JP2008254945A - SINGLE CRYSTAL SiC AND ITS PRODUCTION METHOD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing single crystal SiC, by which high quality single crystal SiC in which polycrystalline domains do not exist in a mixed state can be stably epitaxially grown; and to provide the high quality single crystal SiC obtained by the method. <P>SOLUTION: The method for producing the single crystal SiC includes an arrangement process for arranging a susceptor 5 to which a SiC seed crystal 4 is fixed and a raw material feeding tube 6 for feeding raw materials for producing the single crystal SiC in a crucible 2 and a growth process for growing the single crystal SiC by feeding the raw materials for producing the single crystal SiC together with an inert gas A onto the SiC seed crystal 4 in the crucible 2 having a high temperature atmosphere through the raw material feeding tube 6. In the growth process, SiO<SB>2</SB>particles, carbon (C) particles and at least one kind of specified particles are fed, and the specified particles have a melting point and/or a sublimation point of 900-2,400°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a single crystal SiC used as a semiconductor device material or LED material and a method for manufacturing the same.

  Single crystal SiC (silicon carbide) has a large crystal bond energy, a large dielectric breakdown electric field, and a high thermal conductivity, and thus is useful as a material for a device for harsh environments and power devices. Moreover, since the lattice constant is close to the lattice constant of GaN, it is also useful as a substrate material for GaN-LED.

  Conventionally, for the production of single crystal SiC, the Rayleigh method in which SiC powder is sublimated in a graphite crucible and single crystal SiC is recrystallized on the inner wall of the graphite crucible, and the raw material arrangement and temperature distribution are optimized based on this Rayleigh method. An improved Rayleigh method in which a SiC seed single crystal is placed in the recrystallized portion and epitaxially recrystallized, and the gas source is transported onto the SiC seed single crystal heated by the carrier gas and epitaxially grown while chemically reacting on the crystal surface. CVD method, and sublimation proximity method in which SiC powder is epitaxially recrystallized on the SiC seed single crystal in a state where the SiC powder and the SiC seed single crystal are brought close to each other in a graphite crucible (Chapter 4 of Non-Patent Document 1). reference).

  By the way, at present, each of these single crystal SiC manufacturing methods is considered to have a problem. Although the Rayleigh method can produce single crystal SiC with good crystallinity, crystal growth is based on spontaneous nucleation, so that shape control and crystal surface control are difficult, and a large-diameter wafer can be obtained. There is no problem. Although the improved Rayleigh method can obtain a large-diameter single crystal SiC ingot at a high speed of about several hundred μm / h, it has a problem that a large number of micropipes are generated in the crystal because of epitaxial growth in a spiral shape. The CVD method can produce high-quality single crystal SiC with high purity and low defect density, but because of epitaxial growth with a dilute gas source, the growth rate is as slow as about 10 μm / h, and a long single crystal SiC ingot is formed. There is a problem that it cannot be obtained. In the sublimation proximity method, high-purity SiC epitaxial growth can be realized with a relatively simple structure, but there is a problem that it is impossible to obtain a long single-crystal SiC ingot due to structural restrictions.

Recently, by supplying silicon dioxide ultrafine particles and carbon ultrafine particles with an inert carrier gas onto a heated and maintained SiC seed single crystal, and reducing the silicon dioxide with carbon on the SiC seed single crystal, the formula (1 ) Has been reported to epitaxially grow single crystal SiC on a SiC seed single crystal at high speed (see Patent Document 1). In this manufacturing method, it is said that high-quality single-crystal SiC that suppresses defects such as micropipes can be obtained at high speed.
SiO ₂ + 3C → SiC + 2CO ↑ (1)
In the method for producing single-crystal SiC disclosed in Patent Document 1 described above, silicon dioxide ultrafine particles and carbon ultrafine particles are supplied and adhered to the SiC seed crystal surface held in an inert gas atmosphere in an overheated state. The SiC single crystal is grown on the SiC seed crystal by reducing silicon dioxide with carbon on the surface of the SiC seed crystal.

