JP6324810B2 - Vapor growth equipment - Google Patents

Description

  The present invention relates to a vapor phase growth apparatus for growing a crystal on a substrate by reacting a plurality of source gases.

  Group III nitride semiconductor crystals such as aluminum nitride, gallium nitride, and indium nitride have a wide range of band gap energy values, which are about 6.2 eV, about 3.4 eV, and about 0.7 eV, respectively. Degree. These group III nitride semiconductors can form mixed crystal semiconductors having an arbitrary composition, and can take values between the above band gaps depending on the mixed crystal composition.

  Therefore, by using a group III nitride semiconductor crystal, it is possible in principle to produce a wide range of light emitting elements from infrared light to ultraviolet light. In particular, in recent years, development of light-emitting elements using aluminum-based group III nitride semiconductors (mainly aluminum gallium nitride mixed crystals) has been vigorously advanced. By using an aluminum-based group III nitride semiconductor, it is possible to emit light with a short wavelength in the ultraviolet region, an ultraviolet light emitting diode for a white light source, an ultraviolet light emitting diode for sterilization, a laser that can be used for reading and writing of a high-density optical disk memory, and a laser for communication A light emitting light source such as can be manufactured.

  A light-emitting element using a group III nitride semiconductor (for example, an aluminum-based group III nitride semiconductor) is a semiconductor single crystal thin film (specifically, a thickness of about several microns on a substrate, like a conventional semiconductor light-emitting element). The thin film can be formed by sequentially stacking an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer. Such a thin film of a semiconductor single crystal can be formed using a crystal growth method such as a molecular beam epitaxy (MBE) method or a metalorganic chemical vapor deposition (MOCVD) method. Thus, it has been attempted to form a laminated structure suitable as a light emitting device by adopting such a method for the group III nitride semiconductor light emitting device.

  Currently, in the manufacture of group III nitride semiconductor light-emitting devices, a sapphire substrate is generally employed from the viewpoint of crystal quality, ultraviolet light transparency, mass productivity, and cost as a substrate. However, when a group III nitride is grown on a sapphire substrate, there is a difference in lattice constant, thermal expansion coefficient, etc. between the sapphire substrate and the group III nitride (such as aluminum gallium nitride) forming the semiconductor laminated film. As a result, crystal defects (misfit dislocations), cracks, and the like occur, causing the light emitting performance of the device to deteriorate.

  In order to solve these problems, it is desirable to use a substrate having a lattice constant close to that of the semiconductor multilayer film and a thermal expansion coefficient close to that of the semiconductor multilayer film when forming the semiconductor multilayer film. . As the substrate on which the Group III nitride semiconductor thin film is formed, a single crystal substrate is suitable, and among these, a Group III nitride single crystal substrate is most suitable. For example, an aluminum nitride single crystal substrate or an aluminum gallium nitride single crystal substrate is optimal as a substrate on which an aluminum-based group III nitride semiconductor thin film is formed.

  In order to use a single crystal such as a group III nitride as a substrate, it is preferable that the single crystal has a certain thickness (for example, 10 μm or more) from the viewpoint of mechanical strength. Since the MOCVD method has a higher crystal growth rate than the MBE method, it can be said that the MOCVD method is suitable for manufacturing a single crystal substrate. Further, a hydride vapor phase epitaxy (HVPE) method is known as a method for growing a single crystal having a higher film formation rate than the MOCVD method (see Patent Documents 1 to 3). The HVPE method is not suitable for precisely controlling the film thickness as compared with the MBE method or the MOCVD method, but a single crystal with good crystallinity can be grown at a high film formation rate. It can be said that it is particularly suitable for mass production of crystal substrates. Single crystal growth by MOCVD or HVPE is performed by supplying a Group III source gas and a Group V source gas into a reactor and reacting both gases on a heated substrate.

  Regarding the production of a single crystal, for example, Patent Document 4 discloses a reactor main body, a group III source gas generating section for generating a group III halide gas, and a group III halide gas supplied to the reaction zone of the reactor main body. A hydride vapor phase epitaxy apparatus having a group halide gas inlet tube is disclosed. In Patent Document 4, the end inlet of the group III halide gas introduction pipe passes through the end wall of the outer chamber of the reactor body, and the end inlet of the group III halide gas introduction pipe is connected to the reactor. It is described that it is connected to a first nozzle provided inside an inner chamber of the main body.

JP 2003-303774 A JP 2006-073578 A JP 2006-114845 A JP 2013-060340 A

  However, as a result of further investigations by the present inventors, in the single crystal vapor phase growth apparatus, (i) dirt easily adheres to the nozzle for supplying the source gas to the reaction zone, particularly the nozzle for the group III source gas. ii) dirt attached to the nozzle is carried by the gas flow and adheres to the substrate, causing abnormal growth; and (iii) abnormal growth derived from such nozzle dirt is in the case of adopting the HVPE method. It turned out to be particularly noticeable. In order to avoid abnormal growth due to nozzle contamination, it is preferable to clean the nozzles frequently. However, with regard to the workability of attaching and detaching the nozzles and the reproducibility of the nozzle position when attaching the nozzle of the source gas to the apparatus, It was not examined.

  In the vapor phase growth apparatus for growing a crystal on a substrate by reacting a plurality of source gases, the present invention provides the workability of attaching / detaching the source gas nozzle and the reproducibility of the nozzle position when attaching the source gas nozzle to the apparatus. It is an object to provide an enhanced vapor phase growth apparatus. In addition, a crystal growth method using the vapor phase growth apparatus is provided.

