CN106637385A - Cz (Czochralski) crystal heater convenient for temperature gradient regulation and Cz crystal method - Google Patents

Abstract

In the heater for Czochralski single crystal that is convenient for adjusting the temperature gradient of the present invention, the heater body has a first end portion and a second end portion opposite to each other, and a first slot is provided extending from the first end portion to the second end portion and along the The second end portion extends toward the first end portion to provide second slots, the first slots and the second slots are arranged alternately, and part or all of the second slots are adjustment slots for adjusting heat distribution. The Czochralski single crystal method of the present invention comprises the steps of: charging materials; forming a melt by using the aforementioned heater material; adjusting the power of the heater, controlling the longitudinal temperature gradient of the melt, inserting the seed crystal into the surface of the melt for welding, and Single crystal silicon is obtained after seeding, shouldering, shoulder turning, equal-diameter growth, and finishing in sequence. The Czochralski single crystal heater and the Czochralski single crystal method of the present invention, which can adjust the heating power by adjusting the tank, can obtain different temperature distributions, and can form a single crystal that is suitable for high pulling speed, low impurity content, and low defects. A desired, optimized temperature gradient.

Description

Heater for Czochralski single crystal and Czochralski single crystal method for easy adjustment of temperature gradient

technical field

The invention belongs to the technical field of monocrystalline silicon manufacture, and in particular relates to a heater for Czochralski single crystal that is convenient for adjusting temperature gradient, and also relates to a Czochralski single crystal method using the aforementioned heater for Czochralski single crystal that is convenient for adjusting temperature gradient.

Background technique

The Czochralski method is also known as the Czochralski method, or CZ method for short. The characteristic of the CZ method is that the polysilicon material in the crucible is used to form a melt, and then the seed crystal is inserted into the surface of the melt for welding, and the seed crystal is rotated and lifted at the same time. Growth and finishing process, pulling and growing silicon single crystal. With the development of photovoltaic industry, the production cost and finished product quality of Czochralski are facing higher requirements. The thermal field is closely related to a series of parameters such as single crystal pulling speed, impurity content and defect distribution, and directly affects the cost and quality of Czochralski single crystal. The existing Czochralski single crystal thermal field usually adopts a square wave heater made by slotting the cylindrical graphite element. Its control method is single and the heating power is relatively fixed. It is difficult to cooperate with other components of the thermal field to form an optimized temperature. The distribution has gradually failed to keep up with the needs of industrial development.

Contents of the invention

The object of the present invention is to provide a heater for Czochralski single crystal which is convenient for adjusting the temperature gradient, and the temperature parameter of Czochralski single crystal growth can be conveniently adjusted by using it.

The object of the present invention is also to provide a Czochralski single crystal method using the aforementioned heater for Czochralski single crystal which is convenient for adjusting the temperature gradient, which can conveniently adjust the single crystal growth process, thereby improving the quality of the Czochralski single crystal.

A technical solution adopted in the present invention is: a heater for Czochralski single crystal that is convenient for adjusting the temperature gradient, including a heater body, the heater body has a first end portion and a second end portion opposite to each other, and along the first end portion There are a plurality of first slots extending toward the second end and a plurality of second slots extending toward the first end along the second end, the plurality of first slots and the second slots are alternately arranged, and the plurality of Part or all of the second slots are regulating slots for regulating heat distribution.

The present invention is also characterized in that,

The plurality of adjustment slots are distributed symmetrically with respect to the central axis of the heater body.

A heating unit is formed between two adjacent first slots, and the length of the heating unit where the adjustment groove is located along the axial direction of the heater body is less than or equal to the distance between the first end and the second end of the heater body .

Part of the plurality of second slots is an adjustment slot for adjusting heat distribution, and the length of the adjustment slot is shorter than that of the rest of the second slots.

From the second end to the first end, the cross-sectional area of the adjustment slot along the direction perpendicular to the centerline of the heater body gradually decreases.

From the second end to the first end, the cross-sectional area of the adjustment groove along the direction perpendicular to the central line of the heater body becomes gradually larger.

Another technical scheme adopted in the present invention is: the Czochralski single crystal method, comprising the following steps:

charging;

Utilize the aforementioned Czochralski single crystal heater compound which is convenient to adjust the temperature gradient to form a melt;

Adjust the power of the Czochralski single crystal heater that is easy to adjust the temperature gradient, control the longitudinal temperature gradient of the melt, insert the seed crystal into the surface of the melt for welding, and perform seeding, shouldering, shoulder turning, equal diameter growth and Monocrystalline silicon is obtained after finishing.

The present invention is also characterized in that,

During the isometric growth process, keep the crystal rotation at 8-14rpm, the crucible at 4-10rpm, the argon gas flow at 50-90slpm, and the furnace pressure at 10-20Torr.

The heater for Czochralski single crystal that is convenient to adjust the temperature gradient includes a heater body, the heater body has a first end and a second end opposite to each other, and a plurality of first The slot and a plurality of second slots extending from the second end to the first end, the plurality of first slots and the second slots are arranged alternately, and part or all of the plurality of second slots are adjustable Regulating tank for heat distribution.

