JP6916719B2 - Method for producing Group III nitride single crystal laminate and Group III nitride single crystal laminate - Google Patents

Description

The present invention relates to a method for producing a Group III nitride single crystal laminate used for producing an optical device such as a light emitting diode (LED), and a Group III nitride single crystal laminate. In particular, the present invention relates to a method for producing an aluminum nitride single crystal laminate for producing a laminate with a high growth rate and a high yield while suppressing the formation of a polycrystalline body at the outer edge of the laminate.

Group III nitride semiconductors (Al _X Ga _Y In _Z N, X + Y + Z = 1, 0 ≦ X ≦ 1, 0 ≦ Y ≦ 1, 0 ≦ Z ≦ 1) have a direct transition type band structure and are therefore highly efficient. It is possible to manufacture a light emitting element. Such a group III nitride semiconductor device is formed on a single crystal substrate by a gas phase growth method such as a metalorganic vapor deposition (MOCVD) method or a molecular beam epitaxy (MBE) method. It is produced by crystal growth of a group III nitride semiconductor thin film. Among them, the MOCVD method is the most widely used method in the industry at present because the film thickness can be controlled at the atomic layer level and a relatively high growth rate can be obtained.

Further, as a single crystal substrate for crystal growth of a group III nitride semiconductor thin film, a known crystal growth method such as a sublimation (PVT: Physical Vapor Transport) method or a hydride vapor phase epitaxy (HVPE) method can be used. Group III nitride single crystal substrates such as gallium nitride (GaN) and aluminum nitride (AlN) have been used. In the PVT method, a group III metal gas (for example, aluminum gas) and nitrogen gas generated by sublimating a solid group III nitride at a high temperature are supplied onto a low temperature base substrate to precipitate a group III nitride single crystal. It is a method of growing by letting (see Patent Document 1). It has the advantage that it is possible to grow a thick film at a high growth rate. On the other hand, the HVPE method is a method for producing a single crystal by reacting a Group III halide gas (for example, aluminum chloride gas) with a nitrogen source gas (for example, ammonia gas) on a base substrate, and is a PVT method. Although the growth rate is slower than that of the above, there is an advantage that a single crystal having a low impurity concentration can be produced. Both of these are often used as methods for manufacturing a single crystal base substrate for a semiconductor device (see Patent Document 2).

Group III nitride single crystals such as GaN and AlN are known to have a hexagonal wurtzite structure and form various crystal planes. For example, polar planes {0001} plane (+ c plane, -c plane), non-polar planes {10-10} plane (m plane), {11-20} plane (a plane), and semi-polar plane. There is a {1-102} plane (r plane). Polarity indicates the directionality of the atomic arrangement. In a group III nitride single crystal, the {0001} plane is a (0001) plane (+ c plane) having a group III metal polarity (for example, an aluminum polarity in the case of an AlN single crystal) and a plane on the opposite side thereof, and has a nitrogen polarity. Includes (000-1) plane (-c plane) which is a plane. Specifically, a crystal in which a nitrogen atom is arranged vertically above the group III metal atom is called a group III metal polarity, and a crystal in which a group III metal atom is arranged vertically above the nitrogen atom is called a nitrogen polarity. The (0001) plane and the (000-1) plane on the opposite side have different characteristics.

For example, on the aluminum polar surface of an AlN single crystal, one nitrogen atom appearing on the surface is bonded to one aluminum atom, and on the nitrogen polar surface, one nitrogen atom appearing on the surface is bonded to three aluminum atoms. is doing. When a group III nitride semiconductor is grown on a polar surface of nitrogen, the growth rate is slow because the bonding force is weakened because there is only one bond with the group III atoms flying during the growth. Further, for the same reason, group III vacancies and the like are likely to be formed, and the crystal quality may be inferior to that in the case where the group III nitride semiconductor layer is grown on the polar surface of aluminum.

From the above, it may be unsuitable to use the nitrogen polar plane as the growth surface of the semiconductor thin film. Therefore, in general, the group III nitride semiconductor thin film is grown on the group III metal polar plane to nitride the nitride. Semiconductor devices are manufactured.

WO20102063853 Patent No. 3803788 Japanese Unexamined Patent Publication No. 2013-222902 Japanese Unexamined Patent Publication No. 2007-320849 Patent No. 5446945

In order to efficiently manufacture a nitride semiconductor device, it is necessary to be able to cut out as many nitride semiconductor devices as possible from a wafer obtained by laminating a group III nitride semiconductor thin film on a single single crystal substrate. Therefore, there is a demand for a group III nitride single crystal substrate having a large diameter. However, in the production of the Group III nitride single crystal substrate, when the Group III nitride single crystal layer is grown on the base substrate, a large amount of Group III nitride is formed at the end or the outer edge of the Group III nitride single crystal layer. It is known that crystals may grow convexly with respect to the surface of the single crystal layer. This polycrystal is called a crown, and becomes more prominent as the film thickness of the single crystal layer to be grown increases. Since the crystal quality of the crown and its vicinity is poorer than that of other regions and it cannot be used as a substrate for manufacturing semiconductor devices, a group III nitride semiconductor thin film is grown after cutting the crown generating portion. There are problems in terms of productivity, such as a decrease in the number of elements obtained from one single crystal substrate and an increase in the number of steps for cutting the crown generating portion.

Furthermore, when the group III nitride single crystal layer is thickened, the crown develops significantly as the growth time increases, which hinders the supply of the raw material gas to the substrate surface. Therefore, the single crystal in the region close to the crown. There is also a problem that the growth rate of the obtained group III nitride single crystal layer is reduced, the film thickness of the outer peripheral portion is smaller than that of the central portion, and the in-plane film thickness distribution is deteriorated. In particular, the generation of crowns is a phenomenon that occurs remarkably when the AlN single crystal layer on the (0001) plane is grown, and becomes a problem when obtaining the Group III nitride single crystal layer on the (0001) plane having a large film thickness. ing.

Various methods have been proposed so far as a method for suppressing the generation of crowns when obtaining a group III nitride single crystal layer. For example, in Patent Document 3, in order to suppress crown development during the growth of Group III nitride, a polycrystal containing a nitride is arranged around the outer periphery of the base substrate, and Group III nitride is precipitated on the polycrystal. A method of reducing the degree of supersaturation of the outer peripheral portion of the substrate is shown. However, according to this method, although the development rate of the crown can be reduced, there is room for further improvement in reducing the obstruction of the raw material gas supply because large protrusions similar to the crown develop in the surrounding polycrystalline body. there were.

