JP4456856B2 - Method for producing Group III metal nitride crystals - Google Patents

Description

The present invention relates to method for producing nitride crystals of group III metal, and more particularly, III of the semiconductor light-emitting element used as a light source of cold (ultraviolet to violet to blue to green) The present invention relates to a method for producing a group metal nitride crystal.

  Semiconductor light-emitting elements using Group III metal nitride crystals are used as ultraviolet-violet-blue-green light sources. The basic structure is shown in FIG.

  FIG. 1 is a cross-sectional view for explaining the structure of a conventionally known semiconductor light emitting device. On a support substrate 101, an n layer 102 made of an n type semiconductor, a light emitting layer 103, and a p type semiconductor are formed. The p layer 104 is sequentially laminated. A p-type electrode 105 is provided on the p layer 104, while an exposed surface 107 on which the light emitting layer 103 and the p layer 104 are not provided is formed on a part of the n layer 102. An n-type electrode 106 is provided on the exposed surface 107. Then, by applying a forward bias between the p-type electrode 105 and the n-type electrode 106 (that is, applying a positive voltage to the p-type electrode), electrons and holes are combined in the light emitting layer 103. Emits light. At this time, by using a group III metal nitride crystal as a material for the n-layer 102, the light-emitting layer 103, and the p-layer 104, an ultraviolet-violet-blue-green light source is obtained.

By the way, as a material of the support substrate 101, sapphire, SiC, or the like has been conventionally used. However, to form the nitride crystal of the Group III metal on a sapphire or SiC, generation of dislocations due to lattice mismatch can not be avoided between the nitride crystal of the supporting substrate 101 and the group III metal (n layer), 10 ⁷ Crystal defects of ˜10 ⁸ cm ⁻¹ level are generated, and stress is generated at the interface. Further, since the difference in thermal expansion coefficient between sapphire or SiC and the group III metal nitride crystal is large, the quality of the semiconductor light emitting device is deteriorated. Furthermore, since sapphire is particularly hard, it has poor molding processability, and it has been difficult to form it into a desired shape.

  In order to solve these problems, semiconductor light emitting devices that do not use sapphire or SiC as a support substrate material are being developed, and the use of a group III metal nitride crystal itself as a support substrate material has been studied. ing. That is, if an n-layer, a light-emitting layer, a p-layer, etc. (sometimes referred to as a “group III metal nitride crystal layer”) are provided on a group III metal nitride crystal, the group III metal Since the group III metal nitride crystal is laminated on the nitride crystal, there is almost no difference in crystal defects and thermal expansion coefficient, and the group III metal nitride crystal is softer than sapphire and SiC, so it is easy to process. .

Therefore, as a method for growing a group III metal nitride crystal, for example, Patent Document 1 discloses that a seed crystal is formed from a region where a melt containing a group III metal, a flux (for example, a compound containing metal Na or Na) and a nitrogen source are in contact. A technique for growing a nitride crystal of a group III metal by using a metal has been proposed. However, with this technique, it was necessary to maintain the inside of the reaction vessel at a high temperature and high pressure of 750 ° C. and 100 kg / cm ² G in order to grow GaN crystals.
JP 2001-64098 A (see [Claims], [0026], [0058])

  Thus, various methods for producing a Group III metal nitride crystal at a lower pressure than the Na flux method proposed in Patent Document 1 have been studied. In addition to at least one metal selected from Group III metals, It has already been proposed that by using a melt obtained by mixing two or more metals selected from the group consisting of metals or alkaline earth metals, it is possible to produce group III metal nitride crystals even at low pressure [ Non-Patent Document 1 (Journal of the Japanese Society for Crystal Growth, Japanese Society for Crystal Growth, July 2003, Vol. 30, No. 2, p. 38-45)]. This technique makes it possible to produce Group III metal nitride crystals at a relatively low pressure.

