CN-122013303-A - Monocrystalline silicon rod and production method and production equipment thereof

CN122013303ACN 122013303 ACN122013303 ACN 122013303ACN-122013303-A

Abstract

The application provides a monocrystalline silicon rod, a production method and equipment thereof, wherein the production method of the monocrystalline silicon rod comprises the following steps of S1, paving a polycrystalline silicon material at the bottom of a quartz crucible of a monocrystalline furnace, S2, placing a polycrystalline silicon retaining wall in the quartz crucible, wherein the polycrystalline silicon retaining wall is a cylindrical wall body with two through axial ends, the outer diameter of the polycrystalline silicon retaining wall is matched with the inner diameter of the quartz crucible, S3, filling the polycrystalline silicon material into the polycrystalline silicon retaining wall, S4, heating the quartz crucible through the monocrystalline furnace to enable the polycrystalline silicon material to be melted into a silicon melt, and S5, carrying out Czochralski crystal growth on the silicon melt in the polycrystalline silicon retaining wall to obtain the monocrystalline silicon rod. Since the polysilicon charge is filled in the inner space of the polysilicon retaining wall and the bottom of the crucible below. After the melting material, the peripheral side of the silicon melt is surrounded by the polycrystalline silicon retaining wall, so that the physical isolation between the silicon melt and the side wall of the quartz crucible is realized, the most main oxygen introduction source is greatly reduced, and the quality of the obtained monocrystalline silicon rod is improved.

Inventors

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Assignees

无锡松瓷机电有限公司

Dates

Publication Date: 20260512
Application Date: 20260319
Priority Date: 20260109

Claims (10)

1. A method for producing a single crystal silicon rod, characterized in that the method comprises the steps of: S1, paving a polycrystalline silicon material at the bottom of a quartz crucible of a single crystal furnace; S2, placing a polycrystalline silicon retaining wall in the quartz crucible, wherein the polycrystalline silicon retaining wall is a cylindrical wall body with two through axial ends, and the outer diameter of the polycrystalline silicon retaining wall is matched with the inner diameter of the quartz crucible; s3, filling the polysilicon material into the polysilicon guard wall; s4, heating the quartz crucible through a single crystal furnace to enable the polycrystalline silicon material to be melted into a silicon melt; S5, carrying out Czochralski crystal growth on the silicon melt in the polycrystalline silicon retaining wall to obtain a monocrystalline silicon rod.
2. The method for producing a single crystal silicon rod according to claim 1, wherein the outer diameter of the polycrystalline silicon protection wall is 2mm to 3mm smaller than the inner diameter of the quartz crucible, and the wall thickness of the polycrystalline silicon protection wall is 10 mm to 15mm.
3. The method for producing a single crystal silicon rod as defined in claim 1 wherein the purity of the polycrystalline silicon protection wall is not lower than 99.9999%.
4. The method for producing a single crystal silicon rod as set forth in claim 1, wherein in step S3, the filling amount of the polycrystalline silicon material filled into the polycrystalline silicon retaining wall is set such that the liquid level of the silicon melt after melting is lower than the top end opening of the polycrystalline silicon retaining wall.
5. The method for producing a silicon single crystal rod according to claim 1, wherein the single crystal furnace has a bottom heater located at a lower side of the quartz crucible, and a main heater located at a peripheral side of the quartz crucible; in step S4, heating the quartz crucible by a single crystal furnace includes: Starting the bottom heater and the main heater, and controlling the heating power ratio of the bottom heater to the main heater to be (2.5-3.5): 2; monitoring the melting state of the polysilicon material in the polysilicon protective wall, and dynamically adjusting the heating power of the bottom heater and the main heater along with the reduction of the solid-to-liquid ratio of the solid polysilicon material to molten silicon liquid in the quartz crucible so as to form a temperature gradient with the lower temperature higher than the upper temperature in the quartz crucible; when the polysilicon material in the polysilicon guard wall is completely melted, the heating power ratio of the bottom heater and the main heater is controlled to be the same as the heating power ratio at the starting time, so that the polysilicon material in the polysilicon guard wall is kept in a molten state.
6. The method for producing a silicon single crystal rod according to claim 5, wherein the heating power of the bottom heater and the main heater is adjusted according to the solid-to-liquid ratio as shown in the following table: 。
7. The single crystal silicon rod production method as set forth in claim 4 wherein in step S4, the single crystal silicon rod production method further comprises controlling the rotation of the quartz crucible at a rotation speed of 1 to 3rpm while heating the quartz crucible by the single crystal furnace.
8. The method for producing a silicon single crystal rod according to claim 1, wherein the polysilicon retaining wall is produced by cutting and cleaning a hollow cylindrical polysilicon ingot which is scraped due to cracking of the inner wall.
9. A single crystal silicon rod production apparatus for carrying out the single crystal silicon rod production method according to any one of claims 1 to 8, comprising: A quartz crucible; A cylindrical polycrystalline silicon retaining wall, wherein the outer diameter of the cylindrical polycrystalline silicon retaining wall is matched with the inner diameter of the quartz crucible; the single crystal furnace is provided with a bottom heater and a main heater which can independently control the temperature; a control system configured to execute the heating power control program of claim 5 or claim 6.
10. A single crystal silicon rod, characterized in that the single crystal silicon rod is produced by the single crystal silicon rod production method according to any one of claims 1 to 8.