Further, Patent Document 4 describes that GaN polycrystal growth on the side surface of a GaN single crystal can be suppressed by accommodating a GaN seed substrate in a susceptor having a seed substrate accommodating portion having a predetermined depth and growing the GaN seed substrate. There is. However, even in this case, although the development rate of the crown can be reduced, there is room for further improvement in reducing the obstruction of the raw material gas supply because a large convex portion similar to the crown develops at the corner of the seed substrate accommodating portion. was there.

Further, in Patent Document 5, the surface of the nitride semiconductor grown by using the base substrate having the (000-1) surface as the surface and the side surface having the inclined surface is grown so as to be larger than the surface of the base substrate. The manufacturing method to be carried out is shown. However, even if this method is used, the surface area may not be increased due to the generation of crowns. Further, as described above, when manufacturing a substrate for manufacturing a semiconductor device, the surface is preferably a (0001) plane, but the method of Patent Document 5 is not suitable for growth on the (0001) plane. ..

That is, an object of the present invention is to grow a group III nitride single crystal layer on a base substrate having the (0001) plane as a surface, in which the growth of the crown is suppressed and the in-plane thickness distribution of the single crystal layer is improved. It is an object of the present invention to provide a method for producing a group III nitride single crystal laminate to be produced.

In order to solve the above problems, the present inventors have investigated the growth conditions for growing a Group III nitride single crystal on a base substrate. As a result, regarding the ratio of the nitrogen atom weight and the group III atom weight of the nitrogen source gas which is the raw material gas and the group III source gas, the ratio supplied from each gas supply pipe and the ratio actually reaching the base substrate may differ greatly. Furthermore, it was found that there is a correlation between the ratio of the nitrogen atom weight reaching the base substrate and the group III atom weight and the growth of the crown. Therefore, as a result of further studies, it has been found that the generation of crowns can be suppressed by setting the ratio of the nitrogen atomic weight and the group III atomic weight reaching on the base substrate within a specific range, and the present invention has been completed.

That is, in the first invention, a group III nitride that grows a group III nitride single crystal layer on a base substrate made of a group III nitride single crystal by reacting a group III source gas with a nitrogen source gas. a method for producing a single crystal laminate, said base surface for growing a III nitride single crystal layer in the substrate is (0001) plane, the group-III nitride single crystal layer on the outer edge of the surface to be grown Group III nitride characterized by a time-dependent average value of the ratio of nitrogen atom weight to group III atom weight (nitrogen atom weight / group III atom weight) in the group III source gas and the nitrogen source gas reaching This is a method for producing a monocrystalline laminate.

In the production method of the present invention, the following aspects can be preferably adopted.
(1) The half width of the base substrate at a position 10 μm inward from the end with respect to the half width of the ^{E 2} _high peak detected by Raman spectroscopy at the center of the surface on which the Group III nitride single crystal layer is grown. The substrate shall have a ratio value (half-value width at a position 10 μm from the end / half-value width at the center) of 1.2 or less.
(2) Supply at least one halogen-based gas selected from hydrogen halide gas and halogen gas together with the group III source gas and nitrogen source gas.
(3) The base substrate is made of an aluminum nitride single crystal, and the group III nitride single crystal layer is an aluminum nitride single crystal layer.

According to the method for producing a Group III nitride single crystal laminate of the present invention, the generation of crowns can be suppressed even when the plane on which the Group III nitride single crystal of the base substrate is grown is the (0001) plane, so that the outer peripheral region can be suppressed. It is possible to improve the growth rate of the group III nitride single crystal layer and improve the in-plane film thickness distribution of the group III nitride single crystal layer. As a result, the growth time can be reduced and the productivity is improved. In the group III nitride single crystal laminate obtained by the production method of the present invention, the surface area of the group III nitride single crystal layer grown on the base substrate is the surface on which the group III nitride single crystal of the base substrate is grown. Since it can be grown to be larger than the area of, the obtained Group III nitride single crystal layer can be effectively used as a substrate for manufacturing a semiconductor device.

It is the schematic of the base substrate used in this invention. It is the schematic of an example of the vertical vapor phase deposition apparatus used in the manufacturing method of this invention. It is the schematic of an example of the horizontal vapor phase deposition apparatus used in the manufacturing method of this invention.

<Manufacturing method of Group III nitride single crystal laminate>
In the method for producing a Group III nitride single crystal laminate of the present invention, the surface on which the Group III nitride single crystal layer is grown (hereinafter, also referred to as “crystal growth surface”) in the base substrate composed of the Group III nitride single crystal is (hereinafter also referred to as “crystal growth surface”). 0001) plane, and further, the value of the ratio of the nitrogen atom weight to the group III atom weight in the group III source gas and the nitrogen source gas reaching on the outer edge of the crystal growth plane (nitrogen atom weight / group III atom weight, hereinafter "V /". It is characterized in that the time-dependent average value of (also referred to as "III value") is 0.5 to 3.0. The reason why the generation of crowns can be suppressed even when the crystal growth plane is the (0001) plane by such a production method of the present invention is unknown, but the present inventors speculate as follows.

That is, the group III nitride single crystal layer grows due to the reaction between the nitrogen source gas and the group III source gas on the crystal growth plane of the base substrate. At this time, the growth of the single crystal is in the vertical direction with respect to the crystal growth plane. proceed. However, it is presumed that the crystal growth direction is difficult to determine at the end of the base substrate where the crystal growth surface and the side surface of the crystal growth surface are in contact with each other, and crystal growth in multiple directions tends to occur and abnormal growth tends to occur. Will be done. When the crystal growth plane is the (0001) plane, the vertical direction is the [0001] direction (+ c-axis direction), and the parallel direction is the <11-20> direction (a-axis direction) or the <10-10> direction. (M-axis direction). Since the single crystal growth rate in each direction is + c-axis direction> a-axis direction> m-axis direction, if the crystal growth of the Group III nitride single crystal is performed without considering such a growth rate difference. It is presumed that crystal growth occurs in multiple directions and abnormal growth is likely to occur, the polycrystal grows, and a crown is generated.

