Method and device for detecting doping concentration of crystal and method and device for drawing silicon rod

Abstract

The embodiment of the invention provides a crystal doping concentration detection method and device and a silicon rod drawing method and device. The detection method comprises the following steps: acquiring the concentration of a dopant in gas on the surface of a silicon liquid, and acquiring the temperature of the surface of the silicon liquid; and determining the doping concentration of the crystal at the solid-liquid interface of the silicon liquid according to the concentration of the dopant in the gas and the temperature. In the embodiment of the invention, through real-time measurement of the doping concentration of the crystals at the solid-liquid interface, the doping proportion of the added materials can be adjusted, so that the resistivity of the head of the single crystal silicon rod is controlled within a proper range, and the yield and the resistivity concentration ratio of the single crystal silicon rod are improved.

Description

Technical Field

[0001] This application belongs to the technical field of photovoltaic processing, and specifically relates to a method and device for detecting the doping concentration of crystals, and a method and device for pulling silicon rods. Background Art

[0002] The Czochralski method is currently a main method for preparing single crystal silicon rods. The basic principle is to put high-purity polysilicon into a crucible and melt it into silicon liquid in a single crystal furnace. Then, a seed crystal fixed on the seed crystal axis is inserted into the surface of the silicon liquid. After the seed crystal is fused with the silicon liquid, the seed crystal is slowly pulled up and rotated, and the crystal grows at the lower end of the seed crystal to form a single crystal silicon rod. The resistivity of a single crystal silicon rod without impurities is very high and it hardly conducts electricity. However, for a single crystal silicon rod used in a photovoltaic cell, there is a requirement for resistivity, and the polysilicon raw material must be doped to change the resistivity of the single crystal silicon rod.

[0003] Currently, due to temperature fluctuations and other factors, the volatilization rate of the dopant is uncontrollable, so the resistivity of the produced single crystal silicon rod fluctuates greatly, affecting the yield. Moreover, during the pulling process of the single crystal silicon rod, after the previous section of the single crystal silicon rod is pulled, it is necessary to add materials and a certain amount of dopant again to control the resistivity of the subsequent section of the single crystal silicon rod. In the existing technology, only the doping amount can be set according to the resistivity distribution of the currently produced single crystal silicon rod combined with production experience. However, due to the great influence of production process fluctuations on the volatilization of the dopant, the resistivity of the produced single crystal silicon rod still fluctuates greatly by the empirical doping method, affecting the yield and resistivity concentration of the single crystal silicon rod. Summary of the Invention

[0004] This application aims to provide a method for detecting the doping concentration of silicon liquid, as well as a method and device for pulling silicon rods, so as to solve the problem that the resistivity of the existing single crystal silicon rod fluctuates greatly, affecting the yield and resistivity concentration of the single crystal silicon rod.

[0005] To solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, this application discloses a method for detecting the doping concentration of crystals, and the detection method includes:

[0007] Obtain the concentration of the dopant in the gas on the surface of the silicon liquid, and obtain the temperature on the surface of the silicon liquid;

[0008] Determine the doping concentration of the crystal at the solid-liquid interface of the silicon liquid according to the concentration of the dopant in the gas and the temperature.

[0009] The calculation formula for the doping concentration of the crystal is:

[0010]

[0011] Among them, Ccrys is the crystal doping concentration at the solid-liquid interface, Cg is the gas internal dopant concentration on the surface of the silicon liquid, ki is the effective segregation coefficient of the dopant, α is the linear coefficient, where η is the correction coefficient, Mi is the relative atomic mass, and γ i is the activity coefficient of the doping element in the silicon liquid, Pi is the saturated vapor pressure of the doping element at temperature T, Pcham is the pressure in the furnace, R is the gas constant, and ρ i is the density of the doping element, D is the inner diameter of the crucible, H is the height of the silicon liquid, and h is the duration of crystal pulling.

[0012] Optionally, the value range of η is 0.721 - 0.893, and the value range of α is 1.012 - 1.495.

