Method for controlling resistivity of N-type crystal bar by using phosphorus and antimony

Abstract

The invention provides a method for controlling the resistivity of an N-type crystal bar by using phosphorus and antimony, and relates to the field of polycrystalline silicon preparation. The method comprises the following steps: when an N-type crystal bar is produced by adopting a CZ method, S1, doping phosphorus and antimony during polycrystalline silicon production, and obtaining a molten silicon material; s2, introducing a seed crystal, and enabling the mixed silicon material to grow a crystal bar by adopting a CZ method; s3, detecting the resistance of the crystal bar; s4, processing a crystal bar according to the resistance to obtain an N-type crystal bar; and S5, classifying the recycled materials produced by the N-type crystal bars according to different resistances of the crystal bars. By adjusting the proportion of phosphorus and antimony, the problem that the resistivity uniformity of the crystal bar is difficult to control is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polysilicon preparation, and in particular to a method for controlling N-type crystal bar resistivity by using phosphorus and antimony. BACKGROUND

[0002] Currently, the N-type single crystal silicon produced by the Czochralski method (CZ method) in the industry is mainly doped with a single dopant, and the main dopant is phosphorus. After the whole crystal is drawn, the head-to-tail resistivity difference is about 0.7, and the proportion in the optimal interval is small, which is difficult to meet the requirements of a specific resistivity interval. SUMMARY

[0003] To solve the above technical problems, the present application provides a method for controlling N-type crystal bar resistivity by using phosphorus and antimony, which solves the problem of difficulty in controlling the uniformity of crystal bar resistivity by adjusting the ratio of phosphorus and antimony.

[0004] The technical scheme adopted by the present application is as follows:

[0005] A method for controlling N-type crystal bar resistivity by using phosphorus and antimony, comprising:

[0006] When producing N-type crystal bars by the CZ method, the following steps are mainly included:

[0007] S1, doping phosphorus and antimony during polysilicon production, and obtaining molten silicon material;

[0008] S2, introducing a seed crystal and growing a crystal bar from the mixed silicon material by the CZ method;

[0009] S3, detecting the resistance of the crystal bar;

[0010] S4, processing the crystal bar according to the resistance to obtain an N-type crystal bar;

[0011] S5, classifying the back production material of the N-type crystal bar according to the different resistances of the crystal bar.

[0012] Optionally, the doping ratio of phosphorus and antimony is 0-0.5:0.4-0.6.

[0013] Optionally, in step S1, phosphorus or antimony is doped into the silicon material together or phosphorus is doped into the silicon material, and molten silicon is obtained;

[0014] Antimony is doped into the molten silicon by using a supplementary doping tool, and molten silicon material is obtained.

[0015] Optionally, in step S2, the crucible rotation is controlled at 5-6 revolutions, the furnace pressure is 6-7 torr, the proportion of antimony is 0.025-0.03, and the argon flow rate is controlled at 80-100 slpm during the growth of the crystal.

[0016] Optionally, the head-to-tail resistivity difference of the N-type crystal bar is 0.1-0.3.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] 1. By adjusting the ratio of phosphorus and antimony, the problem of difficulty in controlling the uniformity of the resistivity of the crystal bar has been solved.

[0019] 2. By matching the process parameters during the growth of the crystal bar, the stability of the volatilization of high-purity antimony during the drawing process of the crystal bar can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0021] Figure 1 The figure is the resistance change trend graph under the antimony ratio.

[0022] Figure 2 The figure is the data comparison graph of using phosphorus and antimony cartridge doping and candidate doping antimony.

[0023] Figure 3 The figure is the product resistivity loss graph before and after the candidate doping tool doping.

[0024] Figure 4 The figure is the resistance hit rate schematic diagram. DETAILED DESCRIPTION

[0025] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0026] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity and clarity, the description in the following text will describe the components and settings of specific examples. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to the same reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0027] The embodiments of the present application will be described in detail below with reference to the drawings.

