JP2000272997A - Growth of silicon single crystal and silicon wafer using the same and estimation of amount of nitrogen doped in the silicon wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for growing a silicon single crystal, making it possible to expand an OSF area on the whole surface of a wafer and inhibit the generation of a Grown-in defect in a simple production process. SOLUTION: In this method for growing a silicon single crystal by CZ method, the characteristic comprises doping the single crystal with nitrogen so that oxidation- induced stacking faults are generated on the whole surface of the wafer or so that the wafer surface comprises the oxidation-induced stacking faults, oxygen-depositing areas and, if necessary, further oxygen deposit-controlling areas, when a high temperature oxidation treatment is applied. The silicon single crystal is preferably grown at a pulling speed of 0.4 to 0.8 time the maximum pulling speed. In order to improve the electric characteristics of the silicon single crystal, the silicon single crystal is preferably grown in a crystal oxygen concentration of <=9×1017 atoms/cm3. It is preferable to apply a treatment for outward diffusing oxygen to the silicon wafer made from the silicon single crystal. The silicon wafer is cut out from the silicon single crystal grown by the CZ method and doped with the nitrogen, and generates the oxidation-induced stacking faults in a density of >=103/cm2 on the surface, when a high temperature oxidation treatment is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Detailed description of the invention]

[0002]

2. Description of the Related Art A silicon single crystal used as a material for a semiconductor integrated circuit is grown mainly by the Czochralski method (hereinafter referred to as "CZ method").

FIG. 1 is a schematic sectional view of a single crystal growing apparatus for explaining a method of growing a single crystal by the CZ method. As shown in FIG. 1, the crucible 1 includes an inner layer holding container 1a made of quartz and an outer layer holding container 1b made of graphite fitted to the outside of the inner layer holding container 1a. The crucible 1 having such a configuration is supported by a support shaft 1c that rotates at a predetermined speed, and a heater 2 is arranged concentrically on the outside of the crucible 1. The inside of the crucible 1 is filled with a melt 3 of a raw material melted by the heating of the heater 2, and a pulling shaft 4 made of a wire or the like is provided at the center of the crucible 1. A seed crystal 5 is attached to the tip of the pulling shaft 4, and the seed crystal 5 is brought into contact with the surface of the melt 3 to grow a single crystal 6. Further, by pulling the seed crystal 5 while rotating the pulling shaft 4 at a predetermined speed in a direction opposite to the crucible 1 rotated by the support shaft 1c,
The melt 3 is solidified at the tip of the seed crystal 5 to grow the single crystal 6.

The silicon single crystal thus grown is cut out to produce a silicon wafer, which is used for forming a highly integrated circuit. However, it is said that most of the causes of the failure of this highly integrated circuit are caused by particles. These particles are inspected by commercially available surface inspection equipment, but not only those that are generated from the process equipment alone or those that are generated by performing the actual process, but also the crystal defects that are generated during crystal growth. Is detected.

In recent years, semiconductor integrated circuit elements (devices)
Due to the rapid development of integration density of silicon wafers, the demands on the quality of silicon wafers are becoming more stringent. With the further miniaturization of design rules, it is required to strictly control particles on a production line. In order to ensure thorough particle management on the production line, not only product wafers but also dummy wafers used for particle monitoring are put into the line. Naturally, in the particle monitor wafer, it is required that crystal defects detected as particles by the surface inspection device have a low density.

When a silicon single crystal or a cut wafer manufactured by the CZ method is subjected to a high-temperature heat treatment in an oxidizing atmosphere, a ring-like oxidation-induced stacking fault (ring likely distributed oxidati) centered on the pulling axis of the single crystal.
on-induced stacking faults: Hereafter, "OSF ring"
May occur). In addition, several types of minute defects are formed in the plane, and these are crystal defects formed during the growth of the single crystal, and are called so-called Grown-in.
Called a defect.

In a single crystal in which an OSF ring has occurred, the crystal properties are different between an inner region and an outer region and are detected.
Grown-in defects are also different. In the region inside the OSF ring, there are 10 ⁵ to 10 ⁶ grown-in defects / c related to point defects (vacancies) that deteriorate the gate film breakdown voltage characteristics of the MOS device.
m ³ is present. This Grown-in defect is called COP and is based on an octahedral structure with a hollow interior. 0.35μ
For ULSI devices with design rules of m or less,
The COP causes not only the gate film breakdown voltage characteristic but also an element isolation failure.

