Crystal bar axial resistivity control method and crystal bar

Abstract

The invention relates to a method for controlling the axial resistivity of a crystal bar and the crystal bar, and the method comprises the steps: carrying out the equal-diameter growth of a first crystal bar according to a preset equal-diameter parameter, measuring the axial resistivity of the first crystal bar, and drawing a change curve of the axial resistivity of the first crystal bar; calculating the unevenness of the axial resistivity of the first crystal bar; when the unevenness of the axial resistivity of the first crystal bar is greater than or equal to 17%, the evaporation of the antimony element is promoted or inhibited by adjusting the pressure parameter aiming at different change stages of the axial resistivity, so that the concentration of the antimony element in the silicon solution is adjusted; the risk that the reduction trend of the axial resistivity of the crystal bar is large due to the fact that the concentration of the antimony element in the silicon solution is high is reduced, and the risk that the increase trend of the axial resistivity of the crystal bar is large due to the fact that the concentration of the antimony element in the silicon solution is low is also reduced, namely, the difference value between the maximum resistivity and the minimum resistivity is reduced; and thus, the nonuniformity of the axial resistivity is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of crystal rod processing, and in particular to a method for controlling the axial resistivity of a crystal rod and a crystal rod. Background Art

[0002] During the process of equal-diameter growth of the crystal rod, the resistivity of the crystal rod at different growth lengths varies, that is, there are stages where the resistivity gradually increases or decreases, which makes the axial resistivity of the crystal rod unevenly distributed in its own length direction. There is a risk of a large difference in the axial resistivity of the crystal rod at different length positions, that is, there is a risk of a large non-uniformity in the axial resistivity of the crystal rod, thereby affecting the performance of the final product processed from the crystal rod. Summary of the invention

[0003] The present application provides a method for controlling the axial resistivity of a crystal rod and a crystal rod, which can reduce the non-uniformity of the axial resistivity of the crystal rod.

[0004] In a first aspect, the present application provides a method for controlling the axial resistivity of a crystal rod, the method comprising: growing a first crystal rod in equal diameter using preset equal diameter parameters, measuring the axial resistivity of the first crystal rod, and drawing a curve of the change of the axial resistivity of the first crystal rod; calculating the non-uniformity of the axial resistivity of the first crystal rod; when the non-uniformity of the axial resistivity of the first crystal rod is greater than or equal to 17%, processing a second crystal rod with adjusted parameters so that the non-uniformity of the axial resistivity of the second crystal rod is less than 17%; wherein the equal diameter parameters include pressure parameters, and the method for adjusting the equal diameter parameters comprises: in the process of growing the second crystal rod in equal diameter, gradually increasing or decreasing the pressure parameters to suppress or promote the evaporation of doping elements.

[0005] In the present application, for different stages of change of axial resistivity, the evaporation of antimony element is promoted or suppressed by adjusting the pressure parameters, so as to adjust the concentration of antimony element in the silicon solution, thereby reducing the risk of a large decrease in the axial resistivity of the crystal rod due to a high concentration of antimony element in the silicon solution, and reducing the risk of a large increase in the axial resistivity of the crystal rod due to a low concentration of antimony element in the silicon solution, that is, reducing the difference between the maximum resistivity and the minimum resistivity, thereby reducing the non-uniformity of the axial resistivity.

[0006] In one possible design, the axial resistivity of the first crystal rod has at least a first change stage, in which the axial resistivity of the crystal rod is inversely proportional to the length of the isodiametric growth of the crystal rod; the method for adjusting the isodiametric parameter includes: in the process of isodiametrically growing the second crystal rod, in the first change stage, gradually reducing the pressure parameter to promote the evaporation of the doping element.

[0007] In a possible design, the equal diameter parameter includes a flow rate of an inert gas, and the method of gradually reducing the pressure parameter includes: during the equal diameter growth of the second crystal rod, in the first change stage, gradually reducing the flow rate of the introduced inert gas.

[0008] In a possible design, when the length of the first crystal rod is 0 mm, the flow rate of the inert gas is Q01, and when the length of the second crystal rod is 0 mm, the flow rate of the inert gas is Q02, and Q01 and Q02 satisfy: Q02>Q01.

[0009] In a possible design, the isodiametric parameter includes a crucible rotation speed; during the isodiametric growth of the second crystal rod, in the first variation stage, the crucible rotation speed is gradually increased to promote the evaporation of the doping element.

[0010] In a possible design, when the length of the first crystal rod being uniformly grown is 0 mm, the crucible speed is V1, and when the length of the second crystal rod being uniformly grown is 0 mm, the crucible speed is V2, and V1 and V2 satisfy: V2>V1.

[0011] In a possible design, the equal diameter parameter includes a seed crystal rotation speed; during the equal diameter growth of the second crystal rod, in the first variation stage, the seed crystal rotation speed is gradually reduced to promote diffusion of the doping element into the second crystal rod.