  However, when the surface of the III metal nitride crystal becomes rough, it causes deterioration of characteristics when a semiconductor light emitting device is constructed. Therefore, a group III metal nitride crystal with less surface irregularities is desired. The technology disclosed in Non-Patent Document 1 also has room for further improvement. That is, as shown in FIG. 1, the semiconductor light emitting device has an n layer, a light emitting layer, and a p layer formed on the substrate surface, and the total thickness from the n layer to the p layer is about several μm (specifically Is about 3 to 5 μm). For this reason, if irregularities of this size are generated on the surface of the nitride crystal of the metal III, the device itself cannot be formed, which greatly affects the characteristics of the device.

  This invention is made | formed in view of such a condition, The objective is to provide the method which can manufacture the nitride crystal of a group III metal with few unevenness | corrugations on the surface. Another object of the present invention is to provide a semiconductor light emitting device using a group III metal nitride crystal obtained by such a manufacturing method as a base material.

  The method for producing a Group III metal nitride crystal according to the present invention that has solved the above-mentioned problems includes, in a reaction vessel, at least one selected from Group III metals and a group consisting of alkali metals or alkaline earth metals. A method for producing a group III metal nitride crystal on the surface of a seed crystal by immersing a seed crystal in a melt obtained by mixing two or more selected, and bringing the melt into contact with nitrogen. It has a gist in that it operates so as to avoid the stagnation of the melt near the surface of the seed crystal. By avoiding the stagnation of the melt, the growth of the group III metal nitride crystal becomes uniform, so that the group III metal nitride crystal with less unevenness can be obtained.

  According to the present invention, since a group III metal nitride crystal can be grown uniformly, a group III metal nitride crystal with less irregularities on the surface can be reliably produced.

  In addition, by using the group III metal nitride crystal obtained by the method of the present invention as a base material of a semiconductor light emitting device, generation of crystal defects in the group III metal nitride crystal layer formed on the base material is prevented. Since it can be suppressed, the non-luminescent center is reduced (ie, the change to heat is reduced), the semiconductor light emitting device has a high brightness and a long life, and the thermal expansion of the base material and the nitride crystal layer of the group III metal Since the difference in coefficients can also be reduced, a semiconductor light emitting device capable of emitting light with high brightness without generating cracks due to thermal stress.

  With respect to the technique shown in Non-Patent Document 1, the present inventors have conducted intensive studies on measures for improving the surface properties of Group III metal nitride crystals. As a result, when manufacturing a nitride crystal of a group III metal, it has been found that such problems can be solved brilliantly if the operation is performed so as to avoid the stagnation of the melt near the surface of the seed crystal, and the present invention has been completed. Hereinafter, the present invention will be described in detail.

  The method for producing a nitride crystal of a group III metal in the present invention includes, in a reaction vessel, at least one metal selected from group III metals and two or more selected from the group consisting of alkali metals or alkaline earth metals. A seed crystal is immersed in a melt mixed with a metal, and a nitride crystal of a group III metal is produced on the surface of the seed crystal by bringing the melt into contact with nitrogen. It is important to operate so as to avoid the stagnation of the melt in the vicinity of the surface.

  The melt used in the production method of the present invention is a mixture of at least one metal selected from Group III metals and two or more metals selected from the group consisting of alkali metals or alkaline earth metals.

  Group III (Group 13) metals are Al, Ga and In, and in the present invention, a melt containing at least one metal selected from these groups is used. However, since the composition of the Group III metal nitride crystal layer formed on the substrate differs depending on the emission wavelength required for the semiconductor light emitting device, the generation of crystal defects in the Group III metal nitride crystal layer is suppressed. From the viewpoint of reducing the difference in thermal expansion coefficient between the base material and the group III metal nitride crystal layer, the composition of the base material (substrate) is preferably matched to the composition of the group III metal nitride crystal layer. . That is, in order to obtain a semiconductor light-emitting device that serves as a light source having a wavelength of about 250 to 500 nm, it is preferable to use a material containing Ga metal as a base material, and if necessary, an element such as Al or In is mixed. do it. In order to obtain such a substrate, a melt that essentially contains Ga metal may be used, and a melt in which an element such as Al or In is mixed may be used as necessary. The alkali metal is Li, Na, K, Rb, Cs, and Fr, and the alkaline earth metal is Ca, St, Ba, and Ra.