Japanese Patent No. 3505597 Edited by Hiroyuki Matsunami, “Semiconductor SiC Technology and Applications”, Nikkan Kogyo Shimbun (published first edition in March 2003)

  When single crystal SiC was actually manufactured by the method disclosed in Patent Document 1, it was confirmed that the crystal quality of the obtained single crystal SiC was not necessarily good. Specifically, there arises a problem that polycrystalline domains having different crystal orientations coexist in a fine region (typically a region of 5 μm or less) in single crystal SiC.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a single crystal capable of stably and epitaxially growing high-quality single-crystal SiC that does not include polycrystalline domains. An object of the present invention is to provide a method for producing SiC and high-quality single crystal SiC obtained as a result.

Said subject was solved by the means as described in <1> or <5> below. It is described below together with <2> to <4> which are preferred embodiments.
<1> An arrangement step of disposing a susceptor to which a SiC seed crystal is fixed and a raw material supply pipe for supplying a raw material for producing single crystal SiC in the crucible, and production of the single crystal SiC in the crucible in a high temperature atmosphere Including a growth step of growing a single crystal SiC by supplying a raw material together with an inert gas onto a SiC seed crystal through a raw material supply pipe, wherein the growth step includes at least one of SiO ₂ particles, carbon (C) particles, and A method for producing single crystal SiC, wherein the specific particles have a melting point and / or a sublimation point of 900 ° C. or more and 2,400 ° C. or less,
<2> The method for producing single-crystal SiC according to <1>, wherein the supply amount of the specific particles is 100 ppm or more and 2,000 ppm or less in terms of weight with respect to the SiO ₂ particles as a total amount,
<3> At least one selected from the group consisting of Al ₂ O ₃ particles, TiO ₂ particles, ZnO particles, SnO ₂ particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles, and Ta ₂ O ₅ particles. <1> or <2>, the method for producing single-crystal SiC,
<4> The method for producing single-crystal SiC according to any one of <1> to <3>, wherein the inert gas is Ar gas,
<5> Single crystal SiC manufactured by the manufacturing method according to any one of <1> to <4>.

  According to the present invention, a single-crystal SiC manufacturing method capable of stably and epitaxially growing high-quality single-crystal SiC free of mixed polycrystalline domains and the resulting high-quality single-crystal SiC are provided. be able to.

The method for producing single-crystal SiC according to the present invention includes a disposing step in which a susceptor to which a SiC seed crystal is fixed and a raw material supply pipe for supplying a raw material for producing single-crystal SiC are arranged in a crucible, and the high-temperature atmosphere. The crucible includes a growth step of growing the single crystal SiC by supplying the raw material for producing the single crystal SiC together with an inert gas through the raw material supply pipe onto the SiC seed crystal. In the growth step, SiO ₂ particles, carbon ( C) Particles and at least one specific particle are supplied, and the specific particle has a melting point and / or sublimation point of 900 ° C. or higher and 2,400 ° C. or lower.

According to the present invention, when the single crystal SiC is produced by causing the reaction of the formula (1) with the SiO ₂ particles and the carbon (C) particles, the resulting polycrystalline domain It is possible to stably produce and provide high-quality single-crystal SiC that does not contain any of the above.
There are two possible reasons for this, considering the mechanism during manufacture.
First, among the specific particles, particles having a melting point (Tm ° C.) of 900 ° C. or more and 2,400 ° C. or less (for example, Al ₂ O ₃ , TiO ₂ , SnO ₂ , Ga ₂ O ₃ , Nb _2). In this case, one or more types are selected from O ₅ and Ta ₂ O ₅ ). In this case, it is considered that the selected specific particles act as a melt flux of the SiO ₂ particles. As a result, the interfacial energy of the SiC seed single crystal surface during epitaxial growth decreases, and the occurrence of polycrystalline domains due to the disorder of the growth interface Is estimated to be suppressed.
The second case is a case where one or more of the specific particles are selected from particles having a sublimation point (Ts ° C.) of 900 ° C. or more and 2,400 ° C. or less (eg, ZnO). At this time, it is considered that the selected specific particles assist the movement and rearrangement movement of the SiC particles generated by the reaction of the formula (1). As a result, the movement and rearrangement are not sufficiently performed and the orientation is changed. It is presumed that the polycrystalline domains that are incorporated into the SiC seed single crystal while being different are eliminated. Further, for example, ZnO particles are known to sublime at 1,725 ° C., and volume expansion movement and gas ZnO diffusion movement accompanying this sublimation are caused by the movement of SiC particles on the surface of the SiC seed single crystal and Presumed to assist rearrangement movement.