According to a first aspect of the present invention, a reactor having a reaction zone for growing a crystal on a substrate by reacting a plurality of source gases;
A support base disposed in the reaction zone and rotatably supporting the substrate;
A first raw material supply unit that is disposed outside the reactor and supplies a first raw material gas;
A second raw material supply section that is disposed outside the reactor and supplies a second raw material gas;
A first source gas introduction pipe for guiding the first source gas from the first source supply section to the reaction zone;
A second raw material gas introduction pipe for guiding the second raw material gas from the second raw material supply section to the reaction zone;
The first source gas introduction pipe has a detachable first joint between the first source supply section and the outlet of the first source gas introduction pipe,
The vapor phase growth apparatus is characterized in that the first bonding portion is a tapered bonding portion.

  According to a second aspect of the present invention, there is provided a crystal growth method comprising a step of growing a crystal using the vapor phase growth apparatus according to the first aspect of the present invention.

In the crystal growth method according to the second aspect of the present invention,
Separating the portion including the outlet of the first source gas introduction pipe at the first joint portion;
Cleaning the separated portion of the first source gas introduction pipe;
It is preferable to further include a step of attaching the separated and cleaned portion of the first source gas introduction pipe to the first joint portion.

  According to the first aspect of the present invention, in a vapor phase growth apparatus for growing a crystal on a substrate by reacting a plurality of source gases, the workability of attaching and detaching the source gas nozzle and attaching the source gas nozzle to the apparatus It is possible to provide a vapor phase growth apparatus with improved nozzle position reproducibility.

According to the crystal growth method according to the second aspect of the present invention, in the crystal growth method for growing a crystal on a substrate by reacting a plurality of source gases, the vapor phase growth apparatus according to the first aspect of the present invention. Since the first joint portion is a tapered joint portion, gas leakage at the joint portion can be reduced.
In addition, when cleaning the source gas nozzle, it is possible to improve the workability of attaching and detaching the nozzle and the reproducibility of the nozzle position when the source gas nozzle is attached to the apparatus.

It is a figure which illustrates typically the vapor phase growth apparatus 1000 concerning one embodiment of the present invention. It is sectional drawing which shows an example of a taper-shaped junction part. It is the elements on larger scale which picked out the vicinity of the 1st junction part 223 in FIG. It is a figure which illustrates typically the vapor phase growth apparatus 2000 of this invention which concerns on other embodiment. It is a figure which illustrates typically the vapor phase growth apparatus 3000 of this invention which concerns on other embodiment. It is a figure which illustrates typically the vapor phase growth apparatus 4000 of this invention which concerns on other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawing, some symbols may be omitted. In the present specification, “A to B” for the numerical values A and B means “A or more and B or less” unless otherwise specified. In the notation, when the unit of the numerical value A is omitted, the unit attached to the numerical value B is applied as the unit of the numerical value A. In addition, the form shown below is an illustration of this invention and this invention is not limited to these forms.

<1. Vapor growth equipment>
The vapor phase growth apparatus according to the first aspect of the present invention will be described. FIG. 1 is a schematic diagram of a vapor phase growth apparatus 1000 according to an embodiment of the present invention. The vapor phase growth apparatus 1000 includes a reactor 100 having a reaction zone 120 for growing a crystal on a substrate by reacting a first raw material gas and a second raw material gas; A support base 122 that rotatably supports the first raw material supply unit 210 that is disposed outside the reactor 100 and supplies the first raw material gas; and disposed outside the reactor 100 and A second raw material supply unit 310 that supplies two raw material gases; a first raw material gas introduction pipe 220 that guides the first raw material gas from the first raw material supply unit 210 to the reaction zone 120; and a second It has a second source gas introduction pipe 320 that guides the second source gas from the source supply unit 310 to the reaction zone 120. In the vapor phase growth apparatus 1000, the first source gas introduction pipe 220 is attached and detached between the first source gas supply section 210 and the first source gas outlet 220a from which the first source gas flows out. It has a possible first tapered joint 223. The vapor phase growth apparatus 1000 uses a group III halide gas as the first source gas, uses a nitrogen source gas as the second source gas, and grows a group III nitride crystal by the HVPE method.

  The reactor 100 has an outer chamber 101 and an inner chamber 102 formed inside the outer chamber 101, and the inner chamber 102 has a reaction zone 120 inside thereof. A support base (susceptor) 122 is installed in the reaction zone 120, and the support base 122 is connected to a rotational drive shaft 123 to rotatably support the substrate 121. The rotation drive shaft 123 transmits power from an electric motor (not shown) to the support base 122, and rotates the support base 122 at an appropriate rotation speed. The reactor 100 further includes a local heating device 124 such as a high-frequency coil for heating the support table 122. As the local heating device 124, as long as the support base 122 can be appropriately heated, a resistance heater or other known heating means can be employed in addition to the high-frequency coil.

  A group III metal 211 (eg, aluminum, gallium, etc.) is disposed inside the first raw material supply unit 210, and a hydrogen halide gas (eg, hydrogen chloride gas, etc.) is provided in the first raw material supply unit 210. Is supplied to the reaction zone 120 as a first source gas, a group III halide gas (for example, aluminum chloride gas, gallium chloride gas, etc.). The group III halide gas is generated by the reaction of a heated group III metal (eg, aluminum, gallium, indium) solid (211) and a hydrogen halide gas (eg, hydrogen bromide gas, hydrogen chloride gas). Can do. In order to advance this reaction, the first raw material supply unit 210 is heated by the heating device 212 at a temperature suitable for the reaction (for example, about 150 to 1000 ° C. in the generation of aluminum chloride gas, preferably about 300 to 660 ° C. More preferably, the temperature is about 300 to 600 ° C., or about 300 to 1000 ° C. in the generation of gallium chloride gas. As the heating device 212, known heating means such as a resistance heater can be used without particular limitation.