[0012] In a possible design, the axial resistivity of the first crystal rod has at least a second change stage, in which the axial resistivity of the crystal rod is proportional to the length of the isodiametric growth of the crystal rod; the method for adjusting the isodiametric parameter includes: during the isodiametric growth of the second crystal rod, in the second change stage, gradually increasing the pressure parameter to suppress the evaporation of the doping element.

[0013] In one possible design, the equal-diameter parameter includes the flow rate of the inert gas, and the method of gradually increasing the pressure parameter includes: during the equal-diameter growth of the second crystal rod, in the second change stage, gradually increasing the flow rate of the introduced inert gas; and / or, during the equal-diameter growth of the second crystal rod, in the second change stage, gradually reducing the flow rate of the discharged inert gas.

[0014] In a possible design, the isodiametric parameter includes a crucible rotation speed; during the isodiametric growth of the second crystal rod, in the second variation stage, the crucible rotation speed is gradually reduced to suppress the evaporation of the doping element.

[0015] A second aspect of the present application provides a crystal rod, which is processed based on any of the above methods for controlling the axial resistivity of the crystal rod, and the non-uniformity of the axial resistivity of the crystal rod is less than 17%.

[0016] In the present application, for different stages of change of axial resistivity, the evaporation of antimony element is promoted or suppressed by adjusting the pressure parameters, so as to adjust the concentration of antimony element in the silicon solution, thereby reducing the risk of a large decrease in the axial resistivity of the crystal rod due to a high concentration of antimony element in the silicon solution, and reducing the risk of a large increase in the axial resistivity of the crystal rod due to a low concentration of antimony element in the silicon solution, that is, reducing the difference between the maximum resistivity and the minimum resistivity, and further reducing the non-uniformity of the axial resistivity, so as to reduce the influence of the axial resistivity on the performance of the final product processed from the crystal rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for controlling the axial resistivity of a crystal rod provided in the present application in one embodiment;

[0018] Figure 2 A curve showing a change in the axial resistivity of the first crystal rod provided in the present application;

[0019] Figure 3 Schematic diagram of the method for adjusting the equal diameter parameters;

[0020] Figure 4 This is a curve showing a change in the axial resistivity of the second crystal rod provided in the present application in one embodiment.

[0021] Reference numerals:

[0022] S1-first stage of change;

[0023] S2-second stage of change;

[0024] S3-the third stage of change. DETAILED DESCRIPTION

[0025] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0026] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0027] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0028] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0029] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0030] During the equal-diameter growth of the antimony-phosphorus doped crystal rod, the axial resistivity of the crystal rod at different growth lengths varies, that is, along the axial direction of the crystal rod, the axial resistivity of the crystal rod at different length positions is not consistent. There are the following embodiments for the change of the axial resistivity of the crystal rod:

[0031] In one embodiment, the axial resistivity of the crystal rod gradually decreases, that is, when the length of the crystal rod is 0 mm, the axial resistivity of the crystal rod is the largest. Thereafter, as the length of the crystal rod gradually increases, the axial resistivity of the crystal rod gradually decreases. The decrease in the axial resistivity of the crystal rod is mainly affected by the segregation phenomenon of the doping elements. Taking the doping elements including antimony phosphorus as an example, the segregation phenomenon refers to the phenomenon that the antimony phosphorus element is unevenly distributed between the solid phase (crystallized silicon) and the liquid phase (uncrystallized silicon melt) during the crystal pulling process when the silicon melt containing antimony phosphorus elements cools and crystallizes. This phenomenon is caused by the different solubility of antimony phosphorus elements in solid silicon and in liquid silicon. During the process of isodiametric growth, the concentration of antimony phosphorus elements remaining in the silicon melt gradually increases, so that the doping concentration of the crystal rod in the subsequent growth process gradually increases, thereby causing the resistivity of the crystal rod to gradually decrease.

[0032] In another embodiment, the axial resistivity of the crystal rod gradually increases, that is, when the length of the crystal rod is 0 mm, the axial resistivity of the crystal rod is the smallest, and thereafter, as the length of the crystal rod gradually increases, the axial resistivity of the crystal rod gradually decreases. The increase in the axial resistivity of the crystal rod is mainly affected by the evaporation phenomenon of the antimony phosphorus element. The evaporation phenomenon refers to the process of pulling the crystal. When the silicon melt containing antimony phosphorus elements is under high temperature conditions, the antimony phosphorus element will escape from the silicon melt in a gaseous form, resulting in a gradual decrease in the concentration of the antimony phosphorus element remaining in the silicon melt, so that the doping concentration of the crystal rod in the subsequent growth process is gradually reduced, and then the resistivity of the crystal rod is gradually increased.