Description

Monocrystalline silicon rod and production method and production equipment thereof Technical Field The application relates to the field of monocrystalline silicon rod production, in particular to a monocrystalline silicon rod, a production method and production equipment thereof. Background Under the trend of the photovoltaic industry towards higher photoelectric conversion efficiency, the quality of monocrystalline silicon wafers becomes one of key constraint factors. Wherein the oxygen content in the monocrystalline silicon wafer is one of the key parameters affecting the electrical properties of the wafer and the final cell efficiency. Too high an oxygen content may form oxygen-related recombination centers and may generate defects in the subsequent thermal process, significantly reducing minority carrier lifetime, thereby compromising the conversion efficiency of the battery. Currently, the Czochralski method is the dominant technique for preparing single crystal silicon. Research shows that the oxygen impurity in the body of monocrystalline silicon grown by the method mainly comes from a quartz crucible serving as a melting container. The main component of the quartz crucible is silicon dioxide, and molten silicon is in continuous contact with the inner wall of the quartz crucible in the long-time high-temperature process, and chemical reaction and physical erosion are caused. Under this condition, the oxygen element in the quartz crucible is continuously dissolved and migrates to the inside of the silicon melt. As the crystal grows, these oxygen atoms are trapped by the growing crystal lattice, eventually leading to a high as-crystallized oxygen content, which makes it difficult to meet the increasingly stringent requirements of high-efficiency cell components for low oxygen content of silicon wafer raw materials. Therefore, how to effectively inhibit or reduce oxygen pollution from a quartz crucible under the existing process frame of the Czochralski method becomes a key technical bottleneck for improving the quality of the photovoltaic monocrystalline silicon material and further promoting the breakthrough of the battery efficiency. Disclosure of Invention In order to solve the technical problems, the application provides a production method of a monocrystalline silicon rod, which comprises the following steps: a method for producing a single crystal silicon rod, comprising the following steps: S1, paving a polycrystalline silicon material at the bottom of a quartz crucible of a single crystal furnace; S2, placing a polycrystalline silicon retaining wall in the quartz crucible, wherein the polycrystalline silicon retaining wall is a cylindrical wall body with two through axial ends, and the outer diameter of the polycrystalline silicon retaining wall is matched with the inner diameter of the quartz crucible; S3, filling the polysilicon material into the polysilicon guard wall; S4, heating the quartz crucible through the single crystal furnace to enable the polycrystalline silicon material to be melted into silicon melt; s5, carrying out Czochralski single crystal growth on the silicon melt in the polycrystalline silicon retaining wall to obtain a single crystal silicon rod. According to the production process of the monocrystalline silicon rod, a cylindrical polycrystalline silicon retaining wall is arranged in the quartz crucible, and the outer wall of the polycrystalline silicon retaining wall is close to the inner wall of the quartz crucible. During charging, the polysilicon material is filled in the inner space of the polysilicon retaining wall and the bottom of the crucible below. After the melting material, the peripheral side of the silicon melt is surrounded by the polycrystalline silicon retaining wall, so that the physical isolation between the silicon melt and the side wall of the quartz crucible is realized, the most main oxygen introduction source is greatly reduced, and the quality of the obtained monocrystalline silicon rod is improved. In some embodiments, the outer diameter of the polysilicon retaining wall is 2 mm-3 mm smaller than the inner diameter of the quartz crucible, and the wall thickness of the polysilicon retaining wall is 10 mm-15 mm. The outer diameter of the polycrystalline silicon retaining wall is set to be 2 mm-3 mm smaller than the inner diameter of the quartz crucible, allowance is reserved for deformation of the quartz crucible, and meanwhile the polycrystalline silicon retaining wall is facilitated to be smoothly placed into the quartz crucible. The wall thickness of the polycrystalline silicon retaining wall is set to be 10 mm-15 mm, and after all polycrystalline silicon materials filled in the polycrystalline silicon retaining wall are melted into silicon melt, the polycrystalline silicon retaining wall is not melted through, and physical isolation is carried out on the silicon melt and the side wall of the quartz crucible. In some embodiments, the purity of t