JP2004002064A - Process for preparing silicon single crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preparation process for growing a silicon single crystal through Czochralski method with a high productivity and yield without any trouble in operation, even when growing a large-diameter crystal required for realizing cost reduction of a device step, particularly a large-diameter crystal of ≥300 mm (12 inch), at a high rate within a V-rich region. <P>SOLUTION: In the preparation process for growing the silicon single crystal having a crystal grain size of D mm through Czochralski method, a radiation-blocking member is placed around the crystal to cool the crystal by blocking the radiation. The distance between the lower end of the radiation-blocking member and the surface of a silicon melt is adjusted to ≥D/ 8 mm. <P>COPYRIGHT: (C)2004,JPO

Description

【００５４】
その結果、成長速度だけを考慮すると、比較例１の条件＝実施例１の条件＞実施例２の条件の順ではあるが、比較例１の条件では結晶内応力が大きく有転位化しやすいため、トータルの生産性では、有転位化回数を５回以内に抑えられる実施例１の条件及び実施例２の条件のほうが効率良い生産性を達成していることがわかる。
【００５５】
尚、これら輻射カット部材の下端部とシリコン融液面との距離Ｌと結晶の成長速度に関する条件以外のルツボ回転数等の条件は統一した。例えば、他の条件を変更すると相対的に有転位化の回数が変わり得る。従って、上記した有転位化回数は相対的に見た回数であり、絶対的なものではない。
【００５６】
さらに、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
【００５７】
例えば、本発明の実施例では、主にシリコン単結晶の引き上げ時に磁場を印加するＭＣＺ法について説明したが、本発明はこれに限定されず、磁場を印加しない通常のチョクラルスキー法にも適用できる。また、本明細書中で使用したチョクラルスキー法という用語には、通常のチョクラルスキー法とＭＣＺ法のいずれもが含まれる。
【００５８】
【発明の効果】
以上説明したように、本発明によれば、エピタキシャル成長用の基板等に用いられる大口径シリコン単結晶をＶ−ｒｉｃｈ領域で高速成長させる際に、輻射カット部材の下端部とシリコン融液面との距離をＤ／８ｍｍ以上とすることで有転位化の回数を減少させることができる。これにより、操業時間を短くできるため、トータルの生産効率を向上させることができる。
【図面の簡単な説明】
【図１】本発明で用いた単結晶製造装置（Ｌ≧Ｄ／８）の概略構成図である。
【図２】遮熱スクリーンを用いた場合の単結晶製造装置（Ｌ≧Ｄ／８）の概略構成図である。
【図３】単結晶製造装置（Ｌ＜Ｄ／８）の概略構成図である。
【図４】輻射カット部材の下端部とシリコン融液面との距離を変えて、有転位化回数と生産性とを比較した図である。
【符号の説明】
１…メインチャンバー、　２…引上げチャンバー、　３…単結晶、　４…原料融液、　５…石英ルツボ、　６…黒鉛ルツボ、　７…加熱ヒーター、　８…断熱部材、　９…ガス流出口、　１０…ガス導入口、　１１…ガス整流筒、　１２…遮熱部材、　１３…遮熱スクリーン、　１４…シリコン融液面、　Ｄ…結晶直径、　Ｌ…輻射カット部材の下端部とシリコン融液面との距離。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a single crystal silicon for producing a silicon single crystal wafer used as a substrate of a semiconductor device such as a memory or a CPU, and more particularly to a method for producing a silicon single crystal having a large diameter of 300 mm (12 inches) or more. About the method.
[0002]
[Prior art]
When producing a large-diameter silicon single crystal, the Czochralski method (CZ method) is usually used. As shown in FIG. 3, for example, a single crystal manufacturing apparatus using the CZ method includes a quartz crucible 5 containing a raw material melt 4, a graphite crucible 6 supporting the quartz crucible 5, and a crucible surrounding the crucible. It has a heater 7 arranged. After the seed crystal is immersed in the raw material melt 4 in the quartz crucible 5, the rod-shaped single crystal 3 is pulled up from the raw material melt 4. These crucibles 5 and 6 can be moved up and down in the direction of the crystal growth axis, and raise the crucibles 5 and 6 so as to compensate for the decrease in the liquid level of the raw material melt 4 which has crystallized and decreased during crystal growth. As a result, the position of the melt surface 14 of the raw material melt 4 is always kept constant.
