Method for determining antimony volatilization behavior, silicon single crystal rod, silicon wafer and solar cell

Abstract

The invention provides a method for determining the volatilization behavior of antimony, a silicon single crystal rod, a silicon wafer and a solar cell, and the method comprises the steps: determining the volatilization behavior of antimony in a leading and releasing stage and / or an equal-diameter stage: in the leading and releasing stage, pulling out a small end from molten silicon; the total feeding amount and the initial antimony concentration are obtained; the mass, the phosphorus-antimony concentration and the phosphorus concentration of the small head are obtained; according to the total feeding amount, the phosphorus-antimony concentration, the initial antimony concentration and the phosphorus concentration, the volatilization amount of antimony in the small end pulling stage is calculated; in the equal-diameter stage, the actual resistivity of the silicon rod at multiple positions is obtained; converting the actual resistivity at the plurality of positions into actual phosphorus and antimony concentrations; acquiring the actual phosphorus concentration at each position; calculating the actual antimony concentration at each position according to the actual phosphorus-antimony concentration and the actual phosphorus concentration; and according to the actual antimony concentration, the effective segregation coefficient of antimony, the initial phosphorus concentration and the solidification fraction, the volatilization coefficient of antimony in the equal-diameter stage is fitted. By means of the method, the volatilization behavior of antimony in the single crystal pulling process can be determined.

Description

Technical Field

[0001] The present application mainly relates to the field of single crystal silicon preparation, and in particular to a method for determining antimony volatilization behavior, a single crystal silicon rod, a silicon wafer and a solar cell. Background Art

[0002] In the process of preparing silicon rods, the doping step is a key step. By doping different elements in the silicon rods, the electrical properties of the silicon rods can be changed to have different resistivities to meet different application requirements.

[0003] Phosphorus-antimony co-doped single crystal silicon has gradually emerged in the photovoltaic industry due to its excellent resistance concentration. The growth process of phosphorus-antimony co-doped silicon rods faces many technical difficulties. One of the important reasons is that the strong volatilization of antimony makes it difficult to control the resistivity, which limits the large-scale production and application of phosphorus-antimony co-doped single crystal silicon. Therefore, how to determine the volatilization behavior of antimony is a hot issue in this field. Summary of the invention

[0004] The technical problem to be solved by the present application is to provide a method for determining the volatilization behavior of antimony, a single crystal silicon rod, a silicon wafer and a solar cell. The method for determining the volatilization behavior of antimony can determine the volatilization behavior of antimony in the process of pulling a single crystal.

[0005] To solve the above technical problems, the present application provides a method for determining the volatilization behavior of antimony, the method comprising determining the volatilization behavior of antimony in the drawing and releasing stage and / or the equal diameter stage, in the drawing and releasing stage: pulling out a small head from molten silicon; obtaining the total feed amount (M 总 ) and initial antimony concentration (C 0锑 ); obtain the mass of the small head (M1), phosphorus antimony concentration (C M1磷锑 ) and phosphorus concentration (C M1磷 ); According to the total feed amount (M 总 ), the phosphorus antimony concentration (C M1磷锑 ), the initial antimony concentration (C 0锑 ) and the phosphorus concentration (C M1磷 ) Calculate the volatilization amount of antimony during the stage of pulling the small head (E 锑 ); in the equal diameter stage: obtaining the actual resistivity of the silicon rod at multiple positions, wherein the multiple positions are spaced apart along the axial direction of the silicon rod; converting the actual resistivity at the multiple positions into the actual phosphorus antimony concentration (C L磷锑 ); obtain the actual phosphorus concentration (C L磷 ); According to the actual phosphorus antimony concentration (C L磷锑 ) and the actual phosphorus concentration (C L磷 ) to calculate the actual antimony concentration (C) at each location L锑 ); According to the actual antimony concentration (C L锑), the effective segregation coefficient of antimony (K 锑 ), initial phosphorus concentration (C 0锑 ) and solidification fraction (f s ) Fitting the volatility coefficient (X) of antimony in the isodiametric stage.

[0006] In one embodiment of the present application, the volatilization amount (E) is calculated according to the following formula: 锑 ):

[0007] Among them, the N A represents Avogadro's constant, ρ represents the density of silicon, and A r锑 Represents the relative atomic mass of antimony.

