JP2001089294A - Method of continuously pulling up silicon single crystal free from agglomerates of point defects - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably make an ingot into perfect area [P] over whole length in a high yield and to make oxygen concentration and electrical resistance of the ingot uniform over the whole length. SOLUTION: When an area where the agglomerates of interstitial silicon-type point defects are present in an ingot is defined as [I], an area where the agglomerates of vacancy-type point defects are present is defined as [V] and a perfect area free from the agglomerates of interstitial silicon-type point defects and the agglomerates of vacancy-type point defects is defined as [P], a silicon single crystal ingot 25 composed of such perfect area [P] is pulled up by a CZ method while controlling V/G (V: pulling up velocity; G: temperature gradient in the vertical direction of the ingot) to be constant. The ingot is pulled up from the inside area of an internal crucible 12 b while making only the V constant and while rotating the external crucible and rotating the ingot around the direction of the pulling up axis and, further, while supplying a silicon raw material 21 between the external crucible 12a for storing a silicon molten liquid 18 and the internal crucible 12b according to the amount of grown ingot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for pulling a silicon single crystal ingot free of point defect aggregates while continuously supplying a silicon raw material by the Czochralski method (hereinafter referred to as CZ method). . More specifically, the present invention relates to a continuous pulling method for pulling an ingot while applying a magnetic field to a silicon melt in a horizontal direction.

[0002]

2. Description of the Related Art In recent years, in the process of manufacturing a semiconductor integrated circuit, an oxidation-induced stacking fault (hereinafter referred to as OSF) is a cause of lowering the yield.
That. ) Nuclei of oxygen precipitates and microcrystalline particles (Crystal Originated Particl
e, hereinafter referred to as COP. ) Or interstitial dislocations (Int
erstitial-type Large Dislocation, hereinafter referred to as LD. ). OSF introduces minute defects serving as nuclei during crystal growth, becomes apparent in a thermal oxidation step or the like when manufacturing a semiconductor device, and causes defects such as an increase in leak current of the manufactured device. Also COP
Are pits caused by crystals that appear on the wafer surface when the mirror-polished silicon wafer is washed with a mixed solution of ammonia and hydrogen peroxide. When this wafer is measured with a particle counter, these pits are also detected as light scattering defects together with the original particles. This C
OP is an electrical characteristic, for example, a time-dependent dielectric breakdown characteristic (Time Dependent dielectric Breakdown, TDD) of an oxide film.
B), oxide film breakdown voltage characteristics (Time Zero Dielectric Breakdo
wn, TZDB) and the like. Also COP
Is present on the wafer surface, a step is generated in a device wiring process, which may cause disconnection. This also causes a leak and the like in the element isolation portion, and lowers the product yield. Furthermore, LD is also called a dislocation cluster,
Alternatively, when a silicon wafer having this defect is immersed in a selective etching solution containing hydrofluoric acid as a main component, a pit is generated, and thus the silicon wafer is also called a dislocation pit. This LD also causes deterioration of electrical characteristics such as leak characteristics and isolation characteristics.

[0003] From the above, OSF, CO, etc. can be obtained from a silicon wafer used for manufacturing a semiconductor integrated circuit.
There is a need to reduce P and LD. A method for manufacturing a defect-free silicon wafer having no OSF, COP and LD is disclosed in Japanese Patent Application Laid-Open No. H11-1393. This defect-free silicon wafer has a perfect region [P] when a perfect region in which no aggregate of vacancy type point defects and no aggregate of interstitial silicon type point defects are present in a silicon single crystal ingot is defined as [P]. P] is a silicon wafer cut from the ingot. The perfect region [P] is located between the region [I] where the aggregate of the interstitial silicon type point defect exists and the region [V] where the aggregate of the vacancy type point defect exists in the silicon single crystal ingot. Intervene. In the silicon wafer composed of the perfect region [P], the pulling speed of the ingot is V (mm / min), and the temperature gradient in the vertical direction of the ingot at the contact surface between the silicon melt and the ingot is G.
(° C./mm), V / G (mm ² / min · ° C.) is determined so that the OSF generated in a ring shape during the thermal oxidation treatment disappears at the center of the wafer. .