[0003]
Silicon single crystals manufactured by the CZ method are mainly used for manufacturing semiconductor devices. 2. Description of the Related Art In recent years, semiconductor devices have been highly integrated, and elements have been miniaturized. As the miniaturization of the element progresses, the size and density of the grown-in crystal defects generated during the crystal growth become a problem.
[0004]
Here, the grown-in crystal defect will be described. In a silicon single crystal, when the crystal growth rate is relatively high, a grown-in defect such as an FPD (Flow Pattern Defect), which is considered to be caused by voids in which vacancy-shaped point defects are gathered, extends over the entire area in the crystal diameter direction. A region that exists at high density and has these defects is called a V (vacancy) region. Further, as the growth rate was reduced, an OSF (Oxidation Induced Stacking Fault) region was formed in a ring shape from the periphery of the crystal with the decrease in the growth rate, and interstitial silicon was gathered outside the ring. Defects such as LSPDs (Laser Scattering Tomography Defects) and LFPDs (Large Flow Pattern Defects) which are considered to be caused by dislocation loops are present at a low density, and a region where these defects are present is called an I (Interstitial) region. I have. Further, when the growth rate is reduced, the OSF ring shrinks to the center of the wafer and disappears, and the entire surface becomes an I region.
[0005]
In recent years, it has been discovered that an FPD or the like caused by holes, an LSPD or an LFPD caused by interstitial silicon does not exist outside the OSF ring between the V region and the I region. This region is called an N (Neutral) region.
[0006]
As a method for controlling these grown-in crystal defects, a technology for reducing the crystal defect density and a technology for reducing the crystal defect size have been proposed. Further, a method of manufacturing a single crystal which is controlled to be an N region without a grown-in crystal defect has been proposed. However, these methods generally tend to decrease the crystal growth rate and decrease productivity.
[0007]
On the other hand, in a wafer used as a substrate for epitaxial growth, an epitaxial layer is deposited thereon, and in a wafer used as a support substrate for an SOI wafer, an SOI layer is formed thereon via an oxide film. There is little discussion about -in crystal defect quality, and it has been pulled at the highest possible pulling speed to improve productivity. In addition to a substrate for epitaxial growth, a semiconductor device and a supporting wafer for an SOI wafer that are not so sensitive to a grown-in crystal defect require less control of the substrate defect, and have been pulled at the highest possible pulling speed.
[0008]
In this case, it is important to cool the growing single crystal 3 in order to increase the growth rate. In order to achieve this, as a radiation cut member for cutting radiation from the raw material melt 4 toward the single crystal 3 and cooling the growing single crystal 3, for example, a gas rectifying cylinder 11 and a heat shielding member 12 attached thereto Was provided near the raw material melt 4. With this radiation cut member, the growth rate of a small crystal having a crystal diameter of 200 mm (8 inches) or less could be sufficiently increased, and the productivity could be improved. However, when a large-diameter crystal having a diameter of 300 mm (12 inches) or more, which has recently been required to reduce the cost of the device process, is grown at a high speed in the V-rich region, dislocations are generated during the crystal growth, and the single crystal is successfully grown. Phenomenon that the probability of doing was low occurred frequently. As a result, the operating time is prolonged, the productivity is remarkably reduced, and the crucible is deteriorated, which may make it difficult to continue the operation.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of such a problem, and when growing a silicon single crystal by the CZ method, a large-diameter crystal, particularly 300 mm (12 inch), which is required to reduce the cost of a device process. (2) An object of the present invention is to provide a method capable of producing a large-diameter crystal with high productivity and a high yield without hindering the operation even when the large-diameter crystal is grown at a high speed in a V-rich region.