On the other hand, in the region outside the OSF ring, as a Grown-in defect related to a point defect (interstitial silicon) which deteriorates the leakage current characteristics of the device, from 10 ³ to 10 ⁴ dislocation clusters /. There are about ³ cm3.

FIG. 2 is a diagram schematically showing a result obtained by cutting a grown silicon single crystal in parallel with a plane perpendicular to the pulling axis, performing a high-temperature oxidation treatment, and observing the crystal plane. There is a COP region at the center of the silicon single crystal, an OSF ring region extends outside the COP region, and an oxygen precipitation region is located outside the OSF ring region. Further, the oxygen precipitation suppressing region extends outside the oxygen precipitation region, and the dislocation cluster region extends toward the outermost periphery.

In the crystal plane shown in FIG. 2, in the OSF ring region, the oxygen precipitation region circumscribing the OSF ring region, and the oxygen precipitation suppression region, Grown-in defects are present in addition to the fine size or extremely low density oxygen precipitates. It is an area that does not. As described above, the OSF ring region is subjected to the oxidation treatment at a high temperature, resulting in an oxidation-induced stacking fault (Oxidation-induced stacking fault:
(Hereinafter simply referred to as “OSF”).
The nuclei are oxygen precipitates. However, in the state as grown before the high-temperature oxidation treatment, that is, in the state of as-grown, the OS
Since it is extremely difficult to directly detect a nucleus in the F-ring region, it is recognized as a region where no Grown-in defect is observed in the evaluation by the above-described surface inspection device.

The position where the OSF ring is generated is affected by the pulling rate during the growth, and the temperature gradient G from the melting point in the grown silicon single crystal to about 1300 ° C. is obtained. / G. Therefore, by setting the ∨ / G value to a predetermined range during the growth of the single crystal, the OSF ring can appear at an arbitrary position in the crystal plane.

As described above, since the OSF ring can be generated at an arbitrary position, a method of controlling the generation position to reduce the Grown-in defect which is generated concentrically on the wafer surface has been conventionally proposed. First, an OSF ring is generated on the outer peripheral portion of the wafer, and C is generated inside the OSF ring region.
As a method of reducing the density of OP, there is the following proposal.

In Japanese Patent Publication No. 3-80338, a heat treatment at 1100 ° C. or more is performed in a non-oxidizing atmosphere containing hydrogen gas immediately before a step of forming a thermal oxide film on the surface of a silicon wafer.
A method of extinguishing the surface COP has been proposed. Also,
Japanese Patent Laid-Open No. 10-208987 discloses that by increasing the defect density of COP, the defect size is reduced, and the reduced defects are eliminated by heat treatment. further,
Japanese Patent Application Laid-Open No. 10-098047 discloses a method of shifting the size distribution of COP to a smaller one by doping with nitrogen. However, in any of the above-described methods of reducing the COP, heat treatment is required to reduce defects, so that an increase in the number of steps is indispensable, resulting in an increase in manufacturing cost.

Further, no method has been established for verifying how much the added nitrogen concentration is doped in the grown crystal, and a problem remains in terms of guarantee. In particular, when doping with nitrogen gas, it is more difficult to grasp the doping amount than in a solid doping method in which a nitride is melted together with a silicon raw material.

On the other hand, there has been proposed a method in which an OSF ring is generated inside a wafer so that a defective portion is concentrated at a central portion or a defective portion is eliminated at the central portion.
However, in this method, since the pulling speed needs to be significantly reduced, productivity is reduced. Further, in terms of quality, there is a possibility that dislocation may occur due to contraction of the OSF ring inside the crystal.

Further, a method has been proposed in which an oxygen precipitation region and an oxygen precipitation suppression region located outside the OSF ring region are formed over the entire surface of the wafer and are also maintained in the direction of the crystal axis. However, in order to make this method effective, it is necessary to create a hot zone in which the defect distribution is uniform in the plane and to grow a crystal while strictly controlling the ∨ / G value. This makes it difficult to maintain workability.

