JP2015101521A - Method of manufacturing semiconductor crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor crystal by an FZ method capable of acquiring a crystal which has desired electric resistivity and also has the desired electric resistivity entirely in a growth axis direction of one crystal rod.SOLUTION: There is provided a method of manufacturing a semiconductor crystal by an FZ method including a process of forming a straight trunk part of the semiconductor crystal while blowing a dopant gas to a molten zone and controlling electric resistivity. A plurality of parameters which affect the electric resistivity are measured in advance during the process of forming the straight trunk part, and electric resistivity of a manufactured semiconductor crystal is measured; and a multivariate analysis of an influence of the plurality of parameters on the electric resistivity is taken so as to find a dopant supply amount adjustment coefficient based upon the result of the multivariate analysis. Then, when the semiconductor crystal is manufactured by the FZ method, a dopant supply amount is adjusted during the process of forming the straight trunk part according to the found dopant supply amount adjustment coefficient.

Description

  The present invention relates to a method for producing a semiconductor crystal by FZ method (floating zone method or floating zone melting method).

  The FZ method is used, for example, as one method for manufacturing a semiconductor single crystal such as a silicon single crystal that is most frequently used as a semiconductor element. FIG. 4 is a diagram for explaining an example of each manufacturing process in the semiconductor crystal manufacturing method by the FZ method. As shown in FIG. 4, a lower end portion of a semiconductor rod 54 as a raw material is melted and fused to a seed crystal 55 (a seeding step), and further, dislocations generated in the crystal during this seeding are removed. Drawing (necking) is performed (b necking step), and thereafter the crystallization side semiconductor rod 59 is grown while being expanded to a desired diameter (c cone portion forming step). Further, growth is performed while controlling the crystallization side semiconductor rod 59 to a desired diameter (d straight body portion forming step), supply of raw materials is stopped, and the diameter of the crystallization side semiconductor rod 59 is reduced to reduce the crystallization side. The semiconductor rod is separated from the raw material semiconductor rod 54 (e separation step). A semiconductor crystal (FZ silicon single crystal) can be manufactured through the above steps.

  In general, N-type or P-type impurity doping is required to give a desired electrical resistivity to a silicon single crystal. In the FZ method, a gas doping method in which a dopant gas is blown into a melting zone is known (see Non-Patent Document 1).

As the dopant gas, for example, PH ₃ or the like is used for doping P (phosphorus) which is an N-type dopant, and B ₂ H ₆ or the like is used for doping B (boron) which is a P-type dopant. The electrical resistivity of the silicon single crystal varies depending on the concentration difference in the crystals of these N-type and P-type dopants, but when doping only the N-type dopant or only the P-type dopant in normal crystal production, The electrical resistivity decreases as the dopant supply increases.

  In order to obtain a silicon single crystal having a desired electrical resistivity, it is necessary to maintain an appropriate amount of dopant supplied based on the electrical resistivity of the raw material and the desired electrical resistivity. An FZ silicon single crystal having a desired electrical resistivity can be obtained by growing the single crystal by the FZ method while adjusting the concentration and flow rate of the supplied dopant gas to keep the dopant supply amount appropriate. .

  As a device of a gas doping method for obtaining an FZ single crystal having a desired electric resistivity, a plurality of electric resistivity portions are integrated into one single crystal rod by changing the doping gas concentration during the production of one semiconductor crystal rod. Method of manufacturing multi-doped FZ single crystal rod to be formed (Patent Document 1), FZ method of changing dope gas flow rate according to change in electrical resistivity in growth axis direction of raw material rod when using CZ silicon single crystal as raw material rod (Patent Document 2), a method (Patent Document 3) and the like of changing a dopant supply amount according to a crystal growth state during manufacture of an FZ single crystal straight body portion have been proposed.

