JP6398213B2 - Method for producing group 13 nitride crystal - Google Patents

Description

The present invention relates to the production how the 13 nitride crystal.

  Gallium nitride (GaN) -based semiconductors are used in semiconductor devices such as blue light-emitting diodes (LEDs), white LEDs, and semiconductor lasers (LDs: Laser Diodes). In particular, c-plane GaN substrates are used for semiconductor devices.

The GaN substrate is formed on a heterogeneous substrate such as a sapphire substrate or a GaAs substrate by using a growth method such as an ELO (Epitaxial Lateral Overgrowth) method, an advanced-DEEP method, or a VAS (Void-Assisted Separation) method, and an HVPE (Hydride Vapor Phase). After the GaN is grown thick by this method, the GaN thick film is manufactured from a different substrate. The GaN substrate manufactured in this way has a transition density reduced to about 10 ⁶ cm ⁻² and a size of 2 inches has been put into practical use.

  On the other hand, as one of the techniques for producing a GaN substrate using a liquid phase growth method, a flux method is disclosed in which nitrogen is dissolved in a mixed melt of metallic sodium and metallic Ga to crystal-grow GaN.

  The flux method is capable of crystal growth at a relatively low temperature of 700 ° C. to 900 ° C., and the internal pressure of the vessel is relatively low at about 3 MPa to 8 MPa. A method of manufacturing a GaN substrate using this flux method is disclosed (for example, see Patent Documents 1 to 3).

  Patent Document 1 discloses a method of growing a crystal by changing the stirring condition of the melt when the crystal is grown on the substrate. In Patent Document 1, first, the first agitation condition set so that the growth surface is uneven is employed for crystal growth, and then the second agitation condition is set so that the growth surface becomes smooth. It is disclosed that the crystal is grown by employing the above.

  Patent Document 2 discloses that a patterned mask film is formed on a semiconductor layer, and a group 13 nitride crystal is grown in layers using the semiconductor layer exposed from the mask film as a seed crystal. Patent Document 3 discloses a method in which a semiconductor crystal is grown in layers in the a-axis direction on the a-plane of a seed crystal.

  Here, a laser diode having a configuration in which an active layer made of InGaN is formed on the c-plane of a GaN substrate is realized. However, as the In composition of the InGaN quantum well in the active layer increases, the lattice constant difference between the active layer and the GaN substrate increases, thereby increasing the strain. As the strain increases, the c-plane is a polar plane, and the light emission efficiency of the laser diode is greatly reduced by the piezoelectric field.

  Therefore, a pure green laser using a semipolar substrate or a nonpolar substrate instead of a polar substrate such as the c-plane has been reported. For example, as a method of manufacturing a semipolar substrate or a nonpolar substrate using a flux method, a nitride crystal is grown on the c-plane and a crystal is grown in the c-axis direction. It is disclosed to produce a bulk crystal of a group 13 nitride crystal used in the above.

  However, when the crystal is grown in the c-axis direction, melt components such as metal sodium, metal gallium, or a mixture of sodium and gallium are likely to enter the crystal as crystals during crystal growth. For this reason, conventionally, it was necessary to stir the mixed melt during crystal growth. That is, it has been difficult to produce a group 13 nitride crystal in which inclusion is suppressed using the flux method.

The present invention uses a flux method, and an object thereof is to provide a manufacturing how the inclusion of the suppressed 13 nitride crystal.

  In order to solve the above-described problems and achieve the object, the present invention dissolves nitrogen from a gas phase in a mixed melt containing at least an alkali metal and a group 13 metal held in a reaction vessel, In the method for producing a group 13 nitride crystal in which a group 13 nitride crystal is grown in a mixed melt, the reaction vessel is substantially perpendicular to a gas-liquid interface of the mixed melt held in the reaction vessel. A strip having a first plane region, a crystal plane on which a group 13 nitride crystal grows by c-axis orientation and growing as a principal plane, and a longitudinal direction substantially parallel to the a-axis of the group 13 nitride crystal in which the crystal grows A first step of preparing a first seed crystal having a shape, an opposing surface of the main surface of the first seed crystal is in contact with the first planar region, and the longitudinal direction is substantially parallel to the gas-liquid interface. A second step of disposing the first seed crystal so that Forming the mixed melt in a reaction vessel, and starting crystal growth of a group 13 nitride crystal from the main surface of the first seed crystal in the mixed melt; And a fourth step of continuing the crystal growth while enlarging the area of the {10-11} plane, with the {10-11} plane of the group 13 nitride crystal having started growth as the main growth plane. It is a manufacturing method of a physical crystal.

According to the present invention, by using a flux method, it is possible to provide a manufacturing how the inclusion of the suppressed 13 nitride crystal.

FIG. 1 is an explanatory diagram of the first seed crystal. FIG. 2 is a diagram illustrating an example of the first seed crystal. FIG. 3 is a perspective view of the reaction vessel. FIG. 4 is a cross-sectional view of the reaction vessel. FIG. 5 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal. FIG. 6 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal. FIG. 7 is a schematic diagram showing a group 13 nitride crystal. FIG. 8 is a schematic view showing a group 13 nitride crystal. FIG. 9 is a schematic diagram of a manufacturing apparatus. FIG. 10 is an explanatory diagram of the second planar region in the reaction vessel. FIG. 11 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal. FIG. 12 is a schematic diagram showing a group 13 nitride crystal. FIG. 13 is a schematic diagram showing a group 13 nitride crystal. FIG. 14 is a plan view of the second seed crystal. FIG. 15 is an explanatory diagram of the sixth step. FIG. 16 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal. FIG. 17 is a schematic diagram showing a group 13 nitride crystal. FIG. 18 is a schematic view showing a group 13 nitride crystal. FIG. 19 is an explanatory diagram of a reaction vessel. FIG. 20 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal. FIG. 21 is a schematic diagram showing a group 13 nitride crystal. FIG. 22 is a schematic view showing a group 13 nitride crystal.

With reference to the accompanying drawings, a description will be given of the production how such group 13 nitride crystal to the present embodiment. In the following description, the shapes, sizes, and arrangements of the constituent elements are only schematically shown in the drawings so that the invention can be understood, and the present invention is not particularly limited thereby. In addition, similar components shown in a plurality of drawings are denoted by the same reference numerals, and redundant description thereof may be omitted.

(Embodiment 1)
In the method for producing a group 13 nitride crystal of the present embodiment, nitrogen is dissolved from a gas phase in a mixed melt containing at least an alkali metal and a group 13 metal held in a reaction vessel, and the mixed melt This is a method for producing a group 13 nitride crystal in which a group 13 nitride crystal is grown.

  The reaction vessel used in the method for producing a group 13 nitride crystal of the present embodiment has a first plane region that is substantially perpendicular to the gas-liquid interface of the mixed melt held in the reaction vessel.

  The method for producing a group 13 nitride crystal of the present embodiment includes at least a first step, a second step, a third step, and a fourth step in this order.

  The first step is a step of preparing the first seed crystal. The first seed crystal is a strip-shaped crystal whose main surface is a crystal plane in which a group 13 nitride crystal grows by c-axis orientation and whose longitudinal direction is substantially parallel to the a axis of the group 13 nitride crystal in which the crystal grows. It is.

  In the second step, the opposite surface of the main surface of the first seed crystal is in contact with the first planar region of the reaction vessel, and the longitudinal direction of the first seed crystal is substantially parallel to the gas-liquid interface of the mixed melt. In this way, the first seed crystal is disposed.

  The third step is a step of forming a mixed melt in the reaction vessel and starting crystal growth of a group 13 nitride crystal from the main surface of the first seed crystal in the mixed melt.

  The fourth step uses the {10-11} plane of the group 13 nitride crystal that has started crystal growth from the main plane of the first seed crystal as the main growth plane, while increasing the area of the {10-11} plane. This is a process of continuing growth.

  In the method for producing a group 13 nitride crystal of the present embodiment, inclusion is suppressed by including the first step, the second step, the third step, and the fourth step in this order using the specific reaction vessel. It is considered that a group 13 nitride crystal used for manufacturing a semipolar substrate or a nonpolar substrate formed can be obtained.

  The reason for the above effect is not clear, but is presumed as follows. However, the present invention is not limited by the following estimation.

  In the present embodiment, the reaction vessel has a first plane region that is substantially perpendicular to the gas-liquid interface of the mixed melt held in the reaction vessel. In this embodiment, the strip-shaped first seed crystal is formed by mixing the main surface of the first seed crystal with the first planar region of the reaction vessel and the longitudinal direction of the first seed crystal being mixed and melted. The first seed crystal is arranged so as to be substantially parallel to the gas-liquid interface of the liquid. For this reason, the group 13 nitride crystal grows from the main surface of the strip-shaped first-type crystal, with the {10-11} plane as the main growth plane and expanding the area of the {10-11} plane.

  The {10-11} plane tends to be a flat crystal plane. For this reason, it is thought that inclusion is taken in into a crystal | crystallization. For this reason, in the manufacturing method of the group 13 nitride crystal of this embodiment, the precision of the melt by means such as stirring required in the conventional flux method liquid phase epitaxial growth in which crystal growth is performed with the c-plane as the main growth surface. It is considered that a group 13 nitride crystal with reduced inclusion can be produced without control.

  Therefore, in this Embodiment, it is estimated that the group 13 nitride crystal used for manufacture of the group 13 nitride crystal substrate by which inclusion was suppressed can be manufactured using the flux method.

  In this embodiment, a long strip-shaped crystal is used as the first seed crystal. For this reason, the time required for crystal growth for obtaining a larger group 13 nitride crystal can be shortened.

  Further, in the present embodiment, unlike a crystal manufacturing method in which a plurality of crystal start regions are formed on a substrate and adjacent crystals grown therefrom are combined to increase the size, crystal growth is performed from one first seed crystal. By doing so, a group 13 nitride crystal is produced. For this reason, inclusion is suppressed, and there is no generation | occurrence | production of a distortion and a defect, A high quality group 13 nitride crystal can be manufactured.

  Moreover, since the {10-11} plane parallel to the longitudinal direction of the first seed crystal grows preferentially during crystal growth, this crystal plane (growth sector) can be made larger. In the present embodiment, the {10-11} plane is grown in a direction different from the direction facing the gas-liquid interface of the mixed melt. For this reason, the adhesion probability of the miscellaneous crystal generated at the gas-liquid interface of the mixed melt can be effectively suppressed, and polycrystallization of the manufactured group 13 nitride crystal can be prevented.

  Details will be described below.

  First, the first step will be described. In the first step, a first seed crystal is prepared.

  FIG. 1 is an explanatory diagram of the first seed crystal 100. FIG. 1A is a schematic view of the first seed crystal 100 viewed from the main surface 100A side. FIG.1 (b) is A-A 'sectional drawing of Fig.1 (a). The first seed crystal 100 has a main surface 100A as a crystal plane on which a nitride crystal grows by c-axis orientation.

  As shown in FIG. 1, the first seed crystal 100 has a strip shape that is long in the a-axis direction. That is, the longitudinal direction of the first seed crystal 100 is parallel to or substantially parallel to the a-axis of the group 13 nitride crystal grown from the main surface 100A of the first seed crystal 100. In other words, the orthogonal direction orthogonal to the longitudinal direction on the main surface 100A of the first seed crystal 100 is parallel to or substantially parallel to the m-axis. Note that “substantially parallel” means that a deviation of ± 2 ° is included.

  The length of the first seed crystal 100 in the longitudinal direction is not particularly limited. As the length of the first seed crystal 100 in the longitudinal direction is longer, a larger group 13 nitride crystal can be produced in a shorter time. For this reason, what is necessary is just to adjust the length of the longitudinal direction of the 1st seed crystal 100 according to the target manufacturing time etc. previously.

  What is necessary is just to adjust suitably the length (henceforth a width | variety) of the orthogonal direction orthogonal to the said longitudinal direction in 100 A of main surfaces of the 1st seed crystal 100 hereafter. As the width of main surface 100A of first seed crystal 100 increases, the c-plane of group 13 nitride crystal is more likely to be formed. For this reason, since the raw material is used for the growth of the c-plane as the width of the first seed crystal 100 on the main surface 100A increases, the crystal growth rate becomes slower. Moreover, since unevenness | corrugation is easy to be formed in c surface, inclusion (metal gallium, metal sodium, those compounds, etc.) becomes easy to enter. For this reason, it is preferable that the width of the main surface 100A of the first seed crystal 100 is not made larger than necessary, and specifically, it is preferable to be in the following range.