On the other hand, in the production method of the present invention, by setting the V / III value at the end of the crystal growth surface within a specific range, the growth rate in the a-axis direction is particularly improved, and the parallel direction in the crystal growth of the end. It is presumed that the growth rate of is predominant. As a result, it is presumed that the crystal growth proceeds so that the diameter of the formed single crystal layer becomes larger with respect to the base substrate, and the occurrence of abnormal growth at the end can be suppressed.

In general, in order to ensure a sufficient crystal growth rate, the nitrogen source gas and the group III source gas are usually supplied with a V / III value of more than 1.0 as the supply amount from each gas supply port. It was thought that the V / III value, which was supplied and reached the base substrate, was also sufficient for crystal growth. However, the supplied nitrogen source gas and Group III source gas reach the crystal growth plane due to factors such as the temperature in the reaction system, the presence of carrier gas, and the difference in diffusion rate of each gas. It has been clarified by the examination by the present inventors that the temperature may be significantly reduced. Therefore, it is presumed that the generation of crowns could be suppressed for the first time by controlling the V / III value reaching the end of the crystal growth plane.

FIG. 1 shows a schematic view of a base substrate used in the manufacturing method of this experiment. The base substrate 1 has a surface (crystal growth surface) 2 for growing a group III nitride single crystal layer and a side surface 4 substantially perpendicular to the crystal growth surface 2. Further, at the end portion 5 where the crystal growth surface 2 and the side surface 4 are in contact with each other, and the outer edge portion 3 which is a region having a width of 1 mm from the end portion 5 to the center of the crystal growth surface 2 on the crystal growth surface 2. Has.

The V / III value reaching the end of the crystal growth surface greatly depends on the shape of the reactor, the distance between the base substrate and the raw material gas nozzle, the linear velocity of the gas supplied from the nozzle, the temperature environment in the reactor, and the like. Since they are different, the V / III value may be determined so as to be within the above range by performing a fluid analysis or the like according to the reaction apparatus to be used and the reaction conditions prior to the production.

Further, depending on the structure of the crystal growth apparatus and the crystal growth conditions, the crystal growth may be performed while rotating the support base that indicates the base substrate, that is, while rotating the base substrate, or the group III source gas and nitrogen. It is also conceivable to carry out crystal growth while changing the supply amount of the source gas. In the production method of the present invention, it is necessary to set the time-dependent average value of the V / III value that reaches the end of the crystal growth surface during crystal growth in the range of 0.5 to 3.0. If the V / III value over time is lower than 0.5, the crown formation rate increases, and if it is higher than 3.0, the crystal quality of the Group III nitride single crystal layer decreases. Not preferred.

The time-dependent average value of the V / III value is a constant value when the group III source gas and the nitrogen source gas are supplied in a constant supply amount without rotating the base substrate, but crystal growth occurs while rotating the base substrate. Or, when crystal growth is performed while changing the supply amounts of the group III source gas and the nitrogen source gas, the V / III value changes with time. When crystal growth is performed while rotating the base substrate, the average value over time of the V / III value reaching the end is the average of the maximum and minimum values of the V / III value reaching the end. .. On the other hand, when crystal growth is performed while changing the supply amounts of the group III source gas and the nitrogen source gas, the V / III value reaching the entire end and the weighted average value of the time supplied at that value are the average values over time. It becomes.

From the viewpoint of obtaining a high crystal growth rate and efficiently obtaining a high-quality single crystal layer, the average value over time of the V / III value reaching the end of the crystal growth surface is 0.6 to 2.8. , Especially preferably 0.7 to 2.5.

The crystal growth method in the production method of the present invention is a method of growing a group III nitride single crystal on a base substrate by reacting a group III source gas with a nitrogen source gas, and is known as such a crystal growth method. Method can be adopted. Specifically, as a crystal growth method, a PVT method using a group III metal gas as a group III source gas and a nitrogen gas as a nitrogen source gas by heating and sublimating a solid group III nitride, or a group III halogen. There are an HVPE method using a compound gas as a group III source gas, a MOCVD method using a III organic gas as a group III source gas, and the like. Among them, it is preferable to use the HVPE method capable of growing a group III nitride having a low impurity concentration at a relatively high speed.

<Base board>
The base substrate used in the production method of the present invention is not particularly limited as long as the plane on which the group III nitride single crystal layer is grown is the (0001) plane, and a known substrate can be used, but uniform crystal growth. A group III nitride single crystal such as a mixed crystal of aluminum nitride, gallium nitride, indium nitride, gallium nitride, etc. is preferable. In particular, as the base substrate, it is preferable to use a group III nitride single crystal of the same type as the group III nitride single crystal layer to be grown from the viewpoint of suppressing dislocations and cracks.

The shape of the base substrate may be any shape such as a circular shape, a polygonal shape, and an elliptical shape. However, in the manufacturing method of the present invention, the end portion of the base substrate grows in the <11-20> direction, and finally becomes stable in a hexagon with the {10-10} plane as the side surface. Therefore, it is preferable that the side surface of the base substrate is other than the {10-10} surface. However, an orientation flat, an index flat, or a notch may be formed in a part of the substrate in order to determine the orientation of the substrate, and a part of the side surface may be a {10-10} surface by these.

When the crystal quality of the outer edge portion of the crystal growth surface is low, the direction of crystal growth tends to be difficult to stabilize even at the outer edge portion, and polycrystals tend to be easily formed. Therefore, as the base substrate used in the present invention, it is preferable that the in-plane uniformity of the crystallinity of the crystal growth plane is high from the viewpoint of obtaining a uniform single crystal layer. The disorder of the crystallinity of the base substrate is likely to occur during processing of the base substrate (that is, cutting and polishing to a predetermined size), and is likely to occur at the edge or the outer edge of the base substrate.

Crystallinity can be evaluated by the half width of the ^{E 2} _high peak detected by Raman spectroscopy. The surface shape of the region outside 10 μm from the edge to the center is not stable, especially when it has an inclined surface, and it is difficult to focus the laser in Raman spectroscopic analysis. It may not be possible to be accurate. Therefore, the in-plane uniformity of the crystallinity of the base substrate can be evaluated by the full width at half maximum ^{of the E 2} _high peak at a point close to the end, which is measurable.