[0033] In another embodiment, the change in the axial resistivity of the crystal rod includes both a gradually decreasing stage and a gradually increasing stage, and the gradually decreasing stage and the gradually increasing stage occur at least once, that is, the gradually decreasing stage and the gradually increasing stage occur alternately.

[0034] Since the axial resistivity of the crystal rod changes from larger to smaller, the distribution of the axial resistivity of the crystal rod in its length direction is uneven, and there is a risk of a large difference in the axial resistivity of the crystal rod at different length positions, that is, there is a risk of a large non-uniformity of the axial resistivity of the crystal rod, thereby affecting the performance of the final product processed from the crystal rod. Therefore, during the process of equal diameter growth of the crystal rod, it is necessary to adjust the antimony phosphorus concentration doped in the crystal rod to control the distribution of the axial resistivity of the crystal rod. In this field, there are many and more mature ways to adjust the doping concentration of phosphorus, but compared with phosphorus, the control of the doping concentration of antimony is more difficult, which makes the control of the distribution of the axial resistivity of the crystal rod more difficult.

[0035] To this end, the first aspect of the embodiment of the present application provides a method for controlling the axial resistivity of a crystal rod, such as Figure 1 As shown, the method for controlling the axial resistivity of the crystal rod includes:

[0036] The first crystal rod is grown in equal diameter with the process parameters in Table 1 and the preset original equal diameter parameters in Table 2. The equal diameter parameters include the crucible rotation speed, the seed rotation speed, the inert gas flow rate (taking the argon flow rate as an example) and the pressure. In the process of growing the first crystal rod in equal diameter, the crucible rotation speed gradually increases from the initial V01 to V02, and both V01 and V02 are in the range of 3rpm to 8rpm, and V02>V01, as shown in Table 2, taking V01=4rpm and V02=7rpm as an example; in the process of growing the first crystal rod in equal diameter, the seed rotation speed gradually decreases from the initial W01 to W02, and both W01 and W02 are in the range of In the range of 6rpm~10rpm, and W01>W02, as shown in Table 2, taking W01=9rpm and W02=7rpm as an example; in the process of equal-diameter growth of the first crystal rod, the flow rate of the introduced argon gas is Q01 and remains unchanged, 70lpm≤Q01≤110lpm, as shown in Table 2, taking Q01=90lpm as an example; in the process of equal-diameter growth of the first crystal rod, the pressure is P01 and remains unchanged, 4Torr≤P01≤10Torr, as shown in Table 2, taking P01=7Torr as an example.

[0037] The axial resistivity of the first crystal rod is measured, and a variation curve of the axial resistivity of the first crystal rod is plotted. Figure 2 Take the change curve shown as an example. Figure 2 The horizontal axis in is the length of the first crystal rod in the axial direction. Figure 2 The ordinate in is the axial resistivity of the first crystal rod at the corresponding length position, which is given by Figure 2 It can be seen that the axial resistivity of the first crystal rod has three change stages, which first decreases, then increases, and finally decreases. The three change stages are respectively recorded as the first change stage S1 in which the resistivity gradually decreases, the second change stage S2 in which the resistivity gradually increases, and the third change stage S3 in which the resistivity gradually decreases. Figure 2 As shown, in the first change stage S1, the axial resistivity of the first crystal rod decreases from R1 to R2, in the second change stage S2, the axial resistivity of the first crystal rod increases from R2 to R3, and in the third change stage S3, the axial resistivity of the first crystal rod decreases from R3 to R4;

[0038] The non-uniformity of the axial resistivity of the first crystal rod is calculated according to the axial resistivity of the first crystal rod at different positions, and is obtained by Figure 2 The change curve shown in the figure shows that R1>R3>R2>R4. Figure 2 In the variation curve shown, the non-uniformity of the axial resistivity of the first crystal rod is Δr1=100%×(R1-R4) / R1. Figure 2 In the variation curve shown, Δr1 = 20%;

[0039] Determine whether the non-uniformity of the axial resistivity of the first crystal rod is less than a threshold value. Take the threshold value as 17% as an example. When the non-uniformity of the axial resistivity of the first crystal rod is greater than or equal to the threshold value, process the second crystal rod with the adjusted parameters so that the non-uniformity of the axial resistivity of the second crystal rod is less than the threshold value.

[0040] The equal diameter parameter includes a pressure parameter, and the method for adjusting the equal diameter parameter includes:

[0041] During the process of growing the second crystal rod with equal diameter, the pressure parameter is gradually increased or decreased to suppress or promote the evaporation of the doping element.

[0042] Table 1 Process parameters

[0043] Feeding method Polycrystalline pure casting Feeding amount (Kg) 920 Argon gas flow rate (lpm) 90 Furnace pressure (Torr) 7 Crucible speed (rpm) 4-7 Crystal rotation (rpm) 8 Antimony element addition amount (g) 10.19 Phosphorus master alloy addition amount 261.49

[0044] Table 2 Original equal diameter parameters

[0045]

[0046]

[0047] In Table 2, the length of the first crystal rod at 0 mm to 1200 mm corresponds to the first change stage S1, the length at 1200 mm to 3500 mm corresponds to the second change stage S2, and the length at 3500 mm to 5500 mm corresponds to the third change stage S3.