  In addition, in the manufacturing method of the SiC single crystal disclosed in Patent Document 1, when doping is performed in the SiC single crystal, it becomes a dopant in ultrafine particles (silicon dioxide ultrafine particles and carbon ultrafine particles) or a carrier gas. It is described that the components may be mixed. However, there is no mention of positively supplying (doping) any additive to produce higher quality single crystal SiC. Furthermore, no specific dopant component is described.

In the growth step of the method for producing single crystal SiC of the present invention, SiO ₂ particles and carbon (C) particles are selected as essential raw materials, and at least one specific particle is used in addition thereto. The specific particles have a melting point (Tm ° C.) and / or sublimation point (Ts ° C.) of 900 ° C. or more and 2,400 ° C. or less.
The specific particle is not particularly limited as long as it is a compound having the melting point and / or sublimation point, and can be selected from known compounds, but the metal oxide having the melting point and / or sublimation point is particularly preferable. Can be used for
The melting point (Tm ° C.) and / or sublimation point (Ts ° C.) of the specific particles is preferably 1000 ° C. or more and 2,300 ° C. or less, and more preferably 1,100 ° C. or more and 2,100 ° C. or less. preferable.
Preferable specific particles include Al ₂ O ₃ particles, TiO ₂ particles, ZnO particles, SnO ₂ particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles and Ta ₂ O ₅ particles, and may be used alone. It is possible to use more than one.
That is, in the present invention, in the SiC single crystal growth step, SiO ₂ particles, carbon (C) particles, Al ₂ O ₃ particles, TiO ₂ particles, ZnO particles, SnO ₂ particles, Ga ₂ O ₃ particles, Nb More preferably, at least one selected from a particle group consisting of ₂ O ₅ particles and Ta ₂ O ₅ particles (that is, any one type or a plurality of types thereof) is supplied onto the SiC seed single crystal. Among these, the specific particles are preferably Al ₂ O ₃ particles, TiO ₂ particles, ZnO particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles and Ta ₂ O ₅ particles, Al ₂ O ₃ particles, TiO _Two particles, ZnO particles, Ga ₂ O ₃ particles and Ta ₂ O ₅ particles are more preferable, and Al ₂ O ₃ particles, TiO ₂ particles and Ta ₂ O ₅ are more preferable.

The specific particles can be supplied to the SiC seed single crystal together with the SiO ₂ particles and the carbon (C) particles, or may be previously mixed with the SiO ₂ particles or the carbon (C) particles. Further, it may be present as a secondary component in SiO ₂ particles and / or carbon (C) particles.

In addition, the SiO ₂ particles and the carbon (C) particles can be supplied as separate particles, but can also be supplied as secondary particles including the SiO ₂ particles and the carbon (C) particles. In addition, at least one selected from the above specific particles can coexist with the secondary particles, and secondary particles may be formed together with the SiO ₂ particles or the carbon (C) particles.

The supply amount of the specific particles is preferably 100 ppm or more and 2,000 ppm (0.2%) or less in terms of weight with respect to the SiO ₂ particles as a total amount. More preferably, it is 200 ppm or more and 2,000 ppm or less. A supply amount of 100 ppm or more is preferable because an unintentional polycrystalline SiC generation suppression effect appears and a high-quality SiC single crystal can be obtained. Further, the supply amount of 2,000 ppm or less is preferable because it can prevent an increase in defects and distortion due to excessive incorporation of specific particles, occurrence of droplets, unintended color unevenness, and the like.

SiO ₂ particles and carbon (C) types of particles, particle size, particle shape, etc. are not particularly limited, secondary particles comprising a mixture or SiO ₂ particles and carbon (C) particles of SiO ₂ particles and carbon (C) particles Can be suitably used. The types, particle diameters, and particle shapes of the SiO ₂ particles and carbon (C) particles are not particularly limited. For example, high purity silica (fumed silica) obtained by flame hydrolysis, high purity acetylene black, and the like. Etc. can be suitably used.
Two or more of the above SiO ₂ particles and carbon (C) particles may be mixed and used. Further, the SiO ₂ particles and the carbon particles (C) may be pretreated as necessary.
Both SiO ₂ particles and carbon (C) particles are preferably fine particles having a primary particle size of 100 nm or less, more preferably 40 nm or less, even more preferably 20 nm or less, and particularly preferably 5 to 20 nm.

