JP2010037189A - Apparatus and method for growing crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for growing crystals improved in yields of grown crystals with good crystallinity and suppressed in variation in the thicknesses of grown crystals. <P>SOLUTION: This crystal growth apparatus 100a includes a chamber 101, a plurality of rotating sections 103a and 103d, and crucibles, where the plurality of rotating sections 103a and 103d are disposed within the chamber, and the crucible is disposed on each of rotating sections 103a and 103d. The method for growing a crystal comprises steps of first disposing one seed substrate in each crucible, and then while rotating the each crucible, growing a crystal on the seed substrate by sublimation process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crystal growth apparatus and a crystal growth method, for example, an aluminum nitride (AlN) crystal growth apparatus and a crystal growth method.

Aluminum nitride (AlN) crystal has a wide energy band gap of 6.2 eV, a high thermal conductivity of about 3.3 WK ⁻¹ cm ⁻¹ , and a high electrical resistance, so that it is a semiconductor such as an optical device or an electronic device. It is attracting attention as a substrate material for devices.

  As such an AlN crystal growth method, for example, a vapor phase sublimation method is used. The growth of the AlN crystal by the sublimation method is performed by the following steps, for example. That is, the AlN crystal raw material is installed in the raw material container in the lower part of the crucible, and the seed substrate is installed in the seed substrate arrangement part in the upper part of the crucible so as to face the AlN crystal raw material. Then, the AlN crystal raw material is heated to a temperature at which the AlN crystal raw material sublimes. By this heating, the AlN crystal raw material is sublimated to generate sublimation gas, and an AlN single crystal grows on the surface of the seed substrate placed at a lower temperature than the AlN crystal raw material.

  As a crystal growth apparatus used for such a sublimation method, for example, Japanese Patent Application Laid-Open No. 2000-219594 (Patent Document 1) includes a seed substrate placement portion for placing a plurality of seed substrates and one raw material storage portion. A crystal growth apparatus with one crucible is disclosed. In Patent Document 1, a plurality of crystals are grown from a plurality of seed substrates in one crucible.

  Japanese Patent Application Laid-Open No. 2000-327499 (Patent Document 2) discloses a single raw material container, a seed substrate placement part for placing one seed substrate, and a plurality of capillaries extending in the direction of crystal growth from the seed substrate. A crystal growth apparatus having one crucible including the following is disclosed. In Patent Document 2, a plurality of II-IV group semiconductor crystals are grown from a single seed substrate in a plurality of thin tubes of one crucible.

  Japanese Patent Laying-Open No. 2002-53395 (Patent Document 3) discloses a crystal growth apparatus provided with a plurality of crucibles including one raw material container and a seed substrate placement part for placing one seed substrate. ing. In Patent Document 3, one crystal is grown from one seed substrate in each of a plurality of crucibles.

  Japanese Patent Application Laid-Open No. 2004-47658 (Patent Document 4) includes one seed substrate placement unit, a raw material storage unit, and a spacer that is disposed between each of the three seed substrates. A crystal growth apparatus with a crucible is disclosed. The crucible is disposed on a support base, and the support base can be moved up and down by a vertical movement rotation mechanism. In Patent Document 4, three crystals are grown from three seed substrates in one crucible.

JP 2000-219594 A JP 2000-327499 A JP 2002-53395 A JP 2004-47658 A

  However, in the crystal growth apparatus disclosed in Patent Document 1, a plurality of crystals are grown using the same raw material in one crucible. For this reason, the crystallinity of all the crystals depends on the atmosphere of the raw material, and if the raw material contains a defective one, all the crystals are defective. Therefore, there is a problem that the yield for growing a good crystalline crystal is poor.

  Moreover, in the crystal growth apparatus disclosed in Patent Documents 2 to 4, a plurality of crystals are grown in a region partitioned by a thin tube, a crucible, or a spacer. In the plurality of regions for crystal growth, the heating amount is relatively large in the region close to the heating unit, and the heating amount is relatively small in the region far from the heating unit. For this reason, there is a variation in the amount of heating in these regions, which causes a problem of variation in thickness in one grown crystal, that is, in-plane film thickness distribution.