A heating unit is formed between two adjacent first slots, and the length of the heating unit where the adjustment groove is located along the axial direction of the heater body is less than or equal to the distance between the first end and the second end of the heater body .

The beneficial effects of the present invention are: the Czochralski single crystal heater and the Czochralski single crystal method of the present invention, which are convenient to adjust the temperature gradient, use the adjustment tank to adjust the heating power, so that different temperature distributions can be obtained, and can be formed to adapt to high pulling speed, Optimized temperature gradient for various requirements such as low impurity content and low defects.

Description of drawings

Fig. 1 is a kind of structural representation of the heater of the Czochralski single crystal that is convenient to adjust temperature gradient of the present invention;

Fig. 2 is another structural schematic diagram of the heater for Czochralski single crystal which is convenient for adjusting the temperature gradient of the present invention.

In the figure, 10. first end, 20. second end, 1. first slot, 2. second slot, 3. heating unit, 21. adjustment slot.

detailed description

The heater for Czochralski single crystal that is convenient for adjusting the temperature gradient provided by the present invention includes a heater body with opposite first end portions 10 and second end portions 20, and the heater body has a plurality of first end portions 10 The first slot 1 extending to the second end 20 and the plurality of second slots 2 extending from the second end 20 to the first end 10, the plurality of first slots 1 and the plurality of second slots 2 alternate settings. Part or all of the plurality of second slots 2 are regulating grooves 21 for regulating heat distribution.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1

The structure of the Czochralski single crystal heater for adjusting the temperature gradient in this embodiment is shown in FIG. 1 . The heater body has opposite first end portions 10 and second end portions 20 . The heater body has a plurality of first slots 1 extending from the first end 10 to the second end 20 and a plurality of second slots 2 extending from the second end 20 to the first end 10. The first slots 1 and multiple second slots 2 are arranged alternately. Part or all of the plurality of second slots 2 are adjustment grooves 21 for adjusting heat distribution, and the plurality of adjustment grooves 21 are distributed symmetrically with respect to the central axis of the Czochralski single crystal heater. In this embodiment, a part of the plurality of second slots 2 is an adjustment slot 21 for adjusting heat distribution, and in all the second slots 2, the adjustment slots 21 are arranged at intervals among the plurality of second slots 2, that is, There is a second slot 2 between two adjacent adjustment slots 21 . The length of the adjustment groove 21 is smaller than the length of the remaining second slots 2 . Certainly, as required, there may be zero, two, three or more other second slots 2 between two adjacent adjustment slots 21 , and the configurations may be changed according to the requirement of temperature regulation.

A heat generating unit 3 is formed between two adjacent first slots 1, and the length of the heat generating unit 3 where the regulating groove 21 is located along the axial direction of the heater body is less than or equal to the first end 10 and the length of the heater body. The distance between the second ends 20 . In this embodiment, the length of the heating unit 3 where the adjustment groove 21 is located along the axial direction of the heater body is equal to the distance between the first end 10 and the second end 20 of the heater body. The length of the rest of the heating units 3 without the adjusting groove 21 along the axial direction of the heater body is equal to the distance between the first end 10 and the second end 20 of the heater body. In this embodiment, the first end portion 10 and the second end portion 20 are respectively located at the upper end and the lower end in the figure, but it is not limited to only this way.

Of course, the shape of the regulating groove 21 can also be changed, so that from the second end 20 to the inside of the heating unit 3, the cross-sectional area of the regulating groove 21 perpendicular to the centerline direction of the heater body gradually decreases or becomes smaller according to the heating regulation requirements. big.

The Czochralski single crystal heater in this embodiment is convenient to adjust the temperature gradient. There is a temperature difference between the heating unit where the adjustment tank 21 is located and other heating units, thereby forming a heat distribution adjustable heat distribution in the Czochralski single crystal heater. field.

Example 2

The structure of the heater for the Czochralski single crystal that is convenient for adjusting the temperature gradient of this embodiment is shown in Figure 2, which is roughly the same as the technical solution of Embodiment 1, the difference is that the heating unit where the adjustment tank 21 of this embodiment is located The length of 3 is less than the distance between the first end 10 and the second end 20 of the heater body, and the length of the adjustment groove 21 is less than the distance between the first end 10 and the second end 20 of the heater body. Of course, the shape of the regulating groove 21 can also be changed, so that from the second end 20 to the inside of the heating unit 3, the cross-sectional area of the regulating groove 21 perpendicular to the centerline direction of the heater body gradually decreases or becomes smaller according to the heating regulation requirements. big.

The Czochralski single crystal heater of this embodiment is convenient to adjust the temperature gradient. The length of the heating unit 3 where the adjustment groove 21 is located is smaller than the distance between the first end 10 and the second end 20 of the heater body, which can provide a larger temperature difference.