[0017]

As described above, the position where the OSF ring is generated is controlled to reduce defects in the COP region and the OSF ring region, and to expand the oxygen precipitation region and the oxygen precipitation suppression region over the entire surface of the wafer. In this case, the number of steps is increased, which causes an increase in manufacturing cost and a problem that workability is significantly reduced. In particular, when used as a particle monitor wafer, it is necessary to make the production as simple as possible and to reduce the production cost without increasing the number of production steps.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and expands the OSF ring region over the entire surface of a wafer by a simple manufacturing process without increasing the manufacturing cost. An object of the present invention is to provide a silicon single crystal and a silicon wafer that can effectively suppress occurrence of in-defects.

[0019]

SUMMARY OF THE INVENTION A silicon single crystal wafer manufactured by the CZ method can be used in an oxidizing atmosphere at a temperature of 1000-1000.
When the high-temperature oxidation treatment is performed at 1200 ° C. for 1 to 20 hours, an OSF ring may be generated. OSF has stable nuclei of oxygen precipitates which are hardly extinguished even at a high temperature of 1200 ° C. or more, and is induced by the above-described high-temperature oxidation treatment. However, it is extremely difficult to detect OSF nuclei in an as-grown state immediately after growth without performing high-temperature oxidation treatment. In other words, as-gro
The OSF ring region in the wn state can be said to be a region where no Grown-in defect exists.

Normally, the OSF ring appearing on the wafer surface has a width of several to several tens of mm. However, the inventors of the present invention dope nitrogen into the OSF ring during the process of growing a single crystal by the CZ method. It is possible to increase the width,
It has been found that the entire surface of the wafer can be formed into an OSF region.

As described above, the OSF ring has a very small density of oxygen precipitates, but is a region in which other Grown-in defects hardly exist.
With the ring region, a wafer optimal for use as a particle monitor wafer can be obtained. In addition, an oxygen precipitation region exists outside the OSF ring region and an oxygen precipitation suppression region exists outside the OSF ring region. However, almost no Grown-in defects are detected in these regions. If there is, it is effective as a particle monitor wafer.

FIG. 3 is a diagram schematically showing a configuration of a wafer surface effective for use as a particle monitor wafer. 3 (a) shows a wafer having an OSF ring region extended over the entire surface, FIG. 3 (b) shows a wafer comprising an OSF ring region and an oxygen precipitation region circumscribing it, and FIG. 3 (c) shows an OSF ring region and an oxygen precipitation region. And a wafer comprising an oxygen precipitation suppression region. A wafer having the surface configuration shown in the figure is most suitable for monitoring particles, since almost no Grown-in defects are detected.

Furthermore, low-density oxygen precipitates present on the OSF ring can be reduced by reducing the oxygen concentration.
The induction of OSF is suppressed. Therefore, if the crystal growth is performed in a state where the oxygen concentration is low or the wafer is subjected to oxygen outward diffusion treatment to reduce the oxygen concentration, the electrical characteristics can be improved, and a silicon wafer having excellent device characteristics can be obtained. be able to.

Further, O generated when high-temperature oxidation treatment is performed
It was revealed that there is a good correlation between SF density and nitrogen doping amount. That is, the OSF density and the nitrogen doping amount have a positive correlation with each other, and it becomes possible to estimate the doping amount in the crystal by detecting the OSF density. In particular, it is effective for estimating the doping amount when gas is doped with nitrogen.

The present invention has been completed on the basis of the above findings, and has the following (1) a method for growing a silicon single crystal,
The gist is a method for estimating the amount of nitrogen doping in (2) and (3) and the amount of nitrogen doping in (4).

(1) In a method of growing a silicon single crystal by the CZ method, when a wafer is cut out from the grown single crystal and subjected to a high-temperature oxidation treatment, oxidation-induced stacking faults are generated on the entire surface of the wafer. Alternatively, the present invention is a method for growing a silicon single crystal, characterized by doping nitrogen into a single crystal so that the wafer surface is composed of an oxidation-induced stacking fault and an oxygen precipitation region, or an oxygen precipitation suppression region in addition to these regions.

