JP2007001858A - Crystal manufacturing apparatus, group iii nitride crystal and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a group III nitride crystal having a practical size required for manufacturing devices such as a high performance light-emitting diode or an LD, and semiconductor devices; and to provide a crystal manufacturing apparatus capable of growing such a group III nitride crystal. <P>SOLUTION: GaN crystals are continuously grown in a mixed melt 107 of Na and Ga and on the surface 108 of the mixed melt by the reaction of nitrogen gas or a nitrogen component in a mixed melt, supplied from the nitrogen gas, and Ga. Consequently, the crystals each having a large size can be obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a crystal manufacturing apparatus, a group III nitride crystal, and a semiconductor device.

  Currently, most of InGaAlN-based (group III nitride) devices used as purple-blue-green light sources are MO-CVD (metal organic chemical vapor deposition) or MBE ( It is fabricated by crystal growth using a molecular beam crystal growth method) or the like. When sapphire or SiC is used as a substrate, crystal defects due to a large difference in thermal expansion coefficient and lattice constant from the group III nitride increase. For this reason, there is a problem that the device characteristics are poor, for example, it is difficult to extend the life of the light emitting device, or the operating power is increased.

  Furthermore, in the case of a sapphire substrate, since it is insulative, it is impossible to take out the electrode from the substrate side as in the conventional light emitting device, and it is necessary to take out the electrode from the nitride semiconductor surface side where the crystal has grown. . As a result, there is a problem that the device area is increased, leading to high costs. In addition, a group III nitride semiconductor device fabricated on a sapphire substrate is difficult to separate into chips by cleavage, and it is not easy to obtain a resonator end face required for a laser diode (LD) by cleavage. For this reason, at present, resonator end faces are formed by dry etching, or resonator end faces are formed in a form close to cleavage after polishing the sapphire substrate to a thickness of 100 μm or less. Also in this case, it is impossible to easily separate the resonator end face and the chip as in a conventional LD in a single process, resulting in process complexity and cost.

  In order to solve this problem, it has been proposed to reduce crystal defects by performing selective lateral growth and other devices on a sapphire substrate on a group III nitride semiconductor film.

For example, Non-Patent Document 1 (hereinafter referred to as the first prior art) shows a laser diode (LD) as shown in FIG. In the laser diode of FIG. 6, a GaN low-temperature buffer layer 2 and a GaN layer 3 are sequentially grown on a sapphire substrate 1 by an MO-VPE (metal organic chemical vapor deposition) apparatus, and then a SiO ₂ mask 4 for selective growth is formed. To do. The SiO ₂ mask 4 is formed through a photolithography and etching process after depositing a SiO ₂ film by another CVD (chemical vapor deposition) apparatus. Next, a GaN film 3 ′ having a thickness of 20 μm is grown again on the SiO ₂ mask 4 by the MO-VPE apparatus, so that GaN is selectively grown in the lateral direction and selective lateral growth is not performed. Compared with this, crystal defects are reduced. Further, by introducing a modulation-doped strained superlattice layer (MD-SLS) 5 formed thereon, crystal defects are prevented from extending to the active layer 6. As a result, the device lifetime can be increased as compared to the case where the selective lateral growth and modulation-doped strained superlattice layer is not used.

In the case of this first prior art, it is possible to reduce crystal defects compared to the case where a GaN film is not selectively grown in the lateral direction on the sapphire substrate. The aforementioned problems with cleavage still remain. Furthermore, the crystal growth by the MO-VPE apparatus is required twice with the SiO ₂ mask formation process in between, and a new problem that the process becomes complicated arises.

  As another method, for example, Non-Patent Document 2 (hereinafter referred to as the second prior art) proposes to apply a GaN thick film substrate. In the second prior art, after the selective lateral growth of 20 μm of the first prior art described above, a 200 μm thick GaN thick film is grown by an H-VPE (hydride vapor phase epitaxy) apparatus, and then this thickness is increased. The grown GaN film is polished from the sapphire substrate side to a thickness of 150 μm to produce a GaN substrate. Using the MO-VPE apparatus on this GaN substrate, crystal growth necessary for the LD device is sequentially performed to manufacture the LD device. As a result, in addition to the problem of crystal defects, it is possible to solve the above-described problems related to insulation and cleavage by using a sapphire substrate.