[0013] Optionally, the steps of obtaining the gas internal dopant concentration on the surface of the silicon liquid and obtaining the temperature on the surface of the silicon liquid include:

[0014] Using a gas dopant concentration detector to obtain the gas internal dopant concentration on the surface of the silicon liquid, and using a temperature detector to obtain the temperature on the surface of the silicon liquid.

[0015] Optionally, the temperature detector includes the non-contact thermometer, and the non-contact thermometer includes at least one of a thermocouple and an infrared thermometer.

[0016] Optionally, the gas dopant concentration detector includes a gas analyzer.

[0017] In the embodiments of the present application, by obtaining the gas internal dopant concentration on the surface of the silicon liquid and obtaining the temperature on the surface of the silicon wafer; according to the gas internal dopant concentration and the temperature, determining the doping concentration of the crystal at the solid-liquid interface of the silicon liquid. Since the doping concentration of the crystal at the solid-liquid interface is equivalent to the resistivity of the head of the single crystal silicon rod. Therefore, by real-time measuring the doping concentration of the crystal at the solid-liquid interface, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod within a suitable range, improving the yield and resistivity concentration of the single crystal silicon rod.

[0018] In a second aspect, the present application also discloses a detection device for the doping concentration of a crystal, and the detection device includes: a computer, a gas dopant concentration detector, and a temperature detector; where

[0019] The gas doping concentration detector is used to detect the gas internal dopant concentration on the surface of the silicon liquid, and the temperature detector is used to detect the temperature on the surface of the silicon liquid;

[0020] The computer is electrically connected to the gas dopant concentration detector and the temperature detector respectively. The computer is configured to determine the doping concentration of the crystal at the solid-liquid interface of the silicon melt according to the dopant concentration in the gas and the temperature.

[0021] In a third aspect, the present application also discloses a method for pulling a silicon rod, the pulling method comprising:

[0022] Providing a main furnace body, wherein a crucible and a heater are arranged in the main furnace body, and the crucible contains silicon material;

[0023] Starting the heater to melt the silicon material into silicon melt;

[0024] Performing a crystal pulling operation in the silicon melt, and detecting the doping concentration of the crystal at the solid-liquid interface of the silicon melt by using the detection method described in any one of the above;

[0025] Adjusting the doping ratio of the feedstock based on the doping concentration of the crystal

[0026] In a fourth aspect, the present application also discloses a device for pulling a silicon rod. The device for pulling a single crystal silicon rod is characterized in that the pulling device comprises: a main furnace body, a crucible, a heater, a temperature detector and a gas dopant concentration detector; wherein,

[0027] The crucible and the heater are arranged in the main furnace body. The crucible is used for containing silicon material, and the heater is used for melting the silicon material into silicon melt;

[0028] The temperature detector and the gas doping concentration detector are both connected to the main furnace body. The gas doping concentration detector at least partially extends into the main furnace body. The temperature detector is used for detecting the temperature of the silicon melt surface, and the gas doping concentration detector is used for detecting the dopant concentration in the gas on the silicon melt surface, so as to determine the doping concentration of the crystal at the solid-liquid interface of the silicon melt according to the dopant concentration in the gas and the temperature.

[0029] Optionally, the temperature detector includes a non-contact thermometer.

[0030] Optionally, the non-contact thermometer includes at least one of a thermocouple and an infrared thermometer.

[0031] Optionally, the gas dopant concentration detector includes a gas analyzer.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0033] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0034] Figure 1 is a schematic structural diagram of a silicon rod drawing device according to an embodiment of the present application;

[0035] Figure 2 is a step flow chart of a method for detecting the doping concentration of silicon liquid according to an embodiment of the present application;

[0036] Figure 3 is a step flow chart of a method for drawing a silicon rod according to an embodiment of the present application.