[0048] The axial resistivity of the first crystal rod has a first change stage S1, a second change stage S2 and a third change stage S3. Among them, the first change stage S1 and the third change stage S3 are both stages in which the axial resistivity gradually decreases. For the first change stage S1 and the third change stage S3, the evaporation of the antimony element in the silicon melt can be promoted to reduce the concentration of the antimony element in the silicon melt, thereby reducing the rate of decrease of the axial resistivity; the second change stage S2 is a stage in which the axial resistivity gradually increases. For the second change stage S2, the evaporation of the antimony element in the silicon melt can be suppressed to increase the concentration of the antimony element in the silicon melt, thereby reducing the rate of increase of the axial resistivity.

[0049] In this embodiment, for different stages of axial resistivity change, the evaporation of antimony phosphorus is promoted or inhibited by adjusting the pressure parameters, so as to adjust the concentration of antimony phosphorus in the silicon solution, reduce the risk of a high rate of decrease in the axial resistivity of the crystal rod due to a high concentration of antimony phosphorus in the silicon solution, and reduce the risk of a high rate of increase in the axial resistivity of the crystal rod due to a low concentration of antimony phosphorus in the silicon solution, that is, reduce the difference between the maximum resistivity and the minimum resistivity, and then reduce the non-uniformity of the axial resistivity, so as to reduce the influence of the axial resistivity on the performance of the final product processed from the crystal rod, which is conducive to improving the overall electrical performance and market competitiveness of the crystal rod. At the same time, the controllability and repeatability of the crystal rod production are enhanced, the number of trial and error in the crystal rod production process is reduced, and the processing cost of the crystal rod is reduced.

[0050] When the axial resistivity of the crystal rod is in the first change stage S1, that is, the axial resistivity of the crystal rod is inversely proportional to the length of the equal-diameter growth of the crystal rod, the method for adjusting the equal-diameter parameter includes:

[0051] In the process of growing the second crystal rod with equal diameter, in the first change stage S1, the pressure parameter is gradually reduced to promote the evaporation of the doping elements, thereby reducing the concentration of antimony and phosphorus elements in the silicon solution, and then reducing the reduction rate of the axial resistivity of the second crystal rod, so as to reduce the non-uniformity of the axial resistivity of the second crystal rod.

[0052] Among them, Figure 3 As shown, reducing the pressure parameter can be achieved by the following embodiments:

[0053] In one embodiment, the isodiameter parameter includes the flow rate of the inert gas. Taking argon as an example, the method of gradually reducing the pressure parameter includes: during the isodiameter growth of the second crystal rod, in the first change stage S1, gradually reducing the flow rate of the introduced argon gas.

[0054] In another embodiment, the method of gradually reducing the pressure parameter includes: during the process of growing the second crystal rod with equal diameter, in the first change stage S1, gradually increasing the flow rate of the exhausted argon gas.

[0055] In another embodiment, the method of gradually reducing the pressure parameter includes: during the process of growing the second crystal rod with equal diameter, in the first change stage S1, gradually reducing the flow rate of the introduced argon gas, and at the same time, gradually increasing the flow rate of the exhausted argon gas.

[0056] The embodiments of the present application do not specifically limit the specific method of reducing the pressure parameters.

[0057] Since the flow rate of the introduced argon gas needs to be gradually reduced in the first change stage S1, there is a risk that the flow rate of the introduced argon gas in the subsequent growth process is low, resulting in the quality of the second crystal rod being unqualified. For this reason, when the equal-diameter growth length of the first crystal rod is 0 mm, the flow rate of the introduced argon gas is Q01, and when the equal-diameter growth length of the second crystal rod is 0 mm, the flow rate of the introduced argon gas is Q02, 70lpm≤Q02≤110lpm, and Q02>Q01, so as to improve the processing yield of the second crystal rod.

[0058] As shown in Table 2, the constant diameter parameters also include the crucible speed. Figure 3 As shown, in the process of growing the second crystal rod in equal diameter, in the first change stage S1, the crucible speed can be increased, and when the length of the second crystal rod grown in equal diameter is 0 mm, the crucible speed is V3, 3rpm≤V3≤8rpm, and V3>V1. In this embodiment, increasing the crucible speed can promote the evaporation of antimony and phosphorus elements, thereby facilitating the reduction of the antimony concentration in the silicon melt in the first change stage S1, and further facilitating the reduction of the axial resistivity of the second crystal rod in the first change stage S1.

