specific lattice plane 1d, it is necessary that the specific lattice plane 1d is not parallel to the crystal surface 1 s. If the specific lattice plane 1d is parallel to the crystal surface 1s, the angle θ between the lattice plane 1d and the incident X-ray 11 becomes equal to the angle ω between the crystal surface 1s and the incident X-ray 11, so that the X-ray penetration depth cannot be varied on the specific lattice plane 1 d.

Based on the following embodiments, a description will now be provided regarding evaluation performed in such a manner that any specific parallel lattice plane of a crystal is irradiated with X-rays while changing the X-ray penetration depth, uniform distortion of the lattice is evaluated by the change in the plane spacing on the diffraction profile associated with the specific parallel lattice plane, irregular distortion of the lattice is evaluated by the change in the half-value width of the diffraction peak on the diffraction profile, and deviation in plane orientation of the lattice is evaluated by the change in the half-value width on the rocking curve.

(first embodiment)

The nitride crystal of the present embodiment is characterized in thatThe interplanar spacing of any particular parallel lattice plane of the crystal is defined by | d₁-d₂|/d₂The value of (A) represents a uniform distortion on the surface layer of the crystal equal to or lower than 2.1X 10^-3Wherein the plane spacing is obtained by X-ray diffraction measurement by varying a penetration depth of X-rays from the crystal surface while satisfying an X-ray diffraction condition of the specific parallel lattice plane, the plane spacing d being obtained from the plane spacing at the X-ray penetration depth of 0.3 μm₁And said interplanar spacing d at an X-ray penetration depth of 5 μm₂Obtaining the | d₁-d₂|/d₂The value of (c).

Referring to fig. 1, an X-ray penetration depth of 0.3 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal surface layer 1a, and an X-ray penetration depth of 5 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal inner layer 1 c. Referring to FIG. 3(a), the inter-plane distance d at an X-ray penetration depth of 5 μm₂It can be considered as the plane spacing of a specific parallel lattice plane of the nitride crystal in the initial state, and the plane spacing d at the X-ray penetration depth of 0.3 μm₁Reflecting the uniform distortion of the crystal lattice of the crystal surface layer (e.g., tensile stress 30 directed into the lattice plane) due to crystal surfacing effects, and therefore adopts a planar spacing d from the plane at an X-ray penetration depth of 5 μm₂A different value.

Referring to FIG. 3(b), the inter-plane distance d at the X-ray penetration depth of 0.3 μm₁And an in-plane distance d at an X-ray penetration depth of 5 μm₂Shown on the diffraction profile associated with any particular parallel lattice plane of the crystal in the above case. Therefore, the uniform distortion of the crystal surface layer can be obtained by d₁And d₂Relative to d₂Ratio of | d₁-d₂|/d₂Is expressed by the value of (c).

In the nitride crystal of this embodiment, the crystal is represented by | d |₁-d₂|/d₂Uniform distortion of the surface layer expressed as 2.1X 10 or less^-3. Since the nitride crystalThe uniform distortion of the surface layer of (1) satisfies | d₁-d₂|/d₂≤2.1×10^-3The fact of (a) can thus epitaxially grow a semiconductor layer of good crystallinity on the nitride crystal, and can produce a semiconductor device of good characteristics.

(second embodiment)

The nitride crystal of the present embodiment is characterized by having a diffraction intensity distribution diagram of any specific parallel lattice plane of the crystal represented by | v |₁-v₂An irregular distortion on a surface layer of the crystal represented by a value of | is equal to or lower than 150arcsec, wherein the diffraction intensity profile is obtained by X-ray diffraction measurement by varying a penetration depth of X-ray diffraction from a surface of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane, from a half-value width v of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of | is given.

Referring to fig. 1, an X-ray penetration depth of 0.3 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal surface layer 1a, and an X-ray penetration depth of 5 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal inner layer 1 c. Referring to FIG. 4(a), the half-value width v of the diffraction peak at the X-ray penetration depth of 5 μm₂It can be considered that the half-value width of the nitride crystal in the initial state, and the half-value width v of the diffraction peak at the X-ray penetration depth of 0.3 μm₁Reflects the irregular distortion of the crystal lattice of the crystal surface layer due to the crystal surface processing influence (e.g., different inter-plane distances d of the respective lattice planes)₃、d₄-d₅、d₆) Thus assuming a half-value width v of the diffraction peak at an X-ray penetration depth of 5 μm₂A different value.