[0037] Reference numerals: 10 - main furnace body, 11 - crucible, 12 - heater, 13 - temperature detector, 14 - gas dopant concentration detector, 15 - heat exchanger, 16 - thermal insulation cylinder, 17 - thermal shield, 20 - silicon liquid, 30 - single crystal silicon rod. Detailed Embodiments

[0038] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0039] The terms "first" and "second" in the specification and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the related objects before and after.

[0040] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The embodiments of the present application provide a method and device for detecting the doping concentration of silicon liquid, a method for pulling a single crystal silicon rod, and a device for pulling a single crystal silicon rod. The method for detecting the doping concentration of silicon liquid can be used to detect the crystal doping concentration at the solid-liquid interface of the silicon liquid. In a specific application, since the crystal doping concentration at the solid-liquid interface is equivalent to the resistivity of the head of the single crystal silicon rod. Therefore, by measuring the crystal doping concentration at the solid-liquid interface in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod within a suitable range, improving the yield and resistivity concentration of the single crystal silicon rod.

[0043] Referring to Figure 1 , a schematic structural diagram of a device for pulling a silicon rod according to an embodiment of the present application is shown. As Figure 1 shown, the pulling device may specifically include: a main furnace body 10, a crucible 11, a heater 12, a temperature detector 13, and a gas dopant concentration detector 14; wherein, the crucible 11 and the heater 12 are arranged inside the main furnace body 10. The crucible 11 can be used to hold silicon materials, and the heater 12 can be used to melt the silicon materials into silicon liquid 20; the temperature detector 13 and the gas dopant concentration detector 14 are connected to the main furnace body 10. The gas dopant concentration detector 14 at least partially extends into the main furnace body 10. The temperature detector 13 can be used to detect the temperature on the surface of the silicon liquid 20, and the gas doping concentration detector 14 can be used to detect the dopant concentration in the gas on the surface of the silicon liquid 20, so as to determine the doping concentration of the crystal at the solid-liquid interface of the silicon liquid 20 according to the dopant concentration in the gas and the temperature.

[0044] In the embodiments of the present application, by measuring the crystal doping concentration at the solid-liquid interface of the silicon liquid 20 in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod 30 within a suitable range, improving the yield and resistivity concentration of the single crystal silicon rod 30.

[0045] Specifically, the doping ratio for adjusting the feeding can be as follows: When adding silicon material to the crucible 11 again, adjust the ratio of the silicon-based raw material to the dopant in the silicon material. By adjusting the ratio of the silicon-based raw material to the dopant in the newly added silicon material, the doping ratio in the silicon liquid 20 can be adjusted, and accordingly, the doping ratio of the crystal grown from the silicon liquid 20 can be adjusted to achieve the purpose of improving the resistivity of the single-crystal silicon rod 30.

[0046] Specifically, the silicon material can be solid silicon material or liquid silicon material, and the silicon-based raw material can include but is not limited to at least one of single-crystalline silicon material, polycrystalline silicon material, and pulled-back silicon material. The embodiments of the present application do not limit this.

[0047] It should be noted that in the embodiments of the present application, the surface of the silicon liquid can specifically be the surface where the silicon liquid 20 in the crucible 11 contacts the atmosphere in the main furnace body 10. The solid-liquid interface of the silicon liquid 20 can specifically be the interface between the silicon liquid 20 and the crystal grown from the silicon liquid 20.

[0048] In a specific application, the crucible 11 can be a quartz crucible or a graphite crucible, etc. The embodiments of the present invention do not limit the specific type of the crucible 11. The heater 12 can be arranged on the side and / or bottom of the crucible 11 to heat the silicon material in the crucible 11 and melt the silicon material into the silicon liquid 20 so as to grow a single-crystalline silicon rod 30 from the silicon liquid 20. A heat exchanger 15, a heat preservation cylinder 16, and a heat shield 17 can also be arranged in the main furnace body 10. The heat exchanger 15 can be arranged above the crucible 11 and surround the single-crystalline silicon rod 30. The heat exchanger 15 can be used to take away the latent heat of crystallization of the single-crystalline silicon rod 30 to achieve the effect of heat dissipation and increase the crystal growth rate. The heat preservation cylinder 16 can surround the heater 12 to achieve the effect of heat preservation and heat insulation. The heat shield 17 is arranged above the crucible 11 and surrounds the heat exchanger 15. The heat shield 17 can be used to provide a suitable thermal field environment.