[0008] In one embodiment of the present application, the phosphorus antimony concentration (C M1磷锑 ).

[0009] In one embodiment of the present application, the phosphorus concentration (C M1磷 ):

[0010] Among them, the K 磷 represents the effective segregation coefficient of phosphorus, the C 0磷 represents the initial phosphorus concentration, the f s Indicates the solidification fraction.

[0011] In one embodiment of the present application, the step of fitting the volatility coefficient (X) includes: fitting the volatility coefficient (X) based on the following formula: Calculate the theoretical concentration of antimony (C s锑 ); According to the theoretical concentration (C s锑 ) and the actual phosphorus concentration (C L磷 ) Calculate the theoretical phosphorus antimony concentration (Cs 磷锑 ); the theoretical phosphorus antimony concentration (Cs 磷锑 ) is converted into a theoretical resistivity, and the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than a preset difference.

[0012] In one embodiment of the present application, if the absolute value of the difference between the theoretical resistivity and the actual resistivity is not less than a preset difference, the volatility coefficient (X) is fitted again until the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than the preset difference.

[0013] In one embodiment of the present application, according to the actual phosphorus antimony concentration (C L磷锑 ) and the actual phosphorus concentration (CL磷 ) to calculate the actual antimony concentration (C) at each location L锑 ) is: .

[0014] The present application also proposes a single crystal silicon rod. During the process of drawing the single crystal silicon rod, the volatilization behavior of antimony is determined using the method as described above, wherein the axial resistance change rate of the single crystal silicon rod is not greater than 13.6%, and / or the radial resistance change rate of the head of the single crystal silicon rod is not greater than 8%, the radial resistance rate of the middle of the single crystal silicon rod is not greater than 15%, the radial resistance change rate of the tail of the single crystal silicon rod is not greater than 10%, and / or the resistance hit rate of the single crystal silicon rod is not less than 80%.

[0015] The present application also provides a silicon wafer, which is cut from the single crystal silicon rod as described above.

[0016] The present application also proposes a solar cell, wherein the substrate of the solar cell is processed from the silicon wafer mentioned above.

[0017] Compared with the prior art, this application has the following advantages: (1) The amount of antimony volatilization during the small head drawing stage can be accurately calculated. Based on the calculated amount of antimony volatilization, the antimony can be supplemented when adding doping to the next rod according to the number of times the rod is drawn.

[0018] (2) The volatility coefficient of antimony can be determined accurately by reverse deduction of actual data. Based on the volatility coefficient, the resistivity of antimony-doped silicon rods can be precisely controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings: Figure 1 It is a flow chart of a method for determining the volatilization behavior of antimony in the induction stage in one embodiment of the present application; Figure 2 It is a flow chart of a method for determining the volatilization behavior of antimony in the equal diameter stage in another embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0021] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0023] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0024] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0025] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0026] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0027] Next, the method for determining the volatilization behavior of antimony, the single crystal silicon rod, the silicon wafer and the solar cell of the present application are described through examples.

[0028] The method of the present application comprises determining the volatility behavior of antimony during the discharge stage and / or the isodiametric stage. Figure 1 As shown, the method for determining the volatilization behavior of antimony in the discharge stage includes the following steps S110 to S140.

[0029] Step S110: pulling out the small head from the molten silicon; Step S120: Obtain the total amount of feed (M 总 ) and initial antimony concentration (C 0锑 ); Step S130: Obtain the mass of the small head (M1), the phosphorus antimony concentration (C M1磷锑 ) and phosphorus concentration (C M1磷 ); Step S140: According to the total feed amount (M 总 ), initial antimony concentration (C 0锑 )、Phosphorus antimony concentration(C M1磷锑 ) and phosphorus concentration (C M1磷 ) Calculate the volatilization amount of antimony during the stage of pulling the small head (E 锑 ).

[0030] Next, steps S110 to S140 are described in detail.

[0031] In step S110, the small head is pulled out from the molten silicon. In addition to silicon, the molten silicon also contains phosphorus and antimony elements. The total concentration of phosphorus and antimony in the molten silicon can be calculated according to the target resistance of the silicon rod. The specific calculation method can be carried out according to the relevant national standards, which will not be elaborated here.