  Specifically, the width of main surface 100A of first seed crystal 100 is preferably 5 mm or less, more preferably 2 mm or less, and particularly preferably 1 mm or less. The lower limit value of the width may be adjusted as appropriate according to the ease of handling the first seed crystal 100. For example, in the case where crystal growth is started in a state where the first seed crystal 100 is not fixed, if the width of the first seed crystal 100 is shorter than the thickness of the first seed crystal 100, the first seed crystal 100 is likely to fall down. . The thickness of the first seed crystal 100 is the length between the main surface 100A and the opposing surface 100B. For this reason, the width of the first seed crystal 100 is preferably equal to or greater than the thickness of the first seed crystal 100.

  The material of the first seed crystal 100 is not particularly limited as long as the crystal surface on which the group 13 nitride crystal grows by c-axis orientation is used as the main surface 100A. The main surface 100A of the first seed crystal 100 may be one of the two opposing surfaces having a large area among the four long surfaces along the a-axis direction of the strip-shaped first seed crystal 100. .

  The first seed crystal 100 only needs to satisfy the above conditions, and may be a single crystal of the same material as a whole, or may be a stacked body in which the main surface 100A is stacked so as to satisfy the above conditions. .

  Note that the surface of the main surface 100A of the first seed crystal 100 is particularly preferably a (0001) plane of gallium nitride.

  The formation method of the 1st seed crystal 100 is not specifically limited, It can select suitably. For example, a template substrate is produced by epitaxially growing a group 13 nitride crystal on the main surface of a different substrate. And it is good also as the 1st seed crystal 100 by cutting out this template board | substrate in strip shape.

  FIG. 1 shows an example of the first seed crystal 100 configured as a stacked body. In the example shown in FIG. 1, the first seed crystal 100 is a stacked body in which a group 13 nitride crystal 102 is stacked on a heterogeneous substrate 101. In this case, the surface of the first seed crystal 100 on the group 13 nitride crystal 102 side is the main surface 100A.

The material of the different substrate 101 is not particularly limited. For the dissimilar substrate 101, for example, a material in which a group 13 nitride is difficult to nucleate is used. Specifically, a single crystal substrate such as sapphire, SiC, ZnO, or MgAl ₂ O ₄ is used for the different substrate 101.

  As the first seed crystal 100, it is preferable to cut a free-standing substrate of the group 13 nitride crystal 102 from which the heterogeneous substrate 101 is removed into a strip shape, and use the cut crystal. This is because the thermal expansion coefficient of the group 13 nitride crystal to be grown on the first seed crystal 100 and the first seed crystal 100 is taken into consideration in the third step and the fourth step described later.

  Further, a group 13 nitride crystal produced by LPE by the Na Flux method is cut into a strip shape on the template substrate or the group 13 nitride crystal 102 free-standing substrate, and the cut crystal is a first type crystal. It is preferable to use as 100.

  Further, a bulk crystal is produced by crystal growth under the same conditions as the crystal growth in the third step and the fourth step described later (for example, Na flux method using Na as an alkali metal), and the bulk crystal is formed into a strip shape. The first seed crystal 100 may be manufactured by processing.

  FIG. 2 is a diagram illustrating an example of a first seed crystal 150 that is a single crystal first seed crystal 100. In the example shown in FIG. 2, the first seed crystal 150 is made of a single crystal of a group 13 nitride crystal.

  FIG. 2A is a schematic view of the first seed crystal 150 viewed from the main surface side. FIG. 2B is a cross-sectional view taken along the line A-A ′ of FIG. The first seed crystal 150 is the same as the first seed crystal 100 described in FIG. 1 except that it is a single crystal. In the present embodiment, the first seed crystal 100 as a stacked body may be used as the first seed crystal, or the first seed crystal 150 that is a single crystal may be used. Hereinafter, as an example, the case where the first seed crystal 100 is used as the first crystal will be mainly described.

  Next, the second step will be described.

  In the second step, the first seed crystal 100 is disposed in the first planar region in the reaction vessel.

  The reaction container has a first plane region that is substantially perpendicular to the gas-liquid interface of the mixed melt held in the reaction container. “Substantially vertical” indicates a range of 0 ° ± 2 °, where 0 ° is a state in which the angle formed between the first planar region and the gas-liquid interface 24A is vertical.

  The first planar region may be at least a part of the inner wall of the reaction vessel. Moreover, you may provide a 1st plane area | region in reaction container by installing the member which has a 1st plane area | region inside reaction container.

  The method for forming the first planar region is not particularly limited. For example, by processing the inner wall of the reaction vessel into a plane perpendicular to the gas-liquid interface, at least a part of the inner wall is set as the first plane region. Further, for example, a member having a first planar region is installed in the reaction vessel.

  It is sufficient that at least one first plane region is provided in the reaction vessel. A plurality of first planar regions may be provided in the reaction vessel. When providing a plurality of first planar regions in the reaction vessel, the plurality of first planar regions are formed by group 13 nitride crystals grown from the first seed crystal 100 installed in each of the first planar regions. It is preferable to arrange them at intervals so as not to contact each other.

  3 and 4 are explanatory diagrams of the first planar region 26 in the reaction vessel 12. 3 and 4 show, as an example, the case where the first planar region 26 is configured in the reaction vessel 12 by installing the plate-like member 27 having the first planar region 26 in the reaction vessel 12. .

  FIG. 3 is a perspective view of the reaction vessel 12. FIG. 4 is a cross-sectional view of the reaction vessel 12. FIG. 4A is a cross-sectional view of the reaction vessel 12 in a direction orthogonal to the longitudinal direction Y of the first seed crystal 100 arranged in the reaction vessel 12. FIG. 4B is a cross-sectional view in the longitudinal direction Y of the first seed crystal 100 in the reaction vessel 12.

  The reaction vessel 12 holds the mixed melt 24 in the reaction vessel 12. In the example shown in FIGS. 3 and 4, a plate-like member 27 is provided in the reaction vessel 12. The plate-like member 27 is a plate-like member having a first flat area 26 (first flat area 26A, first flat area 26B) facing each other. The plate member 27 is supported by a support portion 25 provided at the bottom inside the reaction vessel 12. The support unit 25 supports the plate member 27 so that the first planar region 26 of the plate member 27 is substantially perpendicular to the gas-liquid interface 24A.

  The material of the plate-like member 27 having the first planar region 26 and the support portion 25 may be any material as long as the group 13 nitride is less likely to nucleate. This material is, for example, a BN sintered body, a nitride such as P-BN, an oxide such as alumina, YAG, or sapphire, or a carbide such as SiC or TaC.

  When the first planar region 26 is configured as at least a part of the inner wall of the reaction vessel 12, the inner wall of the reaction vessel 12 may be made of the material.

  What is necessary is just to adjust the magnitude | size of the plate-shaped member 27 suitably. For example, the size of the plate-like member 27 is preferably adjusted in advance to be larger than the group 13 nitride crystal 103 after crystal growth. In addition, the size of the plate-like member 27 is preferably a size that fits inside the reaction vessel 12.

  In the second step, the first seed crystal 100 is formed such that the opposing surface 100B of the main surface 100A of the first seed crystal 100 is in contact with the first planar region 26, and the longitudinal direction Y of the first seed crystal 100 is the gas-liquid interface 24A. The first seed crystal 100 is placed so as to be substantially parallel to the first. The term “substantially parallel” indicates a range of 0 ° ± 2 °, where 0 ° is a state in which the angle between the longitudinal direction Y of the first seed crystal 100 and the gas-liquid interface 24A is parallel.

  In the example illustrated in FIG. 3, the first seed crystal 100 is placed in the above state by fixing both ends in the longitudinal direction Y of the first seed crystal 100 with screws 30. The method for fixing the first seed crystal 100 is not limited to this method.

  In the present embodiment, the opposing surface 100B of the main surface 100A of the first seed crystal 100 is fixed in close contact with the first planar region 26 of the plate-like member 27. As a result, the bottom surface side of the grown group 13 nitride crystal 103, that is, the (000-1) c-plane nitrogen polar surface faces the first planar region 26 side. Here, the (000-1) plane is easily polycrystallized. For this reason, in order to grow a single crystal, it is desired not to continue the growth on the (000-1) plane side. In the present embodiment, the first seed crystal 100 is installed so that the (000-1) plane faces the first planar region 26 side. For this reason, the growth on the (000-1) plane side of the group 13 nitride crystal 103 is not continued, and polycrystallization can be suppressed.

  In the example illustrated in FIG. 3, the case where one first seed crystal 100 is provided in one first planar region 26 (the first planar region 26 </ b> B in FIG. 3) is illustrated. However, a plurality of first seed crystals 100 may be installed in one first planar region 26. In this case, it is preferable that the plurality of first seed crystals 100 be spaced apart so that the group 13 nitride crystals 103 grown from each first seed crystal 100 do not contact each other.

  Next, the third step will be described.

  In the third step, the mixed melt 24 is formed in the reaction vessel 12, and in the mixed melt 24, the group 13 nitride crystal 103 (see FIGS. 3 and 4) is formed from the main surface 100 A of the first seed crystal 100. Start crystal growth.

  FIG. 5 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal of the present embodiment. Further, in FIG. 5, as an example, the case where the first seed crystal 100 is installed in the first planar region 26 </ b> B of the plate-like member 27 so as to satisfy the above condition is shown. That is, FIG. 5 shows a case where the first seed crystal 100 is installed in the first planar region 26B of the plate-like member 27 and the group 13 nitride crystal 103 is grown as shown in FIG.

  As shown in FIGS. 5A and 5B, in the third step, a mixed melt 24 is formed in the reaction vessel 12 and nitrogen is dissolved from the gas phase. Then, crystal growth of the group 13 nitride crystal 103 is started from the main surface 100A of the first seed crystal 100.

  The mixed melt 24 includes a flux and a raw material such as a group 13 metal.

  As the flux, sodium or a sodium compound (for example, sodium azide) is used. As another example, other alkali metals such as lithium and potassium, and compounds of the alkali metals may be used. Moreover, you may use alkaline earth metals, such as barium, strontium, and magnesium, and the compound of the said alkaline earth metal as a flux. Note that a plurality of types of alkali metals or alkaline earth metals may be mixed and used as the flux.

  As the Group 13 metal used as a raw material, gallium is preferably used, but as another example, other Group 13 metals such as boron, aluminum, and indium, or a mixture thereof may be used.

In the mixed melt 24, a dopant substance such as Ge, Mg, Fe, or Mn (a simple substance or a compound such as B ₂ O ₃ ), an alkaline earth metal serving as a flux such as Ca, Ba, or Sr, or a miscellaneous crystal. Carbon or the like having a reduction effect may be mixed.

  Nitrogen gas is generally used as nitrogen in the gas phase, but ammonia or other gas containing nitrogen can be used. In addition to the gas containing nitrogen, an inert gas such as Ar or other gas can be mixed in the gas phase.

  In the third step, a flux and a Group 13 metal as a raw material are placed in the reaction vessel 12 in which the first seed crystal 100 is installed, and the temperature is raised to the crystal growth temperature in the pressure vessel.

  In this temperature raising process, the reaction vessel may not be filled with the nitrogen source gas, but in order to prevent the dissolution of the first seed crystal 100 as much as possible, it is desirable to fill the nitrogen source gas and raise the temperature. In this temperature rising process, the flux (for example, alkali metal) and the group 13 metal are dissolved to form a mixed melt 24.

  Then, under a predetermined crystal growth temperature and a predetermined nitrogen raw material gas pressure, nitrogen dissolved in the mixed melt 24 from the gas phase reacts with the group 13 metal in the mixed melt 24 to form the first seed crystal. Crystal growth of a group 13 nitride crystal is started from 100 main surfaces 100A.

  This crystal growth is started by adjusting the nitrogen partial pressure, the temperature of the mixed melt, the molar ratio of the raw material to the flux, etc. to the conditions under which the group 13 nitride crystal starts to grow. Is done.

  Specifically, in the third step, the nitrogen partial pressure is preferably in the range of 1 MPa to 6 MPa. In the third step, the temperature of the mixed melt (crystal growth temperature) is preferably in the range of 800 ° C to 900 ° C.

  For example, the ratio of the number of moles of alkali metal to the total number of moles of gallium and alkali metal (for example, sodium) is in the range of 50% to 90%, and the crystal growth temperature of the mixed melt is in the range of 850 ° C. to 900 ° C. Preferably, the nitrogen partial pressure is in the range of 1.5 MPa to 6 MPa.