[0049] In some alternative embodiments of the present application, the gas doping concentration detector 14 can include a gas analyzer. A probe can be connected to the gas analyzer. The probe can extend into the main furnace body 10 and extend to a position close to the surface of the silicon liquid 20 to measure the temperature of the surface of the silicon liquid 20. Since the gas analyzer is a mature device, its detection limits for common dopants such as boron, Ga, P, Mg, Al, Zn, As, Se, etc. are all around parts per billion concentration (ppb) or higher, and accurate detection of the gas concentration on the surface of the silicon liquid 20 can be achieved.

[0050] It should be noted that when the probe detects the gas on the surface of the silicon liquid 20, the position of the probe needs to be fixed so that the distance between the probe and the surface of the silicon liquid 20 is fixed to improve the detection accuracy.

[0051] Exemplarily, the gas analyzer may include, but is not limited to, at least one of a thermal conductivity gas analyzer, an electro-chemical gas analyzer, and an infrared absorption analyzer. In the embodiments of the present application, the specific type of the gas analyzer may not be limited.

[0052] In some alternative embodiments of the present application, the temperature detector 13 may include a non-contact thermometer, that is, the temperature of the surface of the silicon melt 20 is detected in a non-contact manner to achieve accurate detection of the temperature of the surface of the silicon melt 20.

[0053] Optionally, the non-contact thermometer may include at least one of a thermocouple and an infrared thermometer. In the embodiments of the present application, the specific type of the non-contact thermometer may not be limited. Exemplarily, the infrared thermometer may include, but is not limited to, at least one of an infrared thermal imager and an infrared thermometer.

[0054] It should be noted that in practical applications, the temperature detector 13 may also be a contact thermometer, that is, the temperature of the surface of the silicon melt 20 is directly measured by the temperature detector 13 to improve the detection accuracy of the temperature of the surface of the silicon melt 20. In the embodiments of the present application, the specific form of the temperature detector 13 may not be limited.

[0055] The embodiments of the present application also provide a detection device for the doping concentration of a crystal. The detection device includes: a computer, a gas dopant concentration detector, and a temperature detector; wherein, the gas dopant concentration detector is used to detect the concentration of the gas dopant in the gas on the surface of the silicon melt, and the temperature detector is used to detect the temperature of the surface of the silicon melt; the computer is electrically connected to the gas dopant concentration detector and the temperature detector respectively; the computer is used to determine the doping concentration of the crystal at the solid-liquid interface of the silicon melt according to the concentration of the gas dopant and the temperature.

[0056] In practical applications, since the doping concentration of the crystal at the solid-liquid interface is equivalent to the resistivity of the head of the single crystal silicon rod. Therefore, by measuring the doping concentration of the crystal at the solid-liquid interface in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod within a suitable range, and improve the yield and resistivity concentration of the single crystal silicon rod.

[0057] Specifically, the computer may be an electronic device with a computing function such as a single-chip microcomputer or a central control machine. In the embodiments of the present application, the specific type of the computer may not be limited.

[0058] Refer to Figure 2 , which shows a flowchart of the steps of a method for detecting the doping concentration of a silicon melt according to an embodiment of the present application. As Figure 2 shown, the detection method may specifically include the following steps:

[0059] Step 201: Obtain the concentration of gaseous dopants on the surface of the silicon melt, and obtain the temperature on the surface of the silicon melt.

[0060] In the embodiments of the present application, after melting the silicon material in the crucible into a silicon melt, the concentration of gaseous dopants on the surface of the silicon melt can be obtained, and the temperature on the surface of the silicon melt can be obtained.