  However, the process of the second conventional technique is more complicated than that of the first conventional technique, which further increases the cost. Further, when a GaN thick film having a thickness of 200 μm is grown by the second prior art method, the stress accompanying the difference in lattice constant and thermal expansion coefficient from sapphire, which is the substrate, is increased, and the substrate is warped or cracked. A new problem arises.

  In order to avoid this problem, Patent Document 1 proposes that the thickness of an original substrate (sapphire and spinel) on which a thick film is grown be 1 mm or more. In this way, by using a substrate having a thickness of 1 mm or more, even when a GaN film having a thickness of 200 μm is grown, the substrate is not warped or cracked. However, such a thick substrate has a high cost of the substrate itself and needs to spend a lot of time for polishing, leading to an increase in the cost of the polishing process. That is, when a thick substrate is used, the cost is higher than when a thin substrate is used. When a thick substrate is used, the substrate is not warped or cracked after the thick GaN film is grown, but stress is relaxed in the polishing process, and warping or cracking occurs during polishing. For this reason, even if a thick substrate is used, a GaN substrate having a high crystal quality cannot be easily produced with a large area.

  On the other hand, Non-Patent Document 3 (hereinafter referred to as “third prior art”) proposes growing a GaN bulk crystal and using it as a homoepitaxial substrate. This technique is a technique for crystal growth of GaN from liquid Ga at a high temperature of 1400 to 1700 ° C. and a nitrogen pressure of several tens of kbar. In this case, a group III nitride semiconductor film necessary for the device can be grown using the bulk-grown GaN substrate. Therefore, a GaN substrate can be provided without complicating the process as in the first and second conventional techniques.

  However, in the third prior art, there is a problem that crystal growth at high temperature and high pressure is required, and a reaction vessel that can withstand the growth becomes extremely expensive. In addition, even with such a growth method, there is a problem that the size of the obtained crystal is at most about 1 cm, which is too small for practical use of the device.

As a technique for solving this problem of GaN crystal growth under high temperature and high pressure, Non-Patent Document 4 (hereinafter referred to as “fourth prior art”) proposes a GaN crystal growth method using Na as a flux. ing. In this method, sodium azide (NaN ₃ ) as a flux and metal Ga are used as raw materials, and sealed in a stainless steel reaction vessel (inner dimensions; inner diameter = 7.5 mm, length = 100 mm) in a nitrogen atmosphere, By holding the reaction vessel at a temperature of 600 to 800 ° C. for 24 to 100 hours, a GaN crystal is grown. In the case of the fourth prior art, crystal growth at a relatively low temperature of about 600 to 800 ° C. is possible, and the pressure in the container is at most about 100 kg / cm ^2, which is higher than that of the third prior art. It is a feature that can be lowered. However, the problem with this method is that the crystal size obtained is small enough to be less than 1 mm. This size is too small for practical use of the device, as in the case of the third prior art.
Japanese Journal of Applied Physics Vol.36 (1997) Part 2, No.12A, L1568-1571. Applied Physics Letters, Vol. 73, No. 6, P832-834 (1998). Journal of Crystal Growth, Vol.189 / 190, p.153-158 (1998). Chemistry of Materials Vol.9 (1997) p.413-416. JP-A-10-256661

  The present invention does not complicate the process that is the problem of the first and second prior arts, without using the expensive reaction vessel that is the problem of the third prior art, and the third and fourth. The present invention provides a group III nitride crystal and a semiconductor device having a practical size for producing a device such as a high-performance light-emitting diode or LD without reducing the size of the crystal, which is a problem of the prior art. Another object of the present invention is to provide a crystal manufacturing apparatus capable of growing such a group III nitride crystal.

  According to this invention, the crystal manufacturing apparatus includes a reaction vessel and a supply device. The reaction vessel holds a mixed melt containing a group III metal element and an alkali metal. The supply device supplies a substance containing nitrogen element to the reaction vessel from the outside.

  Further, according to the present invention, the group III nitride crystal is supplied at least in the group III metal element by supplying a substance containing at least nitrogen element from the outside in the alkali metal melt or on the surface of the alkali metal melt in the reaction vessel. A group III nitride crystal formed by a crystal growth method in which a group III nitride composed of a group III metal element and a nitrogen element is crystal-grown from a substance containing nitrogen and a substance containing at least a nitrogen element. .