  FIG. 11 is a diagram showing a state in which crystals are grown by the crystal growth apparatus disclosed in Patent Document 2. For example, with reference to FIG. 11, the reason why variation occurs in the thickness of a crystal grown using the crystal growth apparatus disclosed in Patent Document 2 will be described. When the heating unit is arranged on the outer periphery of the crystal device, the thin tube located on the outer periphery is heated to a higher temperature than the thin tube located on the center. For this reason, as shown in FIG. 11, in one crystal in the narrow tube, for example, the thickness on the outer peripheral side is larger than the thickness on the inner peripheral side.

  FIG. 12 is a diagram showing a state in which crystals are grown by the crystal growth apparatus disclosed in Patent Document 4. For example, with reference to FIG. 12, the reason why the thickness of the crystal grown by the crystal growth apparatus disclosed in Patent Document 4 varies will be described. In Patent Document 4, since the heating parts 215 are densely arranged at the center, the center is heated to a higher temperature than the outer periphery inside the crucible 203. In addition, the crucible 203 containing a plurality of seed substrates 212 is disposed on the support base 204, but even if the support base 204 is rotated by the vertical movement rotation mechanism 206, the seed substrate 212 is in a heated state. Only pass through the same area. For this reason, in the grown crystal, for example, the thickness on the center side is larger than the thickness on the outer peripheral side.

  In addition, since the above-mentioned Patent Document 4 only has a region for crystal growth partitioned by the spacer 213, there is a problem that the yield is poor as in the above-mentioned Patent Document 1.

  Accordingly, the present invention is to provide a crystal growth apparatus and a crystal growth method that improve the yield for growing a crystal with good crystallinity and suppress variation in the thickness of the crystal to be grown.

  The crystal growth apparatus of the present invention includes a chamber, a plurality of rotating parts, and a crucible. The plurality of rotating parts are arranged in the chamber. The crucible is arranged on each rotating part.

  According to the crystal growth apparatus of the present invention, by arranging one seed substrate in each of a plurality of crucibles, it is possible to grow crystals on the seed substrate independently for each crucible. For this reason, the influence by the atmosphere of the raw material of another crucible, etc. can be reduced, and a plurality of crystals can be grown simultaneously. Therefore, the yield for growing crystals with good crystallinity can be improved.

  Moreover, since the crucible is arrange | positioned on each rotation part, each crucible on a rotation part can be rotated by a rotation part. For this reason, when heating is performed to grow a crystal, the temperature difference in each crucible is relaxed. Since the crystal growth rate depends on the heating temperature, variations in the thickness of the crystal grown on the seed substrate (in-plane film thickness distribution) can be suppressed.

  As described above, it is possible to improve the yield of growing a crystal with good crystallinity and to suppress variation in the thickness of the crystal to be grown.

  Preferably, the crystal growth apparatus further includes a heating unit disposed so as to cover the outer periphery of the chamber, and the distance from the heating unit to each rotating unit is the same.

  Thereby, since each distance from a heating part to several crucibles becomes the same, the dispersion | variation in the calorie | heat amount added to several crucibles can be suppressed. For this reason, the dispersion | variation in the thickness between the some crystals grown for every crucible can be suppressed.

  The crystal growth method of the present invention is a method for growing a plurality of crystals using any of the crystal growth apparatuses described above, and includes the following steps. First, one seed substrate is placed inside each crucible. Then, while rotating each crucible, a crystal is grown on the seed substrate by the sublimation method.

  According to the crystal growth method of the present invention, since the above crystal growth apparatus is used, the influence of the atmosphere of other crucible raw materials is reduced, and crystals are simultaneously grown on the seed substrate at the same time independently for each crucible. Can be made. Therefore, the yield for growing crystals with good crystallinity can be improved.

  In addition, since the crystal is grown while rotating each crucible, the temperature difference in each crucible is alleviated. Therefore, variation in the thickness of the crystal grown on the seed substrate can be suppressed.

  Preferably, in the crystal growth method, an aluminum nitride (AlN) crystal is grown in the growing step.

  In order to grow AlN crystals, it is necessary to heat each crucible to a high temperature. When crystal growth is performed by heating to a high temperature, the temperature distribution in the plurality of crucibles becomes large. However, according to the crystal growth method of the present invention, since each crucible is rotated, the temperature difference in the crucible can be reduced. Therefore, the crystal growth method of the present invention is suitably used for the growth method of AlN crystal grown at a high temperature.

  In the crystal growth method, preferably, in the growing step, a crystal having a thickness of 1 mm or more is grown.