  In a more preferred embodiment, the ratio of the number of moles of alkali metal to the total number of moles of gallium and alkali metal (for example, sodium) is in the range of 60% to 75%, and the crystal growth temperature is 860 ° C. to 870 ° C. More preferably, the nitrogen partial pressure is in the range of 2 MPa to 3.5 MPa.

  The group 13 nitride crystal 103 grown from the main surface 100A of the first seed crystal 100 is a c-axis oriented single crystal.

  Next, the fourth step will be described.

  FIG.5 (c)-FIG.5 (e) are explanatory drawings of a 4th process.

  In the fourth step, the {10-11} plane of the group 13 nitride crystal 103 that has started crystal growth from the main surface 100A of the first seed crystal 100 in the third step is defined as {10-11} } Continue crystal growth while increasing the surface area.

  Specifically, the crystal region in contact with the mixed melt 24 in the group 13 nitride crystal 103 which has started crystal growth from the main surface 100A of the first seed crystal 100 protrudes from the main surface 100A of the first seed crystal 100. Grow up. By this crystal growth, a group 13 nitride crystal 103 larger than the first seed crystal 100 is obtained.

  The grown group 13 nitride crystal 103 has a large area on the bottom side in contact with the plate-like member 27, and the cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystal 100 (see FIG. 4B) is It has a substantially triangular shape or a trapezoidal shape with the first crystal 100 side as a base. A recess 105 may be formed on the upper portion of the group 13 nitride crystal 103 (on the opposite side of the bottom surface).

  The same applies when the first seed crystal 150 is used instead of the first seed crystal 100.

  FIG. 6 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal using the first seed crystal 150. FIG. 6 shows a case where the first seed crystal 150 is installed in the first planar region 26A of the plate member 27 and the group 13 nitride crystal 151 is grown as shown in FIG.

  As shown in FIG. 6A and FIG. 6B, in the third step, a mixed melt 24 is formed in the reaction vessel 12, and nitrogen is dissolved from the gas phase. Then, crystal growth of the group 13 nitride crystal 151 is started from the main surface of the first seed crystal 150. The scene of crystal growth in the third step is the same as when the first seed crystal 100 is used as the seed crystal.

  FIG.6 (c)-FIG.6 (e) are explanatory drawings of a 4th process.

  In the fourth step, the {10-11} plane of the group 13 nitride crystal 151 that has started crystal growth from the main surface of the first seed crystal 150 in the third step is the {10-11} plane. Continue crystal growth while expanding the area.

  Specifically, in the group 13 nitride crystal 151 that has started crystal growth from the main surface of the first seed crystal 150, the crystal region in contact with the mixed melt 24 protrudes from the main surface of the first seed crystal 150. To do. By this crystal growth, a group 13 nitride crystal 151 larger than the first seed crystal 150 is obtained.

  The crystal-grown group 13 nitride crystal 151 has a large area on the bottom surface side in contact with the plate member 27, and the cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystal 150 (see FIG. 4B) is It has a substantially triangular shape or a trapezoidal shape with the first crystal 150 side as a base. Note that a recess 153 may be formed on the upper portion of the group 13 nitride crystal 151 (on the opposite side of the bottom surface).

  7 and 8 are schematic views showing the group 13 nitride crystals 103 and 151 having undergone crystal growth. FIG. 7 is a schematic diagram showing a perspective view of the group 13 nitride crystals 103 and 151 having grown crystals. FIG. 8A is a schematic view of the grown group 13 nitride crystals 103 and 151 as viewed from the opposite side of the bottom surface (the side in contact with the first seed crystal 100 or the first seed crystal 150). FIG. 8B is a cross-sectional view taken along the line A-A ′ of FIG.

  The grown group 13 nitride crystals 103 and 151 have a cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystals 100 and 150, a triangular shape with a base on the first seed crystals 100 and 150 side, or a base Shape. In the examples shown in FIGS. 7 to 8, the case where the cross-sectional shape is a triangular shape is shown.

  The trapezoidal shape is a shape including an upper side, a base parallel to the upper side, and two sides connecting the upper side and the base. Note that at least one of the two sides connecting the upper side and the bottom side may be constituted by a plurality of sides. In this case, although it is strictly a polygon, in the present invention, if the top side and the bottom side are parallel, it is defined as a trapezoid. The triangle shape is not limited to a regular triangle as long as it is a triangular shape having three sides that are not parallel to each other. Further, at least one of the three sides may be composed of a plurality of sides. In this case, strictly speaking, it is a polygon, but in the present invention, a triangle is defined if three of a plurality of sides constituting a triangular shape are at least twice as long as the other sides. One side among the sides constituting the triangular shape is the bottom side. Note that the trapezoidal base and the triangular base are both sides that form part of the bottom surface of the group 13 nitride crystal 103 that is in contact with the main surface 100A of the first seed crystal 100.

  Of the surfaces constituting group 13 nitride crystals 103 and 151, the bottom surface is the (000-1) plane of the c-plane.

  Of the surfaces constituting group 13 nitride crystals 103 and 151, two surfaces continuous to the bottom surface are flat {10-11} surfaces. In other words, in the group 13 nitride crystals 103 and 151, the two faces of the triangular cross section that is a cross section perpendicular to the longitudinal direction Y are flat with respect to the two hypotenuses that are continuous with the base and in the longitudinal direction Y. {10-11} plane. That is, among the planes constituting the group 13 nitride crystals 103 and 151, the crystal plane with the largest area grown in the mixed melt 24 during crystal growth is the {10-11} plane.

  Specifically, one of these two surfaces is the (10-11) surface and the other is (−1011).

  Of the {10-11} planes of the group 13 nitride crystals 103 and 151, on the crystal plane facing the gas-liquid interface 24A (see FIG. 4), miscellaneous crystals generated near the gas-liquid interface 24A are present. There is a possibility of adhesion. On the other hand, among the {10-11} planes of the group 13 nitride crystals 103 and 151, the crystal plane facing the opposite side of the gas-liquid interface 24A (see FIG. 4) has a markedly established miscellaneous crystal adhesion. Lower.

  In addition, the group 13 nitride crystals 103 and 151 that have grown have a cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystals 100 and 150 in the group 13 nitride crystals 103 and 151, and the first seed crystal 100, In the case of a trapezoidal shape with the 150 side as the base, the upper side surface is a c-plane.

  That is, the group 13 nitride crystals 103 and 151 manufactured by the method for manufacturing a group 13 nitride crystal according to the present embodiment are arranged on the upper side of the crystal facing the bottom surface when the first seed crystal 100 or 150 side is the bottom surface. Compared to the bottom surface, the two surfaces that are larger than the bottom surface and grow in contact with the mixed melt 24 are {10-11} surfaces.

  The conditions for crystal growth in the fourth step are realized by adjusting the nitrogen partial pressure, the temperature of the mixed melt, the ratio of the number of moles of alkali metal to the total number of moles of gallium and alkali metal (for example, sodium), etc. it can.

  Specifically, in the fourth step, the nitrogen partial pressure is adjusted to a partial pressure at which nitrogen in the mixed melt 24 has a relatively low degree of supersaturation. Specifically, it is preferable to be within a range of 2 MPa to 3.5 MPa. Further, in the fourth step, the temperature of the mixed melt 24 (crystal growth temperature) becomes a problem when a reaction vessel made of a material such as YAG or alumina dissolves or reacts with the melt to grow crystals. Adjust to a safe temperature. Specifically, it is preferable to set it within the range of 860 ° C to 880 ° C. Furthermore, when using a reaction vessel made of a material that is stable even at high temperatures, the temperature can be raised.

  Further, the ratio of the number of moles of alkali metal to the total number of moles of gallium and alkali metal (for example, sodium) is such that the {10-11} plane is easily formed under the aforementioned conditions of nitrogen and temperature, 50% to 80%. It is preferable that the content be within the range of 60% to 75%.

  By setting the third step to the same crystal growth conditions (temperature, partial pressure, alkali metal molar ratio, etc.) as the fourth step, the third step and the fourth step are continued under the same conditions. Can be advanced.

  FIG. 9 is a schematic diagram of the manufacturing apparatus 1 for performing the third step and the fourth step in the present embodiment.

  As shown in FIG. 9, the manufacturing apparatus 1 includes a closed pressure-resistant container 11 made of stainless steel. The pressure vessel 11 can be removed from the manufacturing apparatus 1 at the valve 21 portion, and only the pressure vessel 11 portion can be put in the glove box and operated.

  A reaction vessel 12 is provided in the pressure vessel 11. The reaction vessel 12 holds the mixed melt 24. A support portion 25 is installed at the bottom inside the reaction vessel 12. The support part 25 supports the plate member 27. The plate-like member 27 is a plate-like member provided with a first flat region 26 (first flat region 26A, first flat region 26B). The support part 25 supports the plate-like member 27 so that the first planar region 26 is perpendicular to the gas-liquid interface 24A.

  In the first planar region 26 of the plate-like member 27, the first seed crystal 100 and the first seed crystal 150 are installed by the first process and the second process.

  The material of the reaction vessel 12 can be selected as appropriate. For example, a BN sintered body, a nitride such as P-BN, an oxide such as alumina or YAG, a carbide such as SiC, or the like can be used for the reaction vessel 12. The reaction vessel 12 can be removed from the pressure vessel 11.

The pressure vessel 11 is connected to a gas supply pipe 14 for supplying nitrogen (N ₂ ) gas, which is a raw material for the group 13 nitride crystal, and dilution gas for adjusting the total pressure. The gas supply pipe 14 is branched into a nitrogen supply pipe 17 and a gas supply pipe 20, and can be separated by valves 15 and 18, respectively.

  As the diluent gas, it is desirable to use an argon (Ar) gas that is an inert gas, but the present invention is not limited to this, and other inert gases such as helium (He) may be used as the diluent gas.

  Nitrogen gas is supplied from a nitrogen supply pipe 17 connected to a gas cylinder of nitrogen gas and the like, and after the pressure is adjusted by the pressure control device 16, the nitrogen gas is supplied to the gas supply pipe 14 through the valve 15. On the other hand, a dilution gas (for example, argon gas) is supplied from a gas supply pipe 20 connected to a gas cylinder of the dilution gas and the pressure is adjusted by a pressure control device 19, and then the gas supply pipe is connected via a valve 18. 14. The nitrogen gas and the dilution gas whose pressures are adjusted in this way are respectively supplied to the gas supply pipe 14 and mixed.

  Then, a mixed gas of nitrogen and dilution gas is supplied from the gas supply pipe 14 to the pressure vessel 11 through the valve 21.

  The gas supply pipe 14 is provided with a pressure gauge 22 so that the pressure in the pressure vessel 11 can be adjusted while the pressure gauge 22 monitors the total pressure in the pressure vessel 11.

  Nitrogen gas is a raw material of gallium nitride, and argon, which is an inert gas, is mixed with it to increase the total pressure and suppress the evaporation of sodium, while controlling the pressure of the nitrogen gas independently. It is. Thereby, crystal growth with high controllability becomes possible.

  In this embodiment, the nitrogen partial pressure can be adjusted by adjusting the pressures of the nitrogen gas and the dilution gas with the valves 15 and 18 and the pressure control devices 16 and 19 as described above. Further, since the total pressure in the pressure vessel 11 can be adjusted, the total pressure in the pressure vessel 11 can be increased to suppress evaporation of alkali metal (for example, sodium) in the reaction vessel 12. That is, it is possible to separately control the nitrogen partial pressure, which is a nitrogen material that affects the crystal growth conditions of gallium nitride, and the total pressure that affects the suppression of evaporation of sodium (flux).

  Further, a heater 13 is disposed outside the pressure vessel 11, and the temperature of the mixed melt 24 can be adjusted by heating the pressure vessel 11 and the reaction vessel 12.

  In carrying out the third step and the fourth step, first, a substance used as a flux and a raw material are charged into the reaction vessel 12. And after setting a raw material etc., it supplies with electricity to the heater 13, and the pressure vessel 11 and the reaction vessel 12 inside it are heated to crystal growth temperature. Then, a substance used as a flux in the reaction vessel 12 and raw materials are melted to form a mixed melt 24. Further, nitrogen as a raw material can be supplied into the mixed melt 24 by bringing the partial pressure of nitrogen into contact with the mixed melt 24 and dissolving it in the mixed melt 24.

  Then, under a predetermined crystal growth temperature and a predetermined nitrogen partial pressure, nitrogen dissolved in the mixed melt 24 from the gas phase reacts with the group 13 metal in the mixed melt 24 to cause a reaction in the mixed melt 24. The crystal growth of the group 13 nitride crystals 103 and 151 is started from the main surfaces of the first seed crystals 100 and 150 installed in the first crystal (third step).