Referring to FIG. 4(b), the half-value width v of the diffraction peak at the X-ray penetration depth of 0.3 μm₁And diffraction at an X-ray penetration depth of 5 μmHalf-value width v of peak shooting₂Shown on the diffraction profile associated with any particular parallel lattice plane of the crystal in the above case. Therefore, the irregular distortion of the crystal surface layer can be represented by v₁And v₂Of the difference between₁-v₂The value of | represents.

In the nitride crystal of the present embodiment, the crystal is composed of | v |₁-v₂The | value represents an irregular distortion of the surface layer equal to or lower than 150 arcsec. Satisfies | v due to irregular distortion of the surface layer of the nitride crystal₁-v₂The fact that | is 150 ≦ (arcsec), therefore, a semiconductor layer of good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be produced.

(third embodiment)

The nitride crystal of the present embodiment is characterized by being measured from | w on a rocking curve measured by varying the depth of penetration of X-rays from the surface of the crystal with respect to X-ray diffraction of any particular parallel lattice plane of the nitride crystal₁-w₂A deviation in plane orientation of the specific parallel lattice plane expressed by a value of | is equal to or lower than 400arcsec where a half-value width w of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of | is given.

Referring to fig. 1, an X-ray penetration depth of 0.3 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal surface layer 1a, and an X-ray penetration depth of 5 μm corresponds to a distance from the surface of the nitride crystal to the inside of the crystal inner layer 1 c. Referring to FIG. 5(a), the half-value width w at X-ray penetration depth of 5 μm₂It can be considered as the half-value width of the crystal in the initial state and the half-value width w at the X-ray penetration depth of 0.3 μm₁Reflecting deviations in the orientation of the lattice planes of the crystal surface layer due to crystal surface processing effects (e.g., respective specific parallel lattice planes 51d, 52 of each crystal regiond and 53 d) and thus assumes a half-value width w corresponding to the diffraction peak at an X-ray penetration depth of 5 μm₂A different value.

Referring to FIG. 5(b), the half-value width w at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction peak at an X-ray penetration depth of 5 μm₂Shown on the rocking curve associated with any particular parallel lattice plane of the crystal in the above case. Thus, the deviation of the plane orientation of a specific parallel lattice plane of the crystal surface layer can be represented by w₁And w₂Of difference between₁-w₂The value of | represents.

In the nitride crystal of the present embodiment, from | w₁-w₂The | value represents that the deviation of the plane orientation of a specific parallel lattice plane of the surface layer is equal to or lower than 400 arcsec. The plane orientation deviation of the specific parallel lattice plane due to the surface layer of the nitride crystal satisfies | w₂-w₂The fact that the relation | ≦ 400(arcsec) makes it possible to epitaxially grow a semiconductor layer of good crystallinity on a nitride crystal and to produce a semiconductor device of good characteristics.

The crystallinity evaluated by the crystallinity evaluation methods of the above-described first to third embodiments is not limited to those affected by surface processing, which have been described, and may include crystal distortion and the like occurring when crystals grow.

In the nitride crystals of the first to third embodiments that have been described, the crystal surface preferably has a surface roughness Ry of 30nm or less. The surface roughness Ry is the sum of the height from the average plane of the sampling portion extracted from the roughness-bent plane to the highest peak thereof and the depth from the average plane to the lowest bottom, and is measured at 10 μm on each side in the average plane direction thereof as a reference region (i.e., 10 μm × 10 μm — 100 μm:. mu.m)²). Due to the fact that the nitride crystal has a surface roughness Ry of 30nm or less, a semiconductor layer of good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be produced.

In the nitride crystals of the first to third embodiments that have been described, the crystal surface preferably has a surface roughness Ra of 3nm or less. The surface roughness Ra is a value obtained by averaging the sum of the absolute values of deviations of the average plane of the sampled portion extracted from the roughness curved plane from the measurement curved surface using the reference region, which is measured 10 μm on each side in the average plane direction as the reference region. Due to the fact that the nitride crystal has a surface roughness Ra of 3nm or less, a semiconductor layer of good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be produced.

In the nitride crystals of the first to third embodiments that have been described, it is preferable that the surface of the crystal be parallel to the C-plane of the wurtzite-type structure. C-plane represents the 0001 plane and 000-1 plane. The surface of the group nitride crystal is parallel to each of the above-mentioned planes of the wurtzite-type structure, or approximately parallel (for example, an oblique angle of less than 0.05 ° between the surface of the nitride crystal and the C-plane of the wurtzite-type structure), whereby a semiconductor layer of good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be produced.