  Furthermore, according to the present invention, a semiconductor device is a semiconductor device manufactured using the group III nitride crystal according to claim 2.

  Furthermore, according to this invention, a semiconductor device uses a manufacturing method for manufacturing a group III nitride crystal by supplying a substance containing a nitrogen element from the outside to a mixed melt containing a group III metal element and an alkali metal. A semiconductor device including a manufactured substrate made of a group III nitride crystal.

  Preferably, the semiconductor device is an optical device.

  Preferably, the semiconductor device is an electronic device.

  Furthermore, according to the present invention, the crystal manufacturing apparatus includes a reaction vessel, a supply device, and first and second heating devices. The reaction vessel holds a mixed melt containing a group III metal element and an alkali metal. The supply device supplies a substance containing nitrogen element to the reaction vessel from the outside. The first heating device heats a region where the group III nitride crystal grows. A 2nd heating apparatus heats the area | region where the mixture or compound comprised with a group III metal element and another element exists. The first and second heating devices respectively heat the region where the group III nitride crystal grows and the region where the mixture or compound exists to different temperatures.

  As described above, according to the present invention, in the reaction vessel, a substance containing at least nitrogen element is supplied from the outside in a metal melt having a low melting point and a high vapor pressure or on the surface of the metal melt. A group III nitride composed of a group III metal element and a nitrogen element is grown from a substance containing a group metal element and a substance containing at least a nitrogen element, and has a low melting point and high vapor pressure. By using the melt and crystal growth in the metal melt or on the surface of the metal melt, it becomes possible to continuously supply an appropriate amount of a group III metal component necessary for high-quality crystal growth. As a result, it is possible to achieve growth of large-sized, high-quality group III nitride crystals with low crystal defects at low cost (in order to grow large-sized crystals of high quality, crystals grow with an appropriate amount of group III metal components. It is necessary to supply continuously to the field to be used, and this can be realized by using a metal melt as a field for crystal growth). That is, without complicating the process which is the problem of the first and second prior arts described above, without using the expensive reaction vessel which is the problem of the third prior art, and the third and fourth. A III-nitride crystal and a semiconductor device having a practical size for producing a device such as a high-performance light-emitting diode or LD without reducing the size of the crystal, which is a problem of the prior art be able to.

  In addition, according to the present invention, by supplying a substance containing at least a nitrogen element from the outside and crystal-growing a group III nitride crystal from a substance containing at least a group III metal element and a substance containing at least a nitrogen element, a semiconductor is obtained. It is possible to provide a group III nitride crystal that is large enough to produce a device and has high crystal quality at a low cost.

  Furthermore, according to the present invention, a high-performance device can be realized at low cost by manufacturing a semiconductor device using the group III nitride crystal according to claim 2. That is, this group III nitride crystal is a high-quality crystal with few crystal defects, and a device is produced using this group III nitride crystal, or as a substrate for growing a group III nitride thin film crystal. A high-performance device can be realized by performing device fabrication from thin film growth. The high performance mentioned here means, for example, semiconductor lasers and light emitting diodes, which have not been realized in the past and have high output and long life, and in the case of electronic devices, low power consumption, low noise, and high speed. It can operate and operate at high temperature, and the light receiving device has low noise and long life.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  The present invention relates to a substance containing at least a group III metal element (for example, Ga (gallium)) and a substance containing at least a nitrogen element in a low melting point and high vapor pressure metal melt or on the surface of the metal melt in a reaction vessel. And crystal growth of a group III nitride composed of a group III metal element and a nitrogen element.

  More specifically, the temperature of the reaction vessel can be controlled so that the group III nitride can grow crystals. Further, the reaction vessel contains a metal having a low melting point and a high vapor pressure, and the metal having a low melting point and a high vapor pressure forms a melt in a temperature region where the group III nitride can grow crystals. In this temperature-controlled reaction vessel, a metal having a low melting point and a high vapor pressure becomes a melt, and is composed of a group III metal element and a nitrogen element in the metal melt or on the surface of the metal melt. Group nitride crystals grow. Here, a substance containing at least a group III metal element and a substance containing at least a nitrogen element are raw materials for the group III nitride.