  Further, by maintaining the crystal growth conditions in the fourth step, the group 13 nitride crystals 103 and 151 that have started crystal growth continue crystal growth with the {10-11} plane as the main growth plane.

  Through the first to fourth steps, the group 13 nitride crystals 103 and 151 are manufactured.

  Then, the group 13 nitride crystals 103 and 151 grown in the fourth step are cooled to room temperature. Thereafter, the group 13 nitride crystals 103 and 151 are separated from the plate member 27 or the reaction vessel 12.

  Note that, during the cooling process of the group 13 nitride crystals 103 and 151, due to the difference in thermal expansion coefficient between the plate-like member 27 or the reaction vessel 12 and the group 13 nitride crystals 103 and 151, the first seed crystals 100 and 150 In some cases, the crystal of the main surface or the vicinity thereof is broken, and the plate member 27 or the reaction vessel 12 and the group 13 nitride crystals 103 and 151 are already separated.

  Through the above process, the group 13 nitride crystals 103 and 151 can be manufactured.

(Embodiment 2)
In the present embodiment, a case will be described in which the reaction vessel 12 includes a first planar region 26 and a second planar region substantially parallel to the gas-liquid interface 24A.

  In the present embodiment, the reaction vessel 12 includes a first planar region 26 and a second planar region. The first planar region 26 is the same as that in the first embodiment. The second plane region is a plane region that is substantially parallel to the gas-liquid interface 24A of the mixed melt 24 held in the reaction vessel 12.

  The second planar region may be at least a part of the inner wall of the reaction vessel 12. Further, the second planar region may be provided in the reaction vessel 12 by installing a member having the second planar region inside the reaction vessel 12.

  The method for forming the second planar region is not particularly limited. For example, by processing a part of the inner wall of the reaction vessel 12 into a plane parallel to the gas-liquid interface 24A, at least a part of the inner wall is set as the second plane area. Further, for example, a member having a second planar region is installed in the reaction vessel 12.

  The position of the second planar region in the reaction vessel 12 may be arranged on the gas-liquid interface 24A side from the first seed crystals 100, 150 installed in the reaction vessel 12. The second planar region is preferably located in the vicinity of the surface on the gas-liquid interface 24A side of the first seed crystals 100, 150, and more preferably in contact with the surface on the gas-liquid interface 24A side. By arranging the second planar region and the surface of the first seed crystals 100, 150 on the gas-liquid interface 24A side so as to be in contact with each other, the group 13 nitride crystal 103 that grows from the first seed crystals 100, 150, It is possible to suppress the adhesion of miscellaneous crystals to 151.

  FIG. 10 is an explanatory diagram of the second planar region 29A in the reaction vessel 12. FIG. FIG. 10 shows, as an example, a case where the plate-like member 29 having the second flat region 29A is installed in the reaction vessel 12 to form the second flat region 29A in the reaction vessel 12.

  10 is a cross-sectional view of the reaction vessel 12 in a direction orthogonal to the longitudinal direction Y (see FIG. 4) of the first seed crystal 150 arranged in the reaction vessel 12.

  The reaction vessel 12 holds the mixed melt 24 in the reaction vessel 12. A plate-like member 27, a support portion 25, and a plate-like member 29 are provided in the reaction vessel 12.

  The plate-like member 27 includes a first planar region 26 (first planar region 26A, first planar region 26B). The plate-like member 27 and the support portion 25 are the same as those in the first embodiment.

  The plate-like member 29 is a plate-like member having the second flat area 29A. In the example shown in FIG. 10, the plate member 29 is supported by the support portion 25 via the plate member 27. Specifically, the second planar region 29A of the plate member 29 is substantially parallel to the gas-liquid interface 24A, and the second planar region 29A faces the bottom side of the reaction vessel 12 (the side opposite to the gas-liquid interface 24A). Thus, it is supported by the support portion 25.

  The material of the plate-like member 29 having the second planar region 29A may be any material that does not easily generate group 13 nitride. This material is, for example, a BN sintered body, a nitride such as P-BN, an oxide such as alumina, YAG, or sapphire, or a carbide such as SiC or TaC.

  When the second planar region 29A is configured as at least part of the inner wall of the reaction vessel 12, the inner wall of the reaction vessel 12 may be made of the material.

  What is necessary is just to adjust the magnitude | size of the plate-shaped member 29 suitably. For example, the size of the plate-like member 29 is preferably adjusted in advance to be larger than the group 13 nitride crystal 201 after crystal growth. Further, the size of the plate-like member 29 is preferably a size that fits inside the reaction vessel 12.

  The first step and the second step are the same as in the first embodiment.

  In the second step, as described above, the first seed crystals 100 and 150 are contacted with the first planar region 26 so that the main surface of the first seed crystals 100 and 150 is in contact with the first planar region 26. , 150 are arranged such that the longitudinal direction Y of the first seed crystals 100, 150 is substantially parallel to the gas-liquid interface 24A. At this time, as described above, it is preferable to arrange the first seed crystals 100 and 150 so that the surface on the gas-liquid interface 24A side is located in the vicinity of the second planar region 29A, and the first seed crystals 100 and 150 are arranged so as to be in contact with each other. Further preferred.

  Next, the third step and the fourth step will be described.

  In the present embodiment, crystal growth is performed under the same conditions as in the first embodiment except that the second planar region 29A is further provided in the reaction vessel 12.

FIG. 11 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal of the present embodiment. FIG.
The case where the first seed crystal 150 is used as the first seed crystal is shown. Further, FIG. 11 shows an environment in which the second planar region 29A and the first planar region 26 are configured by installing the plate-like member 27 and the plate-like member 29 in the reaction vessel 12 (see FIG. 10). ), The case of crystal growth was shown.

  In the example shown in FIG. 11, the opposing surface of the main surface of the first seed crystal 150 is in contact with the first planar region 26 of the plate-like member 27, and the longitudinal direction Y of the first seed crystal 150 is substantially parallel to the gas-liquid interface 24A. In addition, an example in which the first seed crystal 150 is disposed so that the surface on the gas-liquid interface 24A side is in contact with the second planar region 29A of the plate-like member 29 is shown.

  As shown in FIGS. 11A and 11B, in the third step, a mixed melt 24 is formed in the reaction vessel 12, and in the mixed melt 24, from the main surface of the first seed crystal 150. Crystal growth of the group 13 nitride crystal 201 (see FIGS. 10 and 11) is started.

  The mixed melt 24 and the crystal growth conditions in the third step are the same as those in the first embodiment.

  FIG.11 (c)-FIG.11 (e) are explanatory drawings of a 4th process.

  In the fourth step, the {10-11} plane of the group 13 nitride crystal 201 that has started crystal growth from the main surface of the first seed crystal 150 in the third step is defined as the {10-11} Continue crystal growth while expanding the area of the surface.

  Specifically, in the group 13 nitride crystal 201 that has started crystal growth from the main surface of the first seed crystal 150, the crystal region in contact with the mixed melt 24 protrudes from the main surface of the first seed crystal 150. To do. Further, the surface of the group 13 nitride crystal 201 on the second planar region 29A side grows along the second planar region 29A. For this reason, the group 13 nitride crystal 201 forms a plane substantially parallel to the gas-liquid interface 24A and grows.

  By this crystal growth, a group 13 nitride crystal 201 larger than the first seed crystal 150 is obtained.

  The crystal-grown group 13 nitride crystal 201 has a large area on the bottom surface side in contact with the plate member 27, and the cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystal 150 (see FIG. 4B) is It has a substantially right triangle shape with the base of the single crystal 150 side.

  12 and 13 are schematic views showing the group 13 nitride crystal 201 grown. FIG. 12 is a schematic view showing a perspective view of the group 13 nitride crystal 201 having grown crystal. FIG. 13A is a schematic view of a group 13 nitride crystal 201 grown as a crystal, as viewed from the opposite side of the bottom surface (side in contact with the first seed crystal 150). FIG. 13B is a cross-sectional view taken along the line A-A ′ of FIG.

  The grown group 13 nitride crystal 201 has a cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystal 150 having a substantially right triangle shape with the first seed crystal 150 side as a base. Of the surfaces constituting group 13 nitride crystal 201, the bottom surface is the (000-1) plane of the c-plane.

  Further, the surface of the group 13 nitride crystal 201 on the second planar region 29A side grows along the second planar region 29A. For this reason, the group 13 nitride crystal 201 has a plane substantially parallel to the gas-liquid interface 24A.

  Of the two faces that form the group 13 nitride crystal 201 and are continuous with the bottom face, the face grown in contact with the mixed melt 24 is a flat {10-11} face.

  Note that microcrystal 202 (see FIG. 11) may slightly adhere to the bottom surface of group 13 nitride crystal 201, but growth is limited by first planar region 26 of plate-like member 27.

  Through the above steps, the group 13 nitride crystal 201 can be manufactured.

(Embodiment 3)
In the present embodiment, a case where a group 13 nitride crystal is manufactured using a second seed crystal instead of the first seed crystals 100 and 150 used in the above embodiment will be described.

  The reaction vessel 12 used in the method for producing a group 13 nitride crystal of the present embodiment is the same as that of the first embodiment. That is, the reaction vessel 12 includes a first planar region 26.

  The method for producing a group 13 nitride crystal of the present embodiment includes at least a fifth step, a sixth step, and a seventh step in this order. The fifth step is a step of preparing the second seed crystal.

  The second seed crystal is a group 13 nitride crystal, in which the a-axis direction is one of the three a-axes of the group 13 nitride crystal in the longitudinal direction and is orthogonal to the a-axis direction. The cross section is triangular. The second seed crystal has a (000-1) plane whose bottom surface is long in the longitudinal direction Y among the three surfaces that are continuous in the longitudinal direction Y on each of the three sides constituting the triangular cross section. At least one of the other two surfaces continuous in the longitudinal direction Y is the (10-11) plane or the (-1011) plane.

  In the sixth step, in the mixed melt 24, the bottom surface of the second seed crystal is in contact with the first flat region 26, and the longitudinal direction Y of the second seed crystal is substantially parallel to the gas-liquid interface 24A. And a step of arranging the second seed crystal. In the seventh step, the mixed melt 24 is formed in the reaction vessel 12, and in the mixed melt 24, crystal growth of the group 13 nitride crystal is started from the {10-11} plane of the second seed crystal, This is a step of continuing crystal growth while enlarging the {10-11} plane of the group 13 nitride crystal that has started growth.

  Hereinafter, each step will be described in detail.

  The fifth step is a step of preparing the second seed crystal. FIG. 13 is an explanatory diagram of the second seed crystal 300. FIG. 13A is a plan view of the second seed crystal 300 viewed from the c-axis direction side, and FIG. 13B is a cross-sectional view taken along the line A-A ′ of FIG.

  As shown in FIG. 13, the second seed crystal 300 is a group 13 nitride crystal, in which one a-axis direction among the three a-axis directions of the group 13 nitride crystal is the longitudinal direction Y, and The cross section in the orthogonal direction orthogonal to the a-axis direction is triangular. The second seed crystal 300 has a (000-1) plane whose bottom surface is long in the longitudinal direction Y among the three surfaces that are continuous in the longitudinal direction Y on each of the three sides constituting the triangular cross section. At least one of the other two surfaces continuous to the bottom surface is the (10-11) surface or the (-1011) surface.

  FIG. 14 is a plan view of the second seed crystal 300. FIG. 14A is a plan view of the second seed crystal 300 as viewed from the opposite side of the bottom surface. FIG. 14B is a cross-sectional view taken along the line A-A ′ of FIG.

  As shown in FIG. 14, the second seed crystal 300 has a triangular cross section and a hexagonal bottom surface. The second seed crystal 300 is a long single crystal having a longitudinal direction Y in one a-axis (for example, <11-20>) direction. The bottom surface of the second seed crystal 300 is a (000-1) plane. Further, in the example shown in FIG. 14, the case where one of two surfaces continuous in the m-axis direction is the (10-11) plane and the other is the (−1011) plane with respect to the bottom surface is shown.

  The manufacturing method of the second seed crystal 300 is not particularly limited. For example, the second seed crystal 300 is manufactured by crystal growth of the first seed crystal 100 and the first seed crystal 150 through the first to fourth steps of the first embodiment by the flux method. Also good.

  The length in the longitudinal direction Y of the second seed crystal 300 is not particularly limited. As the length of the second seed crystal 300 in the longitudinal direction Y is longer, a larger group 13 nitride crystal can be produced in a shorter time. For this reason, what is necessary is just to adjust the length of the longitudinal direction of the 2nd seed crystal 300 according to the target manufacturing time etc. previously.