  Generally, when a crystal having a large thickness of 1 mm or more is grown, the thickness variation of the crystal to be grown becomes large. However, according to the crystal growth method of the present invention, each crucible can be rotated, so that the temperature difference in the crucible can be reduced. Therefore, the crystal growth method of the present invention is suitably used for a crystal growth method with a large thickness.

  According to the crystal growth method and the crystal growth apparatus of the present invention, it is possible to improve the yield for growing a crystal with good crystallinity and to suppress the variation in the thickness of the crystal to be grown.

It is sectional drawing which shows schematically the crystal growth apparatus in Embodiment 1 of this invention. It is a schematic diagram which shows a state when it sees from the II-II line | wire in FIG. FIG. 3 is a schematic diagram schematically showing a state when viewed from line III-III in FIG. 1. It is sectional drawing which shows schematically the reaction container containing the crucible in Embodiment 1 of this invention. It is a flowchart which shows the crystal growth method in Embodiment 1 of this invention. It is a schematic diagram which shows roughly the crystal growth apparatus in Embodiment 2 of this invention. It is a schematic diagram which shows roughly the crystal growth apparatus in Embodiment 3 of this invention. It is sectional drawing which shows schematically the crystal growth apparatus in Embodiment 4 of this invention. It is a schematic diagram which shows roughly the state seen from IX-IX in FIG. It is sectional drawing which shows schematically the crystal growth apparatus in Embodiment 5 of this invention. It is a figure which shows the state which carried out the crystal growth with the crystal growth apparatus disclosed by patent document 2. FIG. It is a figure which shows the state which carried out the crystal growth with the crystal growth apparatus disclosed by patent document 4. FIG.

  Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing a crystal growth apparatus in the present embodiment. FIG. 2 is a schematic diagram schematically showing a state when viewed from line II-II in FIG. FIG. 3 is a schematic diagram schematically showing a state when viewed from the line III-III in FIG. FIG. 4 is a cross-sectional view schematically showing a reaction vessel including a crucible in the present embodiment. With reference to FIGS. 1-4, the crystal growth apparatus 100a in this Embodiment is demonstrated. The crystal growth apparatus 100a is an apparatus for growing a crystal by a sublimation method.

  As shown in FIGS. 1 to 4, the crystal growth apparatus 100 a includes a chamber 101, reaction vessels 110 a to 110 f including a plurality of crucibles 115, a plurality of rotating units 103 a to 103 f, a heating unit 105, and a radiation thermometer. 107 is mainly provided.

  The chamber 101 has an introduction part 101 a for flowing a carrier gas such as nitrogen gas into the crucible 115 and a discharge part 101 b for discharging the carrier gas to the outside of the chamber 101. The planar shape of the chamber 101 is, for example, a circle.

  In this chamber 101, a plurality of rotating parts 103a to 103f are arranged. The rotating parts 103a to 103f of the present embodiment are arranged on the outer peripheral side of the center part inside the chamber 101, and are not arranged in the center part. These rotating parts 103a to 103f are arranged, for example, at intervals of 5 mm or more. In this case, the influence of crystal growth in the crucible 115 on the rotating parts 103a to 103f becomes less susceptible to each other.

  The rotating parts 103a to 103f have a mounting part (for example, mounting part 103aA) for mounting the reaction vessels 110a to 110f and a supporting part (for example, a supporting part 103aB) connected to the mounting part. Yes. The rotating parts 103a to 103f are rotatable around the support part (for example, in the direction of the arrow in FIG. 1). The rotating parts 103a to 103f may further include a mechanism (not shown) for rotating the support part (for example, the support part 103aB).

  Reaction vessels 110a to 110f are respectively arranged on the rotating parts 103a to 103f. The planar shapes of the reaction vessels 110a to 110f are almost the same as the placement surfaces of the rotating parts 103a to 103f.

  As shown in FIG. 4, the reaction vessel 110 a includes a crucible 115 having a heated function and a heat insulating material 119. The crucible 115 has an exhaust part 115a. A heat insulating material 119 is provided around the crucible 115 so as to ensure ventilation between the inside and outside of the crucible 115. The heat insulating material 119 has an introduction part 119 a for flowing a carrier gas such as nitrogen gas into the crucible 115 and a discharge part 119 b for discharging the carrier gas to the outside of the chamber 101.