  In the present invention, a melt containing two or more metals selected from the group consisting of alkali metals or alkaline earth metals is used. This is because the use of two or more types increases the solubility of nitrogen in the melt and facilitates the formation of group III metal nitride crystals.

  Here, the melt containing two or more metals selected from the group consisting of alkali metals or alkaline earth metals is (a) a melt containing two or more metals selected from the group consisting of alkali metals. Or (b) a melt containing two or more metals selected from the group consisting of alkaline earth metals, or (c) at least one metal and alkaline earth selected from the group consisting of alkali metals. It may be a melt containing at least one metal from the group consisting of similar metals. Among these, it is particularly preferable to use the melt of the above (c). By using an alkali metal and an alkaline earth metal in combination, nitrogen is easily dissolved in the melt, and the growth of a nitride crystal of a group III metal is promoted. Can be promoted.

  As the alkali metal, Li, Na, or K is preferably used, and Na is particularly preferably used. Therefore, the melt is preferably selected from the group consisting of alkali metals or alkaline earth metals and containing two or more metals that essentially contain Li, Na, or K. More preferably, it is a melt containing two or more metals selected from the group consisting of alkali metals or alkaline earth metals and containing at least Na. On the other hand, it is preferable to use Ca as the alkaline earth metal. Therefore, the melt containing Na and Ca is most preferable.

  The proportion of metals selected from Group III metals in the melt is preferably at least 0.1 mol% in total, and the proportion of two or more metals selected from the group consisting of alkali metals or alkaline earth metals is: The total amount is preferably at least 0.1 mol%. For example, in the case of a melt obtained by selecting Ga from Group III metal and selecting and mixing Na and Ca from alkali metal or alkaline earth metal, Ga is 0.1 to 99.9 mol%, and Na and Ca are 0.1 to What is necessary is just to set it as 99.9 mol%. At this time, the ratio of Na and Ca is about 0.1: 99.9 to 99.9: 0.1 in terms of mol ratio.

The seed crystal immersed in the melt is not limited as long as the nitride of the group III metal is crystallized, and the group III metal nitride crystal formed in advance may be used as the seed crystal. For example, a laminate in which a group III metal nitride crystal is previously formed on a base material such as sapphire, SiC, Si, ZrB ₂ , or AlN by a known method may be used as a seed crystal.

  In addition, when using the said laminated body as a seed crystal, what is necessary is just to provide the nitride crystal of the group III metal used as a seed | species (nucleus) on the said base material surface, The thickness is not specifically limited. Such a substrate can be peeled off and removed from the group III metal nitride crystal by using a laser or the like.

In order to easily peel and remove the seed crystal and the group III metal nitride crystal formed on the surface of the seed crystal, an SiN film or an SiO ₂ film is formed in advance on the surface of the seed crystal, and this film is formed. It is preferable to use a partially etched seed crystal and form a group III metal nitride crystal on the etched surface.

As described above, by forming a SiN film or SiO ₂ film between the seed crystal and the group III metal nitride crystal, the group III metal nitride crystal grows, This is because the nitride crystal of the group III metal can be easily recovered by dissolving the SiO ₂ film with phosphoric acid or the like.

As a method for forming a SiN film, a SiO ₂ film or the like on the surface of the seed crystal, for example, a method such as a CVD method can be employed.

  It is preferable that the group III metal nitride crystal used as the seed crystal is doped in advance with an impurity serving as a donor or an acceptor. That is, it is preferable that a group III metal nitride crystal used as a seed crystal is doped in advance with Si or Mg as an impurity to be n-type or p-type. When a group III metal nitride crystal doped with impurities is used as a seed crystal and a group III metal nitride crystal is grown by the method described later, the seed crystal is formed into a newly formed group III metal nitride crystal layer. This is because impurities such as Si and Mg diffuse therein, and n-type and p-type nitride crystals can be obtained. Group III metal nitride crystals that are not doped with impurities have high resistivity and cannot achieve high output of the semiconductor light emitting device.