  Next, the sixth step will be described.

  FIG. 15 is an explanatory diagram of the sixth step. In the sixth step, in the mixed melt 24, the second seed crystal 300 has a bottom surface in contact with the first planar region 26, and the longitudinal direction Y is substantially parallel to the gas-liquid interface 24A. A seed crystal 300 is arranged. The sixth step is the same as the second step of the first embodiment except that the second seed crystal 300 is used instead of the first seed crystals 100 and 150.

  FIG. 15 is a cross-sectional view of the reaction vessel 12. FIG. 15A is a cross-sectional view of the reaction vessel 12 in a direction orthogonal to the longitudinal direction Y of the second seed crystal 300 disposed in the reaction vessel 12. FIG. 15B is a cross-sectional view in the longitudinal direction Y of the second seed crystal 300 in the reaction vessel 12.

  The reaction vessel 12 holds the mixed melt 24 in the reaction vessel 12. In the example shown in FIG. 15, the reaction vessel 12 includes a support portion 25 and a plate-like member 27. The support portion 25 and the plate-like member 27 are the same as those in the first embodiment. The reaction vessel 12 holds the mixed melt 24 inside. The mixed melt 24 is the same as in the first embodiment.

  In the sixth step, the second seed crystal 300 is formed such that the bottom surface (that is, the (000-1) plane) of the second seed crystal 300 is in contact with the first planar region 26 and the longitudinal direction Y of the second seed crystal 300 is The second seed crystal 300 is installed so as to be substantially parallel to the gas-liquid interface 24A. As a result, in the second seed crystal 300, one of the three surfaces that are continuous in the longitudinal direction Y and the other two surfaces that are continuous to the bottom surface is in each of the three sides constituting the triangular cross section. It will be in the state which faced the opposite side to 24 A of liquid interfaces.

  The installation method of the 2nd seed crystal 300 is not limited. For example, as in the first embodiment, both end portions in the longitudinal direction Y of the second seed crystal 300 are fixed with screws 30.

  Further, similarly to the first embodiment, a plurality of second seed crystals 300 may be provided in one first plane region 26. In this case, it is preferable that the plurality of second seed crystals 300 be spaced apart so that the group 13 nitride crystals 301 grown from the second seed crystals 300 do not contact each other.

  Next, the seventh step will be described.

  FIG. 16 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal of the present embodiment.

  In the seventh step, the mixed melt 24 is formed in the reaction vessel 12, and in the mixed melt 24, crystal growth of the group 13 nitride crystal is started from the {10-11} plane of the second seed crystal 300, Crystal growth is continued while enlarging the {10-11} plane of the group 13 nitride crystal that has started crystal growth (see FIGS. 16A to 16C).

  In the seventh step, similarly to the third step (Embodiment 1), the flux and the group 13 metal as a raw material are placed in the reaction vessel 12 in which the second seed crystal 300 is installed. The temperature is raised to the crystal growth temperature. In this temperature raising process, the flux (for example, alkali metal) and the group 13 metal are dissolved to form a mixed melt 24.

  Then, under the same crystal growth conditions (crystal growth temperature and nitrogen raw material gas pressure) as in the first embodiment, nitrogen dissolved in the mixed melt 24 from the gas phase and the group 13 metal in 24 in the mixed melt are: The surface of the second seed crystal 300 on the side in contact with the mixed melt 24 (in the example shown in FIGS. 14 to 15, the (10-11) plane and the (−1011) plane) is a group 13 nitride crystal 301. Crystal growth starts. Then, crystal growth is performed while increasing the area of this plane (that is, {10-11} plane) (see FIGS. 16A to 16C).

  The crystal-grown group 13 nitride crystal 301 has a large area on the bottom surface side in contact with the plate-like member 27, and the cross-sectional shape perpendicular to the longitudinal direction Y (see FIG. 15B) of the second seed crystal 300 is It has a substantially triangular shape or a trapezoidal shape with the two seed crystal 300 side as a base. A recess 305 may be formed on the upper portion of the group 13 nitride crystal 301 (opposite the bottom surface).

  FIGS. 17 and 18 are schematic views showing a group 13 nitride crystal 301 with crystal growth. FIG. 17 is a schematic diagram showing a perspective view of the group 13 nitride crystal 301 on which the crystal has grown. FIG. 18A is a schematic view of the group-grown nitride crystal 301 grown as a crystal, as viewed from the opposite side of the bottom surface (second seed crystal 300 side). FIG. 18B is a cross-sectional view taken along the line A-A ′ of FIG.

  The grown group 13 nitride crystal 301 has a (000-1) plane at the bottom surface (surface on the second seed crystal 300 side). Further, the bottom surface side of the group 13 nitride crystal 301 is larger than the crystal upper side (the side opposite to the bottom surface), and the two surfaces continuous to the bottom surface are {10-11} planes.

  That is, the group 13 nitride crystal 301 has a substantially triangular or trapezoidal cross-sectional shape perpendicular to the longitudinal direction Y of the second seed crystal 300.

  Of the surfaces constituting the group 13 nitride crystal 301, two surfaces that are continuous with the bottom surface are flat {10-11} surfaces. In other words, in the group 13 nitride crystal 301, two faces of the triangular cross-section that is a cross-section perpendicular to the longitudinal direction Y are continuous {10 -11} plane.

  The crystal-grown group 13 nitride crystal 301 has a trapezoidal shape in which the shape of the cross section of the group 13 nitride crystal 301 perpendicular to the longitudinal direction Y of the second seed crystal 300 is the second seed crystal 300 side. In this case, the upper side surface is a (0001) c plane.

  That is, in the group 13 nitride crystal 301 manufactured by the method for manufacturing a group 13 nitride crystal of the present embodiment, when the second seed crystal 300 side is the bottom surface, the bottom surface side is larger than the crystal upper side facing the bottom surface. Two surfaces that are large and grow in contact with the mixed melt 24 and continue to the bottom surface are {10-11} planes.

  Specifically, one of these two surfaces is the (10-11) surface and the other is (−1011).

  Of the {10-11} plane of the group 13 nitride crystal 301, a miscellaneous crystal generated near the gas-liquid interface 24A is attached to the crystal plane facing the gas-liquid interface 24A (see FIG. 15). there is a possibility. On the other hand, among the {10-11} planes of the group 13 nitride crystal 301, the crystal plane facing the side opposite to the gas-liquid interface 24A (see FIG. 15) has a markedly lower probability of miscellaneous crystal adhesion. .

  Such conditions for crystal growth in the seventh step can be realized by adjusting the conditions to be the same as those in the third step and the fourth step in the first embodiment.

  Through the above steps, the group 13 nitride crystal 301 can be manufactured.

(Embodiment 4)
In the present embodiment, the second seed crystal 300 is used as the seed crystal, as in the third embodiment. In the present embodiment, as the reaction vessel 12, the reaction vessel 12 including the first flat region 26 and the second flat region 29A substantially parallel to the gas-liquid interface 24A is used as in the second embodiment. Use.

  The second seed crystal 300 is the same as that in the third embodiment. Further, the first planar region 26 and the second planar region 29A in the reaction vessel 12 are the same as those in the second embodiment.

  FIG. 19 is an explanatory diagram of the reaction vessel 12 in the present embodiment. As in the second embodiment (see FIG. 10), the reaction vessel 12 has a plate-like member 29 having a second flat region 29A, a plate-like member 27 having a first flat region 26, and the like in the reaction vessel 12. And a support portion 25 for supporting them.

  A second seed crystal 300 is installed in the reaction vessel 12.

  In the present embodiment, the fifth to seventh steps are performed as in the third embodiment. Thereby, the group 13 nitride crystal 401 is manufactured.

  In the sixth step, in the mixed melt 24, the bottom surface of the second seed crystal 300 is in contact with the first planar region 26, and the longitudinal direction Y of the second seed crystal 300 is substantially the air-liquid interface 24A. The second seed crystal 300 is arranged so as to be parallel. At this time, the end of the second seed crystal 300 on the gas-liquid interface 24A side is preferably disposed in the vicinity of the second planar region 29A, and is disposed so as to be in contact with the second planar region 29A. Further preferred.

  In the present embodiment, the seventh step is performed under the same conditions as in the third embodiment except that the second planar region 29A is further provided in the reaction vessel 12.

  FIG. 20 is an explanatory diagram of the manufacturing process of the group 13 nitride crystal of the present embodiment. FIG. 20 uses the second seed crystal 300. FIG. 20 shows an environment in which the second planar region 29A and the first planar region 26 are configured by installing a plate-like member 27 and a plate-like member 29 in the reaction vessel 12 (see FIG. 19). ), The case of crystal growth was shown.

  In the example shown in FIG. 20, the first seed crystal 150 (see Embodiment 1) is grown as the second seed crystal 300 through the first to fourth steps of the first embodiment. The example using the manufactured second seed crystal 300 was shown.

  In the sixth step, as shown in FIG. 20A, the opposing surface of the main surface of the second seed crystal 300 is in contact with the first planar region 26 of the plate-like member 27, and the longitudinal direction Y ( The second seed crystal 300 is arranged so that (not shown) is substantially parallel to the gas-liquid interface 24A (see FIG. 19). In the example shown in FIG. 20A, as the sixth step, an example is shown in which the end of the second seed crystal 300 on the gas-liquid interface 24A side is in contact with the second planar region 29A of the plate-like member 29. It was.

  As shown in FIGS. 20B to 20C, in the seventh step, the mixed melt 24 is formed in the reaction vessel 12, and the {10− Crystal growth of the group 13 nitride crystal 401 is started from the 11} plane. Then, the crystal growth is continued while enlarging the {10-11} plane of the group 13 nitride crystal 401 that has started crystal growth.

  Crystal growth conditions in the sixth step and the seventh step are the same as those in the third embodiment.

  FIG.11 (c)-FIG.11 (e) are explanatory drawings of a 4th process.

  Specifically, the crystal region in contact with the mixed melt 24 in the group 13 nitride crystal 401 that has started crystal growth from the {10-11} plane of the second seed crystal 300 protrudes from the second seed crystal 300. grow up. In addition, the region on the second planar region 29A side in the group 13 nitride crystal 401 grows along the second planar region 29A. For this reason, the group 13 nitride crystal 401 forms a plane substantially parallel to the gas-liquid interface 24A and grows.

  By this crystal growth, a group 13 nitride crystal 401 larger than the second seed crystal 300 is obtained.

  The crystal-grown group 13 nitride crystal 401 has a large area on the bottom surface side in contact with the plate member 27, and the cross-sectional shape perpendicular to the longitudinal direction Y of the second seed crystal 300 has the second seed crystal 300 side as the bottom. It is a substantially square shape.

  FIG. 21 and FIG. 22 are schematic views showing a group 13 nitride crystal 401 having undergone crystal growth. FIG. 21 is a schematic diagram showing a perspective view of a group 13 nitride crystal 401 having undergone crystal growth. FIG. 22A is a schematic view of the grown group 13 nitride crystal 401 as viewed from the opposite side of the bottom surface (side in contact with the second seed crystal 300). FIG. 22B is a cross-sectional view taken along the line A-A ′ of FIG.

  The crystal-grown group 13 nitride crystal 401 has a substantially quadrangular shape in which the cross section of the second seed crystal 300 perpendicular to the longitudinal direction Y has a base on the second seed crystal 300 side. Of the surfaces constituting group 13 nitride crystal 401, the bottom surface is the (000-1) plane of the c-plane.

  In addition, the surface of the group 13 nitride crystal 401 on the second planar region 29A side grows along the second planar region 29A. For this reason, the group 13 nitride crystal 401 has a plane substantially parallel to the gas-liquid interface 24A.

  Further, of the two faces that form the group 13 nitride crystal 401 and are continuous with the bottom face, the face grown in contact with the mixed melt 24 is a flat {10-11} face.

  Although microcrystals 404 (see FIG. 20) may slightly adhere to the bottom surface of group 13 nitride crystal 401, growth is limited by first planar region 26 of plate-like member 27.

  Through the above steps, the group 13 nitride crystal 401 can be manufactured.

(Embodiment 5)
In the present embodiment, a method for manufacturing a group 13 nitride crystal substrate from the group 13 nitride crystal manufactured in the above embodiment will be described.

  The manufacturing method of the present embodiment includes a processing step of processing the group 13 nitride crystal manufactured in the above embodiment so that the c-plane, nonpolar plane, or semipolar plane is the main plane.