In the nitride crystal of the first to third embodiments that have been described, it is preferable that the surface of the crystal forms an oblique angle of 0.05 ° to 15 ° with respect to the C-plane of the wurtzite-type structure. Providing a bevel angle of 0.05 ° or more can reduce defects at a semiconductor layer that is epitaxially grown on a nitride crystal. However, when the oblique angle exceeds 15 °, a gradient or difference in level tends to occur. From this viewpoint, the preferable bevel angle is 0.1 ° to 10 °.

(fourth embodiment)

The present embodiment is a nitride crystal substrate formed of the nitride crystal of the first to third embodiments that have been described. One or more semiconductor layers are epitaxially grown on at least one main surface of the nitride crystal substrate of the present embodiment to provide a nitride crystal substrate including the oneOr a plurality of nitride crystal substrates containing epitaxial layers as semiconductor layers, the one or more semiconductor layers being epitaxial layers (also called epitaxial layers). In this case, when the lattice constant k of the nitride crystal substrate is₀(i.e., lattice constant in an axis perpendicular to the crystal growth plane (the explanation is also true for the following description of the present embodiment)) and the lattice constant k of the semiconductor layer satisfy (| k-k)₀If the relation of I/k) is not more than 0.15, a semiconductor layer can be epitaxially grown on the nitride crystal substrate. Preferably satisfies (| k-k)₀The relation of |/k) is less than or equal to 0.05. From this viewpoint, the semiconductor layer is preferably a group III nitride layer.

(fifth embodiment)

The present embodiment is a semiconductor device including one or more semiconductor layers formed by epitaxial growth on at least one main surface side of the nitride crystal substrate of the above-described fourth embodiment or the above-described nitride crystal substrate containing an epitaxial layer. In the semiconductor device thus obtained, since at least one of uniform distortion, irregular distortion, and plane orientation deviation of the nitride crystal surface layer serving as the substrate is small, the semiconductor layer formed on at least one main surface of the nitride crystal substrate or the epitaxial layer-containing nitride crystal substrate has good crystallinity, and good device characteristics can be obtained.

The fact described above in relation to the semiconductor layer of the fourth embodiment can also be applied to the semiconductor layer of the present embodiment. More specifically, when the lattice constant k of the nitride crystal substrate is₀(i.e., lattice constant in an axis perpendicular to the crystal growth plane (the explanation is also true for the following description of the present embodiment)) and the lattice constant k of the semiconductor layer satisfy (| k-k)₀If the relation of I/k) is not more than 0.15, a semiconductor layer can be epitaxially grown on the nitride crystal substrate. Preferably satisfies (| k-k)₀The relation of |/k) is less than or equal to 0.05. From this viewpoint, the semiconductor layer is preferably a group III nitride layer.

The semiconductor device of the present embodiment may be a light emitting element such as a light emitting diode or a laser diode, an electronic component such as a rectifier, a bipolar transistor, a field effect transistor or a HEMT (high electron mobility transistor), a semiconductor sensor such as a temperature sensor, a pressure sensor, a radiation sensor or a visible-ultraviolet radiation detector, or a SAW device (surface acoustic wave device).

(sixth embodiment)

Referring to fig. 6, the semiconductor device of the present embodiment is a semiconductor device including the above-described nitride crystal substrate or nitride crystal substrate containing an epitaxial layer as a substrate 610, and includes a light emitting element including a plurality of (i.e., three or more) semiconductor layers 650 formed by epitaxial growth on one of main surface sides of the nitride crystal substrate or nitride crystal substrate containing an epitaxial layer (substrate 610), a first electrode 661 formed on the other main surface side of the nitride crystal substrate or nitride crystal substrate containing an epitaxial layer (substrate 610), and a second electrode 662 formed over an outermost semiconductor layer of the plurality of semiconductor layers 650. The semiconductor device further comprises a conductor 682 carrying said light emitting element. The side of the light emitting element defined by the substrate 610 is a light emitting side, and the side defined by the outermost semiconductor layer side is a mounting side. The plurality of semiconductor layers 650 include a p-type semiconductor layer 630, an n-type semiconductor layer 620, and a light emitting layer 640 formed between the conductive semiconductor layers. Due to the above structure, a semiconductor device whose nitride crystal substrate side is the light emitting side can be formed.