In general, the outer edge portion tends to have a damaged layer remaining due to the influence of processing, and the half width is larger than that of the center of the crystal growth plane. ^{In the present invention, the value of the ratio of the half width to the half width of the E 2} _high peak detected by Raman spectroscopy at the center of the crystal growth plane at a position 10 μm inside from the end (position 10 μm inside from the end). It is preferable that the substrate has a half-value width / center half-value width) of 1.2 or less. By using the above base substrate, abnormal growth of the outer edge portion can be suppressed. A commercially available microlaser Raman spectrophotometer can be used to evaluate the half width of the ^{E 2} _{high peak.} For example, a laser having a wavelength of 531.98 nm is used as an excitation laser, and the slit width and grating are adjusted so that a wavenumber resolution of ^{0.5 cm -1 or less can be obtained.} At the time of measurement, the excitation laser output is adjusted to about 10 mW, the measurement spot is set to a diameter of about 1 μm using an objective lens 100 times, and the excitation laser is irradiated to measure the local Raman spectrum. The half width ^{of the E 2} _high peak in the obtained spectrum is calculated. The E ² _high peak is detected at ^{657.4 cm -1} in the case of the aluminum nitride single crystal. The detected wave number of the peak may fluctuate depending on the stress of the substrate.

Further, from the viewpoint of suppressing chipping at the end portion of the base substrate and turbulence of the gas flow during growth, it is preferable to have an inclined surface at the outer edge portion of the base substrate. The inclined surface may be a crystal plane or not a crystal plane, and the width and depth of the inclined surface may be any distance.

Further, as the base substrate used in the present invention, stable step flow growth can be promoted on the surface to improve the crystal quality, and the manufactured Group III nitride single crystal laminate is used as the device manufacturing substrate. It may have an off-angle from the viewpoint that it can be easily put into an epiready state. The range of the off angle is ± 10 ° or less, more preferably 0.05 ° or more and 4 ° or less, and further preferably 0.1 ° or more and 2 ° or less.

Such a base substrate is manufactured by a known method such as a PVT method or an HVPE method. It is preferable to cut the produced boule with a wire saw or the like to form a substrate, and then CMP the surface of the substrate to flatten the substrate as a base substrate. After cutting, the outer edge often has rattling or voids, which are factors that promote crown growth. Therefore, it is preferable to remove the rattling and voids on the outer edge of the substrate by cutting or chamfering before or after performing CMP on the surface. However, since cutting or chamfering may damage the outer edge or scratch the surface, it is preferable to perform these processes before CMP.

<Crystal growth device>
As the manufacturing apparatus used in the manufacturing method of the present invention, a known manufacturing apparatus used in the vapor phase growth method can be used. Specifically, as such a manufacturing apparatus, a vertical manufacturing apparatus that supplies a group III source gas and a nitrogen source gas from a vertical direction to a support base on which a base substrate is placed, or a vertical manufacturing apparatus that supplies a nitrogen source gas from a direction parallel to the support base III. Examples include horizontal manufacturing equipment that supplies a family source gas and a nitrogen source gas.

FIG. 2 is a schematic view of an example of a vertical vapor deposition apparatus used in the manufacturing method of the present invention. The device 10 shown in FIG. 2 has a reaction tube 11, a base substrate 1 arranged inside the reaction tube, and a rotatable substrate support (susceptor) 12 on which the base substrate 1 is installed. The susceptor is heated by local heating means. It has a shower head type raw material gas supply nozzle 15 having a group III source gas supply port 13 for blowing out group III source gas from above the base substrate to the surface of the base substrate and a nitrogen source gas supply port 14 for blowing out nitrogen source gas. It also has a pushing gas supply nozzle that supplies a pushing gas for efficiently supplying a nitrogen source gas and a group III source gas to the surface of the substrate.

The vertical gas phase growth device of FIG. 2 is a manufacturing device that supplies the group III source gas and the nitrogen source gas to the base substrate from the vertical direction, but from the direction parallel to the base substrate as shown in FIG. When a horizontal gas phase growth device that supplies a group III source gas and a nitrogen source gas is adopted, the V / III values of the group III source gas and the nitrogen source gas that reach the end of the crystal growth surface of the base substrate are the above gases. It tends to be different in the place near the supply port and the place far from the supply port. Therefore, it is preferable to perform crystal growth while rotating the support, that is, rotating the base substrate, from the viewpoint that the V / III value reaching the entire end portion can be made uniform and a uniform single crystal layer can be easily obtained. The rotation speed of the support base may be appropriately determined according to the size and growth rate of the Group III nitride single crystal. If the rotation speed is too low, the averaging effect of the V / III value is weak, and if it is too high, it tends to affect the crystallinity of the Group III nitride single crystal. good.

<Group III source gas>
The group III source gas used in the production method of the present invention is not particularly limited, and a known raw material gas used in producing a group III nitride single crystal may be used. Among them, the effect of the present invention is remarkable when a group III source gas containing aluminum is used. For example, in the case of the HVPE method, an aluminum halide gas such as aluminum chloride gas or aluminum iodide gas is used. The aluminum halogenated gas is suitable as the raw material gas used in the present invention because it has high reactivity and a high growth rate can be obtained.

For example, the halogenated aluminum gas may be supplied by vaporizing solid aluminum halide, and the halogenated aluminum gas is produced by reacting metallic aluminum with a halogen-based gas for producing a raw material such as hydrogen chloride gas or chlorine gas. You may get it. When the halogenated aluminum gas is produced from metallic aluminum, it is preferable to use a solid having a purity of 99.99% or more as the aluminum as a raw material of the halogenated aluminum gas. The dimensions and shape of solid aluminum are not particularly limited, but in consideration of the contact efficiency between aluminum and the halogen-based gas for producing raw materials, the ease of circulation of the halogen-based gas, etc. in the equipment actually used. For example, pellets having a diameter of 0.1 to 10 mm and a length of 0.1 to 10 mm can be preferably used.

Further, the halogenated aluminum gas may be obtained by utilizing the reaction between the organometallic gas containing aluminum and the halogen-based gas for producing a raw material.

