Method for preparing single crystal silicon, crystal rod and single crystal production system
By adding dopant to the silicon raw material before purification during the preparation of single crystal silicon, and feedback adjustment is performed by detecting resistivity, the abnormal resistivity problem of crystal rods caused by operational errors by production personnel is solved, and the pass rate and accuracy of production are improved.
Patent Information
- Application Number
- CN202411961486.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-04
AI Technical Summary
During the preparation of single crystal silicon, production personnel are prone to forget to add or add more or less dopants, resulting in abnormal resistivity of the crystal rod.
Doping doped silicon raw materials before purification reduces the operation steps of on-site production personnel to add dopants to silicon materials, and feedback adjustments are made by detecting the resistivity of polycrystalline silicon ingots to ensure that the resistivity is within the preset range.
It reduces the operation steps and errors of production personnel, and improves the production pass rate and production accuracy of crystal rods.
Smart Images
Figure CN119753821A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of single crystal silicon preparation, and in particular to a single crystal silicon preparation method, a crystal rod and a single crystal generation system. Background Art
[0002] In the photovoltaic industry, it is necessary to use the CZ method to pull P-type or N-type single crystal silicon rods with different resistivities. In order to obtain the target resistivity, different dopants need to be added to the polysilicon material. In the current single crystal preparation process, solid phase doping can be used for doping. The unvaporized solid dopant (or doping material containing solid dopants, hereinafter referred to as solid dopant) is mixed with the silicon material to be added, so that the solid dopant and the silicon material are melted and reacted together to achieve solid phase doping. In actual production, production personnel need to calculate and weigh the required dopants. It may happen that they forget to add dopants, add more or less dopants, which leads to abnormal resistivity of the crystal rod. Summary of the invention
[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is to provide a method for preparing single crystal silicon, which can reduce the operation steps of on-site production personnel, reduce the probability of making mistakes, and thus improve the production qualification rate of crystal rods.
[0004] According to the method for preparing single crystal silicon in an embodiment of the first aspect of the present invention, the preparation method comprises: S1, adding a dopant to a silicon raw material, wherein the dopant is at least one of nitrogen, arsenic and antimony; S2, purifying the silicon raw material to prepare a polycrystalline silicon ingot; S5, placing the polycrystalline silicon ingot into a crucible for melting, and growing a single crystal silicon by a Czochralski method.
[0005] According to the method for preparing single crystal silicon in an embodiment of the present invention, by doping the silicon raw material before purification, on-site production personnel do not need to add dopants to the silicon material, thereby reducing the operating steps of on-site production personnel and lowering the probability of errors, thereby improving the production qualification rate of crystal rods.
[0006] According to some embodiments of the present invention, the dopant is antimony.
[0007] According to some embodiments of the present invention, the mass concentration of the dopant antimony in the silicon raw material is less than 70 ppmw.
[0008] According to some embodiments of the present invention, the mass concentration of the dopant antimony in the silicon raw material is 35 ppbw-70 ppmw.
[0009] According to some embodiments of the present invention, the preparation method further includes: step S3, detecting the resistivity of the polycrystalline silicon ingot, and confirming that the resistivity satisfies a preset resistance range.
[0010] According to some embodiments of the present invention, the preparation method also includes: step S3, step S3 includes: S31, detecting the resistivity of the polycrystalline silicon ingot; S32, confirming that the resistivity is less than a preset resistance range, and calculating the difference between the resistivity and the preset resistance range; the step S5 includes: S51, calculating the amount of the dopant required to be additionally added to the single crystal furnace based on the difference; S52, placing the polycrystalline silicon ingot and the dopant to be added into the single crystal furnace; S53, growing single crystal silicon using the Czochralski method.
[0011] According to some embodiments of the present invention, the preparation method further includes: step S4, crushing the polycrystalline silicon ingot.
[0012] According to some embodiments of the present invention, the dopant is also at least one of boron, gallium or phosphorus.
[0013] According to the crystal rod of the second aspect of the present invention, the crystal rod is prepared according to the method for preparing single crystal silicon of the first aspect of the present invention.
[0014] The crystal rod according to the present invention is prepared by the method for preparing single crystal silicon according to the first aspect, thereby improving the production accuracy of the crystal rod.
[0015] According to the single crystal growing system of the third aspect of the present invention, the method for preparing single crystal silicon according to the first aspect of the present invention is applicable to the single crystal growing system.
[0016] The single crystal growth system according to the present invention includes the method for preparing single crystal silicon according to the first aspect, thereby improving the production quality of the single crystal growth system.
[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a flow chart of a method for preparing single crystal silicon according to an embodiment of the first aspect of the present invention. DETAILED DESCRIPTION
[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.
[0020] Reference below Figure 1 A method for preparing single crystal silicon according to an embodiment of the first aspect of the present invention is described.