The ratio of the supply amount of the SiO ₂ particles and carbon (C) particles is not particularly limited, and a desired composition ratio can be selected as appropriate, but the weight ratio of SiO ₂ particles to carbon (C) particles (SiO ₂ : C) is The range of 1: 1.5 to 5: 1 is typical. A more preferred weight ratio is 1.5: 1 to 3: 1.

The type, particle size, particle shape, etc. of the specific particles are not particularly limited, and any of the commercially available powder raw materials can be obtained and used. In addition to the aforementioned SiO ₂ particles and carbon (C) particles, it is preferable that these particle groups are all non-toxic and can be handled and manufactured safely. However, it is also possible to use toxic specific particles after performing safety management.
The average primary particle diameter of these specific particles is preferably 400 nm or less, more preferably 100 nm or less, and still more preferably 50 nm or less. An average particle size of 400 nm or less is preferable because segregation due to specific particles can be prevented.

On the SiC seed single crystal of a feed (hereinafter also referred to as “raw material particles”) composed of SiO ₂ particles, which are the raw material for producing SiC, carbon (C) particles, and at least one specific particle in addition to that. The supply to is preferably a method that can be continuously supplied without interruption, and the specific method is not particularly limited. For example, a commercially available powder feeder that can continuously transport powder can be used. However, it is preferable that the supply pipe and the inside of the single crystal SiC manufacturing apparatus have a hermetic structure substituted with an inert gas such as argon or helium, preferably with argon gas, in order to prevent oxygen contamination.

  Regarding the supply conditions of the raw material particles onto the SiC seed single crystal, it is sufficient that these raw material particles are supplied in a state of being mixed on the SiC seed single crystal. You may mix on a SiC seed single crystal.

In addition, when doping into single crystal SiC, if it is p-type, simple and high quality single crystal can be obtained by adding the Al ₂ O ₃ particles at a high concentration (0.1 to 0.2%). SiC production can be performed. Also, Al (CH ₃ ) ₃ , B ₂ H _6, etc. can be used for p-type doping. In the case of n-type, it is easy to dope nitrogen as a gas source in the atmosphere.

  The SiC seed crystal used in the production method of the present invention is preferably a SiC seed single crystal wafer, and the type, size, and shape thereof are not particularly limited, and are appropriately selected depending on the type, size, and shape of the target single crystal SiC. it can. For example, an SiC seed single crystal wafer obtained by pretreating an SiC single crystal obtained by the modified Rayleigh method as necessary can be suitably used. The seed crystal may be a just substrate or an off-angle substrate. Examples of the SiC seed single crystal include a just-surface Si surface substrate and a (0001) Si surface substrate having an off angle of several degrees.

The single crystal SiC production temperature is not particularly limited, and can be appropriately set according to the size, shape, type, etc. of the target single crystal SiC, but the preferred production temperature is in the range of 1,600 to 2,400 ° C. The temperature can be measured, for example, as the temperature outside the crucible.
The single crystal SiC production temperature is preferably selected as appropriate according to the specific particles used, and the single crystal SiC production temperature is selected at a temperature higher than the melting point and / or sublimation point of the specific particles used. preferable.

  The structure of the single crystal SiC manufacturing apparatus used for the single crystal SiC manufacturing method of the present invention is not particularly limited. That is, the seed crystal size, crucible heating method, crucible material, raw material particle supply method, atmosphere adjustment method, growth pressure, temperature control method, etc. are the target single crystal SiC size, shape, type, raw material for single crystal SiC production and It can be appropriately selected according to the type and amount of the specific particles. For example, PID temperature control technology can be used for temperature measurement and temperature control.

  The shape of the crucible used in the present invention is not particularly limited as to the outer shape, and can be appropriately selected according to the size and shape of the target single crystal SiC. The material of the crucible is preferably made of graphite in consideration of the operating temperature range.