The group III source gas is preferably supplied on the base substrate together with the carrier gas. As the carrier gas, hydrogen gas and / or various inert gases can be used. As the carrier gas, one kind of gas may be used, or two or more kinds of gases may be mixed and used. Above all, it is preferable to use one or more kinds selected from hydrogen gas and nitrogen gas as the carrier gas in that it does not adversely affect the production of the Group III nitride single crystal. When the group III source gas is supplied in a state of being diluted with the carrier gas, the concentration of the group III source gas may be, for example, 0.0001 to 50% by volume. The supply amount of the group III source gas can be, for example, 0.005 to 500 sccm.

<Nitrogen source gas>
As the nitrogen source gas used in the production method of the present invention, a reactive gas containing nitrogen is adopted, but it is preferable to use ammonia gas in terms of cost and ease of handling.

This nitrogen source gas is usually diluted appropriately with the following carrier gas and supplied onto the base substrate. When supplying the carrier gas together with the carrier gas onto the base substrate, the supply amount of the nitrogen source gas and the supply amount of the carrier gas may be determined according to the size of the apparatus and the like.

Considering the ease of producing a Group III nitride single crystal and the like, the amount of carrier gas supplied is preferably in the range of 10 to 10000 sccm, and more preferably in the range of 50 to 5000 sccm. As the concentration of the nitrogen source gas, a practical concentration may be selected from the range of 0.001% by volume or more and 90% by volume or less with respect to the carrier gas. The amount of nitrogen source gas supplied is preferably in the range of 0.01 to 1000 sccm.

<Halogen gas>
In the production method of the present invention, it is preferable to contain at least one halogen-based gas selected from a hydrogen halide gas and a halogen gas together with the group III source gas and the nitrogen source gas. By supplying the halogen-based gas together with the group III source gas and the nitrogen source gas, when the group III nitride single crystal is grown, the polycrystal is decomposed at the outer edge portion, and the crown growth rate is suppressed. Examples of the halogen gas include chlorine gas and bromine gas. Examples of the hydrogen halide gas include hydrogen chloride gas and hydrogen bromide gas. Above all, it is preferable to use hydrogen chloride gas in consideration of low corrosiveness to the gas pipe, ease of handling and economy. The halogen-based gas can be supplied together with the group III source gas from the group III source gas supply nozzle, or can be supplied together with the nitrogen source gas from the nitrogen source gas supply nozzle. Further, the halogen-based gas alone or the halogen-based gas and the carrier gas may be supplied from a halogen-based gas supply nozzle arranged separately. Further, the nozzle may be supplied from the entire upstream side of the growth portion instead of the nozzle arranged so as to blow out onto the substrate, or may be supplied upward from around the susceptor by the supply port arranged below the susceptor. You may. The supply amount of the halogen-based gas is preferably 100 to 5000% by volume, more preferably 500 to 3000% by volume, based on the supply amount of the Group III source gas.

<Pushing gas>
In the present invention, in order to efficiently supply the raw material gas of the group III source gas and the nitrogen source gas onto the base substrate in the reactor at a predetermined V / III value, the group III source gas and the nitrogen source gas are used. It is preferable to supply a pushing gas into the reactor to form a flow of the raw material gas separately from the carrier gas used for supplying the gas. As the supply flow path of the pushing gas, from the viewpoint of flow control of the group III source gas and the nitrogen source gas, it is supplied from the entire upstream side of the growth part, or the outer periphery of the supply pipe of the group III source gas and the nitrogen source gas. It is preferable to provide it in the portion. As the pushing gas, hydrogen gas and / or various inert gases can be used. As the pushing gas, one kind of gas may be used, or two or more kinds of gases may be mixed and used. Above all, it is preferable to use one or more kinds selected from hydrogen gas and nitrogen gas as the pushing gas in that it does not adversely affect the production of the Group III nitride single crystal. The amount of pushing gas supplied can be appropriately determined according to the volume of the reactor, but is generally preferably, for example, 50 to 50,000 sccm, and more preferably 100 to 10,000 sccm. Further, it is preferable to remove impure gas components such as oxygen, water vapor, carbon monoxide, and carbon dioxide in advance using a refiner.

<Base substrate temperature>
The temperature of the base substrate (growth temperature) at the time of crystal growth is not particularly limited, and known conditions can be adopted. Specifically, the growth temperature is preferably 1000 to 1700 ° C. Above all, in the case of producing an aluminum-based group III nitride single crystal using aluminum halide gas, particularly an aluminum nitride single crystal, the temperature (growth temperature) of the base substrate is preferably 1200 to 1600 ° C. In this case, the supply amount of the halogenated aluminum gas is preferably in the range of 0.001 to 100 sccm.

<Growth rate of group III nitride single crystal>
It is preferable to supply a sufficient amount of the aluminum halide gas so that the growth rate of the aluminum-based group III nitride single crystal is 10 μm / h or more, more preferably 15 μm / h or more. From the viewpoint of increasing crystallinity, the upper limit of the crystal growth rate is preferably 100 μm / h or less, but when a means for heating the base substrate from the outside is provided, it should be 100 μm / h or more. (The upper limit of the growth rate when an external heating means is provided is about 300 μm / h).

<Pressure in the reactor>
The pressure inside the reactor is preferably in the range of 0.2 to 1.5 atm during the growth of the group III nitride single crystal, although it may be appropriately determined depending on the raw material to be used and the like.

<Cooling after growth of group III nitride single crystal>
Cooling after the growth of the group III nitride single crystal is preferably performed at a rate at which stress or cracks do not occur in the base substrate. Specifically, it is 10 minutes to 15 hours, and 30 minutes to 6 hours is preferable in consideration of processing efficiency.

<Group III nitride single crystal laminate>
According to the method for producing a group III nitride single crystal laminate of the present invention, the generation of crowns can be suppressed even when the crystal growth plane of the base substrate is the (0001) plane, so that the growth rate of the outer peripheral region is improved. , The in-plane film thickness distribution of the group III nitride single crystal layer can be improved.

Here, the evaluation of the crown growth generated at the end portion and the outer edge portion of the group III nitride single crystal layer can be evaluated by the value of the ratio of the weight increase amount of the crown to the weight increase amount of the single crystal layer due to the growth. For example, the sum of the weight increase of the single crystal layer and the weight increase of the crown is calculated by subtracting the weight of the base substrate measured in advance from the weight of the group III nitride laminate after growth. Further, by removing only the crown from the Group III nitride laminate by grinding or the like and then weighing, the weight increase amount of the single crystal layer and the weight increase amount of the crown are calculated, respectively. By the above method, the value of the ratio of the weight increase of the crown to the weight increase of the single crystal layer can be calculated.