  A heating unit 105 is disposed so as to cover the outer periphery of the chamber 101. The heating unit 105 in the present embodiment is disposed in the central portion outside the crucible 115 and covers the entire circumference of the central portion outside. As the heating unit 105, for example, a high-frequency heating coil for heating the crucible 115 is used.

  As shown in FIGS. 2 and 3, it is preferable that the distances L103a to L103f from the heating unit 105 to the respective rotating units 103a to 103f are the same. The distances L103a to L103f are distances connecting the heating unit 105 and the centers of the rotating units 103a to 103f. In other words, the distances L103a to L103f are the shortest distances from the centers of the rotating units 103a to 103f to the heating unit 105.

  A radiation thermometer 107 for measuring the temperature above and below the crucible 115 is provided at the top and bottom of the chamber 101. In the present embodiment, an upper radiation thermometer 107 in FIG. 1 measures the temperature above the crucible 115, that is, the temperature of the seed substrate 11. A radiation thermometer 107 in the lower part of FIG. 1 measures the temperature below the crucible 115, that is, the temperature of the raw material 15.

  Such a crystal growth apparatus 100a is suitably used when growing an AlN crystal. The crystal growth apparatus 100a is preferably used when growing a crystal having a thickness of 1 mm or more.

  Next, the crystal growth method in the present embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing the crystal growth method in the present embodiment. The crystal growth method in the present embodiment is a method for growing a plurality of crystals using the crystal growth apparatus 100a.

  As shown in FIGS. 1-5, first, the seed substrate 11 is arrange | positioned inside each crucible 115 (step S1). The seed substrate 11 is not particularly limited, but when an AlN crystal is grown, an AlN substrate, a SiC (silicon carbide) substrate, or the like is preferably used from the viewpoint of improving crystallinity.

  Next, the raw material 15 is arrange | positioned inside each crucible 115 so that the seed substrate 11 may mutually face (step S2). In the case of growing an AlN crystal, for example, an AlN polycrystal such as an AlN powder, an AlN compact, and an AlN fired body is used.

  Next, the crystal 13 is grown on the seed substrate 11 by sublimation while rotating each crucible 115 (step S3). This step S3 is performed as follows, for example.

  By rotating the rotating parts 103a to 103f, the crucible 115 in the reaction vessels 110a to 110f arranged on the rotating parts 103a to 103f is rotated around the supporting part (for example, the supporting part 103aB) of the rotating parts 103a to 103f. Let In this state, in each of the crucibles 115 in the reaction vessels 110a to 110f, the heating unit 105 sublimates the raw material 15 to generate a sublimation gas, and this sublimation is performed on the seed substrate 11 installed at a lower temperature than the raw material 15. Send gas. By recrystallizing the sublimation gas on the seed substrate 11, the crystal 13 grows.

  In this growth step S3, it is preferable to grow an AlN crystal as the crystal 13. When growing the AlN crystal, the raw material 15 is heated to, for example, 2000 ° C. or more and 2300 ° C. or less, and the seed substrate 11 is heated to a temperature lower than the heating temperature of the raw material 15, for example, 1800 ° C. or more and 2000 ° C. or less.

  Further, in this growing step S3, it is preferable to grow the crystal 13 having a thickness of 1 mm or more. Thereby, what is called an ingot can be grown.

  The crystal 13 can be grown by the above steps S1 to S3. Note that although the case where the crystal 13 is grown in all the crucibles 115 has been described in the present embodiment, the present invention is not particularly limited thereto, and the crystal 13 may be grown in two or more crucibles 115.

  As described above, in the present embodiment, the crystal growth apparatus 100a including the plurality of rotating parts 103a to 103f arranged in the chamber 101 and the crucible 115 arranged on each of the rotating parts 103a to 103f. Is used to grow the crystal 13.

  Thereby, the crystal 13 can be grown independently in each crucible 115 of the reaction vessels 110a to 110f. For this reason, even if the crystal 13 grown in at least one crucible 115 is defective due to the raw material 15 or becomes polycrystalline, the influence on the crystal 13 in another crucible 115 can be reduced. it can. Therefore, a plurality of crystals 13 can be grown simultaneously without being influenced by the atmosphere of the raw material 15 of the other crucible 115. Therefore, the yield for growing the crystal 13 having good crystallinity can be improved.