[0004] In addition to the pulling method disclosed in JP-A-11-1393, a so-called batch type pulling method for pulling a silicon single crystal ingot from a quartz crucible containing a predetermined amount of silicon melt is shown in FIG. As shown in FIG. 13, as the amount of the silicon melt 1 decreases, the position of the crucible 2 is raised in order to keep the position of the liquid surface of the silicon melt at a predetermined height during pulling (FIG. 13B). As a result, the top part 3a and the tail part 3b of the ingot 3 have different heat histories. That is, in the initial stage of crystal pulling shown in FIG. 13A and the final stage of pulling shown in FIG. 13B, the thermal environment to which the ingot receives depends on the amount of the silicon melt. In the figure, reference numeral 4 denotes a graphite crucible, 5 denotes a heater, 6 denotes a heat retaining cylinder, and arrows indicate the flow of heat. Due to this difference in heat history, the above-mentioned temperature gradient G decreases as it approaches the tail portion 3b. Therefore, Japanese Patent Application Laid-Open No.
In the pulling method disclosed in Japanese Patent Application Laid-Open Publication No. H10-115, in order to keep V / G constant, the pulling speed V is decreased as the crystal length increases, thereby growing an ingot consisting of the perfect region [P].

[0005]

However, in the conventional pulling method in which the pulling speed is reduced as the length of the ingot, that is, the crystal length is increased, it is not easy to grasp the exact change in the temperature gradient G. Since the melt depth and the relative position of the crucible to the heater change, the temperature gradient distribution in the radial direction, albeit minute, also changes. Therefore, V /
It is difficult to control the G constant to make the ingot a perfect area [P] over its entire length, and as a result, the perfect area [P] in the ingot straight body part
Occupancy could not be high enough. In addition, in the conventional pulling method, when the amount of the silicon melt in the crucible decreases as the crystal length increases, as shown in FIG. 13B, the silicon melt in the tail 3b of the ingot 3 is larger than that in the top 3a. There was a problem that the oxygen concentration was reduced due to the decrease in the area of the inner surface of the quartz crucible in contact with the substrate. Furthermore, when a dopant is added together with a silicon raw material in order to change the characteristics of a silicon single crystal as a semiconductor, the segregation phenomenon increases the crystal length and the dopant concentration in the silicon melt in the crucible increases. In this case, a high-concentration dopant is dissolved, which causes a problem that the tail portion has a lower resistivity than the top portion.

An object of the present invention is to provide a method for continuously pulling a silicon single crystal which makes an ingot a perfect region [P] stably with high yield over the entire length. Another object of the present invention is to provide a method for continuously pulling a silicon single crystal which makes the oxygen concentration of the ingot uniform over the entire length. Still another object of the present invention is to provide a method for continuously pulling a silicon single crystal which makes the resistivity of an ingot uniform over its entire length.

[0007]

The invention according to claim 1 is
As shown in FIG. 1, the pulling speed of the silicon single crystal ingot 25 is V (mm / min), the temperature gradient in the vertical direction of the ingot at the contact surface between the silicon melt 18 and the ingot 25 is G (° C./mm), The region where the aggregate of the interstitial silicon type point defect exists in the inside is [I],
When the region where the aggregates of the vacancy type point defects exist is [V], and the perfect region where the aggregates of the interstitial silicon type point defects and the aggregates of the vacancy type point defects do not exist is [P],
This is an improvement in the method of pulling the silicon single crystal ingot 25 comprising the perfect region [P] by the CZ method while controlling V / G to be constant. Its characteristic configuration is that the outer crucible 12a and the inner crucible 12a in which the silicon melt 18 is stored.
b, while supplying the silicon raw material 21 in accordance with the growth amount of the ingot 25, the pulling speed V is increased while rotating the outer crucible 12a and rotating the ingot 25 from the inner region of the inner crucible 12b about the pulling axial direction. The only thing is to pull up with a constant. In the invention according to claim 1, since the silicon raw material 21 is supplied in accordance with the growth amount of the ingot 25 during the pulling, the melt depth of the silicon melt 18 and the relative position of the crucible 12 with the heater 13 remain unchanged. , The temperature gradient G of the ingot 25 can be made constant, and the temperature gradient distribution in the radial direction can be fixed. For this reason, by pulling up only the control condition V / G of the control condition V / G for creating the perfect area [P], the ingot 25 can be stably obtained over the entire length with a high yield.
Can be Further, since the contact area between the crucible 12a and the silicon melt 18 does not change during the pulling, the oxygen concentration of the ingot 25 can be made uniform over the entire length.