[0010]
[Means for Solving the Problems]
The present invention has been made in order to solve the above problems, and in a method of growing a crystal by the Czochralski method, a radiation cut member that is arranged so as to surround the crystal and cuts radiation to cool the crystal is used. A method for growing a silicon single crystal, wherein the distance between the lower end of the radiation cut member and the silicon melt surface is D / 8 mm or more when growing a silicon single crystal having a crystal diameter of Dmm. (Claim 1).
[0011]
As described above, by growing the crystal with the distance between the lower end portion of the radiation cut member and the silicon melt surface being D / 8 mm or more, even if the crystal is grown in the V-rich region where the growth rate is high, dislocations are formed. Are less likely to occur, and the number of dislocations can be reduced. Accordingly, by improving the success rate of the single crystal growth, total productivity and yield can be greatly improved. In addition, the problem that the crucible is deteriorated due to the prolonged operation time and it becomes difficult to continue the operation is eliminated.
[0012]
In this case, it is preferable that the growth rate of the grown crystal is 150 / Dmm / min or more (Claim 2), and the grown silicon single crystal is formed in a V-rich region having a growth speed higher than that of the OSF region. It is preferable to grow a crystal of (claim 3).
As described above, by setting the growth rate of the grown crystal to 150 / Dmm / min or more, for example, the grown crystal can be grown at a high speed in the V-rich region, so that the operation time can be shortened and the productivity can be improved. It can be greatly improved.
[0013]
In this case, it is preferable that the radiation cut member is a gas rectifying cylinder or a heat shielding screen (claim 4).
In this way, by using the radiation cut member as a gas rectifying cylinder or a heat shield screen, the crystal to be grown can be shielded from the radiation from the heater or the raw material melt, and the crystal can be cooled effectively, and the crystal growth rate can be reduced. Can be speeded up.
[0014]
In this case, it is preferable that the crystal diameter Dmm of the silicon single crystal to be grown is 300 mm (12 inches) or more (Claim 5).
According to the present invention, even if the crystal diameter Dmm of the silicon single crystal to be grown has a large diameter of 300 mm (12 inches) or more and is grown at high speed in the V-rich region, dislocations are unlikely to occur. A single crystal can be grown with less than 5 times per single crystal.
[0015]
Further, according to the present invention, there is provided a silicon single crystal manufactured by the manufacturing method (claim 6). Further, a silicon wafer cut from the silicon single crystal is provided (claim 7).
A silicon wafer cut from a silicon single crystal manufactured according to the present invention is used for a wafer used for a substrate for epitaxial growth, or a substrate for a semiconductor device that is not very sensitive to a grown-in crystal defect or a support substrate for an SOI wafer. It can be used as a wafer. In particular, by setting the crystal diameter Dmm to 300 mm (12 inches) or more, the cost of the device process can be reduced.
[0016]
The inventors of the present invention have examined the reason why large-diameter crystals, in particular, silicon single crystals having a diameter of 300 mm or more are grown by using a radiation cut member so that dislocations are likely to occur and the number of dislocations increases.
During crystal growth, in addition to the amount of heat flowing from the raw material melt, solidification latent heat generated by a phase change from liquid to solid during crystal growth enters the crystal. The solidification latent heat increases as the crystal growth rate increases. The heat that has flowed in is released from the crystal surface. However, if the heat is not released, the crystal is not cooled and the crystal does not grow. Therefore, in order to grow the crystal at a high speed, it is necessary to cool the crystal.
[0017]
In order to achieve this, it is effective to cut the radiation from the raw material melt or the like toward the crystal, and arrange a radiation cut member for cooling the growing crystal near the raw material melt to grow the crystal. In the case of a crystal having a crystal diameter of 200 mm (8 inches) or less, even with this method, dislocations were small and the growth rate could be sufficiently increased. However, when attempting to produce a large-diameter crystal having a crystal diameter of 300 mm (12 inches) or more, dislocations occur during crystal growth, and the probability of growing a single crystal decreases.