In the above method for growing a silicon single crystal, when the maximum outer diameter of the grown crystal is Dmax and the minimum outer diameter is Dmin, it is expressed by (Dmax−Dmin) / Dmin × 100 (%). It is desirable to grow at a pulling rate of 0.4 to 0.8 times the maximum pulling rate, with the rate at which the crystal deformation rate becomes 1.5 to 2.0% as the maximum pulling rate. Furthermore, in order to improve the electrical characteristics, the concentration of oxygen contained in the crystal was 9 × 10 ¹⁷ atom
It is desirable to grow at s / cm ³ or less.

(2) A silicon wafer characterized by being cut out from a silicon single crystal manufactured by the growing method of (1). This silicon wafer is desirably subjected to an oxygen outward diffusion process in order to improve electrical characteristics.

(3) OSF induced by high-temperature oxidation
By measuring the density of the crystal, the amount of doping into the crystal can be easily grasped. Therefore, when the silicon single crystal grown by doping with nitrogen by the CZ method is cut out and subjected to a high-temperature oxidation treatment, A silicon wafer characterized in that oxidation-induced stacking faults of 10 ³ / cm ² or more occur.

(4) When a wafer cut from a silicon single crystal grown by doping with nitrogen by the CZ method is subjected to a high-temperature oxidation treatment, the density of oxidation-induced stacking faults detected on the wafer surface is determined. This is a method for estimating the amount of nitrogen doping in a silicon wafer, which is characterized by estimating the amount of doping.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, when a wafer is cut from a grown single crystal and subjected to a high-temperature oxidation treatment by doping nitrogen during the growth, the entire area of the wafer crystal plane is subjected to OS.
It is characterized by comprising a region made of F, an OSF and an oxygen precipitation region, or an oxygen precipitation suppression region in addition to these regions. At this time, the effect of expanding the OSF ring region appears when the nitrogen doping amount of the silicon single crystal is 1 × 10 ¹² atoms / cm ³ , but it is preferable that the amount be 1 × 10 ¹⁴ atoms / cm ³ or more. This is to sufficiently exert the effect of expanding the OSF ring region by adding nitrogen. Although the upper limit of the nitrogen doping amount is not particularly specified, it is preferable to set the upper limit to 5 × 10 ¹⁵ atoms / cm ³ , since dislocation is likely to occur when the concentration is extremely high.

Here, the concentration of nitrogen doped in the wafer is calculated from the amount of nitrogen doped into silicon before pulling, the distribution coefficient of nitrogen with the silicon melt and the solid phase, and the solidification rate of the crystal. That is, the initial nitrogen concentration C ₀ in silicon is calculated from the atomic weight of the raw material silicon and the number of added nitrogen atoms, and the nitrogen concentration C _N in the crystal is calculated by the following equation (a).

C _N = C ₀ k (1-x) ^{k -1} (a) In the above equation (a), k is a parallel segregation coefficient of nitrogen, and is 7 × 10
^-4 can be used. x is the solidification rate, expressed as the crystal pulling weight divided by the initial charge.

In general, when a single crystal is grown by high-speed pulling, an OSF ring appears on the outer peripheral portion of the wafer. When the OSF ring appears inside the wafer, the effect of expanding the OSF ring region by nitrogen doping can be effectively functioned. Therefore, OSF
Under pulling conditions where the ring appears at the outermost periphery of the wafer or outside the wafer, or the OSF ring disappears at the center, the effect of nitrogen doping is reduced. Therefore, in the present invention, it is desirable to assume a pulling condition in which the OSF ring is not located at the outermost periphery of the wafer or disappears at the center of the wafer.

Specifically, the maximum outer diameter of the grown crystal is
When Dmax and Dmin are the minimum outer diameter, (Dmax-Dmin)
/ Dmin × 100 (%) Crystal deformation rate is 1.5 ~ 2.0%
It is desirable that the growth be performed at a pulling speed of 0.4 to 0.8 times the maximum pulling speed, where the maximum pulling speed is the maximum pulling speed. By setting the lower limit of the pulling speed to 0.4 times the maximum pulling speed, the OSF ring does not disappear at the center. On the other hand, the upper limit of the pulling speed is 0.8
By doubling, it is located at the outermost periphery of the wafer,
In addition, there is no possibility that it goes out of the wafer.