Which has a good heat releasing property, the heat being generated from the light emitting layer, as compared with a semiconductor device whose semiconductor layer side is the light emitting side. Therefore, even when operating at high power, temperature rise of the semiconductor device is suppressed, and light emission at high luminance can be obtained. An insulating substrate such as a sapphire substrate must have a single-sided electrode structure in which two kinds of electrodes, i.e., n-and p-electrodes, are formed on a semiconductor layer. However, the semiconductor device of the present embodiment may have a double-sided electrode structure in which electrodes are formed on the semiconductor layer and the substrate, respectively, and a main portion of the main surface of the semiconductor device may serve as a light emitting surface. In addition, for example, when a semiconductor device is mounted, the manufacturing process can be simple because wire bonding is required only once. This advantage, etc. can also be obtained.

(seventh embodiment)

The present embodiment is a method of manufacturing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method for manufacturing the semiconductor device comprises the following steps: the nitride crystal of the first embodiment is selected as a nitride crystal substrate on at least one of the principal surface sides of which one or more semiconductor layers are epitaxially grown.

Since the nitride crystal of the first embodiment of the nitride crystal substrate selected as the semiconductor device of the seventh embodiment has its surface layer whose uniform distortion is small, a semiconductor layer having good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be formed. The above-described fact concerning the semiconductor layers of the fourth and fifth embodiments can be applied to the semiconductor layer of the seventh embodiment.

(eighth embodiment)

This embodiment is a method for producing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method for manufacturing the semiconductor device comprises the following steps: the nitride crystal of the second embodiment is selected as a nitride crystal substrate on at least one of the principal surface sides of which one or more semiconductor layers are epitaxially grown.

Since the nitride crystal of the second embodiment of the nitride crystal substrate selected as the semiconductor device of the eighth embodiment has a surface layer whose irregular distortion is small, a semiconductor layer having good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be formed. The above-described fact concerning the semiconductor layers of the fourth and fifth embodiments can be applied to the semiconductor layer of the eighth embodiment.

(ninth embodiment)

This embodiment is a method for producing a semiconductor device including a nitride crystal substrate or a nitride crystal substrate containing an epitaxial layer including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate. The method for manufacturing the semiconductor device comprises the following steps: the nitride crystal of the third embodiment is selected as a nitride crystal substrate, on at least one principal surface side of which one or more semiconductor layers are epitaxially grown.

Since the nitride crystal of the third embodiment of the nitride crystal substrate selected as the semiconductor device of the ninth embodiment has the surface layer whose plane orientation deviation of the specific parallel lattice plane is small, a semiconductor layer having good crystallinity can be epitaxially grown on the nitride crystal, and a semiconductor device of good characteristics can be formed. The above-described fact concerning the semiconductor layers of the fourth and fifth embodiments can be applied to the semiconductor layer of the ninth embodiment.

The nitride crystal may be grown by a vapor phase growth method such as HVPE (hydride vapor phase epitaxy) method or a sublimation method, or a liquid phase growth method such as a flux method.

The nitride crystal to be formed into the nitride crystal substrate of the semiconductor device is cut from the nitride crystal obtained from the above-described growth method, and subjected to surface processing such as grinding and polishing so as to smooth the surface thereof. In mechanical processing such as grinding and mechanical polishing included in the above-described surface processing, hard particles are cut into the crystal to remove the material, so that a processing-affecting layer (damaged layer) having deteriorated crystallinity is left on the surface of the nitride crystal to be formed into the nitride crystal substrate. Therefore, it is necessary to reduce the process-affected layer in order to produce a group III nitride semiconductor layer on the substrate smoothed by the mechanical processing. The CMP process is most suitable for reducing the process-affected layer because it can reduce both the process-affected layer and the surface roughness.

It is not necessary to completely remove the processing-affected layer on the substrate surface, and the surface quality can be improved by the annealing treatment before the epitaxial growth. Annealing prior to growth causes rearrangement at the crystal surface and allows epitaxial growth of a semiconductor layer with good crystallinity.

As a preferred example of the surface treatment method for improving the crystallinity of the nitride crystal surface layer, a CMP surface treatment method will now be described. The pH value x and the oxidation-reduction potential value y (mV) in the slurry solution preferably used for CMP satisfy both the following formulas (2) and (3):

y≥-50x+1000 (2)

y≤-50x+1900 (3)

if y < -50x +1000, the polishing rate becomes low. If y > -50x +1900, the polishing pad and the polishing apparatus are subjected to a large corrosive action, and therefore stable polishing becomes difficult.

From the viewpoint of further increasing the polishing rate, it is further preferable to additionally satisfy the following formula (4):

y≥-50x+1300 (4)

the slurry for CMP usually contains an acid such as hydrochloric acid, sulfuric acid or nitric acid, and/or a base such as KOH or NaOH added thereto. However, if such an acid and/or base is used alone, the effect of oxidizing the surface of chemically stable gallium nitride is small. Therefore, it is preferable to increase the oxidation-reduction potential by adding an oxidizing agent so that the relationship of the above formulas (2) and (3), or the above formulas (3) and (4) can be satisfied.