  When a high-frequency heating coil is used as the heating unit 105, the current distribution generated by receiving the crucible 115 can be diffused by rotating each crucible 115. For this reason, since local deterioration of the crucible 115 can be suppressed, deterioration of the crystallinity of the crystal 13 grown by deterioration of the crucible 115 can be suppressed.

  In addition, since the heating unit 105 is disposed so as to cover the outer periphery of the chamber 101, a temperature distribution in which the temperature increases from the center of the chamber 101 toward the outer peripheral side can be formed. In the present embodiment, the crucibles 115 in the reaction vessels 110a to 110f are rotated around the support portions (for example, the support portions 103aB) of the rotation portions 103a to 103f by the rotation portions 103a to 103f. For this reason, since the crucible 115 passes through the region where the temperature distribution of the chamber 101 is high and the region where the temperature is low, the difference in temperature heated in the seed substrate 11 is alleviated. Therefore, variation in temperature difference between the seed substrate 11 and the raw material 15 can be suppressed in each crucible, so that variation in growth rate can be suppressed. As a result, variation in the thickness of the crystal 13 grown on the seed substrate 11 can be suppressed in each crucible 115 in each of the reaction vessels 110a to 110f. That is, variations in the film thickness within the plane of the crystal 13 can be suppressed.

  The size of the crucible 115 only needs to allow the crystal 13 to grow. In this case, it is not necessary to enlarge the crucible 115 as compared with the case where a plurality of seed substrates are arranged in one crucible to grow a plurality of crystals. For this reason, since convection due to the large diameter of the crucible can be suppressed, variations in the thickness of the crystal 13 to be grown can be effectively suppressed.

  Furthermore, in the present embodiment, the distances L103a to L103f from the heating unit 105 to the respective rotating units 103a to 103f are the same. That is, the distance from the center of the crucible 115 in the reaction vessels 110a to 110f to the heating unit 105 is the same. For this reason, the heating state of the seed substrate 11 and the raw material 15 in the crucible 115 on the rotating parts 103a to 103f is the same. Therefore, variation in the thickness of the crystal 13 grown inside each crucible 115 can also be suppressed. That is, variations in film thickness between the crystals 13 can be suppressed.

  As described above, the crystal 13 grown by the crystal growth apparatus 100a and the crystal growth method can improve the yield of growing the crystal 13 having good crystallinity and suppress the variation in the thickness of the crystal 13 to be grown. . For this reason, when the crystal 13 is a semiconductor crystal such as an AlN crystal, for example, a light emitting element such as a light emitting diode or a laser diode, a rectifier, a bipolar transistor, a field effect transistor, an electronic element such as a HEMT, a temperature sensor, a pressure sensor, or a radiation. It can be suitably used for sensors, semiconductor sensors such as visible-ultraviolet light detectors, SAW devices, and the like.

(Embodiment 2)
FIG. 6 is a schematic diagram schematically showing a crystal growth apparatus in the present embodiment. FIG. 6 shows a state when viewed from the line II-II in FIG. With reference to FIG. 6, the crystal growth apparatus 100b in this Embodiment is demonstrated.

  As shown in FIG. 6, the crystal growth apparatus 100 b in the present embodiment basically has the same configuration as the crystal growth apparatus 100 a in the first embodiment, but includes a crucible at the center of the chamber 101. The difference is that a reaction vessel 109 is further provided. The reaction vessel 109 is the same as the reaction vessel 110a shown in FIG.

  This reaction vessel 109 is for measuring whether the growth conditions are constant, and is not for growing a crystal having good crystallinity and suppressing variation in thickness. That is, since the crucible 115 of the reaction vessel 109 is located at the center of the chamber 101, the heating state is almost constant. Therefore, by measuring the temperature of the crucible in the reaction vessel 109 with the radiation thermometer 107, the crystal growth in the crucible 115 in the reaction vessels 110a to 110f is completed, and then again in the crucible 115 in the reaction vessels 110a to 110f. The same conditions can be used when crystal growth is performed. Therefore, in the crucible 115 of the reaction vessels 110a to 110f, the crystal 13 having good crystallinity and suppressing thickness variation can be grown. Therefore, according to the present embodiment, it is advantageous when performing crystal growth a plurality of times using the crystal growth apparatus 100b or when manufacturing a large number of crystals 13.