When used as a monitor wafer, the concentration of oxygen contained in the crystal is not particularly specified.
By pulling up under conditions of low oxygen concentration, it becomes possible to reduce the nuclei of OSF. According to the study of the present inventors, a wafer in which the OSF ring region spreads over the entire surface and the oxygen concentration contained is 9 × 10 ¹⁷ atoms / cm ³ or less,
It shows that it has good electrical properties and can be used not only as a monitor wafer but also as a product wafer.

Further, even if a single crystal is grown at an oxygen concentration exceeding 9 × 10 ¹⁷ atoms / cm ³ , the generation of OSF is suppressed by subjecting the wafer to the oxygen outward diffusion treatment, and the electrical characteristics are reduced. Can be improved. The oxygen outward diffusion treatment here is a heat treatment for shrinking the size of the oxygen precipitate, as shown in the examples described later, 1200 ° C., and further 1300 ° C.
The above high temperature treatment is desirable.

Further, according to the study by the present inventors, the expected doping amount and the OS generated when high-temperature oxidation treatment is performed
It becomes clear that it has a good correlation with the F density. That is, by measuring the OSF density induced by the high-temperature oxidation treatment, the nitrogen doping amount in the crystal can be easily grasped. As a result of various studies from this point of view, in order to effectively exert the effect of expanding the OSF ring region by nitrogen doping, when high-temperature oxidation treatment is performed, oxidation-induced lamination of 10 ³ / cm ² or more on the wafer surface It is desirable that defects occur. This evaluation method is particularly effective for doping with nitrogen gas.

As the nitrogen doping method, a nitride is mixed in a raw material or a melt, a single crystal is grown while flowing nitrogen or a nitrogen compound gas in a furnace, or nitrogen is added to high-temperature polycrystalline silicon before melting. Any method may be used as long as it is a commonly used method such as spraying a gas or a nitrogen compound gas. Further, a single crystal pulling method by adding an FZ silicon crystal to which nitrogen is added as a raw material or a wafer having a silicon nitride film formed on its surface to raw silicon, or melting polycrystalline silicon in a nitrogen or nitrogen compound gas atmosphere Then, a method of adding nitrogen to the raw silicon, a method of growing a single crystal using a nitride crucible or a quartz crucible using nitrogen as a crucible can also be adopted.

[0040]

EXAMPLES In order to confirm the effects of the present invention, the following four experiments were performed.

(Example 1) Using a single crystal growing apparatus shown in FIG. 1, 100 kg of high-purity polycrystalline silicon was melted in a crucible, and boron was used as a doughant with a diameter of 200 mm and a crystal orientation of <10.
0> single crystal was grown. The pulling speed at the time of raising was 0.6 times or 0.9 times the maximum pulling speed. Oxygen concentration is 13-15
It was grown to be × 10 ¹⁷ atoms / cm ³ .

In order to examine the effect of adding nitrogen, a nitrogen gas was flowed into the furnace at a rate of 10 l / min from the point where the single crystal grew to 100 mm below the shoulder. A test piece was cut out from the grown single crystal in parallel to the crystal axis, and the temperature was 800 ° C × 4 hr + 1 in an oxygen atmosphere.
A thermal oxidation treatment at 000 ° C. × 16 hours was performed. Thereafter, X-ray topographic photographs were taken.

FIGS. 4A and 4B schematically show the results of observation with a topographic photograph. FIGS. 4A and 4B show the results obtained when nitrogen doping was performed at 0.6 or 0.9 times the maximum pulling speed. )
Shows the results when nitrogen was not doped at 0.9 times the maximum pulling rate. As shown in FIG. 3 (c), when the growth rate is 0.9 times the maximum pulling rate without nitrogen doping, the OSF ring is generated on the outer periphery of the single crystal.

As shown in FIG. 3A, in the crystal pulled at a rate 0.6 times the maximum pulling rate, the OS
It can be seen that the width of the F-ring increases and the entire surface gradually changes to a ring region. On the other hand, in FIG. 3B, when the pulling speed becomes 0.9 times the maximum pulling speed, the ring region does not show so large expansion despite the nitrogen doping. Therefore, even when nitrogen is doped, the pulling speed affects the expansion behavior of the OSF ring width.