  Further, the present invention provides the above-described group III nitride crystal growth method, wherein the mixture is composed of a group III metal element and other elements in a low melting point and high vapor pressure metal melt or on the surface of the metal melt. A group III metal component is supplied from the compound.

  Here, the Group III metal component supplied from the mixture or compound composed of the Group III metal element and other elements is at least nitrogen in the low melting point and high vapor pressure metal melt or on the surface of the metal melt. By reacting with a substance containing an element, a group III nitride crystal grows.

  In the following description, it is assumed that the metal having a low melting point and a high vapor pressure is Na, and the substance containing at least a group III metal element is metal Ga.

  FIG. 1 is a diagram showing a configuration example of a crystal growth apparatus according to the present invention. In the example of FIG. 1, reaction vessel 101 contains Na as a low melting point and high vapor pressure metal and metal Ga as a substance containing at least a group III metal element. The mixed melt 102 is formed in a temperature region where the crystal grows.

Further, a space region in the reaction vessel 101 is filled with nitrogen gas (N ₂ ) 103 as a substance containing at least nitrogen element. The nitrogen gas 103 can be supplied from the outside of the reaction vessel 101 through the nitrogen supply pipe 104, and the pressure adjusting mechanism 105 is provided in the apparatus of FIG. 1 in order to adjust the nitrogen pressure. The pressure adjustment mechanism 105 includes, for example, a pressure sensor and a pressure adjustment valve. The nitrogen pressure in the reaction vessel 101 is controlled to, for example, 50 atm by the pressure cooking mechanism 105.

  The reaction vessel 101 is provided with a heating device 106 that can be controlled to a temperature at which crystals can be grown. By controlling the temperature of the group III nitride crystal to grow in the reaction vessel 101 by the heating device 106 (for example, 750 ° C.), the low melting point and high vapor pressure metal Na and the group III metal raw material Ga A mixed melt 102 is formed. At this time, Ga, which is a group III metal, is supplied from the mixed melt 102, and the inside of the reaction vessel 101 is kept constant at the growth temperature by the heating device 106, so that a GaN crystal as a group III nitride is 107 in the mixed melt. The crystal grows on the mixed melt surface 108.

  As described above, in the crystal growth apparatus of FIG. 1, Ga reacts with the nitrogen component in the Na / Ga mixed melt 107 and the mixed melt surface 108 and the nitrogen component in the melt supplied from the nitrogen gas or nitrogen gas. Thus, a continuous GaN crystal grows and a crystal having a large crystal size can be obtained.

  FIG. 2 is a diagram showing another configuration example of the crystal growth apparatus according to the present invention. In FIG. 2, the same parts as those in FIG.

  In the configuration example of FIG. 2, there is a melt holder 211 of a mixed melt of Ga and Na outside the reaction vessel 101, and this melt holder 211 is maintained at a temperature at which the mixture of Ga and Na can exist as a melt. Yes. By supplying a pressure higher than the pressure in the reaction vessel 101 with nitrogen gas from the pressure supply pipe 212 on the upper side of the melt holder 211, the mixed melt of Ga and Na held in the melt holder 211 is obtained. It can be supplied into the reaction vessel 101 via the melt holder supply pipe 213.

  As described above, in the configuration example of FIG. 2, it is possible to supply a mixture or a compound composed of a group III metal element and another element (for example, a mixed melt of Ga and Na) from the outside of the reaction vessel 101. It has become. Here, a controlled amount of the mixture or compound composed of the group III metal element and other elements supplied from the outside of the reaction vessel 101 can be supplied into the reaction vessel 101.

  Thus, by supplying a mixed melt of Ga and Na from the outside of the reaction vessel 101, in addition to the continuous GaN crystal growth described in the explanation of FIG. 1, the amount of Ga in the reaction vessel 101 is increased. Can be kept constant, and the GaN crystal can be grown more stably.

  In the example of FIG. 2, a mixture or compound composed of a group III metal element and other elements is supplied from the outside of the reaction vessel 101, but is composed of a group III metal element and other elements. Instead of supplying the mixture or compound from outside, as shown in FIG. 1, the mixture or compound composed of the group III metal element and other elements is present in the reaction vessel 101 from the beginning. Also good. In this case, a mixed melt of Ga and Na, which is a mixture or compound composed of a Group III metal element and another element, is present in the reaction vessel 101 from the beginning (Group III metal element and other element and (A mixture or compound composed of a metal melt with a low melting point and a high vapor pressure), crystal growth continues stably with little disturbance, and a GaN crystal with few crystal defects grows. It becomes possible.