The oxidizing agent added to the CMP slurry is not particularly limited, but is preferably selected from: chlorinated isocyanuric acids such as trichloroisocyanuric acid, chlorinated isocyanurates such as sodium dichloroisocyanurate, permanganates such as potassium permanganate, dichromates such as potassium dichromate, bromates such as potassium bromate, thiosulfates such as sodium thiosulfate, hypochlorous acid, nitrates, hydrogen peroxide solution and ozone. Each of these oxidizing agents may be used alone, or two or more of them may be used in combination.

Preferably, the CMP slurry has a pH of 6 or less, or 8 or more. An acidic slurry having a pH of 6 or less, or an alkaline slurry having a pH of 8 or more is brought into contact with the group III nitride crystal to etch and remove the processing-affected layer of the group III nitride crystal, so that the polishing rate can be increased. From this viewpoint, it is more preferable that the pH of the slurry is 4 or less, or 10 or more.

The acid and base for controlling the pH of the slurry are not particularly limited and may be selected from, for example, inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, organic acids such as formic acid, acetic acid, citric acid, malic acid, tartaric acid, succinic acid, phthalic acid and fumaric acid, bases such as KOH, NaOH and NH₄OH and amines, and salts such as sulfates, carbonates and phosphates. In addition, the pH can be controlled by adding the above-mentioned oxidizing agent.

The CMP slurry preferably contains particles. These particles can increase the polishing rate. The particles contained in the slurry are not particularly limited, and may be hard particles having a hardness higher than that of the nitride crystals, soft particles having a hardness lower than that of the nitride crystals, or a particle mixture of the hard particles and the soft particles.

Comparative example 1

An n-type AlN crystal grown by an HVPE method and doped with Si and having a thickness of 500 μm was used as a nitride crystal, and was mechanically polished as follows. Ga-side C-plane ((0001) plane) of n-type GaN crystal having a diameter of 50mm and a thickness of 500 μm was buffed by a buff while a slurry containing diamond particles in a dispersed manner was supplied to a scribe tableThis mechanically polishes the n-type GaN crystal. The scoring station is a copper or tin scoring station. Particles having three different diameters (6 μm \3 μm and 1 μm) were prepared, respectively, and the particle diameters of the particles used were decreased stepwise according to the progress of mechanical polishing. However, the polishing pressure in the mechanical polishing was 100gf/cm²To 500gf/cm²The rotational speed of the scoring table is 30rpm to 100 rpm.

Then, a measurement operation was performed on the n-type GaN crystal subjected to mechanical polishing to measure diffracted X-rays from the (10-13) plane of the wurtzite-type structure while changing the X-ray penetration depth from 0.3 μm to 5 μm, thereby obtaining the plane pitch of the (10-13) plane (the specific parallel lattice plane in this measurement) and the half-value width of the diffraction intensity peak on the diffraction profile and the half-value width of the diffraction intensity peak on the rocking curve. Combining a parallel optical system with CuK_α1Is used for X-ray diffraction measurement. The X-ray penetration depth is controlled by changing at least one of an X-ray incident angle ω to the crystal surface, an inclination angle χ of the crystal surface, and a rotation angle Φ in the crystal surface. The surface roughness Ry and surface roughness Ra of the N-type GaN crystal were measured using AFM (atomic force microscope: DIMENSION N3100, produced by VEECO Corp). The results are shown in table 1.

Referring to fig. 6, by the MOCVD method, on one of the main surface sides of the substrate 610 of n-type GaN crystal: an n-type GaN layer 621 (dopant: Si) of 1 μm thickness forming the n-type semiconductor layer 620, and an n-type Al layer of 150nm thickness also forming the n-type semiconductor layer 620_0.1Ga_0.9N layer 622 (dopant: Si), light-emitting layer 640, p-type Al layer of 20nm thickness forming p-type semiconductor layer 630_0.2Ga_0.8An N layer 631 (dopant: Mg), and a p-type GaN layer 632 (dopant: Mg) having a thickness of 150nm also forming the p-type semiconductor layer 630. Thereby obtaining an epitaxially grown layer for a light-emitting element. The light emitting layer 640 has a multiple quantum well (quantum well) structure in which four barrier layers each having a thickness of 10nm formed of a GaN layer and Ga each having a thickness of 3nm are formed_0.85In_0.15Three well layers formed by N layers are alternately layered.