[0028] The embodiment of the present application provides a method for controlling resistivity of N-type crystal bar by using phosphorus and antimony, comprising the following steps:

[0029] In the production of N-type crystal bar by using the CZ method, the following steps are mainly included:

[0030] S1, doping phosphorus and antimony in the production of polysilicon and obtaining molten silicon material;

[0031] S2, introducing a seed crystal and growing a crystal bar from the mixed silicon material by using the CZ method;

[0032] S3, detecting the resistance of the crystal bar;

[0033] S4, processing the crystal bar according to the resistance to obtain an N-type crystal bar;

[0034] S5, classifying the remanufactured material of the N-type crystal bar according to different resistances. More specifically, the phosphorus-doped single crystal remanufactured material needs to be classified according to different resistance rates, and the co-doped remanufactured material can be directly classified according to the processing segment, for example, the head part is classified as one type, the tail part is classified as one type, the middle segment is classified as one type, and the 40 and 50 segment is classified as one type. The 10, 20 and 30 segments are limited to the feeding amount, and after simulation analysis, the resistance difference is only within 0.05, and the 40 and 50 segments are limited to the feeding amount, and the resistance difference is also only within 0.05.

[0035] In one of the embodiments, the doping ratio of the phosphorus and the antimony is 0-0.5:0.4-0.6.

[0036] In one of the embodiments, in the step S1, the phosphorus or the antimony is jointly doped into the silicon material or the phosphorus is doped into the silicon material, and the molten silicon is obtained.

[0037] The antimony is doped into the molten silicon by using a supplementary doping tool, and the molten silicon material is obtained. The phosphorus is normally loaded into the middle of the silicon material, after all the silicon material is added into the furnace and completely melted, the antimony is doped into the molten silicon by using the supplementary doping tool, and the phosphorus, antimony and silicon molten mixture is obtained.

[0038] In one of the embodiments, in the step S2, the crystal rotation is controlled at 6-8 revolutions, the crucible rotation is controlled at 5-6 revolutions, the furnace pressure is 6-7 torr, the exertion ratio of the antimony is 0.025-0.03, and the argon flow rate is controlled at 80-100 slpm.

[0039] In one of the embodiments, the head-tail resistivity difference value of the N-type crystal bar is 0.1-0.3.

[0040] When the antimony and phosphorus are added by the complex feeding cylinder, the antimony and phosphorus are added in the second last cylinder of silicon material, and the antimony and phosphorus are mixed after the silicon material is melted in the furnace, and the molten silicon material is obtained. The crystal bar is grown by the crystal transfer, the crucible transfer, the furnace pressure and the argon. The crystal bar is detected by resistance, and the crystal bar is processed after the detection, and the N-type crystal bar is obtained. The reprocessing material in the processing process is classified according to the resistance of the crystal bar.

[0041] By using the doping method, the head resistance hit rate (1.3±0.1) of the crystal bar is 65%, and the qualified resistance concentration ratio is 98.23%.

[0042] In another embodiment, in order to reduce the influence of high-purity antimony volatilization caused by uncertain factors on the resistivity of the crystal bar, phosphorus is added to the second last cylinder of silicon material, and antimony is added by using a supplementary doping tool after the addition of the material is completed. The overall resistivity of the crystal bar is more concentrated, and the resistance hit rate is more accurate.

[0043] By using the doping method, the head resistance hit rate (1.3±0.1) of the crystal bar is 65%, and the qualified resistance concentration ratio is 98.23%.

[0044] The segregation coefficients of antimony and phosphorus are 0.023 and 0.35 respectively; the volatilization ratio of antimony in high-temperature melt is about 0.02, the initial doping antimony and phosphorus are obtained under different proportions (7:3; 6:4), the radial resistivity simulation distribution of the whole crystal bar is simulated, and the proportion and doping weight of antimony and phosphorus are adjusted according to the actual resistivity value of the subsequent output crystal bar.

[0045] The adjusted proportion is shown in Table 1.