[0032] In step S120, the total feed amount (M 总 ) and initial antimony concentration (C 0锑 ), total feed amount (M 总 ) refers to the mass of all raw materials added to the crucible. The raw materials added to the crucible may include polycrystalline silicon, phosphorus master alloy and high-purity metal antimony. The raw materials in the crucible are heated to obtain molten silicon (i.e. molten silicon). Initial antimony concentration (C 0锑 ) refers to the concentration of antimony in molten silicon.

[0033] In step S130, the mass of the small head (M1), the phosphorus antimony concentration of the small head (C M1磷锑 ) and phosphorus concentration in the small head (C M1磷 The mass of the small head can be obtained by weighing. The phosphorus antimony concentration (C M1磷锑 To elaborate, use a portable resistance tester or BCT-400 measurement system to measure the resistivity of the small head under standard test environment, and then convert the resistivity into the phosphorus antimony concentration (C M1磷锑 The phosphorus concentration of the small head (C M1磷 ):

[0034] Among them, K 磷 represents the effective segregation coefficient of phosphorus, C 0磷 represents the initial phosphorus concentration, f s represents the solidification fraction, the initial phosphorus concentration (C 0磷 ) refers to the concentration of phosphorus in molten silicon.

[0035] In some other embodiments, an ICP-MS instrument can be used to measure the small head to obtain the phosphorus antimony concentration (C M1磷锑 ) and phosphorus concentration (C M1磷 ).

[0036] In step S140, according to the total feed amount (M 总 )、Antimony concentration(C 0锑 )、Phosphorus antimony concentration(C M1磷锑 ), and phosphorus concentration (C M1磷 ) Calculate the volatilization amount of antimony during the stage of pulling the small head (E 锑 The volatile amount (E 锑 ):

[0037] Among them, N A represents Avogadro's constant, ρ represents the density of silicon, A r锑 represents the relative atomic mass of antimony, and the parameters in the formula obtained in steps S120 to S140 are substituted into the above formula to calculate the volatilization amount of antimony (E 锑 ), calculate the volatile amount (E 锑 ) can be used as a basis for supplementary doping of antimony elements.

[0038] In order to more clearly understand the above method of the present application, a non-limiting example 1 is given here.

[0039] Example 1 Silicon rods were pulled using a 1700 type single crystal furnace with a crucible diameter of 36 inches. 940 kg of polycrystalline silicon, 128 g of phosphorus master alloy and 11 g of high-purity antimony metal were loaded into the crucible. The phosphorus concentration was 25%, the crystal rotation was 8 r / min, the crucible rotation was 4 r / min~6 r / min, and the argon flow rate was 100 slpl. The purity of silicon material is greater than 99.999%, and the purity of antimony material is greater than 99.99%. Antimony material is added to silicon material in a certain molar ratio, and the mixture is placed in a crucible. The quartz crucible is placed in a vacuum induction furnace and evacuated to a vacuum degree of less than 10^-3Pa. High-purity argon gas is then filled in to maintain the gas pressure in the furnace at about 0.1MPa. The temperature is raised to 1500°C and kept for 1 hour to completely melt the silicon material and antimony material to form molten silicon. The temperature is then lowered to 1450°C to start crystal growth. During the crystal growth process, the antimony content and temperature in the molten silicon and the environmental conditions for crystal growth (such as atmosphere) are precisely controlled.

[0040] As described in the following table, the resistivity of multiple small heads and the phosphorus antimony concentration (C M1磷锑 ), initial phosphorus concentration (C 0磷 ) and initial antimony concentration (C 0锑 ).

[0041] serial number Resistivity (Ω·cm) Weight (kg) <![CDATA[C M1磷锑 (atom / cm 3 , <![CDATA[C 0磷 (atom / cm 3 , <![CDATA[C 0锑 (atom / cm 3 , M1 1.21 12 3.96885E+15 2.8E+15 1.3E+17 M2 1.29 11 3.70805E+15 2.6E+15 1.2E+17 M3 1.38 13 3.45246E+15 2.5E+15 1.1E+17

[0042] The phosphorus concentration of the small head (C M1磷 ):

[0043] Combine the parameters in the table with the phosphorus concentration (C M1磷 ), the volatilization amount of antimony (E 锑 ):

[0044] By analogy, the volatilization amount of antimony between each small head during pulling can be calculated. Based on the calculated volatilization amount of antimony, the antimony can be supplemented according to the number of times the rod is released when adding doping.