[0061] It should be noted that the concentration of gaseous dopants on the surface of the silicon melt can specifically be: the dopant concentration of the furnace gas in the region 12 mm - 30 mm away from the surface of the silicon melt.

[0062] Optionally, a gas dopant concentration detector can be used to obtain the concentration of gaseous dopants on the surface of the silicon melt, and a temperature detector can be used to obtain the temperature on the surface of the silicon melt. The gas dopant concentration detector can specifically be a gas analyzer. Since a gas analyzer is a mature device, its detection limits for common dopants such as Ga and P are both around parts per billion (ppb), and it can achieve accurate detection of the gas concentration on the surface of the silicon melt.

[0063] Optionally, the temperature detector can be a non-contact thermometer, and the non-contact thermometer can include at least one of a thermocouple, an infrared thermal imager, and an infrared thermometer. The embodiments of the present application may not limit the specific type of the non-contact thermometer.

[0064] Step 202: Determine the doping concentration of the crystal at the solid-liquid interface of the silicon melt according to the concentration of gaseous dopants and the temperature.

[0065] In the embodiments of the present application, after obtaining the concentration of gaseous dopants and the temperature on the surface of the silicon melt, the doping concentration of the crystal at the solid-liquid interface of the silicon melt can be determined. Since the doping concentration of the crystal at the solid-liquid interface is equivalent to the resistivity of the head of the single crystal silicon rod. Therefore, by measuring the doping concentration of the crystal at the solid-liquid interface in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod within a suitable range, and improve the yield and resistivity concentration of the single crystal silicon rod.

[0066] In a specific application, there are mainly three transmission paths for dopants in the silicon melt: solid-liquid interface segregation, silicon melt convection mass transfer, dopant volatilization, etc. The main factor affecting the resistivity of the produced single crystal silicon rod is the concentration of dopants in the liquid phase at the solid-liquid interface. In practical applications, the doping concentration at the solid-liquid interface of the silicon melt and the average doping concentration on the surface of the silicon melt can be approximately regarded as a linear relationship, which can be expressed as:

[0067] c crys =k i ·c int =k i·(a·c sur ) (Formula 1)

[0068] Among them, Ccrys is the doping concentration of the crystal at the solid-liquid interface (equivalent to the resistivity of the head of the single crystal silicon rod), ki is the effective segregation coefficient of the dopant, Cint is the dopant concentration of the silicon liquid at the solid-liquid interface, Csur is the average dopant concentration on the surface of the silicon liquid, and α is the linear coefficient.

[0069] It can be seen from Formula 1 that if the average dopant concentration Csur on the surface of the silicon liquid can be measured, the resistivity of the head of the single crystal silicon rod can be measured in real time, and the resistivity distribution of the previous section of the single crystal silicon rod can be obtained in time during subsequent continuous crystal pulling and doping feeding, so as to achieve precise doping. In this way, the resistivity of the head of the subsequent single crystal silicon rod can be controlled within a suitable range, and the yield and resistivity concentration of the single crystal silicon rod can be improved.

[0070] The average dopant concentration on the surface of the silicon liquid affects the evaporation rate of the dopant, which can be expressed as:

[0071]

[0072] Among them, η is the correction coefficient, Mi is the relative atomic mass, γ i is the activity coefficient of the doping element in the silicon liquid, Pi is the saturation vapor pressure of the doping element at temperature T, Pcham is the pressure in the furnace, R is the ideal gas constant, with a value of 8.314 J / (mol·K), ρ i is the liquid density of the doping element, D is the inner diameter of the crucible, H is the height of the silicon liquid, and h is the duration of crystal pulling.