Japanese Patent No. 2617263 JP 2008-87984 A Japanese Patent No. 4957600

“Floating-Zone Silicon” by WOLFGAN KELLER, ALFRED MUHLBAUER, p. 82-92, MARCEL DEKKER, INC. Issue

  Conventionally, in a straight body forming process in which the crystal growth state is substantially constant, the amount of dopant supplied in the straight body forming process is kept constant without changing, so that the FZ silicon single crystal to be manufactured can have a desired electric power. It was thought that it could be resistivity. Alternatively, in actual FZ single crystal production, the growth state during crystal growth is not completely constant, and even if there is a change, the amount of dopant supplied is changed in accordance with the change in the crystal growth state (independent of the production equipment, etc.) It was considered that an FZ silicon single crystal having a substantially constant desired electrical resistivity can be obtained over the entire growth axis direction of one crystal rod by adopting the same adjustment method.

  However, when considering actual production and production, there is a difference in the crystal production state due to the FZ single crystal production machine and the materials used, or a difference in the crystal production state due to changes over time. However, with all the same adjustments, the degree of adjustment and the deviation required during the crystal production may actually occur.

  The present invention has been made in view of such circumstances, and is an FZ method capable of obtaining a crystal having a desired electrical resistivity and a desired electrical resistivity over the entire growth axis direction of one crystal rod. An object of the present invention is to provide a method for producing a semiconductor crystal.

In order to solve the above problems, in the present invention, in the method of manufacturing a semiconductor crystal by the FZ method, including the step of forming the straight body portion of the semiconductor crystal while controlling the electrical resistivity while blowing the dopant gas to the melting zone,
In advance, during the straight body forming step, a plurality of parameters affecting the electrical resistivity are measured, the electrical resistivity of the manufactured semiconductor crystal is measured, and the influence of the plurality of parameters on the electrical resistivity is multivariate Analyzing and determining the dopant supply adjustment factor based on the results of the multivariate analysis, and then manufacturing the semiconductor crystal by the FZ method, depending on the obtained dopant supply adjustment factor, Provided is a method for producing a semiconductor crystal, characterized in that a dopant supply amount is adjusted during a part forming step.

  As described above, during the straight body forming process, the dopant supply amount is appropriately set based on the coefficient obtained in advance by the multivariate analysis for the change of a plurality of parameters while being based on the preset dopant supply amount. If adjusted, even if the parameter between batches changes suddenly, the fluctuation of the dopant concentration in the crystal is suppressed, and the electric resistivity is almost constant at a desired value over the entire growth axis direction of one crystal rod. It becomes possible to manufacture a semiconductor crystal.

  Preferably, the plurality of parameters are any two or more of a neck diameter, a melt diameter, a zone length, a crystal temperature, and an upper axis speed.

  Thus, as the plurality of parameters for setting the dopant supply amount adjustment coefficient, it is preferable to use any two or more of the above-described parameters that have a large influence on the resistivity.

  In addition, the dopant supply amount adjustment coefficient is accumulated each time the data obtained in a plurality of batches of the plurality of parameters and the electrical resistivity, and newly multivariate analysis is performed using the accumulated data. It is preferable to update.

  FZ crystal production is generally performed in a batch mode. In this way, instead of data for a single batch, in this way, data obtained in a plurality of batches are accumulated, and a re-calculation of the dopant supply amount adjustment coefficient is performed every time, so that any time that is recognized or not recognized is recognized. Even if there is a change in the crystal production state due to change, replacement of the member, etc., and there is a change in the relationship between each parameter and the electrical resistivity of the obtained crystal, it is possible to appropriately adjust the dopant supply amount accordingly, A crystal having a desired electrical resistivity can be obtained stably.

  Preferably, the dopant supply amount adjustment coefficient is determined by weighting a parameter having a strong correlation with the electrical resistivity among the plurality of parameters.

  In this way, the variation generated between batches can be further reduced.

  The semiconductor crystal is preferably a silicon single crystal.

  According to the method for producing a semiconductor crystal of the present invention, a silicon single crystal having an electric resistivity of almost a desired value over the entire growth axis direction can be produced easily and stably.