[0008] The invention according to claim 2 is the invention according to claim 1, wherein the crucible 12 is pulled while the ingot 25 is being pulled up.
This is a continuous pulling method in which a magnetic field is applied in a horizontal direction to the silicon melt 18 stored in a. In the invention according to claim 2,
By applying a magnetic field in the horizontal direction, convection of the silicon melt is suppressed, and the silicon melt 18 is removed from the inner crucible 12b.
The amount of oxygen dissolved in the ingot 25 can be further reduced, and the oxygen concentration of the ingot 25 can be made uniform at a low concentration over the entire length.

The invention according to claim 3 is the invention according to claim 1 or 2, which is a continuous pulling method in which a dopant is supplied together with the silicon raw material 21 in accordance with the segregation coefficient of the dopant. In the invention according to claim 3, by supplying the dopant as described above, the resistivity of the ingot 25 can be made uniform over the entire length.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a continuous pulling apparatus 10 for silicon single crystal used in the continuous pulling method of the present invention comprises a double crucible 1 in a chamber 11 which is kept airtight.
2, a heater 13 and a raw material supply pipe 14. The double crucible 12 is constituted by an outer crucible 12a made of quartz and an inner crucible 12b made of quartz which is a cylindrical partition provided in the outer crucible. An inner region of the inner crucible is provided below the inner crucible 12b. A communication portion 12c communicating with the outside region is formed. The double crucible 12 is placed on a graphite crucible 17 on a shaft 16 which is vertically provided at the lower center of the chamber 11, and is driven to rotate at a predetermined rotation speed in a horizontal plane about the axis of the shaft 16. Has become. A silicon melt 18 is stored in the double crucible 12. Heater 1
Numeral 3 is for heating and melting the silicon raw material in the crucible, and for maintaining the resulting silicon melt 18 at a predetermined temperature. The heater 13 is provided so as to surround the graphite crucible 17, and a heat retaining cylinder 19 is provided outside the heater 13. An electromagnet 20 for applying a magnetic field in the horizontal direction to the silicon melt 18 in the crucible 12 via the heat retaining cylinder 19, the heater 13 and the graphite crucible 17 is provided outside the chamber.

The raw material supply pipe 14 receives the silicon raw material 21 from the upper end thereof and removes the silicon raw material 21 from the lower end opening of the silicon raw material 21 between the crucible 12a and the inner crucible 12b.
Is supplied continuously on the liquid level of The raw material supply pipe 14 is supported at an upper end thereof by supporting means (not shown) and is suspended therefrom. Here, the silicon raw material is supplied so that the liquid level position of the silicon melt does not change according to the growth amount of the ingot. Examples of the silicon raw material 21 include flake-like silicon produced by pulverizing an ingot of polycrystalline silicon, and granular polycrystalline silicon precipitated by a pyrolysis method from a gaseous raw material. If necessary, a dopant such as boron (B) or phosphorus (P) is further added. This dopant is added according to its segregation coefficient. Although not shown, a pull-up mechanism and an inlet for introducing an inert gas such as Ar gas into the chamber are provided at an upper portion of the chamber 11. The pulling wire 22 which is a part of the pulling mechanism is configured to move up and down while rotating at a predetermined rotation speed above the double crucible 12. At the tip of the pulling wire 22, a silicon single crystal seed crystal 23 is attached via a chuck.