[0018]
This is because as the crystal diameter increases, the distance from the center of the crystal to the crystal surface increases, making it difficult for the heat in the center to escape. The temperature rises because the crystal center is hardly cooled, while the crystal surface is cooled immediately. That is, in a large-diameter crystal, it is considered that the temperature gradient between the crystal surface and the crystal center becomes large, so that the thermal stress inside the crystal becomes large, so that dislocation is likely to occur during growth.
[0019]
Therefore, in the present invention, the crystal is grown with the distance L between the lower end of the radiation cut member arranged so as to surround the crystal and the silicon melt surface being D / 8 mm or more. As described above, by keeping the distance between the lower end portion of the radiation cut member and the silicon melt surface at D / 8 mm or more, the thermal stress inside the crystal can be reduced, and the dislocation of the large-diameter crystal can be prevented. it can.
[0020]
That is, the present inventors changed the distance L between the lower end portion of the radiation cut member and the silicon melt surface variously, and pulled up a large-diameter crystal (300 mm). And when L is D / 8 mm or more and a single crystal is grown at a speed of 150 / Dmm / min or more, and when the distance L between the lower end of the radiation cut member and the silicon melt surface is less than D / 8 mm, 150 / Dmm / When the number of dislocations was compared between the case where a single crystal was grown at a speed of at least min and L was D / 8 mm or more, the number of dislocations was less than 5 per single crystal. I found out.
[0021]
In addition, single crystals were grown, compared and studied when the single crystal growth rate was 150 / Dmm / min or more and when the single crystal growth rate was less than 150 / Dmm / min. As a result, when the growth rate was 150 / Dmm / min or more, crystals in the V-rich region could be grown. In addition, it was possible to improve productivity.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a single crystal manufacturing apparatus used in the present invention.
As shown in FIG. 1, the single crystal manufacturing apparatus has a member for melting raw silicon, a mechanism for pulling up crystallized silicon, and the like, and these are housed in a main chamber 1. A pulling chamber 2 extending upward from the ceiling of the main chamber 1 is connected, and a mechanism (not shown) for pulling the single crystal 3 is provided above the pulling chamber 2.
[0023]
A quartz crucible 5 for accommodating the molten raw material melt 4 and a graphite crucible 6 for supporting the quartz crucible 5 are provided in the main chamber 1, and these crucibles 5 and 6 are moved up and down by a driving mechanism (not shown). It is freely supported. The drive mechanism of the crucibles 5 and 6 can raise the crucibles 5 and 6 by an amount corresponding to the lowering of the liquid level in order to compensate for the lowering of the liquid level of the raw material melt 4 accompanying the pulling of the single crystal 3. .
[0024]
A heater 7 for melting the raw material is disposed so as to surround the crucibles 5 and 6. Outside the heater 7, a heat insulating member 8 is provided so as to surround the periphery thereof in order to prevent heat from the heater 7 from being directly radiated to the main chamber 1.
[0025]
In addition, an inert gas such as an argon gas is introduced into the main chamber 1 from a gas inlet 10 provided in an upper part of the pulling chamber 2. The introduced inert gas passes between the single crystal 3 being pulled and the gas rectifying cylinder 11 which is a heat shield cut member, and passes between the lower part of the heat shield member 12 and the silicon melt surface 14. Is discharged from the gas outlet 9.
[0026]
Further, as another embodiment of the present invention, FIG. 2 shows a schematic configuration diagram in the case where a heat shielding screen 13 having a shape whose diameter is reduced from top to bottom is used as a heat shielding cut member. .
[0027]
In the figure, D represents the crystal diameter, and L represents the distance between the lower end of the radiation cut member and the silicon melt surface. In the present invention, a crystal is grown with the distance L between the lower end of the radiation cut member and the silicon melt surface being D / 8 mm or more.
[0028]
As described above, by setting the distance L between the lower end portion of the radiation cut member and the silicon melt surface to D / 8 mm or more, a crystal in the V-rich region is grown at a high growth rate of, for example, 150 / Dmm / min or more. However, dislocations hardly occur, and for example, a single crystal having a large diameter such as 300 mm or more in diameter with less than 5 dislocations per single crystal can be grown. Therefore, a large diameter single crystal can be manufactured with high productivity and high yield. Further, there is no problem that the number of dislocations is 5 or more per single crystal, and the crucible is deteriorated due to a long operation time, and it is difficult to continue the operation.