  According to the present invention, in the semiconductor crystal manufacturing method using the FZ method, at least during the straight body forming step, the supply amount of the dopant supplied to the crystallization side semiconductor crystal is controlled according to the change in the crystal growth state. Since the growth is performed, it is possible to easily obtain a semiconductor crystal having a desired axial profile that is substantially constant over the entire length without fluctuation in electric resistivity in the crystal growth axis direction. In particular, by adjusting the dopant supply amount based on the results of multivariate analysis, the dopant supply amount can be adjusted in accordance with the manufacturing apparatus to be used and the manufacturing conditions. This prevents, for example, the occurrence of a portion in the semiconductor crystal where the electrical resistivity is outside the desired range and becomes unusable, and improves the yield and productivity in the manufacturing process, resulting in improved semiconductor single crystal supply stability. Is also possible.

It is the schematic of an example of the semiconductor crystal manufacturing apparatus used for the manufacturing method of the semiconductor crystal of this invention. It is the figure which showed only the inside of the chamber of the semiconductor crystal manufacturing apparatus in FIG. It is an enlarged view of the melting zone vicinity in the manufacturing method of the semiconductor crystal by FZ method. It is a figure explaining an example of each manufacturing process in the manufacturing method of the semiconductor crystal by FZ method. It is a graph which shows the comparison of the electrical resistivity of an Example and a comparative example.

  In the straight body part formation process of the conventional FZ silicon single crystal manufacturing process, when crystal growth is performed while controlling the diameter of the FZ silicon single crystal to a desired diameter, the quality is uniform throughout the entire crystal straight body part to be manufactured. In order to stabilize, crystal production conditions such as crystal movement speed and crystal rotation speed are not changed as much as possible, and constant conditions are used. Here, with respect to the single crystal growth state in the straight body part forming step, if the crystal growth state such as the crystal diameter and the length of the melting zone during crystal growth is kept constant, the dopant supply amount in the straight body part forming step With respect to the above, by making it constant without changing, the FZ silicon single crystal to be manufactured can have a desired electrical resistivity, and even if the crystal growth state during crystal growth is not constant and fluctuates, By controlling the amount of dopant supplied in accordance with the change of the crystal growth state during crystal growth (all the same control independent of the manufacturing equipment etc.), the electrical resistivity is increased over the entire growth axis direction of one crystal rod. It was thought that crystals with a substantially constant value could be obtained.

  However, when the present inventors investigated actual FZ single crystal production, a difference in crystal production state due to the FZ single crystal production machine / used member, or a difference in crystal production state due to changes over time, occurs. It has been found that the adjustment amount of the supply amount is not uniform, and if the adjustment is the same for all, the adjustment degree and deviation necessary for the crystal production may actually occur.

  As a result of diligent investigations to address the above problems, the present inventors have an influence on electrical resistivity during crystal growth (during the straight body forming process) in the production of semiconductor crystals by the FZ method. And measuring the electrical resistivity of the FZ crystal obtained by the crystal growth. From these data, the influence of each parameter on the resistivity is obtained by multivariate analysis. By determining the dopant supply amount adjustment coefficient when controlling the dopant supply amount to be supplied according to the change in the crystal growth state, a crystal having a desired electrical resistivity over the entire growth axis direction of one crystal rod can be obtained. It came to invent the manufacturing method of the semiconductor crystal which can be acquired.

Hereinafter, the present invention will be described more specifically, but the present invention is not limited thereto.
First, FIG. 1 is a schematic view of an example of a semiconductor crystal manufacturing apparatus used in the semiconductor crystal manufacturing method of the present invention. As shown in FIG. 1, a semiconductor crystal manufacturing apparatus 1 used in a method for manufacturing a semiconductor crystal according to the present invention includes a mixed dopant gas doping nozzle 20 (mixed dopant gas supply means 20), an Ar gas supply pipe 22 (Ar gas supply means). 22) and a concentrated dopant gas supply pipe 24 (a concentrated dopant gas supply means 24), and the Ar gas supplied from the Ar gas supply means 22 is supplied with the concentrated dopant gas supplied from the concentrated dopant gas supply means 24. The mixed dopant gas diluted in (1) can be supplied into the chamber 11 of the manufacturing apparatus by the mixed dopant gas supply means 20. Moreover, it has the gas supply control means (The mixed dopant gas supply control means 21, Ar gas supply control means 23, the rich dopant gas supply control means 25) which controls each gas supply means.