  In order to dope a group III metal nitride crystal used as a seed crystal with impurities such as Si or Mg in advance, for example, when forming a group III metal nitride crystal as a seed crystal on a substrate surface such as sapphire A known doping method may be employed in a vapor deposition method [for example, a metal organic chemical vapor deposition method (MOCVD method) or the like].

  Note that the shape of the seed crystal is not particularly limited, and generally a plate-like shape may be used.

  In the production method of the present invention, a group III metal nitride crystal is formed on the surface of the seed crystal by bringing the melt into contact with nitrogen. That is, by bringing the melt in the reaction vessel into contact with nitrogen, nitrogen is dissolved into the melt, and this nitrogen combines with the group III metal in the melt to form a group III metal nitride crystal. A part of the generated nitride crystal floats in the melt, but since the group III metal nitride crystal is immersed in the melt as a seed crystal, most of the generated nitride crystal is a seed crystal. Grows sequentially from the surface.

  In the production method of the present invention, it is important to operate so as to avoid the stagnation of the melt near the surface of the seed crystal. That is, the seed crystal grows by coming into contact with a melt containing a group III metal and N ions. When the crystal growth proceeds at this time, the group III metal and N ions present in the vicinity of the seed crystal are sequentially Is consumed. Therefore, the concentration of the group III metal and the N ion in the vicinity of the seed crystal varies, and the group III metal may be excessive or the N ion may be excessive. It was considered that the variation in the crystal concentration caused the crystal growth and the surface properties of the crystal were deteriorated.

  Here, the N concentration is a concentration when converted to N atoms, and is calculated by converting N constituting the nitride, free N ions, and the like into N atoms.

  The magnitude of the N concentration in the melt is evaluated using the degree of growth of the nitride crystal of the group III metal. That is, in the production method of the present invention, details will be described later, but as specific means for increasing the N concentration, nitrogen radicals are brought into contact with the melt, the melt near the seed crystal is heated, or nitrogen is melted. A method such as blowing into the liquid is adopted. At this time, if only the conditions such as presence / absence of nitrogen radicals, presence / absence of heating, presence / absence of blowing are changed and other conditions such as temperature, pressure and time are all made equal, nitriding of the group III metal formed on the surface of the seed crystal By measuring the thickness of the product crystal, it is possible to evaluate the influence of conditions such as presence / absence of nitrogen radicals, presence / absence of heating, presence / absence of blowing on crystal growth. In other words, the thickness of the generated nitride crystal indicates that the III metal and N ions present in the melt are combined and crystallized, so that the thicker the thickness, the higher the N ion concentration in the melt. The present inventors consider that this is shown.

  Next, specific modes for carrying out the production method of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a schematic explanatory diagram of an apparatus used for producing a group III metal nitride crystal, and an ultrasonic generator is provided to avoid stagnation of the melt near the surface of the seed crystal. . That is, the nitrogen cylinder 1 and the crucible 5 are connected by the pipe 2, and the nitrogen gas in the nitrogen cylinder 1 is supplied to the crucible 5 through the pipe 2. In the crucible 5 is stored a melt 7 in which at least one metal selected from Group III metals and two or more metals selected from the group consisting of alkali metals or alkaline earth metals are mixed. When the nitrogen gas comes into contact with the melt 7, it dissolves into the melt 7 and becomes a nitride of N ions or Group III metals. Further, a seed crystal 6 is immersed in the melt 7, and a group III metal nitride crystal grows using the seed crystal 6 as a nucleus. An ultrasonic generator 3 is provided in the middle of the pipe 2, and vibration generated by the ultrasonic generator 3 is transmitted to the crucible 5 through the pipe 2 a to vibrate the crucible 5.

  As described above, if the crucible 5 is vibrated, even if a group III metal or N ion is consumed in the process of growing a group III metal nitride crystal on the surface of the seed crystal 6, As a result, the seed crystal 6 itself also vibrates and convection occurs in the melt 7. As a result, variations in Group III metal and N ion concentration can be suppressed.