  In other words, the mixture or compound composed of the Group III metal element and other elements may be present in a region spatially separated from the region where the Group III nitride crystal grows.

  FIG. 3 is a diagram showing another configuration example of the crystal growth apparatus according to the present invention. In FIG. 3, the same parts as those in FIG.

  The configuration example of FIG. 3 differs from the configuration example of FIG. 1 in that in the configuration example of FIG. 3, the heating device of the reaction vessel 101 is replaced with a first heating device 106 that heats a region where a group III nitride crystal grows. In this case, the region 311 where the mixture or compound composed of the group III metal element and the other element is present is separated from the second heating device 312 for heating.

  In the example of FIG. 3, an intermetallic compound of Ga and Na is used as a mixture or compound composed of a group III metal element and another element, and the intermetallic compound is a region where a group III nitride crystal grows. It exists in the area | region 311 isolate | separated from. The second heating device 312 that heats the intermetallic compound is separated from the first heating device 106 that heats the region where the crystal grows, so that the temperature can be controlled independently.

  In other words, the temperature of the region where the mixture or compound composed of the Group III metal element and other elements is present can be made different from the temperature of the region where the Group III nitride crystal grows.

  In the above example, the first heating device 106 and the second heating device 312 are controlled to be separated. However, the heating device is not necessarily separated, and there is only one heating device. It is sufficient that the temperature of the region where the group nitride crystal is grown is different from the temperature of the region where the mixture or compound composed of the group III element and other elements is present.

  Specifically, the crystal growth region is heated to, for example, 750 ° C. as the crystal growth temperature by the first heating device 106, and the region 311 where the intermetallic compound exists is held at 530 ° C. by the second heating device 312. In this state, Ga, which is a group III metal component, gradually elutes from the intermetallic compound existing in the region 311 into the mixed melt 102 of Ga and Na, and GaN crystals as group III nitrides 107 in the mixed melt. Crystal growth occurs on the mixed melt surface 108. Here, since Ga, which is a Group III metal component, gradually dissolves from the intermetallic compound of Ga and Na, it becomes possible to continuously grow a high-quality Group III nitride crystal stably.

  Thus, in the configuration example of FIG. 3, the mixture or compound composed of the group III metal element and other elements is in the region 311 away from the regions 107 and 108 where the group III nitride crystal grows. The group III metal component is supplied from the region 311 where a mixture or compound composed of the group III metal element and other elements is present to the regions 107 and 108 where the group III nitride crystal is grown. The group III metal component supplied to the regions 107 and 108 where the group III nitride crystal grows reacts with the nitrogen component containing the nitrogen element, thereby allowing the group III nitride crystal to grow stably and continuously. Can do.

  In the above-described example, the temperature of the regions 107 and 108 where the group III nitride crystal is grown is different from the temperature of the region 311 where the mixture or compound composed of the group III element and other elements is present. Although the case has been described, the present invention only requires that the two regions are spatially separated even if the temperatures of these two regions are not different.

  In other words, the mixture or compound composed of the Group III metal element and other elements may be present in a region spatially separated from the region where the Group III nitride crystal grows.

  FIG. 4 is a diagram showing another configuration example of the crystal growth apparatus according to the present invention. In the configuration example of FIG. 4, the reaction vessel 401 contains Na as a metal having a low melting point and a high vapor pressure, and Na is a Na melt 402 in a temperature region where a group III nitride crystal grows. Further, in the lower part of the reaction vessel 401, for example, GaN 409 is present as a mixture or compound composed of a group III metal element and other elements, and the GaN 409 is covered with a Na melt 402.

Further, a space region in the reaction vessel 401 is filled with nitrogen gas (N ₂ ) 403 as a substance containing at least nitrogen element. The nitrogen gas 403 can be supplied from the outside of the reaction vessel 401 through the nitrogen supply pipe 404. At this time, a pressure adjusting mechanism 405 is provided to adjust the nitrogen pressure. The pressure adjustment mechanism 405 includes a pressure sensor and a pressure adjustment valve. By this pressure adjustment mechanism 405, the nitrogen pressure in the reaction vessel 401 is controlled to 50 atm, for example.