The silicon single crystal ingot 25 of the present invention
Is grown by immersing the seed crystal 23 in the silicon melt 18 in the inner region of the inner crucible 12b and then pulling up the wire 22. A cylindrical heat shielding member 24 is provided to block heat radiation from the heater to the ingot 25. A feature of the present invention is that the silicon melt is pulled up from the silicon melt by the CZ method with a predetermined pulling speed profile based on Voronkov's theory. In general, C
When a silicon single crystal ingot is pulled from a silicon melt by the Z method, as a defect in the silicon single crystal, a point defect and an aggregate of point defects (aggl)
omerates: three-dimensional defects). Point defects have two general forms: vacancy type point defects and interstitial silicon type point defects. A vacancy-type point defect is one in which one silicon atom has separated from one of the normal positions in the silicon crystal lattice. Such holes become hole type point defects. On the other hand, if an atom is found at a position (interstitial site) other than the lattice point of the silicon crystal, this becomes an interstitial silicon point defect.

[0013] Point defects are generally formed at the interface between the silicon melt (molten silicon) and the ingot (solid silicon). However, by continuously pulling up the ingot, the portion that was the contact surface starts to cool down with pulling up. During cooling, vacancy-type point defects or interstitial silicon-type point defects merge with each other by diffusion to form vacancy agglomerates or interstitial agglomerates. Is formed. In other words, the aggregate is a three-dimensional structure generated due to the merging of point defects. Aggregates of vacancy-type point defects are LSTDs (Laser Scattering Tomograms) in addition to the COPs described above.
An agglomerate of interstitial silicon-type point defects includes a defect called an LD, which includes a defect called an aph defect or an FPD (Flow Pattern Defects). The FPD is a source of a trace exhibiting a unique flow pattern that appears when a silicon wafer produced by slicing an ingot is chemically etched with a Secco etchant for 30 minutes, and the LSTD is a silicon single crystal. When silicon is irradiated with infrared rays, it has a different refractive index from silicon and generates scattered light.

Boronkov's theory states that, in order to grow a high-purity ingot with a small number of defects, the pulling speed of the ingot is V (mm / min), and the temperature gradient at the contact surface between the ingot and the silicon melt is G (° C. / mm), V /
G (mm ² / min · ° C.). In this theory, as shown in FIG. 2, V / G is taken on the horizontal axis, and the vacancy-type point defect concentration and the interstitial silicon-type point defect concentration are set on the same vertical axis, and the V / G and the point defect concentration are compared. The relationship is schematically represented, and the boundary between the vacancy region and the interstitial silicon region is V / G
It is explained that it is determined by. More specifically, when the V / G ratio is equal to or higher than the critical point, an ingot having an increased vacancy type point defect concentration is formed, whereas when the V / G ratio is equal to or lower than the critical point, the ingot having an increased interstitial silicon type point defect concentration is formed. It is formed. In FIG. 2, [I] shows a region ((V / G) ₁ or less) where an interstitial silicon type point defect is dominant and an interstitial silicon type point defect aggregate is present.
[V] is a region ((V / G) ₂ where the vacancy type point defect in the ingot is dominant and the vacancy type point defect aggregate exists.
[P] indicates a perfect region ((V / G) ₁ to (V / G) ₂ ) where no aggregate of vacancy type point defects and no aggregate of interstitial silicon type point defects exist. An area [(V / V) adjacent to the area [P] has an area ((V /
G) ₂ to (V / G) ₃ ).

The predetermined pull rate profile of the present invention is such that when the ingot is pulled from the silicon melt,
The ratio of the pulling rate to the temperature gradient (V / G) is equal to or higher than the first critical ratio ((V / G) ₁ ) for preventing the generation of aggregates of interstitial silicon type point defects, and The agglomerates are determined to be maintained at or below a second critical ratio ((V / G) ₂ ) which limits the agglomerates to the region where the agglomerates of vacancy type point defects exist in the center of the ingot. The pulling speed profile is determined by simulation based on the above-described Boronkov theory by slicing the reference ingot in the axial direction experimentally or by combining these techniques. That is, after the simulation,
This is performed by confirming the axial slice of the ingot and the sliced wafer, and repeating the simulation. For the simulation, a plurality of kinds of pulling speeds are determined within a predetermined range, and a plurality of reference ingots are grown. As shown in FIG. 3, the pulling speed profile for the simulation is from a high pulling speed (a) such as 1.2 mm / min to a low pulling speed (c) of 0.5 mm / min and again a high pulling speed (d). It is adjusted to. The low pull rate may be 0.4 mm / min or less, and the change in pull rates (b) and (d) is preferably linear.