[0073] Specifically, the activity coefficient γ i is an empirical value and is related to the type of dopant. For dopant B (boron element), γ i is between 3.7 and 4.0. For dopant Ga (gallium element), γ i is between 1.6 and 1.8. For dopant P (phosphorus element), γ i is between 0.3 and 0.5. The gas constant R and the density ρ of the doping element i are related to the type of dopant. The duration of crystal pulling h can be the timing time starting from when the silicon material is completely melted into silicon liquid, or the timing time starting from the start of seeding. The inner diameter D of the crucible can specifically be the inner diameter of the straight section at the top of the crucible. The height of the silicon liquid can be calculated based on the remaining material amount in the crucible and the crucible size. Specifically, when the initial height of the silicon liquid is H1, the initial material amount is V1, and the inner diameter D of the straight section of the crucible is known, the height H of the silicon liquid in the crucible can be calculated by detecting the remaining material amount V2 in the silicon liquid. The specific calculation formula is as follows:

[0074]

[0075] Since the gas analyzer can be used to online test the dopant concentration cg in the gas near the surface of the silicon melt, the dopant volatilization rate k can be deduced as follows:

[0076]

[0077] Combining the above formulas (1), (2) and (4), by installing a gas analyzer near the surface of the silicon melt and online detecting the content of the doping element in the atmosphere, the crystal doping concentration can be indirectly calculated as follows:

[0078]

[0079] The temperature T in step 201 can be obtained by using a non-contact thermometer, and η and α can be measured through experiments. Therefore, except for cg, the other parameters are known or can be obtained through conversion or measurement. After Figure 1 the gas analyzer of the single crystal silicon rod drawing device shown measures the dopant concentration cg in the gas, the crystal doping concentration at the solid-liquid interface of the silicon melt can be determined through formula (5).

[0080] Specifically, by testing the dopant concentrations on the surfaces of the silicon melts with different melting powers, different melting times, and different furnace pressures in multiple groups, and through linear fitting, the specific values of η and α can be determined. Through multiple experiments, it can be measured that the value range of η is 0.721 - 0.893, and the value range of α is 1.012 - 1.495.

[0081] To verify the reliability of the crystal doping concentration detection method of the embodiment of the present application, the inventor designed relevant verification experiments, and the specific process is as follows: Use a 32-inch furnace platform to draw phosphorus-doped M10 products. 80 hours after the melting of the charge (that is, the drawing duration h is 80 hours, and at this time the single crystal silicon rod has grown isodiametrically by 350 mm), the phosphorus dopant concentration in the atmosphere on the surface of the silicon melt is detected once every 1 minute by using a gas analyzer, and the change rate of the phosphorus dopant concentration with time is obtained as 0.33 ppma / min. The average liquid surface temperature within 10 minutes is detected by using a temperature detector as 1723 K (the corresponding phosphorus saturation vapor pressure Pi is 2.34 * 10^8 Pa). According to the computer detection data, the height H of the silicon melt at this time is 642 mm. Substitute the above data into formula (5), and calculate that the doping concentration of the crystal at the solid-liquid interface at this time is 7.32 * 10^15 atoms / cm 3 . Similarly, when the lengths of the single crystal silicon rods are 1000 mm, 1500 mm, and 2000 mm respectively, the doping concentrations of the single crystal silicon rods are calculated in the same way. And after the single crystal silicon rod drawing is completed, the knife is broken at the corresponding lengths, and the resistivity at the center of the cross-section is detected and converted to the doping concentration, and the results are shown in the following table.

[0082] Comparison between the calculated value and the measured conversion value of the crystal doping concentration in Table 1

[0083]

[0084] As shown in Table 1, at different lengths of single crystal silicon rods, the difference between the crystal doping concentration calculated by the embodiments of the present application and the crystal doping concentration obtained through actual measurement and conversion is extremely small, and the two show good correlation. The test data shows that before and after applying this solution, the average head resistivity hit rate of the single crystal silicon rods produced by the same group of furnace platforms has increased from 57% to 82%. That is, by measuring the doping concentration of the crystal at the solid-liquid interface in real time and adjusting the doping ratio of the feedstock accordingly, the resistivity of the head of the single crystal silicon rod can be controlled within a suitable range, significantly improving the hit rate of the resistivity of the head of the single crystal silicon rod, thereby achieving the purpose of improving the yield and resistivity concentration of the single crystal silicon rod.