  Further, the semiconductor crystal manufacturing apparatus 1 includes a crystal manufacturing condition control unit 26 that controls crystal manufacturing conditions, a detection unit 27 that detects a crystal growth state, and a controller 28 that gives a signal to each control unit. Here, a plurality of crystal production condition control means 26 for controlling the crystal production conditions can be provided for the crystal production conditions to be controlled such as the power supplied to the high-frequency coil 16, the upper shaft speed, and the drive circuit. Similarly, a plurality of controllers 28 that provide signals to the respective control means can be provided depending on the type of signal transmitted, the control means that provides the signals, and the like.

  Next, FIG. 2 is a view showing only the inside of the chamber 11 of the semiconductor crystal manufacturing apparatus 1 shown in FIG. An upper shaft 12 and a lower shaft 13 are provided in the chamber 11. A semiconductor rod (raw material crystal) having a predetermined diameter is attached to the upper shaft 12 as a raw material semiconductor rod 14, and a seed crystal 15 is attached to the lower shaft 13. Further, the high-frequency coil 16 for melting the raw material semiconductor rod 14 is provided, and the crystallization side semiconductor rod (silicon single crystal) 9 can be grown while moving the melting zone 18 relative to the raw material semiconductor rod 14. Further, the dopant gas can be supplied from the mixed dopant gas doping nozzle 20 (mixed dopant gas supply means 20) during the growth.

  With such a characteristic configuration, the semiconductor crystal manufacturing apparatus 1 has a straight body portion 19 of a crystallization side semiconductor rod (silicon single crystal) 9 that crystallizes from a melting zone 18 formed by melting the raw material semiconductor rod 14. In accordance with the change in the crystal growth state detected by the detecting means 27, one or more of an Ar gas supply amount, a concentrated dopant gas supply amount, and a mixed dopant gas supply amount is selected as the gas supply control means. By controlling with (mixed dopant gas supply control means 21, Ar gas supply control means 23, concentrated dopant gas supply control means 25), the amount of dopant supplied to the crystallization side semiconductor rod is controlled.

  For example, the semiconductor crystal manufacturing apparatus shown in FIGS. 1 and 2 can be used in the semiconductor crystal manufacturing method according to the present invention. First, for example, a silicon polycrystalline rod having a predetermined diameter is attached to the upper shaft 12 as a raw material semiconductor rod 14, and a seed crystal 15 is attached to the lower shaft 13. After the raw material semiconductor rod 14 is melted by the high frequency coil 16 or the like, it is fused to the seed crystal 15. The crystallization-side semiconductor rod 9 grown from the seed crystal is made dislocation-free by the restriction 17 and is lowered relatively while rotating both axes, so that the melting zone 18 is moved upward relative to the raw material semiconductor rod 14. While growing, the crystallization side semiconductor rod 9 is grown.

  After forming the aperture 17, the crystallization side semiconductor rod 9 grown from the seed crystal is grown while being expanded to a desired diameter to form the cone portion 10, and the raw material semiconductor rod 14 and the crystallization side semiconductor rod 9 are formed. A melt zone 18 is formed between the crystallization side semiconductor rod 9 and the crystallization side semiconductor rod 9 while growing to a desired diameter to form a straight body portion 19.

  Here, during the step of forming the straight body portion 19, the amount of dopant supplied to the crystallization side semiconductor rod is controlled in accordance with the change in the crystal growth state. The dopant is added during growth, for example, by supplying a dopant gas from the dope nozzle 20 to the melting zone, so that the crystallization-side semiconductor rod 9 having a desired electrical resistivity can be obtained. This dopant gas is preferably a mixed dopant gas of rich dopant gas and Ar gas.