  A nonpolar plane is a crystal plane of a group 13 nitride crystal having a hexagonal crystal structure in which the number of group 13 atoms and nitrogen atoms is the same in the crystal plane and the charge is not biased and has no polarity in the crystal axis direction. is there. Specifically, the nonpolar plane is an m plane or a plane of a hexagonal crystal.

  The semipolar plane is a crystal plane excluding the c plane and the nonpolar plane, which are polar planes composed of only group 13 atoms or nitrogen atoms. The semipolar plane is defined as semipolar because the number of group 13 atoms and nitrogen atoms are not equal and the charge balance is lost and the polarity is polar, but the degree is between the c-plane polar plane and the nonpolar plane. Has been. Specifically, there are {10-11} plane, {20-21} plane, {11-22} plane, {-1103} plane, etc. of hexagonal crystals (other than c plane and nonpolar plane) All crystal planes are semipolar planes).

  The processing method used in the processing step may be a known method and is not limited.

Since the mixed melt 24 in which the group 13 nitride crystal is grown contains alkali metal, the crystal of the group 13 nitride substrate of the present embodiment contains a small amount of alkali metal as an impurity. In a GaN crystal grown using sodium as an alkali metal, 10 ¹⁴ to 10 ¹⁵ cm ⁻³ sodium is detected by SIMS analysis. The group 13 nitride crystal substrate of the present embodiment is a substrate obtained by processing a group 13 nitride crystal whose main growth surface is a {10-11} plane. For this reason, in the group 13 nitride crystal substrate of the present embodiment, inclusion of metal sodium, metal gallium, and a mixture thereof as they are into the crystal is suppressed.

  Further, since the main surface of the group 13 nitride crystal substrate of the present embodiment is a c-plane, a nonpolar plane, or a semipolar plane, a light-emitting device having an InGaN active layer is manufactured using these substrates. Thus, it is possible to suppress a decrease in light emission efficiency and blue shift of the InGaN active layer having a high In composition. As a result, a semiconductor laser that oscillates in the green wavelength region and a high-power LED can be manufactured.

  In addition, in the group 13 nitride crystal substrate of the present embodiment, the (10-11) plane, the (−1011) plane, the (10-1-1) plane, or the (−101−) whose main surface is semipolar. The substrate which is 1) surface can suppress the light emission efficiency reduction and the blue shift of the InGaN active layer having a high In composition by manufacturing a light emitting device having an InGaN active layer using this substrate. As a result, a semiconductor laser that oscillates in the green wavelength region and a high-power LED can be manufactured.

  Examples are shown below to describe the present invention in more detail, but the present invention is not limited to these Examples. The reference numerals correspond to the respective configurations described above with reference to the drawings.

Example 1
In this example, along with the steps shown in FIGS. 5 and 6, crystal growth was performed using the manufacturing apparatus 1 (see FIG. 9), and the group 13 nitride crystals 103 and 151 were manufactured. In this example, GaN (gallium nitride) was manufactured as the group 13 nitride crystals 103 and 151 using sodium as the alkali metal and gallium as the group 13 metal.

―First step―
First, first seed crystals 100 and 150 were prepared.

  In this example, as the first seed crystal 100, a group 13 nitride crystal 102 was formed by epitaxially growing GaN by MOCVD as a group 13 nitride crystal 103 on a sapphire substrate as a different substrate 101. Thus, a φ2 inch template substrate was produced and cut into a strip shape, thereby producing a first seed crystal 100.

  At the time of cutting, the first seed crystal 100 was cut so that the longitudinal direction thereof was substantially parallel to the a-axis of GaN that is the group 13 nitride crystal 103. Specifically, using a dicing apparatus, along the m-axis of the sapphire substrate as the heterogeneous substrate 101, a plurality of grooves are formed by cutting from the back surface side of the substrate to the middle of the substrate, and then applying pressure. It was divided over. In this way, a strip-shaped first seed crystal 100 was produced in which the longitudinal direction was along the m-axis of the sapphire substrate, that is, the longitudinal direction was substantially parallel to the a-axis of GaN as the group 13 nitride crystal 102. (See FIG. 1).

  The major surface 100A (GaN-side surface) of the produced first seed crystal 100 had a length in the longitudinal direction of 45 mm, and the width (the length in the short direction) of the major surface 100A was 1 mm.

  The first seed crystal 150 was prepared by the following process. In this example, a crystal cut into a strip shape from a φ2 inch GaN free-standing substrate (manufactured by HVPE) having a (0001) plane as a main surface was prepared as the first seed crystal 150.

  Specifically, the first seed crystal 150 was cut into a strip shape by winding the back surface of the GaN free-standing substrate (made of HVPE) several times along the a-axis (m-plane) of GaN.

  The cut first seed crystal 150 corresponds to the first seed crystal 150 described above, and is a single crystal made of the same material as a whole. The cut first seed crystal 150 was in the shape of a strip whose longitudinal direction was substantially parallel to the a-axis of GaN (that is, the longitudinal direction substantially coincided with the a-axis) (see FIG. 2).

  The length of the first seed crystal 150 in the longitudinal direction was 45 mm and the width was 0.8 mm.

  Next, the 2nd process-the 4th process were performed using manufacturing device 1 shown in FIG.

-Second step-
First, a container made of YAG was prepared as the reaction container 12. And the support part 25 was installed in the bottom part inside the reaction container 12 (refer FIGS. 3-4). A plate-like member 27 having the first planar region 26A and the first planar region 26B as two opposing surfaces was prepared and supported by the support portion 25. Note that the support portion 25 is configured such that the first planar region 26 (first planar region 26A, first planar region 26B) of the plate-like member 27 is against the gas-liquid interface 24A of the mixed melt 24 held in the reaction vessel 12. The plate member 27 was supported so as to be vertical.

  In this embodiment, alumina is used as the support portion 25 and the plate-like member 27. The plate-like member 27 is provided with a plurality of screw holes so as to penetrate the first planar area 26B from the first planar area 26A.

  In this example, after the first seed crystal 100 and the first seed crystal 150 were installed on the plate-like member 27, the plate-like member 27 was supported by the support portion 25 in the reaction vessel 12.

  More specifically, the first seed crystal 100 is installed in the first planar region 26 </ b> A of the first planar region 26. At this time, both end portions in the longitudinal direction Y of the first seed crystal 100 are fixed by screw 30 through screw holes so that the longitudinal direction Y of the first seed crystal 100 is parallel to the gas-liquid interface 24A. .

  In addition, the first seed crystal 150 was placed in the first planar region 26 </ b> B of the first planar region 26. At this time, both ends of the first seed crystal 150 in the longitudinal direction Y are fixed by screws 30 through screw holes so that the longitudinal direction Y of the first seed crystal 150 is parallel to the gas-liquid interface 24A. .

  In this embodiment, the opposing surface 100B of the main surface 100A of the first seed crystal 100 is fixed in close contact with the first planar region 26 of the plate-like member 27. As a result, the bottom surface side of the grown group 13 nitride crystal 103, that is, the (000-1) c-plane nitrogen polar surface faces the first planar region 26 side. Here, the (000-1) plane is easily polycrystallized. For this reason, in order to grow a single crystal, it is desired not to continue the growth on the (000-1) plane side. In the present example, the first seed crystal 100 was placed so that the (000-1) plane faces the first planar region 26 side. For this reason, the growth on the (000-1) plane side of the group 13 nitride crystal 103 is not continued, and polycrystallization can be suppressed.

  Note that the support portion 25 and the plate-like member 27 can be detached from the reaction vessel 12.

  The pressure vessel 11 having the reaction vessel 12 therein was separated from the production apparatus 1 at the valve 21 portion, and placed in a glove box having a high purity Ar atmosphere with oxygen of 1 ppm or less and dew point of -80 ° C. or less.

-Third step-
Next, 220 g of gallium (Ga) as a group 13 metal raw material and 154 g of sodium (Na) as a flux were charged into the reaction vessel 12. Note that the molar ratio of gallium to sodium was 0.32: 0.68. Further, 0.72 g of carbon was added to the reaction vessel 12. Sodium was dissolved and made into a liquid state, then placed in the reaction vessel 12 and solidified, and then gallium and carbon were added.

  Next, the reaction vessel 12 was covered with a lid 41 and then placed in the pressure vessel 11.

  Next, the pressure vessel 11 was sealed, the valve 21 was closed, and the inside of the reaction vessel was shut off from the external atmosphere. The series of operations in the manufacturing apparatus 1 were performed in a glove box having a high-purity Ar gas atmosphere. For this reason, the pressure vessel 11 was filled with Ar gas.

  Next, the pressure vessel 11 was taken out of the glove box and incorporated in the manufacturing apparatus 1. Specifically, the pressure vessel 11 was installed at a predetermined position of the heater 13 and connected to a nitrogen and argon gas supply pipe 14 at the valve 21 portion. Next, the valve 21 and the valve 18 were opened, Ar gas was introduced from the gas supply pipe 20, and the internal space 23 of the pressure vessel 11 was filled with Ar gas. At this time, since gas enters from the gap between the reaction vessel 12 and the lid 41, the internal space 28 in the reaction vessel 12 was also filled with Ar gas. Next, the pressure was adjusted by the pressure control device 19 so that the total pressure in the pressure-resistant vessel 11 was 2.6 MPa, and the valve 18 was closed.

  Next, nitrogen gas was introduced from the nitrogen supply pipe 17, the pressure was adjusted by the pressure control device 16, the valve 15 was opened, and the total pressure in the pressure-resistant vessel 11 was set to 4 MPa. That is, the partial pressure of nitrogen in the internal space 23 of the pressure vessel 11 was 1.4 MPa. Thereafter, the valve 15 was closed and the pressure control device 16 was set to 8 MPa.

  Next, the heater 13 was energized to raise the temperature of the reaction vessel 12 to the crystal growth temperature. The crystal growth temperature was 870 ° C. At the crystal growth temperature, gallium and sodium in the reaction vessel 12 melted to form a mixed melt 24. Note that the temperature of the mixed melt 24 is the same as the temperature of the reaction vessel 12. Further, when the temperature was raised to this temperature, in the manufacturing apparatus 1 of the present example, the gas in the pressure resistant vessel 11 was heated and the total pressure was 8 MPa. That is, the nitrogen partial pressure was 2.8 MPa.

  Next, the valve 15 was opened and a nitrogen gas pressure was applied at 8 MPa. This is because the nitrogen partial pressure in the pressure vessel 11 is maintained at 2.8 MPa even when nitrogen is consumed by crystal growth of gallium nitride.

  In this way, nitrogen was dissolved in the mixed melt 24, and crystal growth of GaN as the group 13 nitride crystals 103 and 151 was started from the GaN on the main surfaces of the first seed crystals 100 and 150 (FIG. 5 (b) and FIG. 6 (b)).

-Fourth step-
Next, the temperature inside the reaction vessel 12 was maintained at 870 ° C. and the nitrogen gas partial pressure was maintained at 2.8 MPa, and crystal growth was continued for 300 hours. The GaN single crystal which is the group 13 nitride crystal 103, 151 starts crystal growth from the main surface of the first seed crystal 100, 150, and when the crystal growth is continued, the crystal region in contact with the mixed melt 24 is changed. The crystal grew out of the main surface of the first seed crystals 100 and 150.

  In this example, the {10-11} plane was the main crystal growth plane, and it was observed that the crystal growth continued while the area of the {10-11} plane was increased (FIG. 5 (c) to FIG. 5). 5 (e), FIG. 6 (c) to FIG. 6 (e)). Then, after continuing crystal growth for 300 hours, the heater 13 was turned off, and the temperature of the mixed melt 24 was lowered to room temperature.

  When the pressure vessel 11 was opened after the pressure of the gas in the pressure vessel 11 was lowered, the group 13 nitride crystals 103 and 151 were grown on the first seed crystals 100 and 150 in the reaction vessel 12, respectively. (See FIGS. 5 (e) and 6 (e)).

―Evaluation of group 13 nitride crystals―
GaN as the group 13 nitride crystals 103 and 151 obtained by this crystal growth had the shape shown in FIGS. Specifically, the GaN single crystal as the group 13 nitride crystals 103 and 151 obtained by this crystal growth has a cross-sectional shape perpendicular to the longitudinal direction Y of the first seed crystals 100 and 150. It was triangular with the 100 and 150 sides as the base.

  Of the surfaces constituting group 13 nitride crystals 103, 151, the bottom surface (the surface on the first seed crystal 100, 150 side) was the c-plane (000-1) plane.