  Further, the reaction vessel 401 is provided with a heating device 406 so that the temperature can be controlled so that the crystal can be grown. By controlling the inside of the reaction vessel 401 to a temperature at which the group III nitride crystal grows (for example, 750 ° C.) by the heating device 406, Na which is a metal having a low melting point and a high vapor pressure becomes the melt 402. When GaN 409 is decomposed, Ga is gradually supplied therefrom, and the temperature in the reaction vessel 401 is kept constant at the crystal growth temperature by the heating device 406, so that the GaN crystal as the group III nitride is in the mixed melt. Crystal growth occurs at 407 and the mixed melt surface 408.

  GaN 409 used here is a raw material, and may be not only single crystal but also polycrystalline or amorphous. Further, a crystalline material having many crystal defects or a small crystal size may be difficult to use as a substrate as it is. Accordingly, it is possible to obtain a GaN crystal of a size that can be used as a high-quality substrate at a low cost.

  Thus, in the configuration example of FIG. 4, a mixture or compound composed of a Group III metal element and other elements is decomposed or melted or dissolved in a metal melt near the temperature at which the Group III nitride crystal grows. I try to let them. Thereby, the group III metal component is supplied to the region where the group III nitride crystal grows and reacts with the nitrogen component, so that the group III nitride crystal can be grown.

  In the present invention, a group III nitride semiconductor device can be manufactured using a group III nitride crystal grown by the crystal growth method and the crystal growth apparatus as described above.

  FIG. 5 is a diagram showing a configuration example of a semiconductor device according to the present invention. In the example of FIG. 5, the semiconductor device is configured as a semiconductor laser. Referring to FIG. 5, this semiconductor device has an n-type AlGaN on an n-type GaN substrate 501 using a group III nitride crystal (GaN crystal in the example of FIG. 5) grown in the manner described above. A cladding layer 502, an n-type GaN guide layer 503, an InGaN MQW (multiple quantum well) active layer 504, a p-type GaN guide layer 505, a p-type AlGaN cladding layer 506, and a p-type GaN contact layer 507 are sequentially grown. . As this crystal growth method, a thin film crystal growth method such as MO-VPE (metal organic chemical vapor deposition) method or MBE (molecular beam epitaxy) method can be used.

Next, a ridge structure is formed in the laminated film of GaN, AlGaN, and InGaN, and the SiO ₂ insulating film 508 is formed in a state where only the contact region is drilled. The ohmic electrode Al / Ti 510 is formed to constitute the semiconductor device (semiconductor laser) of FIG.

  By injecting current from the p-side ohmic electrode Al / Ni 509 and the n-side ohmic electrode Al / Ti 510 of this semiconductor laser, this semiconductor laser oscillates and emits laser light in the direction of arrow A in FIG. Can do.

  Since this group III nitride crystal (GaN crystal) of the present invention is used as the substrate 501, this semiconductor laser has few crystal defects in the semiconductor laser device, has a large output operation and a long life. Further, since the GaN substrate 501 is n-type, the electrode 510 can be formed directly on the substrate 501, and two electrodes on the p side and n side are provided on the surface as in the first prior art (FIG. 6). It is not necessary to take out only from this, and it becomes possible to reduce cost. Further, the light emitting end face can be formed by cleaving, and in combination with chip separation, a low-cost and high-quality device can be realized.

  In each of the above examples, Na, which is an alkali metal, is used as a metal having a low melting point and a high vapor pressure. However, not only Na but also K or the like can be used. That is, as the metal having a low melting point and a high vapor pressure, an alkali metal other than Na can be used as long as it is a melt at the temperature at which the group III nitride crystal is grown.

  In the above example, Ga is used as a substance containing at least a group III metal element. However, not only Ga but a single metal such as Al or In, or a mixture or alloy thereof may be used. .

Further, in the above example, at least is used nitrogen gas as a substance containing nitrogen element is not limited to the nitrogen gas, it can also be used NH ₃ or the like gas and NaN ₃ like solid.

  In each of the above examples, GaN is used as a mixture or compound composed of a group III metal element and another element. However, not only GaN but also other group III nitrides such as AlN and InN are used. You can also.