  Then, the melting zone 18 is moved to the upper end of the raw material semiconductor rod 14 to complete the growth of the straight body portion of the crystallization side semiconductor rod 9, and the diameter of the crystallization side semiconductor rod 9 is reduced to reduce the crystallization side semiconductor rod. 9 is separated from the raw material semiconductor rod 14 to manufacture a semiconductor crystal.

  As a method of controlling the amount of dopant supplied to the crystallization side semiconductor rod in accordance with the change of the crystal growth state, for example, from the crystal growth state detected by the detection means 27, the concentrated dopant gas flow rate, Ar gas flow rate, mixed dopant gas flow rate The supply amount of the dopant can be controlled by changing the flow rate and / or concentration of the supplied dopant gas by applying feedback to any one or more.

  The method for producing a semiconductor crystal according to the present invention includes a step of forming a straight body portion of a semiconductor crystal while controlling the electrical resistivity while spraying a dopant gas to the melting zone as described above, and a method for producing a semiconductor crystal by the FZ method. In this method, a semiconductor crystal is manufactured by adjusting the dopant supply amount during the straight body forming step in accordance with the dopant supply amount adjustment coefficient obtained in advance.

A method for determining the dopant supply amount adjustment coefficient is shown below.
First, a semiconductor crystal in which a plurality of parameters affecting the electrical resistivity are measured in advance during the straight body forming step, and the electrical resistivity of the semiconductor crystal is measured. Next, multivariate analysis of the influence of a plurality of parameters on the measured electrical resistivity is performed. Based on the result of this multivariate analysis, a dopant supply amount adjustment coefficient is determined.

  With such a manufacturing method, even if the parameter between batches changes suddenly, the fluctuation of the dopant concentration in the crystal is suppressed, and the electrical resistivity is almost the desired value over the entire growth axis direction of one crystal rod. It becomes possible to manufacture a semiconductor crystal. Further, by adjusting the dopant supply amount based on the result of multivariate analysis, the dopant supply amount can be adjusted in accordance with the manufacturing apparatus to be used and the manufacturing conditions.

  FIG. 3 is an enlarged view of the vicinity of the melting zone in the semiconductor crystal manufacturing method by the FZ method. The plurality of parameters affecting the electrical resistivity include, for example, the diameter (neck diameter) Dn of the crystallization side melt neck in the melting zone in FIG. 3, and the distance between the crystallization side melt neck and the crystallization interface 110. The diameter (melt diameter) Dm of the crystallization-side melt shoulder portion, and the length (zone length) L of the melting zone from the lower surface 111 of the high-frequency coil 16 to the crystallization interface 110 can be exemplified. Also, the temperature of the melting zone (crystal temperature) and the upper shaft speed (raw material supply speed) can be used as parameters. These parameters can be used particularly suitably as a plurality of parameters for setting the dopant supply amount adjustment coefficient. The definitions of the neck diameter, melt diameter, zone length, crystal temperature and the like are not necessarily limited to the case of FIG. If there is a correlation with these parameters, the definition can be changed and used as appropriate for the convenience of measurement.

  Moreover, it is preferable that the semiconductor crystal manufactured with the manufacturing method of the semiconductor crystal of this invention is a silicon single crystal.

  Here, the detail of the determination method of the coefficient used for dopant supply amount control in this invention is demonstrated. In order to obtain a crystal having a desired electrical resistivity, it is necessary to supply a difference between the amount of dopant corresponding to the desired electrical resistivity and the amount of dopant supplied from the raw material semiconductor rod using a dopant gas. At this time, the dopant supplied by the dopant gas injected from the dope nozzle is not entirely introduced into the crystallization side semiconductor rod, and a certain amount of loss is expected. At this time, the ratio of (the amount of introduced dopant / the total amount of dopant injected and supplied from the nozzle) is defined as the transfer rate.