[0085] It should be noted that in practical applications, by measuring the doping concentration of the crystal at the solid-liquid interface in real time, the rotation speed of the crucible can also be adjusted, etc., so as to improve the hit rate of the resistivity of the head of the single crystal silicon rod through the adjustment and cooperation of other process parameters. The embodiments of the present application do not limit this.

[0086] In summary, the method for detecting the doping concentration of silicon liquid described in the embodiments of the present application has at least the following advantages:

[0087] In the embodiments of the present application, by obtaining the concentration of the internal dopant in the gas on the surface of the silicon liquid and obtaining the temperature on the surface of the silicon liquid; according to the concentration of the internal dopant in the gas and the temperature, the doping concentration of the crystal at the solid-liquid interface of the silicon liquid is determined. Since the doping concentration of the crystal at the solid-liquid interface is equivalent to the resistivity of the head of the single crystal silicon rod. Therefore, by measuring the doping concentration of the crystal at the solid-liquid interface in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single crystal silicon rod within a suitable range, improving the yield and resistivity concentration of the single crystal silicon rod.

[0088] Refer to Figure 3 , which shows the step flowchart of a method for pulling a silicon rod described in the embodiments of the present application. As Figure 3 shown, the pulling method specifically may include the following steps:

[0089] Step 301: Provide a main furnace body, which contains a crucible and a heater, and the crucible contains silicon material.

[0090] In the embodiments of the present application, a Figure 1 shown single crystal silicon rod pulling device can be used for pulling a single crystal silicon rod. Specifically, Figure 1The single-crystal silicon rod drawing device shown can be a single-crystal furnace.

[0091] Step 302: Start the heater to melt the silicon material into silicon liquid.

[0092] In the embodiment of the present application, the heater can be used to heat the crucible to melt the silicon material in the crucible to obtain silicon liquid. Specifically, the heater can be correspondingly arranged on the side wall and / or bottom of the crucible, and the power of the heater can also be set according to the actual situation.

[0093] Step 303: Perform a crystal pulling operation in the silicon liquid, and use the detection method described in any of the above embodiments to detect the doping concentration of the crystal at the solid-liquid interface of the silicon liquid.

[0094] In the embodiment of the present application, after melting the silicon material into silicon liquid, the crystal pulling process can be started. Specifically, the crystal pulling process can include processes such as temperature adjustment, seed crystal introduction, shoulder release, shoulder turning, equal diameter, and tailing. Specifically, after starting the temperature adjustment process, the gas analyzer and the non-contact temperature measuring instrument can be started to work, and the doping agent concentration in the gas and the surface temperature of the silicon liquid can be recorded in real time. After obtaining the doping agent concentration in the gas on the surface of the silicon liquid and the temperature of the surface of the silicon liquid, the doping concentration of the crystal at the solid-liquid interface of the silicon liquid can be determined according to the doping agent concentration in the gas and the temperature.

[0095] Step 304: Adjust the doping ratio of the feedstock based on the doping concentration of the crystal.

[0096] In the embodiment of the present application, after obtaining the doping agent concentration in the gas on the surface of the silicon liquid and the temperature, the doping concentration of the crystal at the solid-liquid interface of the silicon liquid can be determined. Since the doping concentration of the crystal at the solid-liquid interface is equivalent to the resistivity of the head of the single-crystal silicon rod. Therefore, by measuring the doping concentration of the crystal at the solid-liquid interface in real time, the doping ratio of the feedstock can be adjusted to control the resistivity of the head of the single-crystal silicon rod within a suitable range, and improve the yield and resistivity concentration of the single-crystal silicon rod.

[0097] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection 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 can be combined in a suitable manner in any one or more embodiments or examples.