The shape of the susceptor holding the SiC seed single crystal wafer is not particularly limited, and can be appropriately selected according to the size and shape of the target single crystal SiC. However, the material of the susceptor is preferably made of graphite in consideration of the operating temperature range.
The normal direction of the surface holding the SiC seed single crystal at the upper end of the susceptor is not particularly limited and can be freely set. It is preferable that the vertical direction of the susceptor is inclined up to 45 ° from the parallel direction. .

The shape of the raw material supply pipe for continuously supplying the raw material for producing single crystal SiC and the specific particles is not particularly limited, and can be appropriately selected according to the size and shape of the target single crystal SiC. However, the material of the supply pipe is preferably made of graphite in consideration of the operating temperature range. The specific particles are supplied onto the SiC seed single crystal through the raw material supply pipe.
The raw material supply pipe may be opposed to the susceptor to which the SiC seed single crystal is fixed in the crucible, or may be arranged at a right angle or obliquely.

FIG. 1 is a conceptual cross-sectional view showing an example of an apparatus for producing single-crystal SiC of the present invention. Here, a high-frequency induction heating furnace 10 is used.
A carbon-made sealed cylindrical crucible 2 (diameter: 100 mm, height: 150 mm) is disposed in a water-cooled sealed chamber 1, and a high-frequency induction heating coil 3 is disposed outside the water-cooled sealed chamber 1.
A susceptor 5 for holding the SiC seed single crystal wafer 4 is inserted through the upper portion of the sealed cylindrical crucible 2. The susceptor 5 extends to the inside of a sealed cylindrical crucible, and can be rotated around the central axis of the susceptor by a rotation mechanism (not shown).
Further, a controllable heat exchange function is provided at the upper end (not shown) of the susceptor, and a heat flow can be generated in the susceptor vertical direction (longitudinal direction). The heat flow rate can be adjusted.
In addition, the normal direction of the surface holding the SiC seed crystal at the lower end of the susceptor can be freely set up to a maximum of 45 ° from substantially parallel to the vertical direction of the susceptor. A SiC single crystal growth layer 9 is grown on the SiC seed crystal 4.

  A raw material supply pipe 6 for supplying a raw material for producing single crystal SiC and specific particles is inserted through the lower portion of the sealed crucible 2. Further, the raw material supply pipe 6 is extended outside the high-frequency induction heating furnace, and a plurality of raw material storage tanks 7 and 7 ′ whose supply amount can be adjusted independently by the control valves 8 and 8 ′, and flow rate adjustment. Each is connected to a possible source of inert carrier gas A (not shown).

The raw material for single crystal SiC production and specific particles used in the present invention may be mixed in advance and then supplied from one storage tank to the inside of the closed crucible, and each of them may include specific particles and other additive raw materials. The raw material particles, or several mixed raw materials are filled into individual storage tanks and mixed in an inert carrier gas in the raw material supply pipe by adjusting the relative supply amount from each storage tank. You may supply continuously in the inside of a crucible.
The high-frequency induction heating furnace can be controlled by a vacuum exhaust system and a pressure control system (not shown), and includes an inert gas replacement mechanism (not shown). In the embodiment of FIG. 1, the supply pipe is arranged on the lower side of the crucible and the susceptor is arranged on the upper side of the crucible. However, it can be arranged upside down as long as the operation of the present invention does not change. It is also possible to arrange the supply pipe obliquely or laterally with respect to the susceptor.

Hereinafter, Examples 1 to 7 will be described together with Comparative Examples 1 to 5.
In addition, it describes below about each particle | grain used by the Example and the comparative example.
SiO ₂ particles (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil 380)
Carbon (C) particles (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka black powder (acetylene black))
Al ₂ O ₃ particles (Kanto Chemical Co., Ltd., aluminum oxide NanoTek ^R)
TiO ₂ particles (Kanto Chemical Co., Ltd., titanium oxide (IV) NanoTek ^R)
SnO ₂ particles (Kanto Chemical Co., Ltd., tin oxide (IV) NanoTek ^R)
ZnO particles (Kanto Chemical Co., Ltd., zinc oxide NanoTek ^R)
Ga ₂ O ₃ particles (manufactured by Kanto Chemical Co., Inc., gallium oxide (III))
Nb ₂ O ₅ particles (manufactured by Kanto Chemical Co., Inc., niobium oxide (V) 3N5)
Ta ₂ O ₅ particles (manufactured by Kanto Chemical Co., Inc., tantalum oxide (V) 3N5)
B ₂ O ₃ particles (manufactured by Kanto Chemical Co., Ltd., boron oxide deer special grade)
Y ₂ O ₃ particles (Kanto Chemical Co., yttrium oxide NanoTek ^R)
ZrO ₂ particles (manufactured by Kanto Chemical Co., Inc., zirconium oxide 3N)
MgO particles (Kanto Chemical Co., Ltd., magnesium oxide 4N)