  Thus, by avoiding the stagnation of the melt 7 in the vicinity of the surface of the seed crystal 6, a group III metal nitride crystal with less irregularities on the surface can be produced.

  In addition, the crucible 5 is arrange | positioned in the muffle furnace 4, and the temperature in a furnace is heated by about 600-850 degreeC. The pressure in the crucible 5 is preferably about 0.1 to 15 MPa.

  FIG. 2 shows a configuration in which an ultrasonic generator is provided in the middle of the pipe 2 and the crucible 5 is vibrated by transmitting vibration generated in the ultrasonic generator to the crucible 5 through the pipe 2a. The sound wave generator 3 may be provided in a muffle furnace and the crucible 5 may be directly vibrated (not shown). However, since the temperature in the muffle furnace needs to be heated to about 600 to 850 ° C. as described above, it is necessary to provide a heat-resistant ultrasonic generator.

  FIG. 3 is a schematic explanatory diagram of another apparatus used when manufacturing a group III metal nitride crystal. The same parts as those in FIG. The apparatus shown in FIG. 3 includes means for pulling up the melt from the melt while rotating the seed crystal in order to avoid the stagnation of the melt near the surface of the seed crystal. That is, above the crucible 5, a rotary pulling device 8 having a turntable 8 a is provided, and the seed crystal 6 is pulled upward while rotating. Further, the tip 2b (nitrogen blowing position) of the pipe 2 connecting the nitrogen cylinder 1 and the crucible 5 is arranged immediately below the seed crystal 6, and nitrogen gas is blown into the melt 7.

  As described above, if the seed crystal 6 is pulled upward while rotating, the melt 7 in the vicinity of the seed crystal 6 moves so as to follow the rotation of the seed crystal 6. Residence can be avoided. Therefore, even if a group III metal or N ion is consumed in the process of growing a group III metal nitride crystal on the surface of the seed crystal 6, new melt 7 is sequentially supplied to the surface of the seed crystal 6. Therefore, variation in group III metal and N ion concentrations can be suppressed. Also, by dipping the tip 2b (nitrogen blowing position) of the pipe 2 into the melt 7, the contact area between the melt 7 and the nitrogen gas bubbles 9 is increased, and nitrogen is efficiently dissolved into the melt 7. To do. Moreover, since the concentration of the group III metal or N ion is higher in the upper part than in the lower part of the crucible 5, the growth rate of the nitride crystal of the group III metal can be increased, and the group III metal can be grown in a shorter time. Nitride crystals can be produced.

  FIG. 3 shows a configuration in which the tip 2b of the pipe 2 is immersed in the melt 7 and nitrogen gas is blown into the melt 7 from below the seed crystal 6, but the nitrogen gas bubbles 9 blown at this time are seeds. In direct contact with the crystal 6, the surface properties of the group III metal nitride crystal may be deteriorated. Therefore, when nitrogen gas is blown into the melt 7, it is preferable that the blown nitrogen gas bubbles 9 are not in direct contact with the seed crystal 6. That is, as shown in FIG. 4, the nitrogen blowing position (that is, the tip 2b of the pipe 2) is arranged away from the lower side of the seed crystal 6 so that the nitrogen blown into the melt 7 does not directly contact the seed crystal 6. It is good to configure.

  As described above, by separating the nitrogen blowing position from below the seed crystal 6, the nitrogen gas does not come into contact with the surface of the group III metal nitride crystal, so that the group III metal nitride crystal grows on the surface. Unevenness does not occur, and the surface properties are kept good. In addition, since nitrogen is blown into the melt 7, the N concentration in the melt 7 increases and the crystal growth rate also increases.

  FIG. 5 is a schematic explanatory view of another apparatus used for producing a group III metal nitride crystal. In order to avoid the stagnation of the melt near the surface of the seed crystal, FIG. The structure which operates while supplying melt is adopted. That is, the bottom of the crucible 5 is provided with a tapered slope, and an opening 5a is provided at the tip of the tapered portion. The opening 5a can be freely opened and closed by a control means (not shown). A rotating device 11 is provided below the crucible 5, and a seed crystal 6 is disposed on a rotating table 11 a provided in the rotating device 11. When the opening 5a is opened, the melt in the crucible 5 is discharged from the opening 5a (the flow of the melt 7 is indicated by a dotted line in FIG. 5) and supplied to the surface of the seed crystal disposed below the crucible 5. Is done.