[0098] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for detecting the doping concentration of a crystal, characterized in that, The detection method includes: Obtaining the concentration of the gaseous dopant on the surface of the silicon liquid and obtaining the temperature of the surface of the silicon liquid; Determining the doping concentration of the crystal at the solid-liquid interface of the silicon liquid according to the concentration of the gaseous dopant and the temperature.

2. The detection method according to claim 1, characterized in that, The calculation formula for the doping concentration of the crystal is: Among them, Ccrys is the crystal doping concentration at the solid-liquid interface, Cg is the gas internal dopant concentration on the surface of the silicon liquid, ki is the effective segregation coefficient of the dopant, α is the linear coefficient, where η is the correction coefficient, Mi is the relative atomic mass, γ i is the activity coefficient of the dopant element in the silicon liquid, Pi is the saturation vapor pressure of the dopant element at temperature T, Pcham is the furnace pressure, R is the gas constant, ρ i is the dopant element density, D is the inner diameter of the crucible, H is the height of the silicon liquid, and h is the crystal pulling duration.

3. The detection method according to claim 2, characterized in that, The value range of η is 0.721 - 0.893, and the value range of α is 1.012 - 1.

495.

4. The detection method according to claim 1, characterized in that, The step of obtaining the concentration of the gaseous dopant on the surface of the silicon liquid and obtaining the temperature of the surface of the silicon liquid includes: Using a gaseous dopant concentration detector to obtain the concentration of the gaseous dopant on the surface of the silicon liquid, and using a temperature detector to obtain the temperature of the surface of the silicon liquid.

5. The detection method according to claim 4, characterized in that, The temperature detector includes the non-contact thermometer, and the non-contact thermometer includes at least one of a thermocouple and an infrared thermometer.

6. The detection method according to claim 4, characterized in that, The gaseous dopant concentration detector includes a gas analyzer.

7. A device for detecting the doping concentration of a crystal, characterized in that, The detection device includes: a computer, a gaseous dopant concentration detector, and a temperature detector; wherein, The gaseous dopant concentration detector is used to detect the concentration of the gaseous dopant on the surface of the silicon liquid, and the temperature detector is used to detect the temperature of the surface of the silicon liquid; The computer is electrically connected to the gaseous dopant concentration detector and the temperature detector respectively, and the computer is used to determine the doping concentration of the crystal at the solid-liquid interface of the silicon liquid according to the concentration of the gaseous dopant and the temperature.

8. A method for drawing a silicon rod, characterized in that, The pulling method includes: Providing a main furnace body, wherein a crucible and a heater are installed in the main furnace body, and the crucible contains silicon materials; Starting the heater to melt the silicon materials into silicon liquid; Performing a crystal pulling operation on the silicon liquid, and using the detection method according to any one of claims 1 to 7 to detect the doping concentration of the crystal at the solid-liquid interface of the silicon liquid; Adjusting the doping ratio of the feeding based on the doping concentration of the crystal.

9. A device for drawing a silicon rod, characterized in that, The pulling device includes: a main furnace body, a crucible, a heater, a temperature detector, and a gaseous dopant concentration detector; wherein, The crucible and the heater are arranged in the main furnace body, the crucible is used to contain silicon materials, and the heater is used to melt the silicon materials into silicon liquid; The temperature detector and the gaseous dopant concentration detector are connected to the main furnace body, at least a part of the gaseous dopant concentration detector extends into the main furnace body, the temperature detector is used to detect the temperature of the surface of the silicon liquid, and the gaseous dopant concentration detector is used to detect the concentration of the gaseous dopant on the surface of the silicon liquid to determine the doping concentration of the crystal at the solid-liquid interface of the silicon liquid according to the concentration of the gaseous dopant and the temperature.

10. The drawing device according to claim 9, characterized in that, The temperature detector includes a non-contact thermometer.

11. The drawing device according to claim 10, characterized in that, The non-contact thermometer includes at least one of a thermocouple and an infrared thermometer.

12. The drawing device according to claim 9, characterized in that, The gaseous dopant concentration detector includes a gas analyzer.

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