Further, since the group III nitride single crystal laminate can suppress the generation of crowns, the in-plane film thickness distribution can be improved particularly even during thick film growth. The film thickness can be measured with a caliper or a plate thickness measuring device by laser irradiation. The film thickness of the Group III nitride single crystal layer can be calculated by subtracting the previously measured plate thickness of the base substrate from the plate thickness of the Group III nitride single crystal laminate.

According to the present invention, the area of the Group III nitride single crystal layer can be made larger than the area of the base substrate. That is, the value of the ratio of the area of the surface of the group III nitride single crystal layer to the area of the crystal growth surface of the base substrate can be made larger than 1. The value of the ratio can be obtained by the area calculated by the image processing software or the diameter measured by using a microscope or the like capable of measuring a caliper or a moving distance.

In the group III nitride single crystal laminate, the crown tends to grow more easily as the thickness of the group III nitride single crystal layer increases. However, according to the production method of the present invention, the generation of the crown can be suppressed. The maximum value of the film thickness of the group III nitride single crystal layer is 500 μm or more, and the minimum film thickness / maximum film thickness is 0.7 or more in the region excluding the outer edge portion of the surface of the nitride single crystal layer. A certain Group III nitride single crystal laminate can be obtained. Such a group III nitride single crystal laminate of the present invention can be effectively used as a substrate for manufacturing a semiconductor device.

Further, according to the present invention, it is possible to grow a group III nitride single crystal laminate having high crystal quality. The crystal quality can be evaluated by the half width (FWHM) of the X-ray locking curve on the (0002) plane, and according to the present invention, a group III nitride single crystal laminate having the half width of 60 seconds can be evaluated. Can grow.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the following examples.
^{The half-value width of the E 2} _high peak by Raman spectroscopy, the half-value width of the X-ray locking curve, the nitrogen atom weight over time / Group III atom weight at the edge of the substrate, and the ratio of the crown weight increase to the weight increase of the Group III nitride single crystal. The ratio of the minimum / maximum film thickness on the surface excluding the outer edge and the area of the surface of the Group III nitride single crystal layer to the area of the crystal growth surface of the base substrate was measured by the following method.

(Half width ^{of E 2} _high peak by Raman spectroscopic analysis)
A laser Raman spectrophotometer NRD-7100 manufactured by JASCO Corporation was used to evaluate the half width ^{of the E 2} _high peak of the microscopic Raman spectrum. A laser having a wavelength of 531.98 nm was used as the excitation laser, and a slit having a width of 10 μm and a length of 1000 μm and a grating having 600 lines / mm were used. The excitation laser output was 10.8 mW, the measurement spot was focused to a diameter of about 1 μm using a 100 times objective lens, and then the excitation laser was irradiated to the aluminum nitride single crystal to measure the local Raman spectrum. The exposure time at this time was set to 5 seconds and integrated three times. The wavenumber of the measured Raman spectrum was calibrated by a Raman shift of a silicon substrate with a wavenumber of 521.448 cm ^{-1 measured under the same conditions. The peak wave number of the measured E 2} _high Raman shift peak (657.4 cm ^-1 ) of the aluminum nitride single crystal was obtained by Lorentz function fitting, and the half width (FWHM) of the peak detected in the wave number was calculated.

(Half width of X-ray locking curve)
An X-ray diffractometer X'Pert PRO-MRD manufactured by PANalytical was used. The optical system on the incident side was a mirror and a Ge220 symmetric 4-crystal monochromator, the Divergence slit was 1/2 °, and the cross slit was 2 mm × 2 mm. The optical system on the light receiving side was an open detector. The X-ray tube voltage was 45 kV and the tube current was 40 mA. The substrate was placed so that X-rays were irradiated to the center of the substrate, and 2θ, z, and ω were adjusted. The substrate angle was set so that the diffraction plane was the (0002) plane, and ω and chi were adjusted so that the peak intensity was maximized. Finally, the ω locking curve was measured, and the full width at half maximum (FWHM) of the detected peak was calculated.

(Atomic weight of nitrogen over time at the edge of the substrate / Atomic weight of Group III)
In the production method shown below, the nitrogen atomic weight / group III atomic weight of the raw material gas reaching the substrate was calculated by fluid analysis. The fluid analysis was performed using ANSYS FLUENT, a general-purpose thermo-fluid analysis software, based on a 3D structure imitating an actual machine and each boundary condition (temperature, pressure, gas type, gas flow rate, etc.). Steady thermal analysis was performed using a DO (Discrete ordinates) model for heat transfer and radiation, and a laminar flow model for flow.
When the susceptor is rotated and grown, the nitrogen atomic weight / group III atomic weight at the position of the substrate end where the nitrogen atomic weight / group III atomic weight is the maximum value and the substrate edge where the nitrogen atomic weight / group III atomic weight is the minimum value The average value of the nitrogen atomic weight / group III atomic weight at the position was defined as N / Al over time.

(Ratio of crown weight increase to Group III nitride single crystal weight increase)
A group III nitride single crystal laminate prepared by growing a group III nitride single crystal layer on the base substrate and the base substrate was weighed. The crown was ground and removed and then weighed again. The difference between the weight of the laminated body before removing the crown and the weight of the laminated body after removing the crown is the amount of increase in crown weight. On the other hand, the difference between the weight of the laminate after removing the crown and the weight of the base substrate is the amount of increase in the weight of the Group III nitride single crystal layer. The ratio of the crown weight increase to the group III nitride single crystal weight increase was calculated by dividing the crown weight increase by the group III nitride single crystal layer weight increase.

(Ratio of minimum film thickness to maximum film thickness on the surface excluding the outer edge (minimum film thickness / maximum film thickness)
On the surface excluding the outer edge portion, the plate thickness of the Group III nitride single crystal laminate was measured by irradiating a laser at intervals of 0.5 mm using a non-contact plate thickness measuring instrument manufactured by FA Systems. The film thickness of the Group III nitride single crystal layer at each measurement point was calculated by subtracting the plate thickness of the base substrate from the plate thickness at each measurement point. The ratio of the minimum film thickness to the maximum film thickness on the surface excluding the outer edge was calculated by dividing the minimum film thickness of all the measurement points by the maximum film thickness.