  In addition, the mixture or compound composed of the Group III metal element and other elements is not limited to Group III nitrides such as GaN, AlN, and InN. For example, an intermetallic compound of Ga and Na is used to form Group III. For example, GaN may be grown as a nitride. In this case, the intermetallic compound of Ga and Na is decomposed near the temperature at which GaN crystal grows (for example, 750 ° C.), and Ga as a group III metal component can be supplied to the crystal growth region. Further, the mixture or compound composed of the group III metal element and other elements is not limited to the above-described one, but may be an alloy composed of the group III metal element and other elements.

  Specifically, examples of the mixture or compound composed of a Group III metal element and another element include an intermetallic compound of Ga and Na or an intermetallic compound of Ga and K. Other alloys include Ga and Fe alloys, Ga and Cu alloys, Ga and Mn alloys, Ga and Cr alloys, and Ga and Co alloys. For example, in the case of an alloy of Ga and Fe, since the growth temperature is decomposed at 750 to 850 ° C., Ga which is a group III metal component can be supplied to the crystal growth region.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention does not complicate the process that is the problem of the first and second prior arts, without using the expensive reaction vessel that is the problem of the third prior art, and the third and fourth. It is applicable to Group III nitride crystals and semiconductor devices of practical size for producing devices such as high-performance light-emitting diodes and LDs without reducing the size of crystals, which is a problem of the prior art. The The present invention is also applied to a crystal manufacturing apparatus capable of growing such a group III nitride crystal.

It is a figure which shows the structural example of the crystal growth apparatus which concerns on this invention. It is a figure which shows the other structural example of the crystal growth apparatus which concerns on this invention. It is a figure which shows the other structural example of the crystal growth apparatus which concerns on this invention. It is a figure which shows the other structural example of the crystal growth apparatus which concerns on this invention. It is a figure which shows the structural example of the semiconductor device which concerns on this invention. It is a figure which shows the conventional laser diode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Reaction container 102 Mixed melt 103 Nitrogen gas 104 Nitrogen supply pipe 105 Pressure adjustment mechanism 106 Heating device (1st heating device)
211 Melt holder 212 Pressure supply pipe 213 Melt holder supply pipe 311 Region where mixture or compound exists 312 Second heating device 401 Reaction vessel 402 Melt 409 GaN
403 Nitrogen gas 404 Nitrogen supply pipe 405 Pressure adjusting mechanism 406 Heating device 501 n-type GaN substrate 502 n-type AlGaN cladding layer 503 n-type GaN guide layer 504 InGaN MQW (multiple quantum well) active layer 505 p-type GaN guide layer 506 p-type AlGaN cladding layer 507 p-type GaN contact layer 508 SiO2 insulating film 509 p-side ohmic electrode Al / Ni
510 n-side ohmic electrode Al / Ti

Claims (7)

A reaction vessel holding a mixed melt containing a Group III metal element and an alkali metal;
A crystal manufacturing apparatus comprising: a supply device that supplies a substance containing nitrogen element to the reaction vessel from the outside.   In the reaction vessel, in the alkali metal melt or on the surface of the alkali metal melt, a substance containing at least a nitrogen element is supplied from the outside, and a substance containing at least a group III metal element and the substance containing at least a nitrogen element are used. A group III nitride crystal formed by a crystal growth method in which a group III nitride composed of a group metal element and a nitrogen element is grown.   A semiconductor device manufactured using the group III nitride crystal according to claim 2.   A substrate made of a Group III nitride crystal manufactured using a manufacturing method for manufacturing a Group III nitride crystal by supplying a substance containing a nitrogen element to a mixed melt containing a Group III metal element and an alkali metal from the outside. A semiconductor device provided.   The semiconductor device according to claim 4, wherein the semiconductor device is an optical device.   The semiconductor device according to claim 5, wherein the semiconductor device is an electronic device. A reaction vessel holding a mixed melt containing a Group III metal element and an alkali metal;
A supply device for supplying a substance containing nitrogen element to the reaction vessel from the outside;
A first heating device for heating a region where a group III nitride crystal grows;
A second heating device that heats a region where a mixture or compound composed of the Group III metal element and other elements is present, and
Each of the first and second heating devices heats a region where the group III nitride crystal grows and a region where the mixture or compound exists to different temperatures, respectively.

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