Example 2 The same growth conditions as for the single crystal shown in FIG. 3A were used, that is, the pulling rate during growth was 0.6 times the maximum pulling rate, and nitrogen gas was flowed into the furnace at 10 l / min. To grow crystals. As a comparative example, a single crystal grown without flowing nitrogen gas was also prepared (Test No. 1).

From the grown single crystal, a wafer-shaped test piece was cut out in parallel with a plane perpendicular to the crystal axis, and G was cut using a commercially available surface inspection device (laser particle counter).
The density of the row-in defects was measured. Table 1 shows the results.
Shown in

[0047]

[Table 1]

As can be seen from Table 1, the nitrogen-doped crystal (Test No. 2) was the same as the nitrogen-doped crystal (Test No. 2).
The number of Grown-in defects is extremely low as compared to 1). From this, it can be said that a wafer in which the OSF ring region has spread over almost the entire surface is effective as a monitor wafer. further,
Perform a thermal oxidation treatment at 1100 ° C x 16Hr in an oxygen atmosphere,
The OSF density was measured, and the nitrogen-doped crystal (test N
In o.2), about 10 ⁴ / cm ² of OSF was counted.

Next, in order to confirm the effect of reducing oxygen,
The nitrogen-doped wafer was subjected to an oxygen outward diffusion treatment by a heat treatment at 1200 ° C. × 4 hours in an Ar atmosphere, and the density of Grown-in defects was measured. Then, at 1100 ° C in an oxygen atmosphere
A 16-hour thermal oxidation treatment was performed, and the OSF density was counted (Test No. 3). The results are also shown in Table 1, and it can be seen that the OSF density on the wafer surface is significantly reduced by performing the oxygen outward diffusion treatment. This means that the heat treatment can be sufficiently used not only for particle monitoring but also as a product wafer. This effect is also observed with inert gases other than Ar, hydrogen or nitrogen or a mixed gas thereof. Regarding the processing temperature, a higher temperature is more suitable, and 1300 ° C.
It is desirable that this is the case.

Example 3 In order to confirm the characteristics of a single crystal grown at a low oxygen level, the pulling speed during growth was set to 0.6 times the maximum pulling speed, and nitrogen gas was flowed into the furnace at 10 l / min. A crystal having an oxygen concentration of 8 × 10 ¹⁷ atoms / cm ³ was grown. The wafer cut out of this silicon single crystal was evaluated for Grown-in defect density using a commercially available surface inspection apparatus (laser particle counter). Further, a thermal oxidation treatment was performed at 1100 ° C. × 16 hours in an oxygen atmosphere, and the OSF density was measured (Test No. 4). Table 1 shows the results.

As is clear from Table 1, the crystal doped with nitrogen in Example 3 (Test No. 4) has a Grown-in defect and an OS in comparison with the crystal not doped with nitrogen in the comparative example (Test No. 1).
Both F are extremely low. In particular, OSF is hardly induced by the high-temperature oxidation treatment. From this, it can be seen that even in a wafer in which the OSF ring region has spread over the entire surface of the wafer, OSF is not induced when the oxygen concentration in the crystal is low.

Example 4 In the same manner as in Example 1, a single crystal was further grown using the growth apparatus shown in FIG. In order to make it easy to estimate the doping amount, a method is adopted in which a silicon wafer on which a nitride film is formed is charged together with a raw material, instead of the nitrogen gas doping method. Nitrogen concentration from 10 ¹³ to 10 ¹⁵ atom
The input amount of the wafer with the nitride film was adjusted so as to have various concentrations in the range of s / cm ³ .

From the grown single crystal, a wafer-shaped test piece was cut out in parallel with a plane perpendicular to the crystal axis, and the cut piece was placed in an oxygen atmosphere.
A thermal oxidation treatment was performed at 1100 ° C. for 16 hours. Then, after selective etching with a light etching solution for 2 minutes, the OSF density was measured with an optical microscope.

FIG. 5 shows the average OSF density measured up to a distance of 40 mm from the center of the wafer. From the figure,
As the doping amount increases, the OSF density increases.
It is clear that there is a good correlation between the F density and the nitrogen concentration of the charge. This indicates that by measuring the density of the OSF induced by the high-temperature oxidation treatment, it is possible to estimate the nitrogen concentration of the charge. Therefore, if OSF of 10 ³ / cm ² or more is counted on the wafer surface,
The nitrogen doping amount of the grown single crystal is 1 × 10 ¹⁴ atoms / cm ³
It can be estimated that this is the case.