[0045] refer to Figure 2 As shown, the method for determining the volatilization behavior of antimony in the isodiameter stage includes the following steps S210 to S250.

[0046] Step S210: obtaining actual resistivity of the silicon rod at a plurality of positions, where the plurality of positions are spaced apart along the axial direction of the silicon rod; Step S220: Convert the actual resistivity at multiple locations into actual phosphorus antimony concentration (C L磷锑 ); Step S230: Obtain the actual phosphorus concentration (C L磷 ); Step S240: According to the actual phosphorus antimony concentration (C L磷锑 ) and actual phosphorus concentration (C L磷 ) to calculate the actual antimony concentration (C L锑 ); Step S250: According to the actual antimony concentration (C L锑 ), the effective segregation coefficient of antimony (K 锑 ), initial phosphorus concentration (C 0锑 ) and solidification fraction (f s ) Fitting the volatility coefficient (X) of antimony in the isodiametric stage.

[0047] Next, steps S210 to S250 are described in detail.

[0048] In step S210, the actual resistivity of the silicon rod at multiple positions is obtained. The multiple positions are spaced apart along the axial direction of the silicon rod. The actual resistivity of the silicon rod at multiple positions can be tested using an instrument.

[0049] In step S220, the actual resistivity at the plurality of locations is converted into the actual phosphorus antimony concentration (C L磷锑), the actual resistivity can be converted into the actual phosphorus antimony concentration (C L磷锑 ), which will not be elaborated.

[0050] In step S230, the actual phosphorus concentration (C L磷 The actual phosphorus concentration (C) at each location can be calculated according to the following formula: L磷 ):

[0051] Among them, K 磷 represents the effective segregation coefficient of phosphorus, C 0磷 represents the initial phosphorus concentration, f s Indicates the solidification fraction.

[0052] In step S240, according to the actual phosphorus antimony concentration (C L磷锑 ) and actual phosphorus concentration (C L磷 ) to calculate the actual antimony concentration (C L锑 In one embodiment, the actual antimony concentration (C) at each location can be calculated according to the following formula: L锑 ) is: .

[0053] In step S250, according to the actual antimony concentration (C L锑 ), the effective segregation coefficient of antimony (K 锑 ), initial phosphorus concentration (C 0锑 ) and solidification fraction (f s ) Fitting the volatility coefficient (X) of antimony in the isodiameter stage. In one embodiment, fitting the volatility coefficient (X) includes the following steps S251 to S254: Step S251: Fitting the volatility coefficient (X) based on the following formula:

[0054] Among them, K 锑 represents the effective segregation coefficient of antimony, C 0锑 represents the initial antimony concentration, f s Indicates the solidification fraction.

[0055] Step S252: Calculate the theoretical concentration (C) of antimony according to the volatility coefficient (X) obtained by fitting. s锑 Specifically, the volatility coefficient (X) obtained by fitting is substituted into the formula in step S251 to calculate the theoretical concentration of antimony (C s锑 ), so that we can obtain the values ​​corresponding to different segregation coefficients (f s ) corresponds to the theoretical concentration of antimony (C s锑 ).

[0056] Step S253: According to the theoretical concentration (C s锑 ) and actual phosphorus concentration (C L磷 ) Calculate the theoretical phosphorus antimony concentration (Cs 磷锑 ). Specifically, the phosphorus antimony concentration (Cs 磷锑 ) is equal to the theoretical concentration (C s锑 ) plus the actual phosphorus concentration (C L磷 ).

[0057] Step S254: The theoretical phosphorus antimony concentration (Cs 磷锑 ) is converted into theoretical resistivity, and the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than the preset difference. Specifically, the theoretical phosphorus antimony concentration (Cs 磷锑 ) is converted into theoretical resistivity. For a qualified volatility coefficient (X), the absolute value of the difference between the theoretical resistivity and the actual resistivity calculated based on the calculation should be less than the preset difference. The preset difference can be set according to the needs. For example, the preset difference is 0.01Ω·cm. If the absolute value of the difference between the theoretical resistivity and the actual resistivity is not less than the preset difference, it means that the volatility coefficient (X) obtained by fitting deviates greatly from the actual situation, and the volatility coefficient (X) needs to be fitted again until the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than the preset difference.