The group III halide gas (first source gas) generated in the first source supply unit 210 is guided to the reaction zone 120 in the reactor 100 by the first source gas introduction pipe 220. The first source gas introduction pipe 220 is disposed so as to blow out a group III halide gas (first source gas) from the upper side of the support base 122 toward the upper side of the support base 122.
The first source gas introduction pipe 220 has one end connected to the other end of the main pipe 221 connected to the first source supply unit 210, and the first source gas outlet 220 a at one end. The other end of the detachable nozzle 222 is detachably joined at the first joint 223. With this configuration, the first source gas introduction pipe 220 has a detachable first joint 223 between the first source supply unit 210 and the first source gas outlet 220a.

The first joint 223 is a tapered joint. As the taper-shaped joint portion, for example, the end portions of two members to be joined (that is, the other end portion of the main pipe 221 and the other end portion of the removable nozzle 222) have substantially the same taper. The two conical surfaces having the above-mentioned two are provided, and the two members can be joined by combining the two members so that the two conical surfaces face each other and contact each other. FIG. 2 is a cross-sectional view showing an example of such a tapered joint. The diameter D of the largest circle formed by the intersection of the plane perpendicular to the rotation axis of the cone bus and the portion of the conical surface combined with the other cone plane is “large diameter”, and perpendicular to the rotation axis of the cone bus The diameter d of the smallest circle formed by the intersection of the first surface and the conical surface with the other conical surface is “small diameter”, and the distance L on the rotation axis between the largest circle and the smallest circle is This is referred to as “taper length”. The “taper” is twice the tangent of the angle formed by the conical genera of the conical surface with respect to the rotation axis ((D−d) / L). The two conical surfaces have “substantially the same taper” means that the absolute value of the difference in taper between the two conical surfaces is less than 0.0012. The taper length L and the taper value t (= (D−d) / L) are ranges in which the detachable nozzle 222 does not fall off when the rotation axis of the conical busbar is horizontal with the two members joined. That is, the selection can be made as appropriate as long as the inequality 4L ² −D ² + d ² > 0 is satisfied. FIG. 3 is a diagram for explaining the derivation of the inequality, and is a partially enlarged view of the vicinity of the first joint 223 in FIG. The rotation axis A of the cone bus is horizontal. At this time, it is assumed that a sufficient static frictional force acts between the two conical surfaces. The detachable nozzle 222 is subjected to a moment to rotate clockwise about the point P as a fulcrum due to gravity. At this time, if ∠PQR = φ ≧ 90 °, the removable nozzle 222 moves away from the main pipe 221 while rotating, and the removable nozzle 222 falls off the main pipe 221. On the other hand, if φ <90 °, such movement occurs on the conical surface near the line segment TQ (where T is the intersection of the perpendicular line from the point P to the line segment QR and the line segment QR). Blocked by normal drag and frictional forces. Although FIG. 3 shows the case where the main pipe 221 is female and the detachable nozzle 222 is male, the same applies to the case where the main pipe 221 is male and the detachable nozzle 222 is female. Therefore, a condition for φ <90 °, that is, cos φ> 0 is obtained.
RS = (D−d) / 2
PS = (D + d) / 2
Therefore, QP = (L ² + ((D + d) / 2) ² ) ^1/2
QR = (L ² + ((D−d) / 2) ² ) ^1/2
From the cosine theorem, cos φ = (QP ² + QR ² −PR ² ) / (2 · QP · QR)
In order to satisfy cosφ> 0, it is sufficient that the numerator is positive, so QP ² + QR ² −PR ² > 0
4L ² −D ² + d ² > 0 after substituting QP and QR and PR = D.
Is obtained. Since this inequality is always satisfied as long as L ≧ D / 2, the taper length L is set to D / 2 or more, preferably to the large diameter D or more with respect to the large diameter D, and the taper t is, for example, 0.02-1. 0, preferably 0.04 or more, more preferably 0.06 or more, preferably 0.7 or less, more preferably 0.5 or less, still more preferably 0.3 or less. The conical surface may be provided with, for example, sandblasting, in which case the surface roughness of the conical surface is a stylus type surface roughness measuring instrument (or a measuring instrument equivalent thereto) defined in JIS B0651. The arithmetic average roughness Ra defined in JIS B0601 is preferably 1 μm or less, and more preferably less than 0.5 μm. Further, the conical surface may be smooth (ground). The airtightness of the taper-shaped joint is preferably in a range where the pressure increase due to leakage does not exceed 1.33 kPa in 5 minutes in the airtightness test prescribed in JIS R3646 7.4. Examples of the material constituting the tapered joint 223 include heat resistant glass, quartz glass, alumina, zirconia, stainless steel, and corrosion resistant alloys such as Inconel, and quartz glass can be preferably used.

Such tapered joints are defined, for example, in JIS R3646 “Interchangeable conical glass ground joints for glassware for chemical analysis” or ISO 383 “Laboratory glassware − Interchangeable conical glass joints”. A common taper joint with shape and dimensions is commercially available and can be preferably used. As the joint surface in the first joint portion 223, the surface roughness within the range specified in JIS R3646 or ISO 383, that is, the arithmetic average roughness Ra specified in JIS B0601, or the roughness specified in ISO / R 468 is used. in addition to be adopted without any particular limitation tapered bonding surfaces having a 1μm or less of the surface roughness as an average value R _a, tapered bonding surfaces with a smooth glass surface not subjected to sandblasting also be employed. A commercially available example of such a taper-shaped joint having a smooth joint surface is “SPC joint” (Shibata Chemical Co., Ltd.).
Regarding the length of the taper portion, JIS R3646 defines standards for long, medium, and short shapes. From the viewpoint of stability during use, a joint having a shape and dimensions defined as a medium or long shape is required. Particularly preferred are joints having a shape and dimensions that are defined as elongated.