A layered structure formed of a Ti layer having a thickness of 200nm, an Al layer having a thickness of 1000nm, a Ti layer having a thickness of 200nm and an Au layer having a thickness of 2000nm was formed as a first electrode 661 on the other main surface side of the substrate 610 of n-type GaN crystal, and heated under a nitrogen atmosphere to form an n-side electrode having a diameter of 100 μm. Further, a layered structure formed of a Ni layer having a thickness of 4nm and an Au layer having a thickness of 4nm was formed as the second electrode 662 on the p-type GaN layer 632, and heated under an inert gas atmosphere to form a p-side electrode. A chip measuring 400 μm on each side was prepared from the above layered structure, and then the above p-side electrode was connected to the conductor 682 with a solder layer 670 made of AuSn. In addition, the n-side electrode and the conductor 681 are connected together with a wire 690, so that the semiconductor device 600 having a structure as a light emitting device is obtained. The semiconductor devices thus obtained were arranged in the manner of an integrating sphere. Then, a current of 20mA was applied to the semiconductor device to emit light, and the output of the light collected by the integrating sphere was measured. However, it was confirmed that there was no light emission from the semiconductor device of this comparative example. The results are shown in Table 1.

(examples 1 to 7)

Semiconductor devices were produced under the same conditions as in comparative example 1 except that CMP was performed under the conditions described in table 1 after mechanical polishing and before X-ray diffraction. The light output of the produced semiconductor device was measured similarly to comparative example 1. The results are shown in Table 1.

[ Table 1]

		Comparative example 1	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7
										CMP	pH of the slurry	Without CMP	9.5	2.4	3.5	3.5	3.5	3.5	3.0
Oxidation-reduction potential (mV) of the slurry	980	1420	1200	1200	1200	1200	1200
								Oxidizing agent	Na-DCIA		TCIA		TCIA	TCIA	TCIA	TCIA	TCIA
Hard particles	-	-	Al2O3	Al2O3	Al2O3	Al2O3	Cr2O3
								Particle diameter (μm)	-		-		0.5	1.0	2.0	0.5	0.8
Soft particles	SiO2	SiO2	-	-	-	SiO2	SiO2
								Volume ratio of mixture ((hard particles): (soft particles))	-		-		-	-	-	10∶90	10∶90
Polishing Rate (. mu.m/hr)	0.4	0.5	1.1	1.6	1.9	0.8	1.5
								Characteristics of	|d1-d2|/d2		2.3×10-3		0.3×10-3	0.3×10-3	1.0×10-3	1.7×10-3	2.1×10-3	0.6×10-3	1.4×10-3
|v1-v2|(arcsec)	290	60	50	90	130	150	80			110
									|w1-w2|(arcsec)		500	130	120	220	340	400	190	300
Surface roughness Ry (nm)	＞100	1.8	1.0	4.1	5.3	8.9	2.9			4.8
									Surface roughness Ra (nm)		＞10	0.15	0.09	0.42	0.51	0.85	0.26	0.45
Light output (mW)	-	15.6	16.4	12.3	9.8	8.2	13.9			10.7

(Note) NA-DCIA: sodium dichloroisocyanurate, TCIA: trichloroisocyanuric acid

Comparative example 2

An n-type AlN crystal grown by a sublimation method to a thickness of 400 μm and doped with Si was used as a nitride crystal, and mechanical polishing was performed similarly to comparative example 1.

Then, a measurement operation was performed on the n-type AlN crystal subjected to mechanical polishing to measure diffracted X-rays from the (11-22) plane of the wurtzite-type structure while changing the X-ray penetration depth from 0.3 μm to 5 μm, thereby obtaining the plane pitch of the (11-22) plane (the specific parallel lattice plane in the measurement) and the half-value width of the diffraction intensity peak on the diffraction profile and the half-value width of the diffraction intensity peak on the rocking curve. Combining a parallel optical system with CuK_α1Is used for X-ray diffraction measurement. The X-ray penetration depth is controlled by changing at least one of an X-ray incident angle ω to the crystal surface, an inclination angle χ of the crystal surface, and a rotation angle Φ in the crystal surface. The surface roughness Ry and surface roughness Ra of the n-type AlN crystal were measured using AFM. The results are shown in table 2.

A semiconductor device using the above AlN crystal as a substrate was produced under the same conditions as in comparative example 1. The light output of the thus produced semiconductor device was measured similarly to comparative example 1. No light emission was confirmed. The results are shown in Table 2.