[0059] As shown in Table 2, the isodiametric parameters also include the seed rotation speed. Figure 3 As shown, in the process of growing the second crystal rod with equal diameter, in the first change stage S1, the rotation speed of the seed crystal can be gradually reduced. In this embodiment, gradually reducing the rotation speed of the seed crystal can promote the diffusion of the doping element into the second crystal rod, thereby reducing the reduction rate of the axial resistivity of the second crystal rod, so as to reduce the non-uniformity of the axial resistivity of the second crystal rod.

[0060] When the axial resistivity of the crystal rod is in the above-mentioned second change stage S2, that is, the axial resistivity of the crystal rod is proportional to the length of the isodiametric growth of the crystal rod, the method for adjusting the isodiametric parameters includes: in the process of isodiametric growth of the second crystal rod, in the second change stage S2, gradually increasing the pressure parameter to suppress the evaporation of the doping element, thereby increasing the concentration of antimony and phosphorus elements in the silicon solution, and then reducing the increase rate of the axial resistivity of the second crystal rod, so as to reduce the non-uniformity of the axial resistivity of the second crystal rod.

[0061] Among them, Figure 3 As shown, increasing the pressure parameter can be achieved through the following embodiments:

[0062] In one embodiment, the method of gradually increasing the pressure parameter includes: during the process of growing the second crystal rod with equal diameter, in the first change stage S1, gradually increasing the flow rate of the introduced argon gas.

[0063] In another embodiment, the method of gradually increasing the pressure parameter includes: during the process of growing the second crystal rod with equal diameter, in the first change stage S1, gradually reducing the flow rate of the discharged argon gas.

[0064] In another embodiment, the method of gradually increasing the pressure parameter includes: during the process of growing the second crystal rod with equal diameter, in the first change stage S1, gradually increasing the flow rate of the introduced argon gas, and at the same time, gradually reducing the flow rate of the exhausted argon gas.

[0065] The embodiment of the present application does not specifically limit the specific method of increasing the pressure parameter.

[0066] During the process of growing the second crystal rod with equal diameter, in the second changing stage S2, the crucible rotation speed may be gradually reduced to suppress the evaporation of the doping elements.

[0067] When the axial resistivity of the crystal rod is in the third change stage S3, the method for adjusting the equal diameter parameter is the same as the method in the first change stage S1, which will not be described again.

[0068] When the first crystal rod is in the first change stage S1, the second change stage S2 and the third change stage S3 at the same time, the method for controlling the axial resistivity of the crystal rod has the following embodiments:

[0069] In the first embodiment, the equal diameter parameter is adjusted for one of the first change stage S1, the second change stage S2 and the third change stage S3. Taking the first change stage S1 as an example:

[0070] In the first change stage S1, compared with the original equal-diameter parameters, the initial crucible speed of the second crystal rod equal-diameter growth is increased to V11, 3rpm≤V11≤8rpm, and V11>V01, and the crucible speed is gradually increased to V12, 3rpm≤V12≤8rpm, and V12>V11 during the equal-diameter growth of the second crystal rod.

[0071] In the first change stage S1, compared with the original equal-diameter parameters, the initial argon flow rate of the second crystal rod equal-diameter growth is increased to Q11, 70lpm≤Q11≤110lpm, and Q11>Q01, the initial pressure is set to P11, 4Torr≤P11≤10Torr, and P11=P01, and during the equal-diameter growth of the second crystal rod, the argon flow rate is gradually reduced to Q12, and the pressure is gradually reduced to P12, 70lpm≤Q12≤110lpm, and Q12<Q11, 4Torr≤P12≤10Torr, and P12<P11.

[0072] In order to make the argon flow rate and pressure meet the requirements of equal-diameter growth of the second crystal rod, the argon flow rate needs to be gradually increased to Q13, and the pressure needs to be gradually increased to the preset P13, 70lpm≤Q13≤110lpm, and Q13>Q12, 4Torr≤P13≤10Torr, and P13>P12.

[0073] Thereafter, the argon flow rate and pressure were kept constant.

[0074] The adjusted equal-diameter parameters are shown in Table 3, where V11=5rpm, V12=7rpm, Q11=100lpm, Q12=80lpm, Q13=90lpm, P11=7Torr, P12=5Torrr, and P13=7Torr are taken as examples.

[0075] Table 3 The adjusted equal diameter parameters of the first embodiment

[0076]

[0077]

[0078] In Table 3, the length of the second crystal rod at 0 mm to 1200 mm corresponds to the first change stage S1, the length at 1200 mm to 4000 mm corresponds to the second change stage S2, and the length at 4000 mm to 5500 mm corresponds to the third change stage S3.