  As described above, by sequentially supplying the melt 7 to the surface of the seed crystal 6, the concentrations of Group III metal and N ions in the melt 7 in contact with the seed crystal 6 become substantially uniform. In addition, since the seed crystal 6 is rotated in the configuration shown in FIG. 5, the melt 7 and the seed crystal 6 are in almost uniform contact with each other, so that there is no variation in the group III metal nitride crystal growth and the surface is uneven. A nitride crystal of a Group III metal with a low content can be obtained.

  Next, a semiconductor light emitting device using a group III metal nitride crystal obtained by the above manufacturing method will be described with reference to FIG.

  The semiconductor light emitting device of the present invention uses a group III metal nitride crystal obtained by the above production method as a base material of the support substrate 101, and uses a group III metal nitride compound semiconductor as the n layer 102, the light emitting layer 103, and the p layer. Used as 104 material. That is, conventionally, sapphire, SiC, or the like is used as a material for the support substrate 101, and a group III metal nitride compound semiconductor is formed thereon. However, as described above, III is formed on sapphire, SiC, or the like. When a group III metal nitride compound semiconductor is formed, crystal defects may occur due to lattice mismatch between the support substrate and the group III metal nitride crystal.

  Therefore, in the semiconductor light emitting device of the present invention, the group III metal nitride crystal according to the present invention is used as the material of the support substrate 101, and the n layer 102 and the light emitting layer 103 made of a group III metal nitride compound semiconductor are formed thereon. If the p layer 104 is formed, the above problem is solved. In addition, the thickness of a support substrate is about 30-500 micrometers normally.

The n layer 102 is a layer made of an n-type group III metal nitride compound semiconductor, and preferably a layer made of an n-type GaN compound semiconductor. Specifically, it is composed of a compound represented by Al _a In _b Ga _1-ab N (0 ≦ a, 0 ≦ b, a + b ≦ 1). For example, Al _a Ga _1-a N where a is 0.5 or less and In _b Ga _1-b N where b is 0.5 or less are preferable.

Although FIG. 1 shows the case where a single layer is formed as the n layer 102, a stacked layer may be formed as the n layer. That is, a stacked structure in which an n-type contact layer and an n-type cladding layer are stacked in this order from the support substrate side may be employed. As the n-type contact layer, a layer made of GaN is common among the above-mentioned compounds constituting the n layer. As the n-type cladding layer, among the above-mentioned compounds constituting the n layer, a layer made of Al _0.3 Ga _0.7 N, a layer made of AlN, a layer made of GaN, etc. are common.

  If the n layer (including the n-type contact layer and the n-type cladding layer) is doped with an n-type impurity such as Si, the carrier concentration can be increased, which is desirable.

  When the n layer has a single layer structure, the thickness of the n layer is generally about 0.5 to 10 μm. On the other hand, when the n layer has a laminated structure of an n-type contact layer and an n-type cladding layer, the n-type contact layer is generally about 0.2 to 10 μm, and the n-type cladding layer is not particularly limited. It is about 0.01 to 3 μm.

The light emitting layer 103 is a layer made of a group III metal nitride compound semiconductor, and it is preferable to form a layer made of a GaN compound semiconductor. Specifically, composed of _{Al c In d Ga 1-cd} N (0 ≦ c, 0 ≦ d, c + d ≦ 1) represented by compounds. In this light emitting layer, for example, if the composition ratio of In and Al in the above compound is adjusted, or if the light emitting layer is doped with an n-type impurity such as Si, Ge or S or a p-type impurity such as Mg or Zn The wavelength of the light to be adjusted can be adjusted in the range from blue to ultraviolet.