(Ratio of the area of the surface of the group III nitride single crystal layer to the area of the crystal growth surface of the base substrate)
The crystal growth surface of the base substrate was photographed at a magnification of 100 times using a stereomicroscope SZX7 manufactured by OLYMPUS. The area of the crystal growth plane was calculated by the image processing software ImageJ based on the captured image. After the growth of the group III nitride single crystal layer, the crown is ground and removed, and in the nitride single crystal laminate after removing the crown, the surface is photographed with a stereomicroscope at a magnification of 100 times in the same manner as the base substrate, and then the surface is subjected to ImageJ. The area was calculated. By dividing the surface area of the Group III nitride single crystal layer by the area of the crystal growth surface of the base substrate, the ratio of the area of the surface of the Group III nitride single crystal layer to the area of the crystal growth surface of the base substrate was calculated. ..

(Manufacturing of base substrate)
(Base substrate A)
As a base substrate, a circular aluminum nitride single crystal substrate having a thickness of 500 μm, a surface of (0001) surface, an off angle of 0.3 °, and a surface of 25 mm in diameter, which was manufactured by a sublimation method, was prepared. Since the end portion of the substrate was chamfered before CMP, the outer edge portion has an inclined surface having a width of 0.2 mm. The half width ^{of the E 2} _high peak by Raman spectroscopy at the center of the substrate ^{is 3.3 cm -1} , and the half width at a position 10 μm inside from the end is 3.5 cm ^-1 (half width at a position 10 μm from the end). / Half width at the center = 1.06). The half-value width of the (0002) X-ray locking curve at the center of the surface of the substrate was 21 seconds. The area of the crystal growth surface of the substrate was 470 mm ² .

(Base substrate B)
The base substrate A was cleaved with a diamond pen so that the side surfaces were m-plane and a-plane, and an aluminum nitride single crystal substrate having a square shape with a 7 mm square surface was prepared. The half-value width ^{of the E 2} _high peak by Raman spectroscopic analysis at the center of the substrate after cleavage ^{is 3.3 cm -1} , and the half-value width at the position 10 μm inside from the end is 3.3 cm ^-1 (at the position 10 μm inside from the end). Half width / center half width = 1.00), and the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 21 seconds. The area of the crystal growth surface of the base substrate was 49 mm ² .

(Base substrate C)
As a base substrate, it is a circular shape with a thickness of 500 μm, a surface of (0001) surface, an off angle of 0.3 °, a diameter of 25 mm with a CMP surface, and an orientation flat in some m directions, manufactured by the sublimation method. An aluminum nitride single crystal substrate having the above was prepared. Since the end portion of the substrate was chamfered before CMP, the outer edge portion has an inclined surface having a width of 0.2 mm. The half width ^{of the E 2} _high peak by Raman spectroscopy at the center of the substrate ^{is 3.3 cm -1} , and the half width at a position 10 μm inside from the end is 3.8 cm ^-1 (half width at a position 10 μm from the end). / Half width at the center = 1.15). The half width of the X-ray locking curve of the (0002) plane at the center of the surface of the substrate was 21 seconds. The area of the crystal growth surface of the substrate was 470 mm ² .

(Base board D)
As a base substrate, it is a circular shape with a thickness of 500 μm, a surface of (0001) surface, an off angle of 0.3 °, a diameter of 25 mm with a CMP surface, and an orientation flat in some m directions, manufactured by the sublimation method. An aluminum nitride single crystal substrate having the above was prepared. Since the end portion of the substrate was chamfered before CMP, the outer edge portion has an inclined surface having a width of 0.2 mm. The half width ^{of the E 2} _high peak by Raman spectroscopy at the center of the substrate ^{is 3.3 cm -1} , and the half width at a position 10 μm inside from the end is 4.5 cm ^-1 (half width at a position 10 μm from the end). / Half width at the center = 1.36). The half width of the X-ray locking curve of the (0002) plane at the center of the surface of the substrate was 21 seconds. The area of the crystal growth surface of the substrate was 470 mm ² .

Example 1
Using the base substrate B, the aluminum nitride single crystal film was laminated by the HVPE method using the vertical vapor deposition apparatus shown in FIG. The substrate was installed in the center of a susceptor having a diameter of 150 mm, which was installed directly under the nozzle. Aluminum trichloride produced by reacting aluminum with hydrogen chloride gas was used as a group III source gas, and ammonia gas was used as a nitrogen source gas. Aluminum trichloride gas 2 sccm, hydrogen chloride gas 18 sccm and hydrogen gas 980 sccm were supplied from the group III source gas supply port, and ammonia gas 2 sccm and hydrogen gas 998 sccm were supplied from the nitrogen source gas supply port. Nitrogen gas 5000 sccm was supplied from the pushing gas supply nozzle. The aluminum nitride single crystal layer was grown while the susceptor was heated to 1450 ° C. The growth time was controlled so that the aluminum nitride single crystal film thickness at the center of the substrate was 100 to 140 μm. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 1.00.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.15, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.96. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.09. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 24 seconds.

Example 2
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that the substrate was installed at a position 40 mm away from the center of the susceptor. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate with time was 0.85 to 0.89 depending on the position.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.22, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.94. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.02. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 27 seconds.

Comparative Example 1
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that the substrate was installed at a position 60 mm away from the center of the susceptor. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate with time was 0.40 to 0.58 depending on the position.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.40, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.95. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.94. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 25 seconds.

Comparative Example 2
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that 0.2 sccm of ammonia gas and 999.8 sccm of hydrogen gas were supplied from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.08.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.53, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.92. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.93. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 42 seconds.

Example 3
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that 5 sccm of ammonia gas and 995 sccm of hydrogen gas were supplied from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 2.52.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.05, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.95. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.11. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 27 seconds.

Comparative Example 3
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that ammonia gas was supplied at 8 sccm and hydrogen gas was supplied at 992 sccm from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 4.03.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.03, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.95. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.12. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 70 seconds.

Example 4
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that aluminum trichloride gas 2 sccm, hydrogen chloride gas 6 sccm, and hydrogen gas 992 sccm were discharged from the group III source gas supply port. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 1.00.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.30, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.95. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.96. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 44 seconds.