[0058] In order to more clearly understand the above method of the present application, a non-limiting example 2 is given here.

[0059] Example 2 In order to quantify the volatility of antimony in the isodiameter stage, the following formula is used to express the concentration of antimony at any position of the silicon rod:

[0060] The volatility coefficient (X) of antimony is determined by reverse deduction of actual data. The specific process is to draw a silicon rod with a complete end (length of 3000mm~4000mm), cut the silicon rod at a certain interval (500mm~800mm) and measure the actual resistivity at the cut-off point, record the relevant data (as shown in the table below), and convert the actual resistivity into the actual phosphorus antimony concentration (C L磷锑 ), actual phosphorus antimony concentration (C L磷锑 ) minus the actual phosphorus concentration (C L磷 ) to obtain the actual antimony concentration (C L锑 ), and the volatility coefficient (X) is obtained by reverse deduction. According to multiple fittings of the experimental data, when the phosphorus concentration is 25%, the fitting value of the volatility coefficient (X) is 1.275. Based on the volatility coefficient (X), the resistivity of the antimony-doped silicon rod can be accurately controlled.

[0061] Rod length (mm) Actual resistivity (Ω·cm) Theoretical resistivity (Ω·cm) Resistivity difference (Ω·cm) Residue weight (g) Solidification fraction <![CDATA[C L磷 (atom / cm 3 , <![CDATA[C L锑 (atom / cm 3 , <![CDATA[(C L磷锑 )(atom / cm 3 , 0 1.13065 1.20 -0.06 940000 9.7507E+14 3.0511E+15 4.026E+15 80 1.13065 1.20 -0.07 868000 7.7% 1.0267E+15 2.9795E+15 4.006E+15 834 1.088 1.205 -0.12 802648 14.6% 1.08E+15 2.9108E+15 3.991E+15 1668 1.043 1.21 -0.17 665296 29.2% 1.2195E+15 2.7524E+15 3.972E+15 2502 1.011 1.21 -0.20 527945 43.8% 1.4164E+15 2.5691E+15 3.986E+15 2917 0.966 1.20 -0.23 459598 51.1% 1.5494E+15 2.4652E+15 4.015E+15 3545 0.946 1.17 -0.23 356173 62.1% 1.8273E+15 2.2848E+15 4.112E+15

[0062] The present application also proposes a single crystal silicon rod, and in the process of drawing the single crystal silicon rod, the volatilization behavior of antimony is determined using the method described above. The volatilization behavior of antimony is determined using the method described above, and the resistance uniformity of the obtained single crystal silicon rod is as follows: the axial resistance change rate of the single crystal silicon rod is not greater than 13.6%, for example, the axial resistance change rate is 6%, 8%, 10% or 12%, and the axial resistance change rate can refer to: the ratio of the difference between the head resistance and the tail resistance to the head resistance, that is, (head resistance-tail resistance) / head resistance). And / or, at the head position of the single crystal silicon rod, the radial resistance change rate is not greater than 8%, for example, the radial resistance change rate is 4% or 6%; at the middle position of the single crystal silicon rod, the radial resistivity is not greater than 15%, for example, the radial resistivity is 4%, 6%, 8%, 10%, 12% or 14%; at the tail position of the single crystal silicon rod, the radial resistance change rate is not greater than 10%, for example, the radial resistance change rate is 4%, 6% or 8%. The above-mentioned radial resistance change rate may refer to: in the radial direction of the same cross section of the single crystal silicon rod, the ratio of the difference between the edge resistance and the center resistance to the center resistance, that is, (edge ​​resistance-center resistance) / center resistance. And or, the resistance hit rate of the single crystal silicon rod is not less than 80%, for example, the resistance hit rate is 85%, 90% or 95%. "Resistance hit rate" refers to the proportion (i.e. m / n) of a batch of single crystal silicon rods (assuming n rods) that fall within (assuming m rods) a predetermined resistance interval (assuming [a, b]). The resistance here may refer to the head resistance, and a and b can be set according to actual needs. In one embodiment, the resistance is within the positive and negative 0.1Ω numerical range of the target resistance and is considered a hit. The present application also proposes a silicon wafer, which is cut from the single crystal silicon rod as described above.