  Although FIG. 1 shows the case where a single layer is formed as the light emitting layer 103, for example, a so-called multiple quantum well structure in which the light emitting layer 103 has a laminated structure composed of a plurality of layers and the composition of the compounds constituting each layer is changed. It is also preferable that The total thickness of the light emitting layer is generally about 0.001 to 0.5 μm.

  The p layer 104 is a layer made of a group III metal nitride compound semiconductor, and preferably a layer made of a p-type GaN compound semiconductor. Although FIG. 1 shows a case where a single layer is formed as the p layer 104, it is general to have a laminated structure in which a p-type cladding layer and a p-type contact layer are laminated in this order from the light emitting layer side.

The p-type cladding layer is made of, for example, a compound represented by Al _e Ga _1-e N (0 <e ≦ 1), and is further doped with a p-type impurity. The value of e is preferably 0.05 or more. The p-type contact layer is composed of, for example, p-type GaN doped with p-type impurities. Examples of the p-type impurity doped in the p-type cladding layer and the p-type contact layer include Mg and Zn. The thickness of the p-type cladding layer is generally about 0.001 to 1.5 μm, and the thickness of the p-type contact layer is generally about 0.01 to 2 μm.

  The material constituting the p-type electrode 105 is required to be in ohmic contact with the p-layer, and examples thereof include Ni, Rh, Pd, Pt, and alloys thereof. The thickness of the p-type electrode is usually about 0.05 to 5 μm.

  The material constituting the n-type electrode 106 is required to have an ohmic contact with the n layer, and examples thereof include Al, Ti, V, and alloys thereof. The thickness of the n-type electrode is usually about 0.05 to 5 μm.

  In forming the n layer 102, the light emitting layer 103, and the p layer 104, a known film forming method such as a known vapor phase growth method (MOCVD method) can be employed. The doping of the n-type impurity into the n layer and the doping of the p-type impurity into the p layer are performed simultaneously with the formation of these layers.

It is sectional drawing for demonstrating the structure of a semiconductor light-emitting device. It is a schematic explanatory drawing of the apparatus used when manufacturing a group III metal nitride crystal. It is a schematic explanatory drawing of the other apparatus used when manufacturing a group III metal nitride crystal. It is a schematic explanatory drawing for demonstrating the other structural example of the apparatus shown in FIG. It is a schematic explanatory drawing of the other apparatus used when manufacturing a group III metal nitride crystal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nitrogen cylinder 2 Piping 2a Piping 2b Piping tip 3 Ultrasonic generator 4 Muffle furnace 5 Crucible 5a Opening 6 Seed crystal 7 Melt 8 Rotating pulling device 8a Rotating table 9 Bubble 11 Rotating device 11a Rotating table 101 Support substrate 102 n Layer 103 light emitting layer 104 p layer 105 p-type electrode 106 n-type electrode 107 exposed surface

Claims (4)

In the reaction vessel,
At least one selected from Group III metals;
The seed crystal is immersed in a melt obtained by mixing two or more selected from the group consisting of alkali metals or alkaline earth metals, and the surface of the seed crystal is nitrided by bringing the melt into contact with nitrogen. A method for producing a physical crystal comprising:
A method for producing a group III metal nitride crystal, wherein the seed crystal is pulled up from the melt while rotating to avoid stagnation of the melt near the surface of the seed crystal. In the reaction vessel,
At least one selected from Group III metals;
The seed crystal is immersed in a melt obtained by mixing two or more selected from the group consisting of alkali metals or alkaline earth metals, and the surface of the seed crystal is nitrided by bringing the melt into contact with nitrogen. A method for producing a physical crystal comprising:
A Group III metal nitride crystal, which is operated so as to avoid stagnation of the melt in the vicinity of the surface of the seed crystal by operating while supplying the melt to the surface of the rotating seed crystal The manufacturing method.   The manufacturing method of Claim 1 or 2 which uses what doped the impurity used as a donor or an acceptor as said seed crystal. The manufacturing method according to claim 1, wherein a seed crystal provided with a SiN film or a SiO ₂ film on a part of its surface is used.

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