  That is, the amount of dopant supplied from the dope nozzle is (amount of additional dopant necessary to obtain a desired electrical resistivity / a preset transition rate). The set transition rate is determined by feedback based on the crystal production results, and is a value that is almost unchanged under the same production conditions.

  The fact that the electrical resistivity varies in the crystal growth axis direction due to the change in the state during the FZ crystal growth can be regarded as the transition rate changing due to the change in the crystal growth state. For this reason, recalculation as needed during crystal growth by using a numerical value obtained by multiplying the set transfer rate by a coefficient (dopant supply adjustment coefficient) k corresponding to the change in the crystal growth state, using the transfer rate during FZ crystal growth as a variable. While supplying a feedback to any one or more of the rich dopant gas flow rate, Ar gas flow rate, and mixed dopant gas flow rate, the dopant supply amount is controlled by changing the flow rate and / or concentration of the supplied dopant gas. . In this way, it is possible to supply a dopant amount according to the crystal growth state at that time, and the electrical resistivity of the obtained crystal becomes substantially constant in the crystal growth axis direction.

  K at this time is defined as a function f (A, B, C,...) Related to parameters A, B, C,. Here, it seems that the original function f can be unified into a universal one, but in actual crystal growth, the numerical value of each parameter varies depending on differences (individual differences) in manufacturing equipment and materials. Even if the function f which has a proven record in the manufacturing facility is applied, an optimal one cannot always be obtained.

  Therefore, for example, data is collected continuously for a plurality of parameters during the FZ crystal growth for each manufacturing facility. Moreover, the actual data of the electrical resistivity of the FZ crystal acquired by the corresponding crystal growth is converted into the transition rate in the crystal growth axis direction. The effect of the variation of each parameter on the change of the transition rate based on the change of the electrical resistivity in the crystal growth axis direction is obtained by multivariate analysis, and the function f is derived. When the functions f thus obtained are used, an adjustment coefficient k suitable for each manufacturing facility can be obtained.

  Furthermore, even in the same manufacturing facility, the necessary degree of adjustment may change due to changes over time. For this reason, FZ crystal production data (multiple parameters and electrical resistivity data) are accumulated in the most recent appropriate range (multiple batches), and a new multivariate analysis is performed using the accumulated data. It is effective to update the adjustment coefficient k each time. If the data storage range in this case is small, adjustment according to the state at that time is possible, but if it is too small, the variation in adjustment increases. If the data storage range is large, the adjustment variation is stable, but if it is too large, the adjustment may not be suitable for the state at that time. What is necessary is just to determine suitably with a manufacture state.

  In addition, among the multiple parameters, the dopant supply adjustment coefficient is determined by weighting parameters that have a strong correlation with the electrical resistivity, that is, by increasing the weight of those that have a large correlation with the transition rate deviation. It is preferable to do. In this way, the adjustment becomes more suitable.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these Examples.

  In the production of a silicon single crystal having a crystal diameter of 200 mm, a conductivity type N type, and a target electric resistivity of 50 Ωcm, a dopant according to the method of adjusting the amount of supplied dopant according to the present invention (Example) and not depending on the variation of the neck diameter In the case of the supply amount adjustment method (comparative example), FZ single crystals were manufactured and 10 crystals were obtained each. The electrical resistivity in the direction of the crystal growth axis of the manufactured silicon single crystal was measured, and the degree of change was compared.

(Example)
From the data for 5 batches of FZ crystal growth, data at each time point during crystal growth of the parameters of neck diameter, zone length, and melt diameter were obtained. Also, the transition rate in the growth axis direction converted from the axial electrical resistivity of the acquired crystal of each batch is acquired, and multivariate analysis is performed using the three parameter data, and the function f used for the dopant supply amount adjustment coefficient k. Was determined as follows.
f [migration rate deviation = A × neck diameter deviation + B / zone length deviation + C × melt diameter deviation + D (constant)]
Here, each coefficient in the equation is as follows.
A: -0.003
B: 2.65
C: -13.42
D: -2.65
The straight body portion was formed at a mixed dopant gas flow rate multiplied by the dopant supply amount adjustment coefficient k determined as described above.