The second source gas introduction pipe 320 guides a nitrogen source gas (second source gas) from the second source supply unit 310 to the reaction zone 120. The second source gas outlet 320a of the second source gas introduction pipe 320 is located above the support base 122 and from above the first source gas outlet 220a of the first source gas introduction pipe 220. A nitrogen source gas (second raw material gas) is arranged to blow upward.
By disposing the second source gas outlet 320a above the first source gas outlet 220a, the nitrogen source gas (second source gas) can be uniformly supplied onto the support base 122. . The second source gas introduction pipe 320 is preferably disposed above the first source gas outlet 220a. However, when ammonia gas is used as the nitrogen source gas, the ammonia gas is relatively Since it is easy to diffuse, the second source gas outlet 320a may be disposed below the first source gas outlet 220a.

  In the present embodiment, since the inner chamber 102 of the reactor 100 has the reaction zone 120 inside, it may be composed of a heat-resistant and acid-resistant nonmetallic material such as quartz glass, alumina, sapphire, and heat-resistant glass. Preferably, the first source gas introduction pipe 220 and the second source gas introduction pipe 320 are preferably made of the same material. The outer chamber 101 may be made of the same material as the inner chamber 102. However, since the outer chamber 101 is not in direct contact with the reaction zone 120, it can be made of a general metal material such as stainless steel.

  In the vapor phase growth apparatus 1000, the first source gas introduction pipe 220 has a taper-shaped detachable first joint portion between the first source gas supply unit 210 and the first source gas outlet 220a. 223. In place of the taper-shaped joint portion 223, when the joint portion is configured such that the outer tube also serving as a nozzle is covered with a middle tube having a constant outer diameter, the nozzle position when the source gas nozzle is attached to the apparatus is likely to vary. . In addition, when the outer diameter of the intermediate tube and the inner diameter of the outer tube are completely matched, the workability of nozzle attachment / detachment decreases. On the other hand, if a clearance is provided between the middle pipe and the outer pipe in consideration of these problems, the leakage of the raw material gas from the joint portion is likely to increase. If a screw-type joint is used instead of the taper-shaped joint 223, it is possible to improve the reproducibility of the nozzle position, but the screw part is liable to stick (stack), and can be attached and detached. In this case, the main pipe or nozzle is easily cracked. In the vapor phase growth apparatus 1000, since the first joint portion 223 is a tapered joint portion, the workability of attaching and detaching the source gas nozzle and the reproducibility of the nozzle position when attaching the source gas nozzle to the device are simultaneously performed. Has been enhanced. Furthermore, workability of attachment / detachment and position reproducibility are improved, and leakage of the raw material gas at the joint can be prevented.

  In the vapor phase growth apparatus 1000, the first bonding portion 223 is provided in a portion of the first source gas introduction pipe 220 that exists inside the reactor 100. According to such a configuration, since the length of the removable nozzle 222 can be manufactured relatively short, the removable nozzle 222 can be easily detached and the risk of breakage can be reduced.

In the above description regarding the present invention, the vapor phase growth apparatus 1000 in which a group III nitride crystal is grown by the HVPE method is mainly exemplified, but the present invention is not limited to this form. For example, a vapor phase growth apparatus in which a group III nitride crystal is grown by MOCVD can be used. More specifically, the first raw material supply unit may be a vapor phase growth apparatus configured to supply a group III organometallic compound gas (for example, trimethylaluminum gas or trimethylgallium gas) as a group III source gas. It is. In that case, the first raw material supply unit adopts the first raw material supply unit configured to supply the gas obtained by vaporizing the group III organometallic compound as the first raw material gas without arranging the group III metal 211 in the first raw material supply unit. Is done.
Further, even when a group III nitride crystal is grown by the HVPE method, it is possible to adopt a form in which the group III metal 211 is not disposed in the first raw material supply unit. For example, a first raw material supply unit in which the group III halide gas separately vaporized or released from the gas storage device is heated to a desired temperature (for example, 150 to 1000 ° C.) by a heating device is employed.
Further, for example, in the case of growing a mixed crystal by the HVPE method, a plurality of types of Group III metals are arranged in the first raw material supply unit, and a Group III halide mixed gas is generated by supplying a halide gas, and the mixing is performed. While it is possible to introduce the gas into the reaction zone 120 through the first source gas supply pipe 220, the first source supply unit is configured such that no Group III metal is disposed, that is, instead of the halide gas. It is also possible to employ a first raw material supply unit that separately generates a group III halide mixed gas and raises the temperature to a desired temperature (for example, 150 to 1000 ° C.) by a heating device.

In the above description relating to the present invention, a vapor phase growth apparatus 1000 configured to supply a group III source gas as a first source gas and a nitrogen source gas as a second source gas to grow a group III nitride crystal. However, the present invention is not limited to this form. Other (or arsenic source gas such as, for example, AsH _3, a phosphorus source gas such as PH _3.) V group material gas as the second source gas by supplying, in the form of growing a crystal other than the III-nitride It is also possible to use a vapor phase growth apparatus. Further, for example, a group II source gas (for example, an organometallic compound or chloride containing Zn or Cd) is supplied as the first source gas, and a group VI source gas (for example, Se, S, O, or the like) is used as the second source gas. Hydride containing oxygen, oxygen, etc.) can be supplied to grow a II-VI group crystal. It is also possible to provide a vapor phase growth apparatus in which a SiC crystal is grown by supplying a chloride or hydride containing Si and a hydrocarbon containing C.