[0029]
However, even if the distance between the lower end portion of the radiation cut member and the silicon melt surface is maintained at D / 8 mm or more, if the growth rate is too high, the stress due to the latent heat of solidification during growth will increase. It is preferable to be 450 / Dmm / min or less at the maximum. In order to maintain this growth rate, it is preferable that the distance between the lower end of the radiation cut member and the growth interface be D / 2 mm or less.
[0030]
As the radiation cut member used in the present invention, a gas straightening cylinder 11 arranged so as to surround the single crystal 3 grown above the raw material melt 4 contained in the crucible or a diameter reduced from the upper part to the lower part. It is preferable to use a heat shield screen 13 having such a shape as described above, and it is more preferable to use a heat shield member 12 attached to them. The radiation cut member protects the crystal to be grown from radiation from the heater 7 and the raw material melt 4, and cools the crystal to increase the crystal growth rate. Is highly effective. Further, by using the heat shielding member 12 for them, the effect of cooling the crystal is further enhanced.
[0031]
In addition, a silicon wafer cut from a silicon single crystal manufactured according to the present invention has a grown-in crystal defect on which a grown-in crystal defect is not so serious because an epitaxial layer is stacked thereon, or a grown-in crystal defect. Since the SOI layer is formed through an insensitive substrate for a semiconductor device or an oxide film, it is useful as a support substrate for an SOI wafer where a grown-in crystal defect hardly causes a problem. In particular, by setting the crystal diameter Dmm of the silicon single crystal to 300 mm (12 inches) or more, the cost of the device process can be reduced.
[0032]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
(Example 1)
A 12 inch diameter crystal was grown using an HZ equipped with a 800 mm (32 inch) diameter crucible whose schematic diagram is shown in FIG. Crystals having a straight body length of about 120 cm were grown while setting a charge amount of the Si raw material charged into the crucible to 320 Kg and applying a transverse magnetic field having a central magnetic field strength of 4000 G.
[0033]
At this time, the distance L between the lower end of the radiation cut member and the silicon melt surface was 50 mm, and the diameter D of the crystal actually grown was 306 mm. D / 8 mm is 306/8 = 38.25 mm, and the distance L between the lower end of the radiation cut member and the silicon melt surface is at least ８ of the crystal diameter (L ≒ D / 6. 1> D / 8).
[0034]
In addition, pulling was performed at a growth rate of 0.8 mm / min, which is high enough to prevent crystal deformation. This growth rate is greater than 150 / D = 150/306 = 0.49 mm / min.
[0035]
Crystals were grown under the above conditions. When the crystal was dislocated, the crystal was melted, the crystal was grown again, and this was repeated until a crystal of 120 cm could be grown. As a result, three dislocations occurred before a crystal having a size of 120 cm was obtained, but crystals without dislocations could be pulled up for the fourth time.
[0036]
From the obtained crystal, a wafer-like sample was sampled about every 30 cm, and the OSF and the FPD were inspected. In the OSF inspection, a wafer-like sample is subjected to wet oxidation at 1150 ° C. for 100 minutes, and then selectively etched with a mixed acid solution of hydrofluoric acid, nitric acid, acetic acid, and water, and the wafer is condensed. The observation was performed under a light and with a microscope. As a result, no OSF was observed. On the other hand, the FPD inspection is to selectively etch a wafer-like sample with a mixture of K ₂ Cr ₂ O ₇ , hydrofluoric acid and water without stirring, and observe a FPD defect observed as a ripple pattern with a microscope. I went in. As a result, FPD defects were observed on the entire surface of the wafer. From the above, it was confirmed that the grown crystal was a V-rich region.
[0037]
(Example 2)
As in Example 1, a crystal having a diameter of 12 inches was grown using HZ equipped with a 32-inch crucible schematically shown in FIG. Crystals having a straight body length of about 120 cm were grown while setting a charge amount of the Si raw material charged into the crucible to 320 Kg and applying a transverse magnetic field having a central magnetic field strength of 4000 G.