[0021] like Figure 1 As shown, according to the method for preparing single crystal silicon in the first embodiment of the present invention, the preparation method comprises:
[0022] S1, doping the silicon raw material with a dopant, wherein the dopant is at least one of nitrogen, arsenic, and antimony; it is understood that the dopant can be any one of these elements alone, or two or all three elements can be used in combination as dopants, wherein which element is selected and how to combine depends on the electrical properties of the desired final product, process conditions, and other factors. In addition, it should be noted that the silicon raw material in this embodiment is prepared by a physical method, and its impurity content is relatively high.
[0023] S2, purifying the silicon raw material to prepare a polycrystalline silicon ingot; wherein the purification is to remove impurities in the silicon raw material to ensure high-purity silicon, thereby ensuring the production quality of single crystal silicon. In addition, it should be noted that the silicon raw material is purified by a directional solidification method.
[0024] S5, placing the polycrystalline silicon ingot into a crucible for melting, and growing single crystal silicon by the Czochralski method.
[0025] In the prior art, usually after the silicon raw material is purified, the purified polycrystalline silicon ingot and dopants are placed in a single crystal furnace for melting at the same time, and then the crystal is pulled. However, since there may be many types of dopants and they are all manually operated by employees, it may happen that the dopants are forgotten to be added, too much or too little dopants are added, which may cause abnormal resistivity of the crystal rod.
[0026] In this embodiment, dopants are added before purification, so that on-site production personnel do not need to add dopants to the silicon material, thereby reducing the operating steps of on-site production personnel and lowering the probability of errors, thereby improving the production qualification rate of crystal rods.
[0027] According to the method for preparing single crystal silicon in an embodiment of the present invention, by doping the silicon raw material before purification, on-site production personnel do not need to add dopants to the silicon material, thereby reducing the operating steps of on-site production personnel and lowering the probability of errors, thereby improving the production qualification rate of crystal rods.
[0028] According to some embodiments of the present invention, the dopant is antimony, wherein the dopant is antimony so that the single crystal can be used to manufacture special devices and integrated circuits, such as tunnel diodes, semiconductor lasers, and infrared detectors.
[0029] According to some embodiments of the present invention, the mass concentration of the dopant antimony in the silicon raw material is less than 70 ppmw. In this way, it can be ensured that the resistivity of the polycrystalline silicon ingot after antimony doping can be less than or meet the resistivity required by the product, thereby improving the qualified rate of the product. For example, the mass concentration of the dopant antimony in the silicon raw material can be 10 ppmw, 20 ppmw, 30 ppmw, 40 ppmw, 50 ppmw or 60 ppmw.
[0030] According to some embodiments of the present invention, the mass concentration of the dopant antimony in the silicon raw material is 35ppbw-70ppmw. In this way, it is possible to prevent the situation where the resistivity exceeds the required range of the product due to the excessive doping concentration in the early stage, and it is also possible to prevent the situation where the doping concentration in the early stage is too small, and then useless addition occurs, thereby reducing the workload of personnel. For example, the mass concentration of the dopant antimony in the silicon raw material can be 40ppmw, 50ppmw or 60ppmw.
[0031] According to some embodiments of the present invention, the preparation method further includes: step S3, detecting the resistivity of the polycrystalline silicon ingot, and confirming that the resistivity satisfies a preset resistance range. It is understandable that in this embodiment, a feedback step is added so that the staff can further confirm that the doping of the dopant is successful, thereby helping to ensure the quality of the single crystal silicon.
[0032] It should be noted that, in this embodiment, the preparation method is: first, doping the silicon raw material with dopants; then, purifying the silicon raw material to prepare a polycrystalline silicon ingot; then detecting the resistivity of the polycrystalline silicon ingot, if the resistivity meets the preset resistance range, placing the polycrystalline silicon ingot in a crucible to melt, and using the Czochralski method to grow single crystal silicon.
[0033] According to some embodiments of the present invention, the preparation method further includes: step S3, step S3 includes:
[0034] S31, detecting the resistivity of the polycrystalline silicon ingot;
[0035] S32, confirming that the resistivity is less than a preset resistance range, and calculating the difference between the resistivity and the preset resistance range;
[0036] Step S5 includes:
[0037] S51, calculating the amount of additional dopant required to be added to the single crystal furnace according to the difference;
[0038] S52, putting the polycrystalline silicon ingot and the dopant to be added into the single crystal furnace;
[0039] S53, single crystal silicon is grown using the Czochralski method.
[0040] It can be understood that in this embodiment, a feedback adjustment step is added so that when the resistivity of the polycrystalline silicon ingot does not meet expectations, dopants can be added to the crucible again, thereby ensuring the production quality of single crystal silicon.