[0079] Taking the data in Table 3 as an example, the initial crucible speed of the second crystal rod is increased to 5rpm. During the equal-diameter growth process, the crucible speed is gradually increased to 7rpm, the argon flow rate is gradually reduced from the initial 100lpm to 80lpm, and the pressure is reduced from the initial 7Torr to 5Torr. Thereafter, in order to make the argon flow rate and pressure meet the requirements of the equal-diameter growth of the second crystal rod, the argon flow rate needs to be gradually increased to 90lpm and the pressure needs to be gradually increased to 7Torr.

[0080] In the second embodiment, the equal diameter parameters are adjusted for any two stages among the first change stage S1, the second change stage S2 and the third change stage S3. Taking the first change stage S1 and the second change stage S2 as an example:

[0081] In the first change stage S1, compared with the original equal-diameter parameters, the initial crucible speed of the second crystal rod equal-diameter growth is increased to V21, 3rpm≤V21≤8rpm, and V21>V01, and the crucible speed is gradually increased to V22, 3rpm≤V22≤8rpm, and V22>V21 during the equal-diameter growth of the second crystal rod.

[0082] In the second changing stage S2, the crucible rotation speed is maintained at V22.

[0083] In the first change stage S1, compared with the original equal-diameter parameters, the initial argon flow rate of the equal-diameter growth of the second crystal rod is increased to Q21, 70lpm≤Q21≤110lpm, and Q21>Q01, the initial pressure is set to P21, 4Torr≤P21≤10Torr, and P21=P01, and the argon flow rate is gradually reduced to Q22 and the pressure is gradually reduced to P22 during the equal-diameter growth of the second crystal rod, 70lpm≤Q22≤110lpm, and Q22<Q21, 4Torr≤P22≤10Torr, and P22<P21. In order to make the argon flow rate and pressure meet the requirements of the equal-diameter growth of the second crystal rod, it is also necessary to gradually increase the argon flow rate to Q23 and the pressure to the preset P23, 70lpm≤Q23≤110lpm, and Q23>Q22, 4Torr≤P23≤10Torr, and P23>P22.

[0084] In the second change stage S2, the argon flow rate is gradually increased from Q23 to Q24, 70lpm≤Q24≤110lpm, and Q24>Q23, and the pressure is gradually increased from P23 to P24, 4Torr≤P24≤10Torr, and P24>P23.

[0085] Thereafter, the argon flow rate and pressure were kept constant.

[0086] The adjusted equal-diameter parameters are shown in Table 4, where V21=5rpm, V22=7rpm, Q21=100lpm, Q22=80lpm, Q23=90lpm, Q24=100lpm, P21=7Torr, P22=5Torrr, P23=7Torr, and P24=9Torr are taken as examples.

[0087] Table 4 The adjusted equal diameter parameters of the second embodiment

[0088]

[0089]

[0090] In Table 4, the length of the second crystal rod at 0 mm to 1200 mm corresponds to the first change stage S1, the length at 1200 mm to 4000 mm corresponds to the second change stage S2, and the length at 4000 mm to 5500 mm corresponds to the third change stage S3.

[0091] Taking the data in Table 4 as an example, in the first change stage S1, the crucible speed gradually increases from the initial 5rpm to 7rpm, the argon flow rate gradually decreases from the initial 100lpm to 80lpm, and the pressure gradually decreases from the initial 7Torr to 5Torr. Thereafter, in order to make the argon flow rate and pressure meet the requirements of equal-diameter growth of the second crystal rod, it is necessary to gradually increase the argon flow rate to the preset 90lpm, and the pressure gradually increase to the preset 7Torr.

[0092] In the second change stage S2, the argon flow rate gradually increases from 80 lpm in the first change stage S1 to 100 lpm, and the pressure gradually increases from 7 Torr in the first change stage S1 to 9 Torr.

[0093] Thereafter, the argon flow rate and pressure were kept constant.

[0094] In the third embodiment, the equal diameter parameters are adjusted for the first change stage S1, the second change stage S2 and the third change stage S3:

[0095] In the first change stage S1, compared with the original equal-diameter parameters, the initial crucible speed of the second crystal rod equal-diameter growth is increased to V31, 3rpm≤V31≤8rpm, and V31>V01, and the crucible speed is gradually increased to V32, 3rpm≤V32≤8rpm, and V32>V31 during the equal-diameter growth of the second crystal rod.

[0096] In the second change stage S2 and the third change stage S3, the crucible rotation speed is maintained at V32.

[0097] In the first change stage S1, compared with the original equal-diameter parameters, the initial argon flow rate of the equal-diameter growth of the second crystal rod is increased to Q31, 70lpm≤Q31≤110lpm, and Q31>Q01, the initial pressure is set to P31, 4Torr≤P31≤10Torr, and P31=P01, and during the equal-diameter growth of the second crystal rod, the argon flow rate is gradually reduced to Q32, and the pressure is gradually reduced to P32, 70lpm≤Q32≤110lpm, and Q32<Q31, 4Torr≤P32≤10Torr, and P32<P31. In order to make the argon flow rate and pressure meet the requirements of the equal-diameter growth of the second crystal rod, it is also necessary to gradually increase the argon flow rate to Q33, and gradually increase the pressure to the preset P33, 70lpm≤Q33≤110lpm, and Q33>Q32, 4Torr≤P33≤10Torr, and P33>P32.