[0038]
At this time, the distance L between the lower end of the radiation cut member and the silicon melt surface was 70 mm, and the diameter D of the crystal actually grown was 306 mm. The distance L between the lower end of the radiation cut member and the silicon melt surface is larger than D / 8 mm (L ≒ D / 4.4> D / 8).
[0039]
In addition, the growth rate was set to 0.65 mm / min, which is high enough to prevent crystal deformation. This growth rate is greater than 150 / Dmm / min.
[0040]
Crystals were grown under the above conditions. When the crystal was dislocated, the crystal was melted, the crystal was grown again, and this was repeated until a crystal of 120 cm could be grown. As a result, dislocations occurred only once before a crystal of 120 cm was obtained, and crystals without dislocations could be pulled up for the second time.
[0041]
From the obtained crystals, wafer-like samples were sampled about every 30 cm, and the same OSF and FPD inspection as in Example 1 was performed. As a result, no OSF was observed. On the other hand, FPD defects were observed on the entire surface of the wafer. From the above, it was confirmed that the grown crystal was a V-rich region.
[0042]
(Example 3)
As in Example 1, a crystal having a diameter of 12 inches was grown using HZ equipped with a 32-inch crucible schematically shown in FIG. Crystals having a straight body length of about 120 cm were grown while setting a charge amount of the Si raw material charged into the crucible to 320 Kg and applying a transverse magnetic field having a central magnetic field strength of 4000 G.
[0043]
At this time, the distance L between the lower end of the radiation cut member and the silicon melt surface was also set to 50 mm, the same as in Example 1, and the diameter D of the crystal actually grown was set to 306 mm. The distance L between the lower end of the radiation cut member and the silicon melt surface is larger than D / 8 mm (L ≒ D / 6.1> D / 8).
[0044]
Further, the growth rate was set to 0.40 mm / min, which was lower than that in Example 1. This growth rate is less than 150 / Dmm / min.
[0045]
Crystals were grown under these conditions. When the crystal was dislocated, the crystal was melted, the crystal was grown again, and this was repeated until a crystal of 120 cm could be grown. As a result, dislocations occurred twice before a crystal of 120 cm was obtained, but crystals without dislocations could be pulled up for the third time.
[0046]
From the obtained crystals, wafer-like samples were sampled about every 30 cm, and the same OSF and FPD inspection as in Example 1 was performed. As a result, an OSF ring was observed inside the wafer. On the other hand, no FPD defect was observed outside the position of the OSF ring. From the above, it was confirmed that the grown crystal was not in the V-rich region.
[0047]
(Comparative Example 1)
A 12 inch diameter crystal was grown using HZ equipped with a 32 inch crucible whose schematic diagram is shown in FIG. Crystals having a straight body length of about 120 cm were grown while setting a charge amount of the Si raw material charged into the crucible to 320 Kg and applying a transverse magnetic field having a central magnetic field strength of 4000 G.
[0048]
At this time, the distance L between the lower end of the radiation cut member and the silicon melt surface was reduced to 30 mm, and the diameter D of the crystal actually grown was 306 mm. The distance L between the lower end of the radiation cut member and the silicon melt surface is smaller than D / 8 mm (L ≒ D / 10.2 <D / 8).
[0049]
Further, even when L = 30 mm, a V-rich region was obtained, and pulling was performed at 0.8 mm / min, which is the same as in Example 1. This growth rate is greater than 150 / D = 150/306 = 0.49 mm / min.
[0050]
Crystals were grown under these conditions. When the crystal was dislocated, the crystal was melted, the crystal was grown again, and this was repeated until a crystal of 120 cm could be grown. As a result, dislocations occurred six times before a crystal of 120 cm was obtained, and crystals without dislocations could be pulled up at the seventh time. Since the number of dislocations was large and it took time to re-melt the dislocation crystals, the production per hour was significantly lower than that of the examples. Therefore, the number of dislocations is desirably suppressed to five or less.