The present invention also provides a Czochralski single crystal method that uses the heater for Czochralski single crystal that is convenient to adjust the temperature gradient as described above. This method can be used to manufacture Czochralski single crystals of various sizes. Here, 8 inches is taken as an example. , illustrating the Czochralski method. Specifically, the method includes the following steps:

The first step is charging. Clean the single crystal furnace according to the conventional method, install the thermal field, and start adding polysilicon after confirming that there is no fault. The feeding amount is 200kg.

In the second step, the chemical material is used to form a melt, and the power of the Czochralski single crystal heater for adjusting the temperature gradient as mentioned above is increased to about 85kw, and the argon flow rate is kept at 50-90slpm, and the furnace pressure is at 10-20Torr. The crucible rotates 4-9 rpm, and the polysilicon melts to form a melt;

The third step is to use the conventional process to sequentially perform seeding, shouldering, shoulder turning and equal diameter growth, and finally finish and cool. After the seeding length reaches 150mm, put shoulders and turn shoulders; when the diameter is equal, keep the crystal rotation 8-14rpm, the crucible rotation 4-10rpm, the argon gas flow rate is 50-90slpm, and the furnace pressure is 10-20Torr, which can realize crystal growth The average casting speed is 1.2mm/min; after finishing, the furnace can be disassembled after cooling.

In the Czochralski single crystal method of this embodiment, the Czochralski single crystal heater that is convenient for adjusting the temperature gradient is used to form an optimized temperature gradient that meets various requirements such as high pulling speed, low impurity content, and low defect.

Claims (10)

1. The heater for Czochralski single crystal that is convenient to adjust the temperature gradient is characterized in that it includes a heater body, and the heater body has opposite first end portions (10) and second end portions (20), along the first end portion (10) and second end portion (20). A plurality of first slots (1) are extended from one end (10) to the second end (20) and a plurality of second slots are extended from the second end (20) to the first end (10). The slots (2), the plurality of first slots (1) and the second slots (2) are alternately arranged, and part or all of the plurality of second slots (2) are for adjusting the heat distribution Groove (21). 2. The heater for Czochralski single crystal that facilitates temperature gradient adjustment according to claim 1, characterized in that the plurality of adjustment grooves (21) are distributed symmetrically with respect to the central axis of the heater body. 3. The heater for Czochralski single crystal that is convenient for adjusting temperature gradient as claimed in claim 1, characterized in that, a heating unit (3) is formed between two adjacent first slots (1), so that The length of the heating unit (3) where the adjustment groove (21) is located along the axial direction of the heater body is less than or equal to the distance between the first end (10) and the second end (20) of the heater body distance. 4. The heater for Czochralski single crystal that is convenient for adjusting the temperature gradient according to any one of claims 1-3, characterized in that, the parts in the plurality of second slots (2) are for adjusting the heat distribution A slot (21), the length of the adjustment slot (21) is smaller than the length of the remaining second slots (2). 5. The heater for Czochralski single crystal that is convenient for adjusting the temperature gradient according to claim 4, characterized in that, from the second end (20) to the first end (10) direction, the adjustment groove (21) The cross-sectional area along the direction perpendicular to the central line of the heater body gradually becomes smaller. 6. The heater for Czochralski single crystal that is convenient for adjusting temperature gradient as claimed in claim 4, characterized in that, from the second end (20) to the first end (10) direction, the adjustment groove (21) The cross-sectional area along the direction perpendicular to the central line of the heater body becomes gradually larger. 7. Czochralski single crystal method, is characterized in that, comprises the following steps: charging; Utilizing the heater compound for Czochralski single crystal that is convenient for adjusting the temperature gradient as described in any one of claims 1-6 to form a melt; Adjusting the power of the Czochralski single crystal heater that is convenient for adjusting the temperature gradient, controlling the longitudinal temperature gradient of the melt, inserting the seed crystal into the surface of the melt for welding, and sequentially performing seeding, shouldering, shoulder turning, Monocrystalline silicon is obtained after equal diameter growth and finishing. 8. The Czochralski single crystal method as claimed in claim 7, characterized in that, during the isodiametric growth process, the holding crystal rotation is 8-14rpm, the crucible rotation is 4-10rpm, and the argon gas flow rate is 50-90slpm, The furnace pressure is 10-20 Torr. 9. The Czochralski single crystal method according to claim 7, wherein the heater for the Czochralski single crystal that is convenient for adjusting the temperature gradient comprises a heater body, and the heater body has opposite first ends (10) and the second end (20), extending along the first end (10) to the second end (20) is provided with a plurality of first slots (1) and along the second end (20) to The first end (10) is extended with a plurality of second slots (2), the plurality of first slots (1) and second slots (2) are alternately arranged, and the plurality of second slots In (2), part or all of them are regulating grooves (21) for regulating heat distribution. 10. The Czochralski method according to claim 9, characterized in that a heating unit (3) is formed between two adjacent first slots (1), and the adjustment slot (21) is The length of the heating unit (3) at the axial direction of the heater body is less than or equal to the distance between the first end (10) and the second end (20) of the heater body.