(Embodiment 3)
FIG. 7 is a schematic diagram schematically showing a crystal growth apparatus in the present embodiment. FIG. 7 shows a state when viewed from the line II-II in FIG. With reference to FIG. 7, the crystal growth apparatus 100c in this Embodiment is demonstrated.

  The crystal growth apparatus 100c in the present embodiment basically has the same configuration as the crystal growth apparatus 100a in the first embodiment, but the shape of the chamber 101 and the arrangement of the rotating part and the reaction vessels 110a to 110d. Is different.

  The chamber 101 has a rectangular cross-sectional shape. In the chamber 101, a plurality of rotating parts are arranged so as to be positioned on the outer peripheral side of the center. A plurality of reaction vessels 110a to 110d including crucibles 115 are arranged on the plurality of rotating parts.

(Embodiment 4)
FIG. 8 is a cross-sectional view schematically showing a crystal growth apparatus in the present embodiment. FIG. 9 is a schematic diagram schematically showing a state seen from IX-IX in FIG. With reference to FIG. 8 and FIG. 9, the crystal growth apparatus 100d in this Embodiment is demonstrated.

  As shown in FIG. 8 and FIG. 9, the crystal growth apparatus 100d in the present embodiment basically has the same configuration as the crystal growth apparatus 100a in the first embodiment, but on the rotating parts 103a to 103f. And a temperature measuring member (not shown) for measuring the temperature of at least one crucible is arranged on at least one of the rotating parts 103a to 103f. Different.

  Specifically, reaction vessels 110a1 to 110a4, 110b1 to 110b4, 110c1 to 110c4, 110d1 to 110d4, 110e1 to 110e4, 110f1 to 110f4 including crucibles are arranged on the rotating parts 103a to 103f, respectively. These reaction vessels have the same configuration except that they are smaller than the reaction vessel 110a shown in FIG. 4 described in the first embodiment.

  In addition, the crucibles arranged on the rotating parts 103a to 103f are equally spaced in the rotating parts 103a to 103f. Between each of these crucibles and the rotating parts 103a to 103f, a rotating part for rotating each crucible is further provided. For example, as shown in FIG. 8, rotating parts 103a1 and 103a4 are arranged under the reaction containers 110a1 and 110a4 to rotate the reaction containers 110a1 and 110a4, respectively. Thereby, each of reaction container 110a1-110a4 rotates centering | focusing on reaction container 110a1-110a4 by an axis | shaft by rotation part 103a1, 103a4. Further, the reaction vessel 110a1 to 110a4 as a whole is rotated about the center of the rotation unit 103a by the rotation unit 103a. For this reason, the temperature difference in the crucible of reaction container 110a1-110a4 can be relieved. Therefore, each of the crystals 13 grown in the crucible can relax the in-plane film thickness distribution.

  The crystal growth apparatus 100d in the present embodiment can grow a large number of small-diameter crystals by arranging a plurality of crucibles in one rotating part 103a to 103f.

(Embodiment 5)
FIG. 10 is a cross-sectional view schematically showing a crystal growth apparatus in the present embodiment. With reference to FIG. 10, the crystal growth apparatus 100e in this Embodiment is demonstrated.

  As shown in FIG. 10, the crystal growth apparatus 100e in the present embodiment basically has the same configuration as the crystal growth apparatus 100a in the first embodiment, but the heating unit 105 is resistance heating. It differs in. For this reason, arrangement | positioning of the heating part 105 and the heat insulating material 119 differs.

  Specifically, a heating unit 105 that is resistance heating is disposed in the chamber 101. A heat insulating material 119 is disposed on the outer periphery of the heating unit 105. That is, the heat insulating material 119 is not arrange | positioned so that the outer periphery of a crucible may be covered.

  Note that the heating unit 105 may be a high-frequency heating method such as a high-frequency heating coil as in the first embodiment, may be a resistance heating method as in the present embodiment, or may be another heating method. There may be.

  The present invention is not particularly limited to the shape of chamber 101, the arrangement, shape, number, etc. of crucibles of rotating parts 103a to 103f and reaction vessels 110a to 110f in the first to fifth embodiments.

  In this example, the effect of crystal growth using a crystal growth apparatus provided with a plurality of rotating parts arranged in the chamber and a crucible arranged on each rotating part was examined.