[0098] In the second change stage S2, the argon flow rate is gradually increased from Q33 to Q34, 70lpm≤Q34≤110lpm, and Q34>Q33, and the pressure is gradually increased from P33 to P34, 4Torr≤P34≤10Torr, and P34>P33.

[0099] In the third change stage S3, the argon flow rate is gradually reduced from Q34 to Q35, 70lpm≤Q35≤110lpm, and Q35<Q34, and the pressure is gradually reduced from P34 to P35, 4Torr≤P35≤10Torr, and P35<P34.

[0100] The adjusted equal-diameter parameters are shown in Table 5, where V31=5rpm, V32=7rpm, Q31=100lpm, Q32=80lpm, Q33=90lpm, Q34=100lpm, Q35=90lpm, P31=7Torr, P32=5Torrr, P33=7Torr, P34=9Torr, and P35=7Torr are taken as examples.

[0101] Table 5 The adjusted equal diameter parameters of the third embodiment

[0102] Length(mm) Growth setting (mm / hr) Crucible speed (rpm) Crystal rotation (rpm) Argon flow rate Pressure setting 0 69 5 9 100 7 50 76 5 8.5 95 6.5 100 81 6 8 90 6 150 87 6 8 85 5.5 300 97 6 7.5 80 5 450 101 6.5 7 80 5 600 102 7 7 80 5 900 104 7 7 85 6 1200 104 7 7 90 7 1500 104 7 7 90 7.5 2000 104 7 7 90 8 2500 104 7 7 95 8.5 3500 104 7 7 95 9 4000 104 7 7 100 9 4500 104 7 7 95 8 5500 104 7 7 90 7

[0103] In Table 5, the length of the second crystal rod at 0 mm to 1200 mm corresponds to the first change stage S1, the length at 1200 mm to 4000 mm corresponds to the second change stage S2, and the length at 4000 mm to 5500 mm corresponds to the third change stage S3.

[0104] Taking the data in Table 4 as an example, in the first change stage S1, the crucible speed gradually increases from the initial 5rpm to 7rpm, the argon flow rate gradually decreases from the initial 100lpm to 80lpm, and the pressure decreases from the initial 7Torr to 5Torr. Thereafter, in order to make the argon flow rate and pressure meet the requirements of equal-diameter growth of the second crystal rod, it is necessary to gradually increase the argon flow rate to the preset 90lpm, and the pressure gradually increase to the preset 7Torr.

[0105] In the second change stage S2, the argon flow rate gradually increases from 80 lpm in the first change stage S1 to 100 lpm, and the pressure gradually increases from 7 Torr in the first change stage S1 to 9 Torr.

[0106] In the third change stage S3, the argon flow rate gradually decreases from 100 lpm in the second change stage S2 to 90 lpm, and the pressure gradually decreases from 9 Torr in the second change stage S2 to 7 Torr.

[0107] Taking the second embodiment as an example, Figure 3 is the variation curve of the axial resistivity of the second crystal rod, such as Figure 3 , the second crystal rod still has the first change stage S1, the second change stage S2 and the third change stage S3. In the first change stage S1, the axial resistivity of the second crystal rod decreases from R5 to R6, in the second change stage S2, the axial resistivity of the second crystal rod increases from R6 to R7, in the third change stage S3, the axial resistivity of the second crystal rod decreases from R7 to R8, and in the third change stage S4, the axial resistivity of the second crystal rod decreases from R7 to R8. Figure 4 It can be seen that R7>R5>R6>R8, the non-uniformity of the axial resistivity of the second crystal rod is Δr2=100%×(R7-R8) / R7, Δr2=13.77%.

[0108] It can be seen that adjusting the isodiametric parameters of at least one of the first change stage S1, the second change stage S2 and the third change stage S3 can significantly reduce the non-uniformity of the axial resistivity of the crystal rod, which is beneficial to improving the performance of the final product processed from the crystal rod. Among them, the number of change stages and the length range of the crystal rod corresponding to each change stage are affected by factors such as the isodiametric parameters and the furnace temperature. The above three change stages and their corresponding crystal rod length ranges are only examples. When adjusting the axial resistivity of the crystal rod, only the isodiametric parameters of one stage in the multiple change stages can be adjusted, or the isodiametric parameters of a part of the multiple change stages can be adjusted, and the isodiametric parameters of all the change stages can be adjusted. The number of change stages for adjusting the isodiametric parameters can be freely selected and combined according to actual conditions.