[0041] It should be noted that, in the present embodiment, the preparation method is: first, doping agent is added to the silicon raw material; then, the silicon raw material is purified to prepare a polycrystalline silicon ingot; then, the resistivity of the polycrystalline silicon ingot is detected. If the resistivity is less than the preset resistance range, then, the difference between the resistivity and the preset resistance range is calculated; and the amount of additional dopant required to be added to the single crystal furnace is calculated based on the difference; then, the polycrystalline silicon ingot and the dopant to be added are put into the single crystal furnace, and the Czochralski method is used to grow single crystal silicon.
[0042] According to some embodiments of the present invention, the preparation method further includes: step S4, crushing the polycrystalline silicon ingot, wherein the crushed silicon material is more convenient to load into the crucible, and the small polycrystalline silicon ingot is easier to melt quickly and evenly.
[0043] It should be noted that in this embodiment, the preparation method is: first, doping the silicon raw material with a dopant; then purifying the silicon raw material to prepare a polycrystalline silicon ingot; then detecting the resistivity of the polycrystalline silicon ingot, if the resistivity meets the preset resistance range, the polycrystalline silicon ingot is crushed, and then the crushed polycrystalline silicon ingot is placed in a crucible for melting, and a single crystal silicon is grown by the Czochralski method. If the resistivity is less than the preset resistance range, the polycrystalline silicon ingot also needs to be crushed; at the same time, the difference between the resistivity and the preset resistance range is calculated; and the amount of additional dopant required to be added to the single crystal furnace is calculated based on the difference; then the crushed polycrystalline silicon ingot and the dopant to be added are simultaneously placed in the single crystal furnace, and a single crystal silicon is grown by the Czochralski method.
[0044] According to some embodiments of the present invention, the dopant is also at least one of boron, gallium or phosphorus. It is understandable that the dopant can be not only one of nitrogen, arsenic and antimony, but also at least one of boron, gallium or phosphorus. In this way, the flexibility of dopant selection in the preparation method can be increased.
[0045] The crystal rod according to the second aspect of the present invention is prepared according to the method for preparing single crystal silicon according to the first aspect of the present invention.
[0046] The crystal rod according to the present invention is prepared by the method for preparing single crystal silicon according to the first aspect, thereby improving the production accuracy of the crystal rod.
[0047] According to the single crystal growing system of the third aspect of the present invention, the method for preparing single crystal silicon according to the first aspect of the present invention is applicable to the single crystal growing system.
[0048] The single crystal growth system according to the present invention includes the method for preparing single crystal silicon according to the first aspect, thereby improving the production quality of the single crystal growth system.
[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.
[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0053] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.
Claims
1. A method for preparing single crystal silicon, characterized in that: The preparation method comprises: S1, adding a dopant to the silicon raw material, wherein the dopant is at least one of nitrogen, arsenic, and antimony; S2, purifying the silicon raw material to prepare a polycrystalline silicon ingot; S5, placing the polycrystalline silicon ingot into a crucible for melting, and growing single crystal silicon by using a Czochralski method.
2. The method for preparing single crystal silicon according to claim 1, characterized in that: The dopant is antimony.
3. The method for preparing single crystal silicon according to claim 2, characterized in that: The mass concentration of the dopant antimony in the silicon raw material is less than 70 ppmw.
4. The method for preparing single crystal silicon according to claim 3, characterized in that: The mass concentration of the dopant antimony in the silicon raw material is 35 ppbw-70 ppmw.
5. The method for preparing single crystal silicon according to claim 1, characterized in that: The preparation method further includes: step S3, detecting the resistivity of the polycrystalline silicon ingot to confirm that the resistivity satisfies a preset resistance range.
6. The method for preparing single crystal silicon according to claim 1, characterized in that: The preparation method further comprises: step S3, which comprises: S31, detecting the resistivity of the polycrystalline silicon ingot; S32, confirming that the resistivity is less than a preset resistance interval, and calculating a difference between the resistivity and the preset resistance interval; Step S5 includes: S51, calculating the amount of the dopant that needs to be additionally added to the single crystal furnace according to the difference; S52, putting the polycrystalline silicon ingot and the dopant to be added into a single crystal furnace; S53, single crystal silicon is grown using the Czochralski method.
7. The method for preparing single crystal silicon according to claim 1, characterized in that: The preparation method further includes: step S4, crushing the polycrystalline silicon ingot.
8. The method for preparing single crystal silicon according to claim 1, characterized in that: The dopant is also at least one of boron, gallium or phosphorus.
9. A crystal rod, characterized in that: The crystal rod is prepared according to the method for preparing single crystal silicon according to any one of claims 1-8.
10. A single crystal production system, characterized in that: The method for preparing single crystal silicon according to any one of claims 1 to 8 is applicable to the single crystal growth system.