  Of the surfaces constituting group 13 nitride crystals 103 and 151, two surfaces continuous to the bottom surface were relatively flat {10-11} surfaces.

  In addition, indentations 105 and 153 were formed slightly along the longitudinal direction Y of the first seed crystals 100 and 150 on the opposite sides of the bottom surfaces of the group 13 nitride crystals 103 and 151, respectively. The size of the recess 153 was smaller than that of the recess 105.

  Further, among the two planes ({10-11} plane) continuous to the bottom surface of the group 13 nitride crystals 103 and 151, the {10-11} plane grown on the gas-liquid interface 24A side has fine crystal grains. One to two crystals were attached. On the other hand, no adhesion of miscellaneous crystals was observed on the {10-11} plane of the two planes that had grown on the opposite side of the gas-liquid interface 24A.

  Further, a c-plane nitrogen polar plane (000-1) plane was formed on the bottom surface of the GaN single crystal as the group 13 nitride crystals 103 and 151. Microcrystals 104 and 152 were slightly attached to this surface (see FIGS. 5 and 6), but crystal growth was limited by the first planar region 26. In addition, the first seed crystals 100 and 150 were located at substantially central portions of the bottom surfaces of the group 13 nitride crystals 103 and 151, respectively.

  In addition, cracks occurred in the sapphire substrate as the different substrate 101 in the first seed crystal 100. On the other hand, no cracks were observed in the first seed crystal 150.

  The size of the GaN single crystal as the group 13 nitride crystals 103 and 151 obtained by crystal growth is about 40 mm in the longitudinal direction Y on the bottom surface, and the length (width) of the bottom surface corresponding to the bottom of the triangular cross section. Was 12 mm, and the height (the length from the bottom to the intersection of the two {10-11} planes) was about 11 mm.

As a result of SIMS (Secondary Ion Mass Spectrometry) analysis of the GaN single crystals as the group 13 nitride crystals 103 and 151, 10 ¹⁴ to 10 ¹⁵ cm ⁻³ of sodium was detected. Further, GaN single crystals as the group 13 nitride crystals 103 and 151 contained sodium at an impurity level, but metal gallium, metal sodium, or gallium and sodium that cause cracks and voids are generated. There was no inclusion of any alloy.

(Example 2)
In this example, the reaction vessel 12 shown in FIG. 10 provided with the plate-like member 27, the support portion 25, and the plate-like member 29 is used as the reaction vessel 12, and the first seed crystal 150 is used as the first seed crystal. Was used.

  Specifically, in this example, the group 13 nitride crystal 201 was manufactured by performing crystal growth using the manufacturing apparatus 1 (see FIG. 9) along the steps shown in FIG. In this example, sodium was used as the alkali metal, gallium was used as the group 13 metal, and GaN (gallium nitride) was manufactured as the group 13 nitride crystal 201.

―First step―
As the first seed crystal 150, the same first seed crystal 150 as in Example 1 was prepared.

  Next, the 2nd process-the 4th process were performed using manufacturing device 1 shown in FIG.

-Second step-
First, an alumina container having an inner diameter of 92 mm and a purity of 99.99% was prepared as the reaction container 12. And the support part 25 was installed in the bottom part inside the reaction container 12 (refer FIG. 10).

  Specifically, a plate-like member 27 having the first flat area 26 </ b> A and the first flat area 26 </ b> B as two opposing surfaces was prepared and supported by the support portion 25. Note that the support portion 25 is configured such that the first planar region 26 (first planar region 26A, first planar region 26B) of the plate-like member 27 is against the gas-liquid interface 24A of the mixed melt 24 held in the reaction vessel 12. The plate member 27 was supported so as to be vertical.

  And the plate-shaped member 29 provided with the 2nd plane area | region 29A was prepared. The plate-like member 29 was supported by the plate-like member 27 so that the second planar region 29A was parallel (that is, horizontal) to the gas-liquid interface 24A.

  In this embodiment, alumina is used as the plate member 29, the support portion 25, and the plate member 27. The plate-like member 27 is provided with a plurality of screw holes so as to penetrate the first planar area 26B from the first planar area 26A.

  In the present embodiment, the plate member 29 is fixed to the plate member 27 so that the second planar region 29 </ b> A is in contact with the plate member 27. And after installing the 1st seed crystal 150 in the plate-shaped member 27 to which this plate-shaped member 29 was fixed, this plate-shaped member 27 was supported by the support part 25 in the reaction container 12.

  Specifically, the first seed crystal 150 is installed in the first planar region 26 </ b> A of the first planar region 26. At this time, both ends of the first seed crystal 150 in the longitudinal direction Y are fixed by screws 30 through screw holes so that the longitudinal direction Y of the first seed crystal 150 is parallel to the gas-liquid interface 24A. . The first seed crystal 150 was placed so that the surface of the first seed crystal 150 on the gas-liquid interface 24A side was in contact with the second planar region 29A.

  Further, the first seed crystal 150 was similarly installed in the first planar region 26B of the first planar region 26.

  Note that the support portion 25, the plate-like member 27, and the plate-like member 29 can be detached from the reaction vessel 12.

  The pressure vessel 11 having the reaction vessel 12 therein was separated from the production apparatus 1 at the valve 21 portion, and placed in a glove box having a high purity Ar atmosphere with oxygen of 1 ppm or less and dew point of -80 ° C. or less.

  Next, the 3rd process-the 4th process were performed using manufacturing device 1 shown in FIG.

  In this example, the production apparatus 1 was used in the same manner as in Example 1, and the production was performed under the same crystal conditions as in Example 1. That is, the third to fourth steps were performed in the same manner as in Example 1 with respect to crystal growth conditions such as the amount of raw material charged, growth temperature, nitrogen gas partial pressure, and growth time.

  Thereby, crystal growth of GaN as the group 13 nitride crystal 201 was started from the GaN of the main surface of the first seed crystal 150 (see FIGS. 11A and 11B).

  Then, by the fourth step, it was observed that the {10-11} plane becomes the main crystal growth plane and the crystal growth is continued while the area of the {10-11} plane is enlarged (FIG. 11 (c)). To FIG. 11 (e)). Then, after continuing crystal growth for 300 hours, the heater 13 was turned off, and the temperature of the mixed melt 24 was lowered to room temperature.

  When the pressure vessel 11 was opened after the pressure of the gas in the pressure vessel 11 was lowered, the group 13 nitride crystal 201 was grown on the first seed crystal 150 in the reaction vessel 12 (FIG. 11 (e)). )reference).

―Evaluation of group 13 nitride crystals―
GaN as the group 13 nitride crystal 201 obtained by this crystal growth has the shape shown in FIGS. Specifically, in the GaN single crystal as the group 13 nitride crystal 201 obtained by this crystal growth, the shape of the cross section perpendicular to the longitudinal direction Y of the first seed crystal 150 has a base on the first seed crystal 150 side. It was a substantially right triangle shape.

  Further, the surface of the group 13 nitride crystal 201 on the second planar region 29A side grew along the second planar region 29A. For this reason, the group 13 nitride crystal 201 has a shape having a plane substantially parallel to the gas-liquid interface 24A.

  Moreover, the surface which contacted the mixed melt 24 among the 2 surfaces which comprise the group 13 nitride crystal 201 and continued to the bottom face was a relatively flat {10-11} surface. Further, during crystal growth, no adhering of miscellaneous crystals was observed on the {10-11} plane facing the side opposite to the gas-liquid interface 24A side.

  In addition, a c-plane nitrogen polar plane (000-1) plane was formed on the bottom surface of the GaN single crystal as the group 13 nitride crystal 201. Although microcrystals 202 were slightly attached to this surface (see FIG. 11), crystal growth was restricted by the first planar region 26.

  The size of the GaN single crystal as the group 13 nitride crystal 201 obtained by crystal growth is such that the length in the longitudinal direction Y on the bottom surface is about 40 mm, and the length (width) of the bottom surface corresponding to the bottom of the triangular section is 6 mm. The height (the length from the bottom to the intersection of the two {10-11} planes) was about 11 mm.

In addition, as a result of SIMS (Secondary Ion Mass Spectrometry) analysis of the GaN single crystal as the group 13 nitride crystal 201, 10 ¹⁴ to 10 ¹⁵ cm ⁻³ of sodium was detected. In addition, the GaN single crystal as the group 13 nitride crystal 201 contains sodium at the impurity level, but metal gallium, metal sodium, or an alloy of gallium and sodium that causes generation of cracks and voids. There was no such inclusion.

(Example 3)
In this example, instead of the first seed crystals 100 and 150 used in Example 1, the second seed crystal 300 used in the third embodiment was used as a seed crystal.

  Specifically, in this embodiment, crystal growth is performed using the manufacturing apparatus 1 (see FIG. 9) along the process shown in FIG. 16, and the group 13 nitride crystal 301 is formed using the second seed crystal 300. Manufactured. In this example, sodium was used as the alkali metal, gallium was used as the group 13 metal, and GaN (gallium nitride) was manufactured as the group 13 nitride crystal 301.

-Fifth process-
First, two second seed crystals 300 were prepared. In this example, a GaN single crystal manufactured by the flux method was prepared as the second seed crystal 300. This second seed crystal 300 is a group 13 nitride in which the a-axis in one direction out of the three a-axes of the group 13 nitride crystal is the longitudinal direction, and the cross section in the orthogonal direction perpendicular to the longitudinal direction is triangular. A physical crystal was prepared. The group 13 nitride crystal as the second seed crystal 300 has a long bottom surface in the longitudinal direction (000-1) among three surfaces that are continuous in the longitudinal direction on each of three sides constituting the triangular cross section (000-1). The other two surfaces that are continuous with the bottom surface were the (10-11) surface and the (-1011) surface.

  That is, the second seed crystal 300 used in this example is the second seed crystal 300 described with reference to FIG.

  That is, the second seed crystal 300 has an AA ′ cross section (a cross section in a direction orthogonal to the longitudinal direction Y) having a triangular shape and a bottom surface having a hexagonal shape, and extends in one a-axis <11-20> direction. It is a stick-shaped single crystal. The bottom surface of the second seed crystal 300 is the (000-1) c-plane nitrogen polar surface, and the slope continuous with the bottom surface is the {10-11} plane (in FIG. 14, (-1011) plane, (10-11) plane reference). ).

  The second seed crystal 300 has a strip-shaped first seed crystal 150 placed on the bottom of the reaction vessel 12 with the (0001) c plane facing upward, and crystal growth is performed while forming a {10-11} plane. It is what was manufactured. In addition, as the second seed crystal 300 used in this example, a material having no microcrystals adhered to the (−1011) plane and the (10-11) plane was selected and used.

  The length of the produced second seed crystal 300 in the longitudinal direction is 50 mm, the length of the base of the triangular cross section (the side constituting the bottom surface ((000-1) plane)) is 5 mm, and the height (from the base) The length to the opposite vertex of the triangular cross section) was 4.7 mm.

-6th and 7th steps
Next, the 6th process-the 7th process were performed using manufacturing device 1 shown in FIG.

  In this example, the production apparatus 1 was used in the same manner as in Example 1, and the production was performed under the same crystal conditions as those in the second to fourth steps of Example 1. For this reason, details different from the first embodiment will be described.

  First, in this example, an alumina container having an inner diameter of 92 mm and a purity of 99.99% was prepared as the reaction container 12. And the support part 25 was installed in the bottom part inside the reaction container 12 (refer FIG. 15). A plate-like member 27 having the first planar region 26A and the first planar region 26B as two opposing surfaces was prepared and supported by the support portion 25. Note that the support portion 25 is configured such that the first planar region 26 (first planar region 26A, first planar region 26B) of the plate-like member 27 is against the gas-liquid interface 24A of the mixed melt 24 held in the reaction vessel 12. The plate member 27 was supported so as to be vertical.

  In this embodiment, alumina is used as the support portion 25 and the plate-like member 27. The plate-like member 27 is provided with a plurality of screw holes so as to penetrate the first planar area 26B from the first planar area 26A.

  In this example, after the second seed crystal 300 was installed on the plate-like member 27, the plate-like member 27 was supported by the support portion 25 in the reaction vessel 12.

  Specifically, the second seed crystal 300 is installed in the first planar region 26 </ b> A of the first planar region 26. At this time, both ends of the second seed crystal 300 in the longitudinal direction Y are fixed by screw 30 through screw holes so that the longitudinal direction Y of the second seed crystal 300 is parallel to the gas-liquid interface 24A. .