Example 5
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that aluminum trichloride gas 2 sccm and hydrogen gas 998 sccm were collected from the group III source gas supply port. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 1.00.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.38, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.92. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.95. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 57 seconds.

Example 6
An aluminum nitride single crystal laminate was produced by the same method as in Example 1 except that the base substrate A was used and the growth time was controlled so that the thickness of the aluminum nitride single crystal at the center of the substrate was 800 to 840 μm. .. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.98.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.20, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.76. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.18. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 25 seconds.

Example 7
An aluminum nitride single crystal laminate was produced by the same method as in Example 6 except that the base substrate C was used. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.98.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.27, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.73. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.13. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 24 seconds.

Example 8
An aluminum nitride single crystal laminate was produced by the same method as in Example 6 except that the base substrate D was used. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.98.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.33, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.70. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.00. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 29 seconds.

Example 9
An aluminum nitride single crystal laminate was produced by the same method as in Example 6 except that the growth time was controlled so that the thickness of the aluminum nitride single crystal at the center of the substrate was 500 to 540 μm. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.98.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.16, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.89. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.14. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 23 seconds.

Example 10
An aluminum nitride single crystal laminate was produced by the same method as in Example 6 except that the growth time was controlled so that the thickness of the aluminum nitride single crystal at the center of the substrate was 300 to 340 μm. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.98.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.10, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.94. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.09. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 27 seconds.

Comparative Example 4
An aluminum nitride single crystal laminate was produced by the same method as in Example 6 except that 0.2 sccm of ammonia gas and 999.8 sccm of hydrogen gas were supplied from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.08.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.71, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.39. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.92. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 35 seconds.

Comparative Example 5
An aluminum nitride single crystal laminate was produced in the same manner as in Example 9 except that 0.2 sccm of ammonia gas and 999.8 sccm of hydrogen gas were supplied from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.08.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.66, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.63. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.94. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 28 seconds.

Comparative Example 6
An aluminum nitride single crystal laminate was produced in the same manner as in Example 10 except that 0.2 sccm of ammonia gas and 999.8 sccm of hydrogen gas were supplied from the nitrogen source gas supply nozzle. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.08.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.49, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.93. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.97. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 27 seconds.

Comparative Example 7
An aluminum nitride single crystal laminate was produced in the same manner as in Example 6 except that the pushing gas was not supplied. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 5.20.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.65, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.13. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.08. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 112 seconds.

Example 11
The aluminum nitride single crystal film was laminated by the HVPE method using the vapor phase growth apparatus shown in FIG. The substrate was installed in the center of a susceptor having a diameter of 70 mm, which was installed diagonally below the outlet of the nozzle. Aluminum trichloride produced by reacting aluminum with hydrogen chloride gas was used as a group III source gas, and ammonia gas was used as a nitrogen source gas. Aluminum trichloride gas 4 sccm, hydrogen chloride gas 36 sccm and hydrogen gas 1760 sccm were supplied from the group III source gas supply port, and ammonia gas 16 sccm and hydrogen gas 184 sccm were supplied from the nitrogen source gas supply port. Nitrogen gas 3250 sccm and hydrogen gas 3250 sccm were supplied from the pushing gas supply nozzle. The aluminum nitride single crystal layer was grown in a state where the susceptor was rotated at 20 rpm and heated to 1450 ° C. The growth time was controlled so that the aluminum nitride single crystal film thickness at the center of the substrate was 800 to 840 μm. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.84.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.16, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.72. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.15. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 26 seconds.

Comparative Example 8
An aluminum nitride single crystal laminate was produced in the same manner as in Example 11 except that the susceptor was not rotated. The average value over time on the outer edge of the substrate at this time was 0.45 to 1.22 depending on the position.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.42, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.48. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 1.04. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 35 seconds.

Comparative Example 9
An aluminum nitride single crystal laminate was produced by the same method as in Example 11 except that 10 sccm of ammonia gas and 190 sccm of hydrogen gas were supplied from the nitrogen source gas supply port. At this time, the average value of nitrogen atomic weight / group III atomic weight on the outer edge of the substrate over time was 0.44.

The value of the ratio of the amount of increase in crown weight to the amount of increase in surface weight of the obtained aluminum nitride single crystal laminate was 0.44, and the minimum / maximum film thickness on the surface excluding the outer edge was 0.40. rice field. The ratio of the surface area of the group III nitride single crystal layer to the crystal growth surface of the base substrate was 0.95. Further, the half width of the X-ray locking curve of the (0002) plane at the center of the surface was 32 seconds.

1: Base substrate 2: Crystal growth surface 3: Outer edge 4: Side surface 5: End 10: Vertical gas phase growth device 11: Reaction tube 12: Suceptor 13: Group III source gas supply port 14: Nitrogen source gas supply port 15: Raw material gas supply nozzle 16: Pushing gas supply nozzle 20: Horizontal gas phase growth device 21: Nitrogen source gas supply nozzle 22: Group III source gas supply nozzle

Claims (4)

A method for producing a Group III nitride single crystal laminate in which a Group III nitride single crystal layer is grown on a base substrate made of a Group III nitride single crystal by reacting a Group III source gas with a nitrogen source gas. hand,
The plane on which the Group III nitride single crystal layer is grown on the base substrate is the (0001) plane.
The time-dependent average value of the ratio of the nitrogen atom weight to the group III atom weight (nitrogen atom weight / group III atom weight) of the group III source gas and the nitrogen source gas reaching on the outer edge of the surface on which the group III nitride single crystal layer is grown is 0. .. A method for producing a group III nitride single crystal laminate, which is characterized by being 5 to 3.0. The ratio of the half width of the base substrate to the half width of the ^{E 2} _high peak detected by Raman spectroscopy at the center of the surface on which the Group III nitride single crystal layer is grown at a position 10 μm inside from the edge of the substrate. The method for producing a Group III nitride single crystal laminate according to claim 1, wherein a base substrate having a value of 1.2 or less is used. The group III nitride single crystal according to claim 1 or 2, wherein at least one halogen-based gas selected from a hydrogen halide gas and a halogen gas is supplied together with the group III source gas and the nitrogen source gas. Method for manufacturing a laminate. The base substrate is made of a single crystal of aluminum nitride.
The group III nitride single crystal layer is an aluminum nitride single crystal layer.
The method for producing a Group III nitride single crystal laminate according to any one of claims 1 to 3.

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