[0046] Table 1 is the resistivity difference value of the adjusted antimony and phosphorus proportion.

[0047] Co-doped embodiments Antimony phosphorus ratio Equal diameter > 3000 mm head-to-tail resistivity difference values Crystal diameter 1 0.35-0.4 0.3 300 2 0.4-0.45 0.25 300 3 0.45-0.5 0.2 300 4 0.5-0.55 0.15 300 5 0.6 0.1 300

[0048] By adjusting the different antimony proportion, the head and tail resistance deviation of the crystal bar is detected, so that the head and tail resistance deviation of the crystal bar is as small as possible under the condition that the resistance is easy to control, and the proportion in the optimal resistance interval is large.

[0049] Before adjusting the antimony and phosphorus ratio, the head and tail resistivity difference of the crystal bar reaches 0.6. After adjusting the antimony and phosphorus ratio to 0.6-0.7, the head and tail resistivity difference of the crystal bar is reduced to 0.3.

[0050] The scheme of adding phosphorus by the complex feeding cylinder and adding antimony by the supplementary doping tool:

[0051] The silicon material is normally fed into the 1-7 cylinder, the amount of high-purity antimony is preferentially calculated, and then the resistance is reached by the remaining impurity concentration.

[0052] After the calculation is completed, the phosphorus is added into the penultimate barrel, if only one barrel is added, the phosphorus is added into the middle of the barrel, and the silicon material in the added barrel is sequentially added into the furnace. After all the silicon material is completely melted, the antimony is added into the furnace using a supplement doping tool to obtain a silicon, phosphorus and antimony mixed melt, and the crystal pulling is started.

[0053] The data of the phosphorus and antimony barrel doping and the antimony doping after the holding are compared as shown in the following table. Figure 2

[0054] The resistivity concentration interval is better when the holding is used for doping (the doping is performed using a supplement doping tool), and the standard deviation is 0.070, which is much smaller than that when the holding is not used for doping (as shown in the following table). Figure 3

[0055] After the holding is used for doping, the product resistivity loss is obviously reduced, and is reduced from the highest value of nearly 5% to <1% (as shown in the following table). Figure 4

[0056] After the holding is used for doping, the optimal resistivity interval hit rate (1.3±0.1) is obviously increased, and is increased from the lowest 59.4% to 80% and tends to be stable.

[0057] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.​​​

Claims

1. A method for controlling the resistivity of an N-type crystal rod using phosphorus antimony, characterized in that: When the CZ method is used to produce N-type crystal rods, it mainly includes the following steps: S1. Phosphorus and antimony are added during the production of polysilicon to obtain molten silicon material; S2, introducing seed crystals and using the CZ method to grow the mixed silicon material into a crystal rod; S3, detecting the resistance of the crystal rod; S4, processing the crystal rod according to the resistance to obtain an N-type crystal rod; S5. Classify the recycled materials produced from the N-type crystal ingots according to the different resistances of the crystal ingots.

2. The method for controlling the resistivity of an N-type crystal rod using phosphorus antimony according to claim 1, characterized in that: The doping ratio of phosphorus to antimony is 0-0.5:0.4-0.

6.

3. The method for controlling the resistivity of an N-type crystal rod using phosphorus antimony according to claim 1 or 2, characterized in that: In step S1, phosphorus or antimony is co-doped into silicon material or phosphorus is doped into silicon material to obtain molten silicon; Antimony is doped into molten silicon using a doping tool to obtain molten silicon material.

4. The method for controlling the resistivity of an N-type crystal rod using phosphorus antimony according to claim 3, characterized in that: In step S2, during the crystal growth process, the crucible rotation speed is controlled at 5-6 revolutions, the furnace pressure is 6-7 Torr, the antimony utilization ratio is 0.025-0.03, and the argon flow rate is controlled at 80-100 slpm.

5. The method for controlling the resistivity of an N-type crystal rod using phosphorus antimony according to claim 1, wherein: The resistivity difference between the head and tail of the N-type crystal rod is 0.1-0.3.

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