[0109] A second aspect of an embodiment of the present application provides a crystal rod, which is processed based on the method for controlling the axial resistivity of the crystal rod described in any of the above embodiments, and the argon gas flow rate in different change stages is set between 30lpm and 170lpm, the furnace pressure is set between 3Torr and 12Torr, and the changes in the crucible rotation speed and the seed crucible rotation speed are superimposed, so as to effectively control the total concentration of antimony and phosphorus in the remaining melt, promote the uniform incorporation of antimony and phosphorus elements, thereby further improving the axial resistivity distribution of the crystal rod, so that the non-uniformity of the axial resistivity of the crystal rod is less than 17%, so as to improve the performance of the final product processed from the crystal rod.

[0110] The above description is only an optional embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling the axial resistivity of a crystal rod, characterized in that: The method for controlling the axial resistivity of the crystal rod comprises: Growing a first crystal rod in equal diameter with preset equal diameter parameters, measuring the axial resistivity of the first crystal rod, and drawing a curve of the change of the axial resistivity of the first crystal rod; calculating the non-uniformity of the axial resistivity of the first crystal rod; When the non-uniformity of the axial resistivity of the first crystal ingot is greater than or equal to a threshold value, processing the second crystal ingot with the adjusted parameters so that the non-uniformity of the axial resistivity of the second crystal ingot is less than the threshold value; Wherein, the isodiametric parameter includes a pressure parameter, and the method for adjusting the isodiametric parameter includes: In the process of growing the second crystal rod with equal diameter, the pressure parameter is gradually increased or decreased to suppress or promote the evaporation of the doping element.

2. The method for controlling the axial resistivity of a crystal rod according to claim 1, characterized in that: The axial resistivity of the first crystal rod has at least a first change stage (S1), and in the first change stage (S1), the axial resistivity of the crystal rod is inversely proportional to the length of the equal-diameter growth of the crystal rod; The method for adjusting the equal diameter parameter comprises: During the process of growing the second crystal rod with equal diameter, in the first change stage (S1), the pressure parameter is gradually reduced to promote the evaporation of the doping element.

3. The method for controlling the axial resistivity of a crystal rod according to claim 2, characterized in that: The constant diameter parameter includes the flow rate of the inert gas, and the method of gradually reducing the pressure parameter includes: During the process of growing the second crystal rod with equal diameter, in the first change stage (S1), the flow rate of the introduced inert gas is gradually reduced.

4. The method for controlling the axial resistivity of a crystal rod according to claim 3, characterized in that: When the length of the first crystal rod being uniformly grown is 0 mm, the flow rate of the inert gas introduced is Q01, and when the length of the second crystal rod being uniformly grown is 0 mm, the flow rate of the inert gas introduced is Q02, and Q01 and Q02 satisfy: Q02>Q01.

5. The method for controlling the axial resistivity of a crystal rod according to any one of claims 2 to 4, characterized in that: The isodiametric parameters include crucible rotation speed; During the process of growing the second crystal rod with equal diameter, in the first changing stage (S1), the crucible rotation speed is gradually increased to promote the evaporation of the doping element.

6. The method for controlling the axial resistivity of a crystal rod according to any one of claims 2 to 4, characterized in that: The isodiametric parameters include seed rotation speed; During the process of growing the second crystal rod with equal diameter, in the first change stage (S1), the rotation speed of the seed crystal is gradually reduced to promote the diffusion of the doping element into the second crystal rod.

7. The method for controlling the axial resistivity of a crystal rod according to claim 1, characterized in that: The axial resistivity of the first crystal rod has at least a second change stage (S2), and in the second change stage (S2), the axial resistivity of the crystal rod is proportional to the length of the equal-diameter growth of the crystal rod; The method for adjusting the equal diameter parameter comprises: During the process of growing the second crystal rod with equal diameter, in the second change stage (S2), the pressure parameter is gradually increased to suppress the evaporation of the doping element.

8. The method for controlling the axial resistivity of a crystal rod according to claim 7, characterized in that: The constant diameter parameter includes the flow rate of the inert gas, and the method of gradually increasing the pressure parameter includes: During the process of growing the second crystal rod with equal diameter, in the second change stage (S2), gradually increasing the flow rate of the introduced inert gas; And / or, during the process of growing the second crystal rod with equal diameter, in the second changing stage (S2), the flow rate of the discharged inert gas is gradually reduced.

9. The method for controlling the axial resistivity of a crystal rod according to claim 7 or 8, characterized in that: The isodiametric parameters include crucible rotation speed; During the process of growing the second crystal rod with equal diameter, in the second change stage (S2), the crucible rotation speed is gradually reduced to suppress the evaporation of the doping element.

10. A crystal rod, characterized in that: The crystal ingot is processed based on the method for controlling the axial resistivity of a crystal ingot according to any one of claims 1 to 9, and the non-uniformity of the axial resistivity of the crystal ingot is less than 17%.

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