  Specifically, six reaction vessels 110a including the crucible shown in FIG. 4 were prepared, and as shown in FIG. 1 to FIG. 3, crucibles were respectively arranged on the plurality of rotating parts 103a to 103f. Using this crystal growth apparatus 100a, six AlN crystals were grown.

  First, one seed substrate 11 was placed inside each crucible (step S1). As the seed substrate 11, a 6H—SiC substrate having a diameter of 2 inches and a main surface of (0002) plane was used.

  Next, the raw material 15 was arrange | positioned to each crucible (step S2). In this example, an AlN sintered body was used as the raw material 15.

  Next, a crystal 13 was grown on the seed substrate 11 by sublimation while rotating each crucible (step S3). The rotational speed of each crucible was set to 5 rpm by the rotating parts 103a to 103f. In this state, the temperature in the crucible using the heating unit 105 was raised while flowing nitrogen gas into the chamber 101. Then, the temperature of the seed substrate 11 is 1800 ° C., the temperature of the raw material 15 is 2000 ° C., the raw material 15 is sublimated, recrystallized on the main surface of the seed substrate 11, and the growth time is 100 hours. A crystal 13 which is an AlN crystal was grown thereon.

  Note that during the growth of the AlN crystal in step S3, the nitrogen gas was kept flowing in the chamber 101, and the exhaust amount of the nitrogen gas was controlled so that the gas partial pressure in the chamber 101 became 50 kPa.

  By performing the above steps S1 to S3, six AlN crystals were grown in each crucible.

  The six AlN crystals had a thickness of 5.0 to 5.5 mm. The thickness variation between the crystals was calculated by dividing the difference between the largest thickness and the smallest thickness among the six AlN crystals by the smallest thickness. As a result, the variation in thickness between crystals was 10%.

  The in-plane film thickness distribution was measured for each of the six AlN crystals. The in-plane film thickness distribution was calculated by dividing the difference between the largest thickness and the smallest thickness in the AlN crystal by the smallest thickness. As a result, the in-plane film thickness distributions of the six AlN crystals were all less than 5%.

Further, the defect density of six AlN crystals was measured by a wet etching (EPD) method as follows. That is, six AlN crystals were sliced into AlN wafers each having a thickness of 400 μm. Thereafter, each AlN wafer was immersed in a melt obtained by mixing KOH (gallium hydroxide) and NaOH (sodium hydroxide) at 250 ° C. for 1 hour. It was calculated by counting the number of pits formed by this wet etching and dividing by the unit area. As a result, in one AlN crystal, there was a defect density of 1 × 10 ⁶ cm ⁻² on the seed substrate 11 side, but in all other AlN crystals, 1 × 10 ⁴ cm ⁻ on the growth surface side. ^The defect density was as low as ² or less. That is, the defect on the seed substrate 11 side generated in one AlN crystal had no effect on the other five AlN crystals.

  As described above, according to this embodiment, the in-plane film thickness is obtained by crystal growth using a crystal growth apparatus including a plurality of rotating parts arranged in the chamber and a crucible arranged on each rotating part. It was confirmed that the distribution can be reduced, the yield for growing crystals with good crystallinity can be improved, and the variation in film thickness between crystals can be suppressed.

  In this example, as shown in FIG. 9, four reaction vessels were placed on each rotating part, and an AlN crystal was grown. That is, a total of 24 crucibles were prepared and 24 AlN crystals were grown.

  First, one seed substrate 11 was placed inside each crucible (step S1). As the seed substrate 11, a 4H—SiC substrate having a diameter of 1 inch and a main surface of (0002) plane was used.

  Next, the raw material 15 was arrange | positioned to each crucible (step S2). In this example, an AlN sintered body was used as the raw material 15.

  Next, a crystal 13 was grown on the seed substrate 11 by sublimation while rotating each crucible (step S3). The rotation speed of the rotating part was 10 rpm. In this state, the temperature in the crucible using the heating unit 105 was raised while flowing nitrogen gas into the chamber 101. Then, the temperature of the seed substrate 11 is 1800 ° C., the temperature of the raw material 15 is 2100 ° C., the raw material 15 is sublimated, recrystallized on the main surface of the seed substrate 11, and the growth time is 150 hours. A crystal 13 which is an AlN crystal was grown thereon.

  During the growth of the AlN crystal in step S3, nitrogen gas was flowed in the chamber 101 at 500 sccm, and the pressure was adjusted so that the gas partial pressure in the chamber 101 was 60 kPa.