  In the above description related to the present invention, the first source gas is a group III source gas, the second source gas is a group V source gas, and the first source gas is introduced to the reaction zone 120. Although the vapor phase growth apparatus 1000 in which the taper-shaped detachable first joint portion 223 is provided in the tube 220 is illustrated, the present invention is not limited to this form. In the vapor phase growth apparatus of the present invention, the source gas introduced into the reaction zone by the source gas introduction pipe having a taper-shaped detachable joint may be any source gas. For example, the first source gas is a group V source gas, the second source gas is a group III source gas, and a group V source is provided by a first source gas introduction pipe provided with a taper-shaped detachable joint. It is also possible to use a vapor phase growth apparatus in which the source gas is guided to the reaction zone. However, since the group III source gas is more likely to generate deposits than the group V source gas, the first source gas provided with a taper-shaped detachable joint using the group III source gas as the first source gas. A mode in which the group III source gas is guided to the reaction zone by the introduction pipe can be preferably adopted.

  In the above description regarding the present invention, a group III halide gas as the first source gas is led to the reaction zone 120 by the first source gas introduction pipe 220 having the taper-shaped detachable first joint 223, The group V source gas as the second source gas is introduced into the reaction zone 120 by the second source gas introduction pipe 320 having no tapered detachable joint, and crystal growth is performed by the HVPE method. Although the phase growth apparatus 1000 has been illustrated, the present invention is not limited to this form. As described above, it is also possible to provide a crystal growth apparatus in which a group III organometallic compound gas is supplied as a group III source gas instead of a group III halide gas and crystal growth is performed by MOCVD. However, since the HVPE method has a high crystal growth rate and deposits easily adhere to the nozzle, the vapor phase growth apparatus of the present invention can be particularly preferably employed when crystal growth is performed by the HVPE method. Further, as described above, the first source gas introduced into the reaction zone by the first source gas introduction pipe having the taper-shaped detachable joint is either a group III halide gas or a group V source gas. However, it is preferable to introduce the group III halide gas, which is likely to generate deposits, to the reaction zone through the first source gas introduction pipe having a taper-shaped detachable joint portion as the first source gas. In the case where the first source gas is an aluminum trichloride gas that is particularly reactive among the group III halide gases and the deposit easily adheres to the nozzle, the effects of the present invention are more easily exhibited. In the vapor phase growth apparatus, aluminum trichloride gas can be particularly preferably used as the first source gas.

  In the above description regarding the present invention, the vapor phase growth apparatus 1000 in which the axis of the first joint portion 223 (the rotation axis of the conical surface of the conical surface forming the joint surface) is horizontally disposed is illustrated. Is not limited to this form. As long as the detachable nozzle does not fall off during the crystal growth and does not affect the crystal growth, the axis of the joint may be inclined out of the horizontal plane. However, it is most preferable that the axis of the joint is horizontal.

  In the above description regarding the present invention, the vapor phase growth apparatus 1000 in the form in which the first bonding portion 223 is provided in the portion of the first source gas introduction pipe 220 existing inside the reactor 100 is exemplified. The present invention is not limited to this form. It is also possible to use a vapor phase growth apparatus in which the first joint is provided in a portion of the first gas introduction pipe existing outside the reactor. FIG. 4 is a diagram schematically illustrating a vapor phase growth apparatus 2000 according to another embodiment of the present invention. In FIG. 4, the first raw material supply unit and the second raw material supply unit are omitted. Elements that have already appeared in FIGS. 1 to 3 are given the same reference numerals as those in FIGS. In the vapor phase growth apparatus 2000 shown in FIG. 4, the first source gas introduction pipe 2220 is a double pipe, and a barrier gas channel is formed outside the first source gas channel. A barrier gas outlet 2220b is formed so as to surround the raw material gas outlet 2220a. As the barrier gas, for example, a general gas such as hydrogen, nitrogen, argon, helium or the like can be used without particular limitation. The first source gas introduction pipe 2220 has a tapered first joint 2223 in a portion existing outside the reactor 100. The first joint 2223 itself has the same configuration as the first joint 223 described above. As in the vapor phase growth apparatus 2000, according to the configuration in which the first joint is disposed outside the reactor, the distance from the second source gas outlet 320a to the first joint 2223 can be increased. it can. For this reason, it is possible to prevent a situation in which the second source gas and the first source gas are mixed or reacted at a position that is not originally intended, so that the deposition of deposits on the nozzle is greatly suppressed. It becomes possible to do.

  In the above description of the present invention, the vapor deposition apparatus 1000, 2000 in a form in which the second source gas introduction pipe 320 that guides the second source gas to the reaction zone 120 is not provided with a taper-shaped detachable joint. However, the present invention is not limited to this form. It is also possible to provide a vapor phase growth apparatus in which the second source gas introduction pipe has a taper-shaped detachable joint. FIG. 5 is a diagram schematically illustrating a vapor phase growth apparatus 3000 according to another embodiment of the present invention. 5, elements already appearing in FIGS. 1 to 4 are given the same reference numerals as those in FIGS. In the vapor phase growth apparatus 3000 shown in FIG. 5, the second source gas introduction pipe 3320 has one end connected to the second source supply unit 310 and the other end of the main pipe 3321 and one end. The other end of the detachable nozzle 3322 having the second source gas outlet 3320a in the part is detachably joined at the second joint 3323. With this configuration, the second source gas introduction pipe 3320 has a tapered shape that can be attached and detached between the second source material supply unit 310 and the second source gas outlet 3320a through which the second source gas flows out. A second joint portion 3323 is provided. The second joint 3323 is configured in the same manner as the first joint 223 described above in relation to the vapor phase growth apparatus 1000. The second joint 3323 is provided in a portion of the second source gas introduction pipe 3320 that exists inside the reactor 100. Since the second joint portion is provided at this position, even if deposits are seen in the second source gas introduction pipe 3320, it can be attached and detached so that it can be replaced with a clean nozzle. It becomes easy and the risk of the deposit falling on the substrate 121 can be reduced.