[0063] The present application also proposes a solar cell, wherein the substrate of the solar cell is processed from the silicon wafer mentioned above.

[0064] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0065] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0066] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0067] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which can be changed according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0068] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for determining the volatilization behavior of antimony, characterized in that: The method comprises determining the volatility behavior of antimony during the discharge stage and / or the isodiametric stage, During the launch phase: Pulling a small head out of molten silicon; Get the total feed amount (M 总 ) and initial antimony concentration (C 0锑 ); Obtain the mass (M1) and phosphorus antimony concentration (C M1磷锑 ) and phosphorus concentration (C M1磷 ); According to the total feed amount (M 总 ), the phosphorus antimony concentration (C M1磷锑 ), the initial antimony concentration (C 0锑 ) and the phosphorus concentration (C M1磷 ) Calculate the volatilization amount of antimony during the stage of pulling the small head (E 锑 ); In the isodiametric stage: Acquire actual resistivity of the silicon rod at a plurality of positions, where the plurality of positions are spaced apart along the axial direction of the silicon rod; The actual resistivity at the plurality of locations is converted into the actual phosphorus antimony concentration (C L磷锑 ); Get the actual phosphorus concentration (C) at each location L磷 ); According to the actual phosphorus antimony concentration (C L磷锑 ) and the actual phosphorus concentration (C L磷 ) to calculate the actual antimony concentration (C) at each location L锑 ); According to the actual antimony concentration (C L锑 ), the effective segregation coefficient of antimony (K 锑 ), initial phosphorus concentration (C 0锑 ) and solidification fraction (f s ) Fitting the volatility coefficient (X) of antimony in the isodiametric stage.

2. The method according to claim 1, characterized in that The volatile amount (E) was calculated according to the following formula 锑 ): Among them, the N A represents Avogadro's constant, ρ represents the density of silicon, and A r锑 Represents the relative atomic mass of antimony.

3. The method according to claim 1, characterized in that The phosphorus antimony concentration (C M1磷锑 ).

4. The method according to claim 1, characterized in that The phosphorus concentration (C) was calculated according to the following formula: M1磷 ): Among them, the K 磷 represents the effective segregation coefficient of phosphorus, the C 0磷 represents the initial phosphorus concentration, the f s Indicates the solidification fraction.

5. The method according to claim 1, characterized in that The step of fitting the volatility coefficient (X) comprises: The volatility coefficient (X) was fitted based on the following formula: ; The theoretical concentration of antimony (C s锑 ); According to the theoretical concentration (C s锑 ) and the actual phosphorus concentration (C L磷 ) Calculate the theoretical phosphorus antimony concentration (Cs 磷锑 ); The theoretical phosphorus antimony concentration (Cs 磷锑 ) is converted into a theoretical resistivity, and the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than a preset difference.

6. The method according to claim 5, characterized in that If the absolute value of the difference between the theoretical resistivity and the actual resistivity is not less than the preset difference, the volatility coefficient (X) is fitted again until the absolute value of the difference between the theoretical resistivity and the actual resistivity is less than the preset difference.

7. The method according to claim 1, characterized in that According to the actual phosphorus antimony concentration (C L磷锑 ) and the actual phosphorus concentration (C L磷 ) to calculate the actual antimony concentration (C) at each location L锑 ) is: .

8. A single crystal silicon rod, characterized in that: During the process of drawing the single crystal silicon rod, the volatilization behavior of antimony is determined using the method according to any one of claims 1 to 7, wherein the axial resistance change rate of the single crystal silicon rod is not greater than 13.6%, and / or the radial resistance change rate of the head of the single crystal silicon rod is not greater than 8%, the radial resistance rate of the middle of the single crystal silicon rod is not greater than 15%, the radial resistance change rate of the tail of the single crystal silicon rod is not greater than 10%, and / or the resistance hit rate of the single crystal silicon rod is not less than 80%.

9. A silicon wafer, characterized in that: The silicon wafer is cut from the single crystal silicon rod as claimed in claim 8.

10. A solar cell, characterized in that: The substrate of the solar cell is processed from the silicon wafer as claimed in claim 9.

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