A plurality of reference ingots pulled at different speeds are individually sliced in the axial direction. Optimal V /
G is determined from the correlation of the results of the axial slicing, wafer validation and simulation, followed by the determination of the optimal pulling speed profile, which is used to produce the ingot. The actual pulling speed profile depends on many variables including but not limited to the desired ingot diameter, the chamber used and the quality of the silicon melt. Gradually lower the pulling speed to V /
Drawing a cross-sectional view of the ingot when G is continuously decreased and V / G is continuously increased by gradually increasing the pulling speed again, the fact shown in FIG. 4 can be understood. In FIG.
The region where the vacancy type point defect aggregates exist in the ingot is [V], the region where the interstitial silicon type point defect aggregates exist is [I], and the vacancy type point defect aggregates and lattices The perfect regions where no aggregates of inter-silicon type point defects are present are indicated as [P]. As shown in FIG.
Axial position P ₁ of the ingot contains a region that aggregates of vacancy type point defects at the center is present. Position P ₃ includes the ring area and the central perfect area where there are aggregates of interstitial silicon type point defects. The position P ₂ is a perfect region because there are no aggregates of vacancy-type point defects at the center and no aggregates of interstitial silicon-type point defects at the edges related to the present invention.

As is apparent from FIG. 4, a plurality of positions P
₁ and the wafer W ₁ and W ₆ respectively corresponding to the P ₆ includes a region in which agglomerates of vacancy type point defects at the center is present. Wafer W ₃ and W ₄ includes a ring and a central perfect area where there are aggregates of interstitial silicon type point defects. All the wafers W ₂ and W ₅ are perfect regions because there are no vacancy type point defects at the center and no interstitial silicon type point defects at the edges. The wafers W ₂ and W ₅ are manufactured by slicing an ingot grown with a pulling speed profile selected and determined so as to entirely form a perfect region as shown in FIG. FIG. 6 is a plan view thereof. For reference, wafers W ₁ and W ₆ produced by slicing an ingot grown with another pulling speed profile are shown in FIG.
Is shown in FIG. 8 is a plan view thereof.

The ingot of the present invention has a position P shown in FIG.
All ₂ and P ₅ is V / G are determined so that a perfect region [P], is pulled by the continuous pulling apparatus 10 shown in FIG. In this continuous pulling apparatus 10, since the silicon raw material is supplied in accordance with the growth amount of the ingot during the pulling, the melt depth of the silicon melt 18 and the crucible 12
Of the ingot does not change, and the temperature gradient G of the ingot can be kept constant. For this reason, only the V of the control condition V / G for creating the perfect region [P] is fixed and pulled up, so that the ingot can be made a perfect region [P] with high yield stably over the entire length.

Since the contact area between the crucible and the silicon melt does not change during the pulling, the oxygen concentration of the ingot can be made uniform over the entire length. Also, by applying a magnetic field in the horizontal direction to the silicon melt 18 by the electromagnet 20, convection of the silicon melt is suppressed, and the inner crucible 12b
Therefore, the amount of oxygen dissolved in the silicon melt can be further reduced, and the oxygen concentration of the ingot can be made uniform at a low concentration over the entire length. Furthermore, silicon raw material 21
In addition, by supplying the dopant in accordance with the segregation coefficient of the dopant, the amount of the dopant dissolved in the ingot becomes constant, and the resistivity of the ingot can be made uniform over the entire length.