  By performing the above steps S1 to S3, a total of 24 AlN crystals were grown in each crucible.

  The 24 AlN crystals thus obtained had a thickness of 10.0 to 10.5 mm. As a result of measuring the thickness variation between the crystals in the same manner as in Example 1, the thickness variation between the crystals was 10%.

  As described above, according to this example, it was confirmed that even when a plurality of crucibles were arranged in one rotating part, the variation in thickness between crystals was suppressed as in Example 1.

  In this example, as shown in FIG. 10, one reaction vessel was placed on each rotating part, and an AlN crystal was grown. That is, a total of four crucibles were prepared and four AlN crystals were grown. Further, the heating method in this example was a resistance heating method.

  First, one seed substrate 11 was placed inside each crucible (step S1). As the seed substrate 11, an AlN single crystal substrate having a diameter of 2 inches and a main surface of (0002) plane was used.

  Next, the raw material 15 was arrange | positioned to each crucible (step S2). In this example, an AlN sintered body was used as the raw material 15.

  Next, a crystal 13 was grown on the seed substrate 11 by sublimation while rotating each crucible (step S3). The rotation speed of the rotating part was 5 rpm. In this state, the temperature in the crucible using the heating unit 105 was raised while flowing nitrogen gas into the chamber 101. Then, the temperature of the seed substrate 11 is 2000 ° C., the temperature of the raw material 15 is 2200 ° C., the raw material 15 is sublimated, recrystallized on the main surface of the seed substrate 11, and the growth time is 100 hours. A crystal 13 which is an AlN crystal was grown thereon.

  During the growth of the AlN crystal in step S3, nitrogen gas was flowed through the chamber 101 at 300 sccm, and the pressure was adjusted so that the gas partial pressure in the chamber 101 was 90 kPa.

  By performing the above steps S1 to S3, a total of four AlN crystals were grown in each crucible.

  The four AlN crystals thus obtained had a thickness of 20.2 to 21.3 mm. As a result of measuring the thickness variation between the crystals in the same manner as in Example 1, the thickness variation between the crystals was 5%.

  As described above, according to this example, it was confirmed that variation in thickness between crystals was suppressed similarly to Example 1 regardless of the method and arrangement of the heating unit.

  Although the embodiments and examples of the present invention have been described above, it is also planned from the beginning to appropriately combine the features of the embodiments and examples. The embodiments and examples 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 embodiments and examples described above but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

  11 seed substrate, 13 crystal, 15 raw material, 100a, 100b, 100c, 100d, 100e crystal growth apparatus, 101 chamber, 101a introduction part, 101b, 119b discharge part, 103a, 103a1, 103a2, 103a3, 103a4, 103b, 103b1, 103b2, 103b3, 103b4, 103c, 103c1, 103c2, 103c3, 103c4, 103d, 103d1, 103d2, 103d3, 103d4, 103e, 103e1, 103e2, 103e3, 103e4, 103f, 103f1, 103f2, 103f3, 103f4 Rotating part, 103aA Placement unit, 103aB support unit, 105 heating unit, 107 radiation thermometer, 109, 110a, 110a1, 110a2, 110a3, 110a4, 110b, 10b1, 110b2, 110b3, 110b4, 110c, 110c1, 110c2, 110c3, 110c4, 110d, 110d1, 110d2, 110d3, 110d4, 110e, 110e1, 110e2, 110e3, 110e4, 110f, 110f1, 110f2, 110f3, 110f4 reaction vessels, 115 crucible, 115a exhaust part, 119 heat insulating material, 119a introduction part.

Claims (5)

A chamber;
A plurality of rotating parts disposed in the chamber;
A crystal growth apparatus comprising a crucible disposed on each of the rotating parts. A heating unit disposed to cover the outer periphery of the chamber;
The crystal growth apparatus according to claim 1, wherein a distance from the heating unit to each of the rotating units is the same. A method for growing a plurality of crystals using the crystal growth apparatus according to claim 1, comprising:
Disposing one seed substrate inside each crucible;
And a step of growing the crystal on the seed substrate by a sublimation method while rotating each crucible.   The crystal growth method according to claim 3, wherein an aluminum nitride crystal is grown in the growing step.   The crystal growth method according to claim 3, wherein, in the growing step, the crystal having a thickness of 1 mm or more is grown.

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