[0055]

According to the silicon single crystal and the silicon wafer of the present invention, the OSF ring region can be expanded over the entire surface of the wafer by a simple manufacturing process without increasing the manufacturing cost, and the generation of a grown-in defect can be achieved. Can be effectively suppressed. As a result, an optimal wafer for particle monitoring can be provided, and by reducing the concentration of oxygen contained, the wafer can be sufficiently used as a product wafer.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a single crystal growing apparatus illustrating a single crystal growing method by a CZ method.

FIG. 2 is a view schematically showing a result obtained by cutting a grown silicon single crystal in parallel with a plane perpendicular to a pulling axis, performing a high-temperature oxidation treatment, and observing a crystal plane.

FIG. 3 is a diagram schematically showing a configuration of a wafer surface effective for use as a particle monitor wafer.

FIGS. 4A and 4B schematically show the results of observation with topographic photographs, wherein FIGS. 4A and 4B show the results when nitrogen is doped, and FIG. 4C shows the results when nitrogen is not doped. .

FIG. 5 is an average of OSF densities measured up to a distance of 40 mm from the center of the wafer.

[Explanation of symbols]

 1: Crucible, 1a: Inner layer holding container 1b: Outer layer holding container, 1c: Support shaft 2: Heater, 3: Melt 4: Pull-up shaft, 5: Seed crystal 6: Single crystal

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masataka Horai 2201 Kamioda, Kokita-cho, Kishima-gun, Saga Prefecture Sumitomo Metal Industries Co., Ltd. Sichix Business Unit F-term (reference) 4G077 AA02 AB01 BA04 CF00 EB01 EB04 EB05 EH04 EH05 EH09 FB01 FE01 FE03 HA12 PA06 4M106 AA01 CB03 CB19 DB01 DJ32

Claims (8)

[Claims] In a method for growing a silicon single crystal by the Czochralski method, when a wafer is cut out from the grown single crystal and subjected to a high-temperature oxidation treatment, oxidation-induced stacking faults are generated on the entire surface of the wafer. A method for growing a silicon single crystal, comprising doping nitrogen into the single crystal. 2. A method for growing a silicon single crystal by the Czochralski method, wherein when a wafer is cut out from the grown single crystal and subjected to a high-temperature oxidation treatment, the wafer surface has an oxidation-induced stacking fault and an oxygen precipitation region; Alternatively, a method for growing a silicon single crystal, characterized by doping nitrogen into a single crystal so as to comprise an oxygen precipitation suppressing region in addition to these regions. 3. When the maximum outer diameter of the grown crystal is Dmax and the minimum outer diameter is Dmin, (Dmax−Dmin) / Dmin × 100
The rate at which the crystal deformation rate expressed in (%) is 1.5 to 2.0% is defined as the maximum pulling rate, and 0.4 times or more of this maximum pulling rate.
3. The method for growing a silicon single crystal according to claim 1, wherein the silicon single crystal is grown at a pulling rate of 0.8 times. 4. The method according to claim 1, wherein the concentration of oxygen contained in the crystal is 9 × 10 ¹⁷ at.
The method for growing a silicon single crystal according to claim 1, wherein the silicon single crystal is grown at oms / cm ³ or less. 5. A silicon wafer cut from a silicon single crystal produced by the method for growing a silicon single crystal according to claim 1. 6. The silicon wafer according to claim 5, wherein an oxygen outward diffusion process is performed. 7. Oxidation-induced stacking faults of 10 ³ / cm ² or more are cut out of a silicon single crystal grown by doping with nitrogen by the Czochralski method and subjected to a high-temperature oxidation treatment. A silicon wafer characterized by the above-mentioned. 8. When a high-temperature oxidation treatment is performed on a wafer cut out of a silicon single crystal grown by doping nitrogen with the Czochralski method, the density is based on the density of oxidation-induced stacking faults detected on the wafer surface. A method for estimating the amount of nitrogen doping in a silicon wafer by estimating the amount of doping using a silicon wafer.