  In the present example, the (000-1) plane, which is the bottom surface of the second seed crystal 300, was fixed in close contact with the first planar region 26 of the plate-like member 27. At this time, the (10-11) plane of the second seed crystal 300 was installed facing the opposite side to the gas-liquid interface 24A (the bottom side of the reaction vessel 12).

  Further, the second seed crystal 300 was installed in the first planar region 26B of the first planar region 26 in the same manner as the first planar region 26A side.

  Note that the support portion 25 and the plate-like member 27 can be detached from the reaction vessel 12.

  The pressure vessel 11 provided with the reaction vessel 12 inside was put in a glove box in the same manner as in Example 1.

  Next, a group 13 nitride crystal 301 was grown under the same crystal growth conditions as in the third and fourth steps of the first embodiment (see FIG. 16).

―Evaluation of group 13 nitride crystals―
The GaN single crystal as the group 13 nitride crystal 301 obtained by this crystal growth had the shape shown in FIGS. Specifically, the GaN single crystal as the group 13 nitride crystal 301 obtained by this crystal growth has a shape of a cross section perpendicular to the a-axis direction that is the longitudinal direction Y of the second seed crystal 300 in the second kind. It was a triangular shape with the base on the crystal 300 side (that is, the (000-1) plane side).

  Further, of the surfaces (outer surfaces) constituting the group 13 nitride crystal 301, the surface grown in contact with the mixed melt 24 was a relatively flat {10-11} surface.

  In addition, in the group 13 nitride crystal 301, a recess 305 was formed along the longitudinal direction Y on the opposite side of the bottom surface.

  Of the two faces ({10-11} face) continuous to the bottom face of the group 13 nitride crystal 301, the {10-11} face (that is, the (-1011) face) grown on the gas-liquid interface 24A side. 1 to 2 microcrystals were attached. On the other hand, adhesion of miscellaneous crystals was not observed on the {10-11} plane (that is, the (10-11) plane) in which the crystal was grown on the opposite side of the gas-liquid interface 24A.

  In addition, a c-plane nitrogen polar plane (000-1) plane was formed on the bottom surface of the GaN single crystal as the group 13 nitride crystal 301. Microcrystals 304 were slightly attached to this surface (see FIG. 16), but crystal growth was restricted by the first planar region 26. In addition, each of the first seed crystals 300 was located at a substantially central portion of the bottom surface of the group 13 nitride crystal 301.

  The size of the GaN single crystal as the group 13 nitride crystal 301 obtained by crystal growth is such that the length in the longitudinal direction Y on the bottom surface is about 40 mm, and the length (width) of the bottom surface corresponding to the bottom of the triangular section is 17 mm. The height (the length from the base to the intersection of the two {10-11} planes) was about 16 mm.

In addition, as a result of SIMS (Secondary Ion Mass Spectrometry) analysis of the GaN single crystal as the group 13 nitride crystal 301, 10 ¹⁴ to 10 ¹⁵ cm ⁻³ of sodium was detected. This GaN single crystal contained sodium at the impurity level, but there was no inclusion such as metal gallium, metal sodium, or an alloy of gallium and sodium that would cause cracks and voids.

Example 4
In this example, the reaction vessel 12 shown in FIG. 10 provided with the plate-like member 27, the support portion 25, and the plate-like member 29 is used as the reaction vessel 12, and the second seed crystal 300 is used as the second seed crystal. Was used.

  Specifically, in this example, crystal growth was performed using the manufacturing apparatus 1 (see FIG. 9) along the process shown in FIG. In this example, sodium was used as the alkali metal, gallium was used as the group 13 metal, and GaN (gallium nitride) was manufactured as the group 13 nitride crystal 401.

-Fifth process-
As the second seed crystal 300, the same second seed crystal 300 as in Example 3 was prepared.

  Next, the 6th process-the 7th process were performed using manufacturing device 1 shown in FIG.

-Step 6-
First, an alumina container having an inner diameter of 92 mm and a purity of 99.99% was prepared as the reaction container 12. And the support part 25 was installed in the bottom part inside the reaction container 12 (refer FIG. 19). A plate-like member 27 having the first planar region 26A and the first planar region 26B as two opposing surfaces was prepared and supported by the support portion 25. Note that the support portion 25 is configured such that the first planar region 26 (first planar region 26A, first planar region 26B) of the plate-like member 27 is against the gas-liquid interface 24A of the mixed melt 24 held in the reaction vessel 12. The plate member 27 was supported so as to be vertical.

  And the plate-shaped member 29 provided with the 2nd plane area | region 29A was prepared. The plate-like member 29 was supported by the plate-like member 27 so that the second planar region 29A was parallel (that is, horizontal) to the gas-liquid interface 24A.

  In this embodiment, alumina is used as the plate member 29, the support portion 25, and the plate member 27. The plate-like member 27 is provided with a plurality of screw holes so as to penetrate the first planar area 26B from the first planar area 26A.

  In this embodiment, the plate-like member 29 is fixed to the plate-like member 27 with the second planar region 29 </ b> A on the plate-like member 27 side. And after installing the 2nd seed crystal 300 in the plate-shaped member 27 to which the plate-shaped member 29 was fixed, this plate-shaped member 27 was supported by the support part 25 in the reaction container 12.

  Specifically, in the present embodiment, the second seed crystal 300 is provided in the first planar region 26A of the first planar region 26. At this time, both ends of the second seed crystal 300 in the longitudinal direction Y are fixed by screw 30 through screw holes so that the longitudinal direction Y of the second seed crystal 300 is parallel to the gas-liquid interface 24A. . In addition, the second seed crystal 300 was placed so that the end of the second seed crystal 300 on the gas-liquid interface 24 </ b> A side was in contact with the second planar region 29 </ b> A of the plate member 29.

  Similarly, the second seed crystal 300 was placed on the first planar region 26 </ b> B of the first planar region 26.

  Note that the support portion 25, the plate-like member 27, and the plate-like member 29 can be detached from the reaction vessel 12.

  The pressure vessel 11 having the reaction vessel 12 therein was separated from the production apparatus 1 at the valve 21 portion, and placed in a glove box having a high purity Ar atmosphere with oxygen of 1 ppm or less and dew point of -80 ° C. or less.

  Next, the 7th process was performed using the manufacturing apparatus 1 shown in FIG.

  In this example, the production apparatus 1 was used in the same manner as in Example 3, and the production was performed under the same crystal conditions as in Example 3. That is, the seventh step was performed in the same manner as in Example 3 with respect to crystal growth conditions such as the amount of raw material charged, growth temperature, nitrogen gas partial pressure, and growth time.

  Thereby, the crystal growth of GaN as the group 13 nitride crystal 401 was started from the second seed crystal 300, and the crystal growth was continued (see FIG. 20B and FIG. 20C). Then, after continuing crystal growth for 300 hours, the heater 13 was turned off, and the temperature of the mixed melt 24 was lowered to room temperature.

  When the pressure vessel 11 was opened after the pressure of the gas in the pressure vessel 11 was lowered, a group 13 nitride crystal 401 was grown on the second seed crystal 300 in the reaction vessel 12 (FIG. 20 (c) )reference).

―Evaluation of group 13 nitride crystals―
GaN as the group 13 nitride crystal 401 obtained by this crystal growth has the shape shown in FIGS. Specifically, the GaN single crystal as the group 13 nitride crystal 401 obtained by this crystal growth has a cross-sectional shape perpendicular to the longitudinal direction Y of the second seed crystal 300, and the bottom of the second seed crystal 300 side. It was a substantially square shape.

  In addition, the surface of the group 13 nitride crystal 401 on the second planar region 29A side grew along the second planar region 29A. Therefore, the group 13 nitride crystal 401 has a shape having a plane substantially parallel to the gas-liquid interface 24A.

  Moreover, the surface which contacted the mixed melt 24 among two surfaces which comprise the group 13 nitride crystal 401 and continued to the bottom surface was a flat {10-11} surface. Moreover, no adhesion of miscellaneous crystals was observed on this {10-11} plane.

  In addition, a c-plane nitrogen polar plane (000-1) plane was formed on the bottom surface of the GaN single crystal as the group 13 nitride crystal 401. Although microcrystals 404 were slightly attached to this surface (see FIG. 20), crystal growth was restricted by the first planar region 26.

  The size of the GaN single crystal as the group 13 nitride crystal 401 obtained by crystal growth was about 40 mm in length in the longitudinal direction Y on the bottom surface, 11 mm in width on the bottom surface, and about 16 mm in height.

Further, as a result of SIMS (Secondary Ion Mass Spectrometry) analysis of the GaN single crystal as the group 13 nitride crystal 401, 10 ¹⁴ to 10 ¹⁵ cm ⁻³ of sodium was detected. In addition, the GaN single crystal as the group 13 nitride crystal 401 contains sodium at an impurity level, but metal gallium, metal sodium, or an alloy of gallium and sodium that causes generation of cracks and voids. There was no such inclusion.

12 Reaction vessel 26, 26A, 26B First planar region 29A Second planar region 100, 150 First seed crystal 300 Second seed crystal 103, 151, 201, 301, 401 Group 13 nitride crystal

International Publication No. 10/092736 JP 2005-12171 A JP 2010-37153 A

Claims (6)

A group 13 nitride in which nitrogen is dissolved from a gas phase in a mixed melt containing at least an alkali metal and a group 13 metal held in a reaction vessel, and a group 13 nitride crystal is grown in the mixed melt. In the method for producing a crystal,
The reaction vessel has a first plane region substantially perpendicular to a gas-liquid interface of the mixed melt held in the reaction vessel,
A strip-shaped first seed crystal is prepared, in which a crystal plane in which a group 13 nitride crystal grows by c-axis orientation is used as a main plane, and a longitudinal direction is substantially parallel to the a axis of the group 13 nitride crystal in which the crystal grows. The first step;
The first seed crystal is disposed so that the surface facing the main surface of the first seed crystal is in contact with the first planar region and the longitudinal direction is substantially parallel to the gas-liquid interface. Two steps,
Forming the mixed melt in the reaction vessel, and in the mixed melt, starting a crystal growth of a group 13 nitride crystal from the main surface of the first seed crystal;
A fourth step of continuing the crystal growth while expanding the area of the {10-11} plane, with the {10-11} plane of the group 13 nitride crystal starting crystal growth from the main plane as the main growth plane;
A method for producing a group 13 nitride crystal.   2. The method for producing a group 13 nitride crystal according to claim 1, wherein a surface of the main surface of the first seed crystal is a (0001) plane of gallium nitride. 3.   The method for producing a group 13 nitride crystal according to claim 1 or 2, wherein a length of the main surface of the first seed crystal in a direction orthogonal to the longitudinal direction is 1 mm or less. The reaction vessel has a second plane region substantially parallel to the gas-liquid interface of the mixed melt held in the reaction vessel,
In the third step and the fourth step, the first seed crystal grows by forming a plane substantially parallel to the gas-liquid interface on the mixed melt side. The method for producing a group 13 nitride crystal according to any one of the above. A group 13 nitride in which nitrogen is dissolved from a gas phase in a mixed melt containing at least an alkali metal and a group 13 metal held in a reaction vessel, and a group 13 nitride crystal is grown in the mixed melt. In the method for producing a crystal,
The reaction vessel has a first plane region substantially perpendicular to a gas-liquid interface of the mixed melt held in the reaction vessel,
A group 13 nitride crystal, wherein one of the three a-axis directions of the group 13 nitride crystal is a longitudinal direction, and each of three sides constituting a cross section perpendicular to the longitudinal direction Of the three surfaces that are continuous in the longitudinal direction, the bottom surface is the (000-1) surface that is long in the longitudinal direction, and at least one of the other two surfaces that are continuous to the bottom surface is the (10-11) surface or (−1011). ) A fifth step of preparing a second seed crystal that is a plane;
In the mixed melt, the second seed crystal is formed so that the bottom surface of the second seed crystal is in contact with the first plane region and the longitudinal direction is substantially parallel to the gas-liquid interface. A sixth step of arranging;
The mixed melt is formed in the reaction vessel, and crystal growth of a group 13 nitride crystal is started from the {10-11} plane of the second seed crystal in the mixed melt, and crystal growth is started. A seventh step of continuing crystal growth while expanding the {10-11} plane of the group 13 nitride crystal;
A method for producing a group 13 nitride crystal. The reaction vessel has a second plane region substantially parallel to the gas-liquid interface of the mixed melt held in the reaction vessel,
6. The group 13 nitride crystal according to claim 5, wherein in the seventh step, the second seed crystal grows by forming a plane substantially parallel to the gas-liquid interface on the mixed melt side. Production method.

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