Using the high frequency induction heating furnace, single crystal SiC was manufactured under the following conditions.
A description will be given with reference to FIG. After weighing so that the weight ratio of SiO ₂ particles to carbon (C) particles was 1: 1.5 to 1: 3, the carbon (C) particles were filled in the raw material storage tank 7 as they were. Further, the weighed SiO ₂ particles include, as Examples 1 to 7, Al ₂ O ₃ particles, TiO ₂ particles, SnO ₂ particles, ZnO particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles, Ta ₂ O. ₅ particles were respectively added as shown in Table 1, and similarly as Comparative Examples 1 to 4, B ₂ O ₃ particles, Y ₂ O ₃ particles, ZrO ₂ particles, and MgO particles were added as shown in Table 1, respectively. As Comparative Example 5, a raw material containing only SiO ₂ particles was also prepared. These were filled in the raw material storage tank 7 ′.

A SiC seed single crystal wafer was fixed to the lower end of the susceptor. The SiC seed single crystal wafer used here was a 2 inch single crystal SiC substrate manufactured by the modified Rayleigh method. After evacuating the inside of the high frequency induction heating furnace, the inside of the high frequency induction heating furnace was replaced with an inert gas (high purity argon). Next, the carbon sealed crucible was heated by the high-frequency induction heating coil, and the surface temperature of the SiC seed single crystal wafer was adjusted to be in the range of 1,600 to 2,400 ° C.
In addition, heating temperature was temperature more than melting | fusing point or sublimation point of the added specific particle, and was made into the temperature range of 1,600-2400 degreeC.
Next, the susceptor on which the SiC seed single crystal wafer was fixed was rotated at a rotation speed of 0 to 20 rpm. In this state, the inert carrier gas (high purity argon) is adjusted to flow in a flow rate range of 0.5 to 10 L / min, and the single crystal SiC production raw material and specific particles are passed through the raw material supply pipe, Single-crystal SiC was manufactured by continuously supplying the SiC seed single-crystal wafer surface disposed in the upper part of the closed crucible. The production results are summarized in Table 1.

Here, the yield in Table 1 indicates the number of times that polycrystalline domain-free single-crystal SiC was obtained when manufactured 10 times.
As shown in Table 1, when at least one specific particle (Al ₂ O ₃ particle, TiO ₂ particle, ZnO particle, Ga ₂ O ₃ particle, and Ta ₂ O ₅ particle) is added to the raw material, It was confirmed that the occurrence of polycrystalline domains can be completely prevented. In addition, when Nb ₂ O ₅ particles and SnO ₂ particles were added to the raw material, it was confirmed that the generation of polycrystalline domains was significantly suppressed as compared with Comparative Example 5. Specifically, when Nb ₂ O ₅ particles are added, single-crystal SiC without polycrystalline domains is produced nine times, the polycrystalline domains are almost free, and when SnO ₂ particles are added, Single crystal SiC without a polycrystalline domain was produced 8 times, and almost no polycrystalline domain was generated.
On the other hand, when each raw material shown in Comparative Examples 1 to 4, that is, B ₂ O ₃ particles, Y ₂ O ₃ particles, ZrO ₂ particles, and MgO particles is added, the effect of suppressing the polycrystalline domain is It was not confirmed. Further, even SiO ₂ particles and carbon (C) particles only raw material (Comparative Example 5), the effect of suppressing the polycrystalline domain was not confirmed.