(examples 8 to 10)

Semiconductor devices were produced under the same conditions as in comparative example 2 except that CMP was performed under the conditions described in table 2 after mechanical polishing and before X-ray diffraction. The results are shown in Table 2.

[ Table 2 ]]

		Comparative example 2	Example 8	Example 9	Example 10
						CMP	pH of the slurry	Without CMP	9.5	2.4	3.5
Oxidation-reduction potential (mV) of the slurry	980	1420	1200
				Oxidizing agent	Na-DCIA		TCIA		TCIA
Hard particles	-	-	Al2O3
				Particle diameter (μm)	-		-		0.5
Soft particles	SiO2	SiO2	-
				Mixed volume ratio ((hard particles): (soft particles))	-		-		-
Polishing Rate (. mu.m/hr)	0.6	0.8	1.4
				Characteristics of	|d1-d2|/d2		2.4×10-3		0.5×10-3	0.4×10-3	1.4×10-3
|v1-v2|(arcsec)	310	80	70			110
					|w1-w2|(arcsec)		510	140	130	220
Surface roughness Ry (nm)	＞100	1.0	1.4			4.5
					Surface roughness Ra (nm)		＞10	0.09	0.12	0.41
Light output (mW)	-	13.9	14.8			10.9

(Note) NA-DCIA: sodium dichloroisocyanurate

TCIA: trichloroisocyanuric acid

As is apparent from tables 1 and 2 described above, high light output is achieved by LEDs, which are semiconductor devices each selectively employing nitride crystal satisfying the following conditions as a nitride crystal substrate: in X-ray diffraction measurement performed under conditions of varying depth of penetration of X-rays from the surface of the crystal while satisfying the X-ray diffraction conditions for any particular parallel lattice plane of the crystal, the surfaceUniform distortion of layer | d₁-d₂|/d₂Equal to or lower than 2.1X 10^-3Wherein the distance d from the plane at the X-ray penetration depth of 0.3 μm₁And said interplanar spacing d at an X-ray penetration depth of 5 μm₂Obtaining the | d₁-d₂|/d₂A value of (d); irregular distortion | v of crystal surface layer₁-v₂I is equal to or lower than 150arcsec, wherein the maximum value of the width at half maximum v of the diffraction intensity peak at the X-ray penetration depth of 0.3 [ mu ] m₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of | is; or deviations of the plane directions | w of specific parallel lattice planes₁-w₂I is equal to or lower than 400arcsec, wherein the peak is defined by the half-value width w of the diffraction intensity peak at said X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of | is given.

Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.

Claims (14)

1. A nitride crystal in which, in a crystal structure,

with respect to the plane spacing of any specific parallel lattice plane (1d) of the nitride crystal (1), from | d₁-d₂|/d₂Is equal to or lower than 2.1X 10-3, wherein the interplanar spacing is obtained by X-ray diffraction measurements by varying the penetration depth of X-rays from the surface (1s) of the crystal while satisfying the X-ray diffraction conditions of the specific parallel lattice plane (1d), the interplanar spacing being obtained from the X-ray penetration depth of 0.3 [ mu ] mThe distance d between the planes₁And said interplanar spacing d at an X-ray penetration depth of 5 μm₂Obtaining the | d₁-d₂|/d₂The value of (c).

2. A nitride crystal in which, in a crystal structure,

on the diffraction intensity distribution diagram of any specific parallel lattice plane (1d) of the nitride crystal (1), from | v₁-v₂An irregular distortion on a surface layer (1a) of the crystal represented by | is equal to or lower than 150arcsec, wherein the diffraction intensity profile is obtained by X-ray diffraction measurement by varying a penetration depth of X-ray diffraction from a surface (1s) of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane (1d), from a half-value width v of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of | is given.

3. A nitride crystal in which, in a crystal structure,

on a rocking curve measured by varying the X-ray penetration depth from the surface of the nitride crystal (1) with respect to X-ray diffraction of any particular parallel lattice plane (1d) of the crystal, by | w₁-w₂A deviation of plane orientation of the specific parallel lattice plane (1d) represented by a value of | is equal to or lower than 400arcsec where a half-value width w of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of | is given.

4. The nitride crystal according to claim 1, wherein

The surface (1s) of the crystal has a surface roughness Ry of 30nm or less.

5. The nitride crystal according to claim 1, wherein

The surface (1s) of the crystal has a surface roughness Ra of 3nm or less.

6. The nitride crystal according to claim 1, wherein

The surface (1s) of the nitride crystal is parallel to the C-plane of the wurtzite-type structure.