[0020]

Next, examples of the present invention will be described together with comparative examples. <Embodiment 1> A silicon single crystal ingot 2 was supplied while supplying granular polycrystalline silicon and boron (B) as a dopant from a raw material supply pipe 14 using a continuous pulling apparatus 10 shown in FIG.
5 was raised. The diameter of the straight body of the ingot was 6 inches, and the length of the straight body was 1000 mm. Here, the silicon melt 1 in the inner region of the inner crucible 12b is pulled up.
8 is a region where the entire length of the ingot corresponds to the position P ₂ shown in FIG. 4, and V / G shown in FIG. 2 is (V / G) ₁ or more.
(V / G) It went so that it might fall in the ₂ or less area | region. A magnetic field (0.35 tesla) was applied to the silicon melt 18 in the horizontal direction by the electromagnet 20.

Comparative Example 1 A silicon single crystal ingot of the same shape and size as in Example 1 was pulled using a conventional batch type pulling apparatus (not shown). The same silicon raw material and quartz crucible as in Example 1 were used. The same boron dopant as in Example 1 was added to the quartz crucible of this apparatus as a dopant. In this apparatus, no magnetic field was applied to the silicon melt. Here pulling ingot total length from the silicon melt in the quartz crucible is an area corresponding to the position P ₂ shown in FIG. 4, the V / G shown in FIG. 2 (V / G) ₁ or (V / G) The operation was performed so as to enter the area of ₂ or less.

<Comparison Evaluation> FIG. 9 shows the temperature gradient in the vertical direction of the ingot at the contact surface between the silicon melt and the ingot in Example 1 and Comparative Example 1. FIG. 10 shows the pulling speeds of Example 1 and Comparative Example 1 when the pulling is performed so that V / G shown in FIG. 2 falls within the range of (V / G) ₁ or more and (V / G) ₂ or less. 9 and 10, both the temperature gradient and the pulling rate are relative values when the pulling rate when the crystal length is 0 mm is set to 1. As is clear from FIG. 9, the temperature gradient of Comparative Example 1 decreases with an increase in the crystal length, whereas the temperature gradient of Example 1 is constant over the entire length of the ingot. Further, as is apparent from FIG. 10, in order to create the perfect area [P], Comparative Example 1 was used.
In Comparative Example, the perfect region [P] could be stably formed at a constant pulling speed over the entire length of the ingot, whereas the pulling speed had to be reduced with an increase in the crystal length. Example 1 and Comparative Example 1
The ratio of the perfect region [P] in each ingot was examined. Table 1 shows the results.

[0023]

[Table 1]

As is evident from Table 1, the continuous CZ method of Example 1 has a higher yield of the perfect region than the batch CZ method of Comparative Example 1. Further, the oxygen concentration and the resistivity at the crystal parts in the pulling directions of Example 1 and Comparative Example 1 were measured. The results are shown in FIGS. As is clear from FIGS. 11 and 12, Comparative Example 1
The oxygen concentration and resistivity of Example 1 decreased significantly with an increase in crystal length, whereas the oxygen concentration and resistivity of Example 1 were almost constant even when the crystal length increased.

[0025]

As described above, according to the first aspect of the present invention, the silicon single crystal is pulled up while the silicon raw material is supplied in accordance with the growth amount of the ingot by the continuous pulling apparatus. The depth of the melt and the relative position of the crucible to the heater do not change, the temperature gradient G of the ingot can be kept constant, and the temperature gradient distribution in the radial direction can be fixed. Therefore, only the control condition V / G of the control condition V / G for creating the perfect area [P] is raised while being constant.
The ingot can be made into the perfect region [P] with high yield stably over the entire length. Further, since the contact area between the crucible and the silicon melt does not change during the pulling, the oxygen concentration of the ingot can be made uniform over the entire length. According to the invention according to claim 2, by applying a magnetic field in a horizontal direction to the silicon melt stored in the outer crucible during pulling of the ingot, convection of the silicon melt is suppressed, and the silicon melt is moved from the inner crucible. The amount of oxygen dissolved in the ingot can be further reduced, and the oxygen concentration of the ingot can be made uniform at a low concentration over the entire length. Further, according to the third aspect of the present invention, by supplying the dopant together with the silicon raw material in accordance with the segregation coefficient of the dopant, the resistivity of the ingot can be made uniform over the entire length.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a continuous pulling apparatus for a silicon single crystal used in a continuous pulling method of the present invention.