(Comparative example)
From the data for 5 batches of FZ crystal growth, acquire the data at each point during the crystal growth of the neck diameter and the transfer rate in the growth axis direction converted from the axial electrical resistivity of the acquired crystal of each batch, and supply the dopant amount A function f used for the adjustment coefficient k was determined as follows.
f [Transition rate deviation = 0.053 x neck diameter deviation]
The straight body portion was formed at a mixed dopant gas flow rate multiplied by the dopant supply amount adjustment coefficient k determined as described above.

  Table 1 and FIG. 5 show a comparison of electrical resistivity between (Example) and (Comparative Example). The axial resistivity deviation in Table 1 represents the standard deviation σ. FIG. 5 is a graph showing a comparison of electrical resistivity between the example and the comparative example.

  As shown in Table 1 and FIG. 5, when the gas doping control method in the semiconductor crystal manufacturing method of the present invention is used (Example), compared with the case where it is not used (Comparative Example), the crystal growth axis direction is higher. The uniformity of electrical resistivity was improved.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.
For example, in the above, changes in the melt zone length (zone length), melt diameter, and neck diameter have been adopted as parameters used for multivariate analysis. The amount of dopant supply may be controlled according to the combination.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor crystal manufacturing apparatus, 9, 59 ... Crystallization side semiconductor rod (silicon single crystal),
10 ... cone section, 11 ... chamber, 12 ... upper shaft, 13 ... lower shaft,
14, 54 ... Raw material semiconductor rod, 15, 55 ... Seed crystal, 16 ... High frequency coil,
17 ... Drawing, 18 ... Melting zone, 19 ... Straight body,
20 ... Mixed dopant gas dope nozzle (mixed dopant gas supply means),
21 ... Mixed dopant gas supply control means,
22 ... Ar gas supply pipe (Ar gas supply means), 23 ... Ar gas supply control means,
24 ... Rich dopant gas supply pipe (rich dopant gas supply means),
25 ... Concentrated dopant gas supply control means, 26 ... Crystal production condition control means,
27 ... detection means, 28 ... controller, 110 ... crystallization interface,
111 ... lower surface of the high frequency coil, Dm ... melt diameter,
Dn ... neck diameter, L ... zone length.

Claims (5)

In the method of manufacturing a semiconductor crystal by the FZ method, including the step of forming a straight body portion of the semiconductor crystal while controlling the electric resistivity while blowing the dopant gas to the melting zone,
In advance, during the straight body forming step, a plurality of parameters affecting the electrical resistivity are measured, the electrical resistivity of the manufactured semiconductor crystal is measured, and the influence of the plurality of parameters on the electrical resistivity is multivariate Analyzing and determining the dopant supply adjustment factor based on the results of the multivariate analysis, and then manufacturing the semiconductor crystal by the FZ method, depending on the obtained dopant supply adjustment factor, A method for producing a semiconductor crystal, comprising adjusting a dopant supply amount during a part forming step.   2. The method of manufacturing a semiconductor crystal according to claim 1, wherein the plurality of parameters are any two or more of a neck diameter, a melt diameter, a zone length, a crystal temperature, and an upper axis speed.   The dopant supply adjustment factor is updated each time by accumulating data obtained from a plurality of batches of the plurality of parameters and the electric resistivity, and newly performing multivariate analysis using the accumulated data. The method for producing a semiconductor crystal according to claim 1, wherein the semiconductor crystal is produced.   4. The dopant supply amount adjustment coefficient is determined by weighting a parameter having a strong correlation with the electrical resistivity among the plurality of parameters. The manufacturing method of the semiconductor crystal of description.   The method for producing a semiconductor crystal according to any one of claims 1 to 4, wherein the semiconductor crystal is a silicon single crystal.

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