  In the above description regarding the present invention, the second bonding portion 3323 is exemplified by the vapor phase growth apparatus 3000 in a form in which the second raw material gas introduction pipe 3320 is provided in a portion existing inside the reactor 100. The present invention is not limited to this form. It is also possible to use a vapor phase growth apparatus in a form in which the second bonding portion is provided in a portion of the second source gas introduction pipe existing outside the reactor. FIG. 6 is a diagram schematically illustrating a vapor phase growth apparatus 4000 according to another embodiment of the present invention. In FIG. 6, the first raw material supply unit and the second raw material supply unit are omitted. 1 to 5 are denoted by the same reference numerals as those in FIGS. 1 to 5 and description thereof is omitted. In the vapor phase growth apparatus 4000 shown in FIG. 6, the second source gas introduction pipe 4320 is a double pipe, and a barrier gas channel is formed outside the second source gas channel. A barrier gas outlet 4320b is formed so as to surround the source gas outlet 4320a. As the barrier gas, for example, a general gas such as hydrogen, nitrogen, argon, helium or the like can be used without particular limitation. The second source gas introduction pipe 4320 has a tapered second joint 4323 at a portion existing outside the reactor 100. The second joint 4323 itself has a configuration similar to that of the first joint 223 described above. As in the vapor phase growth apparatus 4000, according to the configuration in which the second joint is disposed outside the reactor, the distance from the second joint to the first and second source gas outlets is set to the second Therefore, it is possible to further reduce the risk of deposit generation due to the backflow of the raw material gas.

  In the above description regarding the present invention, the vapor phase growth apparatuses 1000, 2000, 3000, and 4000 in which the main joint side has a female shape and the removable nozzle side has a male shape in the first joint portion that is a tapered joint portion. Although illustrated, this invention is not limited to the said form. In the first joining portion, a vapor phase growth apparatus having a male shape on the main pipe side and a female shape on the detachable nozzle side may be used.

  In the above description regarding the present invention, the vapor phase growth apparatus 3000, 4000 in which the main pipe side has a female shape and the detachable nozzle side has a male shape in the second joint portion, which is a tapered joint portion, is exemplified. The present invention is not limited to this form. In the second bonding portion, a vapor phase growth apparatus having a male shape on the main tube side and a female shape on the detachable nozzle side may be used.

  Although not shown in FIGS. 1 to 6, the vapor phase growth apparatus of the present invention may have a structure for supplying an extrusion gas. That is, the first raw material gas and the second raw material gas are uniformly distributed in the reactor 100 so that the first raw material gas and the second raw material gas are uniformly circulated in the reactor 100 without flowing back to the side where the exhaust port 140 is provided. You may have the structure which supplies extrusion gas toward the side in which the exhaust port 140 was provided from the nozzle side of the raw material gas introduction pipe | tube 220 and the 2nd raw material gas introduction pipe | tube 320. FIG. The position where the extrusion gas is supplied in the reactor can be a position outside the flow of the first source gas, the second source gas, and the barrier gas. As the extrusion gas, for example, a general gas such as hydrogen, nitrogen, argon, or helium can be used. The cross-sectional shape of the first and second source gas inlet pipe outlets is not particularly limited, and any shape can be selected according to the dimensions of the substrate to be supplied, such as a circle, an ellipse, and a rectangle. It is. Moreover, it is possible to provide a raw material gas introduction pipe having a plurality of raw material gas outlets by dividing the gas flow path on the way from the taper junction to the raw material gas outlet. The number of outlets to be divided can be arbitrarily determined according to the area of the substrate to which the source gas is supplied, but is generally 2 to 10, preferably 3 to 6 or less.

<2. Crystal growth method>
A crystal growth method according to the second aspect of the present invention will be described. The crystal growth method according to the second aspect of the present invention includes a step of growing a crystal using the vapor phase growth apparatus according to the first aspect of the present invention. And a step of separating the portion including the outlet of the first gas supply pipe at the first joint, a step of washing the separated portion of the first gas supply pipe, Preferably, the method further includes attaching the separated and cleaned portion to the first joint.

  As the group III source gas (first source gas) supplied from the first source supply unit 210 in the vapor phase growth apparatus 1000 (FIG. 1), halogenation of aluminum trichloride, aluminum monochloride, aluminum tribromide, etc. Aluminum; gallium halides such as gallium trichloride and gallium monochloride; group III halide gases such as indium halides such as indium trichloride; and group III organometallic compound gases such as trimethylaluminum and trimethylgallium are not particularly limited. It can be adopted. When producing a mixed crystal, a mixed gas containing a plurality of group III source gases is used. When employing the HVPE method, as described above, the group III metal 211 is disposed in the first raw material supply unit 210, and the first raw material supply unit 210 is heated by the heating device 212 (for example, when aluminum trichloride gas is generated). The temperature is about 150 to 1000 ° C., preferably about 300 to 660 ° C., more preferably about 300 to 600 ° C., and about 300 to 1000 ° C. when gallium chloride gas is generated. The group III halide gas generated in the first raw material supply unit 210 is reacted through the first raw material gas introduction pipe 220 by supplying a halide gas (for example, hydrogen chloride gas) to the first raw material supply unit 210. Can be introduced into the vessel 100. On the other hand, instead of the first raw material supply section in which the group III metal is arranged, a separately generated group III raw material gas (group III halide gas in the case of the HVPE method, group III in the case of the MOCVD method) It is also possible to employ a first raw material supply unit that supplies an organometallic compound gas and raises the temperature to a desired temperature (for example, room temperature to 200 ° C.) using a heating device. These group III source gases are usually supplied in a state diluted with a carrier gas. As the carrier gas, hydrogen gas, nitrogen gas, helium gas, argon gas, or a mixed gas thereof can be used without particular limitation, and a carrier gas containing hydrogen gas is preferably used.