[0051]
From the obtained crystals, wafer-like samples were sampled about every 30 cm, and the same OSF and FPD inspection as in Example 1 was performed. As a result, no OSF was observed. On the other hand, FPD defects were observed on the entire surface of the wafer. From the above, it was confirmed that the grown crystal was a V-rich region.
[0052]
Further, 10 crystals were grown under each condition of Comparative Example 1, Examples 1 and 2 in which the crystal to be grown was a V-rich region, and the medium amount was evaluated. Table 1 and FIG. 4 show a comparison of the number of occurrences of dislocations per crystal and the productivity. The productivity was standardized by the productivity under the conditions of Comparative Example 1.
[0053]
[Table 1]

[0054]
As a result, when only the growth rate is considered, the condition of Comparative Example 1 = the condition of Example 1> the condition of Example 2 is satisfied. It can be seen that in terms of total productivity, the conditions of Example 1 and Example 2 in which the number of dislocations is suppressed to 5 or less achieve more efficient productivity.
[0055]
The conditions other than the conditions related to the distance L between the lower end portion of the radiation cut member and the silicon melt surface and the crystal growth rate, such as the crucible rotation speed, were unified. For example, if other conditions are changed, the number of dislocations may change relatively. Therefore, the number of dislocations described above is a relative number, and is not absolute.
[0056]
Further, the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and any device having the same operation and effect can be realized by the present invention. It is included in the technical scope of the invention.
[0057]
For example, in the embodiments of the present invention, the MCZ method in which a magnetic field is mainly applied at the time of pulling a silicon single crystal has been described. However, the present invention is not limited to this, and may be applied to a normal Czochralski method in which no magnetic field is applied. it can. The term Czochralski method used in the present specification includes both ordinary Czochralski method and MCZ method.
[0058]
【The invention's effect】
As described above, according to the present invention, when a large-diameter silicon single crystal used for a substrate or the like for epitaxial growth is grown at a high speed in the V-rich region, the lower end portion of the radiation cut member and the silicon melt surface are separated. By setting the distance to D / 8 mm or more, the number of dislocations can be reduced. As a result, the operation time can be shortened, and the total production efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a single crystal manufacturing apparatus (L ≧ D / 8) used in the present invention.
FIG. 2 is a schematic configuration diagram of a single crystal manufacturing apparatus (L ≧ D / 8) using a heat shielding screen.
FIG. 3 is a schematic configuration diagram of a single crystal manufacturing apparatus (L <D / 8).
FIG. 4 is a diagram comparing the number of dislocations and the productivity by changing the distance between the lower end of the radiation cut member and the silicon melt surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main chamber, 2 ... Pulling chamber, 3 ... Single crystal, 4 ... Raw material melt, 5 ... Quartz crucible, 6 ... Graphite crucible, 7 ... Heater, 8 ... Heat insulation member, 9 ... Gas outlet, 10 ... Gas Inlet, 11: gas straightening tube, 12: heat shield member, 13: heat shield screen, 14: silicon melt surface, D: crystal diameter, L: distance between the lower end of the radiation cut member and the silicon melt surface.

Claims (7)

In the method of growing a crystal by the Czochralski method, the method uses a radiation cut member that is arranged so as to surround the crystal and cuts radiation to cool the crystal. A method for producing a silicon single crystal, wherein a crystal is grown with a distance between a lower end portion of a cut member and a silicon melt surface being D / 8 mm or more. 2. The method for producing a silicon single crystal according to claim 1, wherein the growth rate of the grown crystal is 150 / Dmm / min or more. The method for producing a silicon single crystal according to claim 1, wherein the growing silicon single crystal is a crystal in a V-rich region having a higher growth rate than an OSF region. The method for producing a silicon single crystal according to any one of claims 1 to 3, wherein the radiation cut member is a gas rectifying cylinder or a heat shield screen. The method for producing a silicon single crystal according to any one of claims 1 to 4, wherein a crystal diameter Dmm of the silicon single crystal to be grown is 300 mm (12 inches) or more. A silicon single crystal manufactured by the method according to claim 1. A silicon wafer cut from the silicon single crystal according to claim 6.

Images