These results were considered as follows. First, in the case of a raw material consisting of only SiO ₂ particles and carbon (C) particles, the melting of SiO ₂ particles during single crystal SiC growth does not occur sufficiently, and as a result, the interface energy of the SiC seed single crystal surface during epitaxial growth is high. Therefore, it is presumed that the occurrence frequency of polycrystalline domains due to the disorder of the growth interface is high.
Subsequently, as in some examples (Al ₂ O ₃ particles, TiO ₂ particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles, Ta ₂ O ₅ particles), there is a melting point on the lower temperature side than the production temperature. When the raw material is added, it is considered that the added particles act as a melt flux of the SiO ₂ particles. As a result, the interface energy of the SiC seed single crystal surface during epitaxial growth is reduced, and a large amount due to disorder of the growth interface is caused. It is presumed that the generation of crystal domains is suppressed.

On the other hand, when the melting point of the additive particles is higher than the production temperature as in some of the comparative examples (Y ₂ O ₃ particles, ZrO ₂ particles, MgO particles), the effect of the SiO ₂ particles as a melting flux is sufficient. As a result, the interface energy on the surface of the SiC seed single crystal during epitaxial growth does not decrease, and it is estimated that there is no change in the occurrence frequency of polycrystalline domains due to the disorder of the growth interface. However, when another raw material having a melting point (less than 900 ° C.) significantly lower than the production temperature was used as in another example of comparative example (B ₂ O ₃ particles), the polycrystalline domain increased. From this, it was estimated that when the melting of the raw material starts from a considerably low temperature range (less than 900 ° C.) than the optimum manufacturing temperature, undesirable phenomena such as promotion of low temperature growth and increase of supersaturation appear. .

  Next, as in another example of the example (ZnO particles), when particles having a sublimation point on the lower temperature side than the production temperature are added, the volume expansion and diffusion motion of the particles are in the vicinity of the SiC seed single crystal. It is considered that the movement of the SiC particles generated and the rearrangement of the SiC particles is assisted, and as a result, the polycrystalline domains that are misplaced and rearranged and are taken into the SiC seed single crystal with different orientations are eliminated. It is estimated that.

From the above results, by adding at least one specific particle to the raw materials (SiO ₂ particles and carbon (C) particles), it was possible to produce higher quality single crystal SiC without occurrence of polycrystalline domains.
In this embodiment, in addition to SiO ₂ particles and carbon (C) particles, Al ₂ O ₃ particles, TiO ₂ particles, B ₂ O ₃ particles, Y ₂ O ₃ particles, ZrO ₂ particles, SnO ₂ particles are used. , MgO particles, ZnO particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles, and Ta ₂ O ₅ particles were prepared. This is because they are easily available and have high safety in handling. .
Therefore, the present invention does not exclude the freedom of selection of other particles other than the above 11 types, which are presumed to exhibit the same effects and actions as those of this patent from the results of Table 1 and the above consideration results.

It is a conceptual sectional view showing an example of an apparatus for manufacturing single crystal SiC of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealed chamber 2 Cylindrical crucible 3 High frequency induction heating coil 4 SiC seed crystal 5 Susceptor 6 Raw material supply pipe 7, 7 'Raw material storage tank 8, 8' Control valve 9 Growth layer 10 High frequency induction heating furnace A Inactive carrier gas

Claims (5)

A disposing step of disposing a susceptor to which a SiC seed crystal is fixed and a raw material supply pipe for supplying a raw material for producing single crystal SiC in a crucible; and
A growth step of growing the single crystal SiC by supplying the raw material for producing the single crystal SiC together with an inert gas through the raw material supply pipe onto the SiC seed crystal in the crucible having a high temperature atmosphere;
In the growth step, SiO ₂ particles, carbon (C) particles, and at least one specific particle are supplied,
The specific particle has a melting point and / or a sublimation point of 900 ° C. or higher and 2,400 ° C. or lower, a method for producing single crystal SiC. _{2. The} method for producing single-crystal SiC according to claim 1, wherein the supply amount of the specific particles is 100 ppm or more and 2,000 ppm or less in terms of weight relative to the SiO ₂ particles as a total amount. The specific particles are at least one selected from the group consisting of Al ₂ O ₃ particles, TiO ₂ particles, ZnO particles, SnO ₂ particles, Ga ₂ O ₃ particles, Nb ₂ O ₅ particles, and Ta ₂ O ₅ particles. The manufacturing method of the single-crystal SiC of Claim 1 or 2.   The method for producing single crystal SiC according to any one of claims 1 to 3, wherein the inert gas is Ar gas.   Single crystal SiC manufactured by the manufacturing method according to any one of claims 1 to 4.

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