  In general, when a group III halide gas is used as the group III source gas, that is, when crystals are grown by the HVPE method having a high film formation rate, deposits are likely to adhere to the nozzle, and this tendency is high in reaction rate. Since it is particularly remarkable when using an aluminum halide gas, the vapor phase growth apparatus and the crystal growth method of the present invention can be preferably used when growing a crystal, particularly a group III nitride crystal, by the HVPE method. It can be particularly preferably used when growing a single crystal of a group III nitride containing aluminum as a group III element (hereinafter sometimes referred to as “Al group III nitride”) by the HVPE method. It can be most preferably used when growing a single crystal of aluminum. From this viewpoint, in the crystal growth method of the present invention, it is particularly preferable that the first source gas is a group III halide gas, particularly an aluminum halide gas, and the second source gas is a nitrogen source gas.

  In the reactor 100 of the vapor phase growth apparatus 1000, the flow of the group III halide gas (first raw material gas) flowing out from the first raw material gas introduction pipe 220 and the nitrogen flowing out from the second raw material gas introduction supply pipe 320 A barrier gas flow may be interposed between the source gas (second source gas) and the source gas. The barrier gas that flows between the flow of the group III source gas and the flow of the nitrogen source gas is inactive, and the diffusion of the group III source gas or the nitrogen source gas into the barrier gas is slow due to the large molecular weight. In terms of (high barrier effect), nitrogen gas, argon gas, or a mixed gas thereof can be preferably used. However, in order to adjust the effect of the barrier gas, nitrogen gas or argon gas or a mixed gas thereof is inert such as hydrogen gas, helium gas, neon gas (that is, does not react with group III source gas and nitrogen source gas). A low molecular weight gas may be mixed.

  Examples of the material of the substrate 121 on which the group III nitride single crystal is deposited include, for example, sapphire, silicon, silicon carbide, zinc oxide, gallium nitride, aluminum nitride, aluminum gallium nitride, gallium arsenide, zirconium boride, and titanium boride. Can be used without restriction.

  In order to obtain a group III nitride single crystal by nitriding the group III source gas introduced into the reactor 100 from the first source supply unit 210 via the first source gas supply pipe 220, a second source supply A nitrogen source gas (second source gas) is introduced from the section 310 into the reactor 100 through the second source gas introduction pipe 320. This nitrogen source gas is usually supplied in a state diluted with a carrier gas. As the nitrogen source gas, a reactive gas containing nitrogen can be used without particular limitation, but ammonia gas can be preferably used from the viewpoint of cost and ease of handling. As the carrier gas, hydrogen gas, nitrogen gas, helium gas, argon gas, or a mixed gas thereof can be used without particular limitation, and a carrier gas containing hydrogen gas is preferably used.

  Before the reaction between the group III source gas and the nitrogen source gas, organic substances adhering to the substrate 121 are removed, and a carrier gas containing hydrogen gas is circulated through the reactor 100 through the support stand 122 to circulate the substrate 121. It is preferable to perform thermal cleaning by heating. When using a sapphire substrate as the substrate 121, it is generally held at 1100 ° C. for about 10 minutes. Thereafter, a group III source gas (first source gas) is introduced into the reactor 100 through the first source gas introduction pipe 220, and a nitrogen source gas (second source gas) is introduced through the second source gas introduction pipe 320. While being introduced into the reactor 100, a group III nitride single crystal is grown on the heated substrate (preferably 1000 to 1700 ° C. in the case of the HVPE method, preferably 1000 to 1600 ° C. in the case of the MOCVD method). The growth of the group III nitride in the crystal growth method of the present invention is usually under a pressure around the atmospheric pressure (in the reactor, when a group III halide gas is used as the group III source gas) when the HVPE method is used. When the MOCVD method is used (that is, as a group III source gas) under the condition that the pressure inside the first source gas inlet tube and the second source gas inlet tube is 0.1 to 1.5 atm. When a group III organometallic compound gas is used, the reaction is usually performed at a pressure of 100 Pa to atmospheric pressure.

  When the HVPE method is used, the supply amount of the group III source gas (group III halide gas) is the supply partial pressure (total gas to be supplied (carrier gas, group III source gas, nitrogen source gas, barrier gas, extrusion gas). The ratio of the volume of the group III source gas in the standard state to the total volume in the standard state. When the MOCVD method is used, the supply amount of the group III source gas (group III organometallic compound gas) is usually selected in the range of 0.1 to 100 Pa in terms of supply partial pressure. The supply amount of the nitrogen source gas is not particularly limited, but generally, a supply amount of 0.5 to 500 times that of the group III source gas to be supplied is preferably employed.

  The growth time is appropriately adjusted so that a desired growth film thickness is achieved. After crystal growth for a certain time, the crystal growth is terminated by stopping the supply of the group III source gas. Thereafter, the substrate 121 is cooled to room temperature. Through the above operation, a group III nitride single crystal can be grown on the substrate 121.

  After the operation of crystal growth is completed, the substrate 121 on which a desired crystal has grown is taken out from the reactor 100. Then, in the first joint portion 223, a portion of the first source gas introduction pipe 220 including the first source gas outlet 220 a (that is, the detachable nozzle 222) is separated from the main pipe 221. The separated removable nozzle 222 is washed to remove deposits attached to the nozzle, and then the removable nozzle 222 is attached to the first joint 223 again. Since the first joint portion 223 is a tapered joint portion, the operability of these attaching / detaching operations is good, and the reproducibility of the nozzle position is also enhanced.

  The vapor phase growth apparatus and the crystal growth method of the present invention can be preferably used when growing a crystal having a film thickness of 10 μm or more on the substrate, particularly a group III nitride crystal, and a crystal having a film thickness of 100 μm or more on the substrate, particularly III It can be particularly preferably used when growing a group nitride crystal.