7. The nitride crystal according to claim 1, wherein

The surface (1s) of the nitride crystal has an off-angle of 0.05 DEG to 15 DEG with respect to the C-plane of the wurtzite-type structure.

8. A nitride crystal substrate formed of the nitride crystal (1) according to claim 1.

9. A nitride crystal substrate containing an epitaxial layer, comprising:

one or more semiconductor layers formed by epitaxial growth on at least one main surface side of the nitride crystal substrate according to claim 8.

10. A semiconductor device comprising, as a substrate (610), the nitride crystal substrate according to claim 8, or an epitaxial-layer-containing nitride crystal substrate including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of said nitride crystal substrate, wherein

The semiconductor device further comprises one or more semiconductor layers (650), the semiconductor layers (650) being formed by epitaxial growth on at least one main surface side of the substrate (610).

11. A semiconductor device comprising, as a substrate (610), the nitride crystal substrate according to claim 8, or an epitaxial-layer-containing nitride crystal substrate including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of said nitride crystal substrate, wherein

The semiconductor device further includes a light emitting element including three or more semiconductor layers (650) formed by epitaxial growth on one of the main surface sides of the substrate (610), a first electrode (661) formed on the other main surface side of the substrate (610), and a second electrode (662) formed over an outermost semiconductor layer among the plurality of semiconductor layers (650), and

further comprising a conductor (682) carrying the light emitting element;

the substrate (610) side of the light emitting element is a light emitting side, the outermost semiconductor layer side is a mounting side, and the plurality of semiconductor layers (650) include a p-type semiconductor layer (630), an n-type semiconductor layer (620), and a light emitting layer (640) formed between these conductive semiconductor layers.

12. A method of manufacturing a semiconductor device including, as a substrate (610), a nitride crystal substrate or an epitaxial-layer-containing nitride crystal substrate including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate, the method comprising the steps of:

a nitride crystal (1) selected as the nitride crystal substrate, the nitride crystal (1) being configured such that: with respect to the plane spacing of any particular parallel lattice plane (1d) of the crystal (1), from | d₁-d₂|/d₂Is equal to or lower than 2.1X 10-3, wherein the interplanar spacing is obtained by X-ray diffraction measurements by varying the penetration depth of X-rays from the surface (1s) of the crystal while satisfying the X-ray diffraction conditions of the specific parallel lattice plane (1d), the interplanar spacing being obtained from the interplanar spacing d at the X-ray penetration depth of 0.3 μm₁And said plane at an X-ray penetration depth of 5 μmDistance d₂Obtaining the | d₁-d₂|/d₂A value of (d); and

one or more semiconductor layers (650) are epitaxially grown on at least one major surface side of the substrate (610).

13. A method of manufacturing a semiconductor device including, as a substrate (610), a nitride crystal substrate or an epitaxial-layer-containing nitride crystal substrate including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate, the method comprising the steps of:

a nitride crystal (1) selected as the nitride crystal substrate, the nitride crystal (1) being configured such that: on the diffraction intensity distribution diagram of any specific parallel lattice plane (1d) of said crystal, from | v₁-v₂An irregular distortion on a surface layer (1a) of the crystal represented by | is equal to or lower than 150arcsec, wherein the diffraction intensity profile is obtained by X-ray diffraction measurement by varying a penetration depth of X-ray diffraction from a surface (1s) of the crystal while satisfying an X-ray diffraction condition of the specific parallel lattice plane (1d), from a half-value width v of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width v of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | v₁-v₂The value of |, and

one or more semiconductor layers (650) are epitaxially grown on at least one major surface side of the substrate (610).

14. A method of manufacturing a semiconductor device including, as a substrate (610), a nitride crystal substrate or an epitaxial-layer-containing nitride crystal substrate including one or more semiconductor layers formed by epitaxial growth on at least one principal surface side of the nitride crystal substrate, the method comprising the steps of:

a nitride crystal (1) selected as the nitride crystal substrate, the nitride crystal (1) being configured such that: on a rocking curve measured by varying the X-ray penetration depth from the surface (1s) of the nitride crystal (1) with respect to X-ray diffraction of any particular parallel lattice plane (1d) of the crystal, by | w₁-w₂A deviation of plane orientation of the specific parallel lattice plane (1d) represented by a value of | is equal to or lower than 400arcsec where a half-value width w of a diffraction intensity peak at the X-ray penetration depth of 0.3 μm₁And a half-value width w of a diffraction intensity peak at said X-ray penetration depth of 5 μm₂Obtaining the | w₁-w₂The value of |, and

one or more semiconductor layers (650) are epitaxially grown on at least one major surface side of the substrate (610).