FIG. 2 is a diagram based on Bornkov's theory showing that when the V / G ratio is above the critical point, a vacancy-rich ingot is formed, and when the V / G ratio is below the critical point, an interstitial silicon-rich ingot is formed. .

FIG. 3 is a characteristic diagram showing a change in pulling speed for determining a desired pulling speed profile.

FIG. 4 is a schematic diagram of an X-ray topography showing a region where agglomerates of pores of a reference ingot according to the present invention exist, a region where an aggregate of interstitial silicon exists, and a perfect region.

FIG. 5 is an explanatory view of an ingot and a wafer in which no aggregate of vacancy type point defects and no aggregate of interstitial silicon type point defects of the present invention are present.

FIG. 6 is a plan view of the wafer.

FIG. 7 is an explanatory view of an ingot and a wafer having a hole-rich region in the center and a defect-free region between the hole-rich region and an edge portion of the wafer.

FIG. 8 is a plan view of the wafer.

FIG. 9 shows Example 1 and Comparative Example 1 when the crystal length is increased.
FIG. 3 is a diagram showing a change in a temperature gradient of FIG.

FIG. 10 is a diagram showing a change in pulling speed in Example 1 and Comparative Example 1 when the crystal length increases.

FIG. 11 is a diagram showing a change in oxygen concentration in Example 1 and Comparative Example 1 when the crystal length increases.

FIG. 12 is a diagram showing a change in resistivity of Example 1 and Comparative Example 1 when the crystal length increases.

FIG. 13A is a configuration diagram of a conventional batch type pulling apparatus in an initial stage of pulling. (B) The block diagram of the conventional batch type pulling apparatus in the final stage of pulling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Continuous silicon single crystal pulling apparatus 11 Chamber 12 Double crucible 12a Outer crucible 12b Inner crucible 13 Heater 14 Raw material supply pipe 18 Silicon melt 20 Electromagnet 21 Silicon raw material 25 Silicon single crystal ingot

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Ryuichi Endo 1-5-1, Otemachi, Chiyoda-ku, Tokyo Mitsui Material Silicon Co., Ltd. (72) Hisashi Furuya 1-5, Otemachi, Chiyoda-ku, Tokyo No. 1 Mitsubishi Materials Silicon Co., Ltd. F-term (reference) 4G077 AA02 BA04 EH07 EH09 EJ02 PF55 RA03 5F053 AA12 AA13 AA14 BB04 BB08 BB13 DD01 FF04 GG01 HH04 RR01 RR03

Claims (3)

[Claims] 1. A pulling speed of a silicon single crystal ingot (25) is V (mm / min), and a temperature gradient in a vertical direction of the ingot at a contact surface between the silicon melt (18) and the ingot (25) is G (° C.). / Mm), and the region where the aggregates of interstitial silicon type point defects exist in the ingot is [I]
When the region where the aggregates of the vacancy type point defects are present is [V], and the perfect region where the aggregates of the interstitial silicon type point defects and the aggregates of the vacancy type point defects are not present is [P]. And pulling the silicon single crystal ingot (25) composed of the perfect region [P] by the Czochralski method while controlling V / G to a constant value, wherein the silicon crucible (18) is stored in an outer crucible ( Ingot (25) of silicon raw material (21) between 12a) and inner crucible (12b)
The outer crucible (12a)
A point defect aggregate wherein the ingot (25) is pulled up from the inner region of the inner crucible (12b) while keeping the pulling speed V constant while rotating the ingot (25) about the pulling axial direction. Method of continuous pulling of silicon single crystal where no silicon exists. 2. The pulling crucible (1) while pulling up the ingot (25).
The continuous pulling method according to claim 1, wherein a magnetic field is applied in a horizontal direction to the silicon melt (18) stored in 2a). 3. The method according to claim 1, wherein the dopant is supplied together with the silicon raw material in accordance with the segregation coefficient of the dopant.
Or the continuous pulling method according to 2.