  In the above description of the present invention, the crystal growth method using the vapor phase growth apparatus 1000 illustrated in FIG. 1 has been exemplified, but the crystal growth method of the present invention is not limited to this mode. As described above for the vapor phase growth apparatus of the present invention, the vapor phase growth apparatus (see FIGS. 4 and 6) in which the first joint is provided outside the reactor, or the first source gas introduction pipe In addition to the second source gas introduction pipe, a crystal growth method using a vapor phase growth apparatus (see FIGS. 5 and 6) in which a taper-shaped joint that can be attached and detached is provided. It is.

  In the case of using a vapor phase growth apparatus (see FIGS. 5 and 6) in which the second source gas introduction pipe is provided with a detachable tapered joint, after the operation of crystal growth is completed. In addition, it is preferable that not only the detachable nozzle of the first source gas introduction pipe but also the detachable nozzle of the second source gas introduction pipe is similarly separated, cleaned, and reattached. That is, for example, when the crystal growth apparatus 3000 shown in FIG. 5 is used, a portion of the second source gas introduction pipe 3320 including the second source gas outlet 3320a (that is, the attachment / detachment) in the second joint 3323. The removable nozzle 3322) is separated from the main tube 3321; the separated removable nozzle 3322 is cleaned to remove deposits attached to the nozzle; the cleaned removable nozzle 3322 is reattached to the second joint 3323 Is preferred. Since the second joint portion 3323 is a tapered joint portion, the operability of these attaching / detaching operations is good, and the reproducibility of the nozzle position is also enhanced.

1000, 2000, 3000, 4000 Vapor deposition apparatus 100 Reactor 101 Outer chamber 102 Inner chamber 120 Reaction zone 121 Substrate 122 Support (susceptor)
123 Rotary drive shaft 124 Local heating device 140 Exhaust port 210 First raw material supply unit 211 Group III metal 212 (first raw material supply unit) heating device 220, 2220 First raw material gas introduction pipes 220a, 2220a First Source gas outlet 2220b Barrier gas outlet 221 (of the first source gas introduction pipe) Main pipe 222 (of the first source gas introduction pipe) Removable nozzles 223 and 2223 of the first source gas introduction pipe Junction part 310 2nd raw material supply part 320, 3320, 4320 2nd raw material gas introduction pipe 320a, 3320a, 4320a 2nd raw material gas blow-out opening 4320b (second raw material gas introduction pipe) Barrier gas blow-out opening 3321 (first Main pipe 3322 (of the second source gas introduction pipe) detachable nozzles 3323, 4323 (of the second source gas introduction pipe) 2 joints

Claims (13)

A reactor having a reaction zone for growing a crystal on a substrate by reacting a plurality of source gases;
A support base disposed in the reaction zone and rotatably supporting the substrate;
A first raw material supply unit disposed outside the reactor and supplying a first raw material gas;
A second raw material supply unit disposed outside the reactor and supplying a second raw material gas;
A first source gas introduction pipe for guiding the first source gas from the first source supply section to the reaction zone;
A second source gas introduction pipe for guiding the second source gas from the second source supply unit to the reaction zone;
The first source gas introduction pipe has a detachable first junction between the first source supply section and the outlet of the first source gas introduction pipe,
It said first joint portion is Ri junction der tapered,
It said first joint, heat-resistant glass, quartz glass, alumina, zirconia, stainless steel, or characterized that you have been composed of corrosion resistant alloys, vapor phase growth apparatus.   The vapor phase growth apparatus according to claim 1, wherein the axis of the first joint is disposed horizontally. The first joint is provided in a portion of the first source gas introduction pipe existing inside the reactor;
The vapor phase growth apparatus according to claim 1 or 2. The first joint is provided in a portion of the first source gas introduction pipe that exists outside the reactor.
The vapor phase growth apparatus according to claim 1 or 2. The second source gas introduction pipe has a detachable second joint portion between the second source gas supply section and the outlet of the second source gas introduction pipe,
5. The vapor phase growth apparatus according to claim 1, wherein the second bonding portion is a taper-shaped bonding portion. The second joint is provided in a portion of the second source gas introduction pipe existing inside the reactor;
The vapor phase growth apparatus according to claim 5 . The second joint portion is provided in a portion of the second source gas introduction pipe existing outside the reactor;
The vapor phase growth apparatus according to claim 5 . Crystal growth is performed under conditions where the pressure inside the reactor, the inside of the first source gas introduction pipe, and the inside of the second source gas introduction pipe is 0.1 to 1.5 atm.
The vapor phase growth apparatus according to any one of claims 1 to 7 . Crystal growth is performed by hydride vapor phase epitaxy,
The vapor phase growth apparatus according to any one of claims 1 to 8 . The first source gas is a group III halide gas;
The second source gas is a nitrogen source gas;
Grow group III nitride crystals,
The vapor phase growth apparatus according to claim 9 . Crystal growth method characterized by comprising the step of growing the crystal by a vapor growth apparatus according to any one of claims 1-10. Growing a crystal by a vapor growth apparatus according to any one of claims 1-10,
Separating the portion including the outlet of the first source gas introduction pipe in the first joining portion;
Cleaning the separated portion of the first source gas introduction pipe;
And a step of attaching the separated and cleaned portion of the first source gas introduction pipe to the first joint portion. In the vapor phase growth apparatus, the second source gas introduction pipe is provided with a detachable second joint between the second source supply section and the outlet of the first source gas introduction pipe. The second joint is a tapered joint,
Separating the portion including the outlet of the second source gas introduction pipe in the second joining portion;
Cleaning the separated portion of the second source gas introduction pipe;
The crystal growth method according to claim 12 , further comprising a step of attaching the separated and cleaned portion of the second source gas introduction pipe to the second joint portion.

Images