Heater for drawing single crystal and single crystal furnace system

Abstract

The utility model provides a heater for drawing single crystal and a single crystal furnace system, which comprise an upper heating structure, a middle heating structure and a lower heating structure which are coaxially arranged and are sequentially arranged along the direction from the top end to the bottom of a quartz crucible, the upper heating structure, the middle heating structure and the lower heating structure are connected with the first electrode pin and the second electrode pin respectively, and the height of the upper heating structure, the height of the middle heating structure and the height of the lower heating structure are different in the axial direction of the upper heating structure. The upper heating structure, the middle heating structure and the lower heating structure are different in resistance and are connected in parallel, so that the upper heating structure, the middle heating structure and the lower heating structure are different in heating value, and the protruding height of a solid-liquid interface during single crystal drawing can be reduced; and a solid-liquid interface becomes flat.

Description

TECHNICAL FIELD

[0001] The utility model belongs to single crystal drawing technical field especially is concerned with a kind of heater for drawing single crystal and single crystal furnace system. BACKGROUND

[0002] With the resistivity requirement of heavy doped single crystal lower and lower, single crystal appears broken wire problem in growth process, and affects the output of low resistivity single crystal. The main reason is that, in the single crystal growth process, the solid-liquid growth interface is too convex, which causes the impurities to gather in the boundary layer center, and the composition undercooling occurs, causing single crystal broken wire. SUMMARY

[0003] In view of the above problems, the utility model provides a kind of heater for drawing single crystal and single crystal furnace system to solve the above or other former problems existing in prior art.

[0004] To solve the above technical problems, the utility model adopts the technical scheme of a kind of heater for drawing single crystal, including coaxially arranged upper heating structure, middle heating structure and lower heating structure, upper heating structure, middle heating structure and lower heating structure are sequentially arranged along the top end to the bottom direction of quartz crucible, upper heating structure, middle heating structure and lower heating structure are connected with first electrode foot and second electrode foot respectively, along the axial direction of upper heating structure, the height of upper heating structure, the height of middle heating structure and the height of lower heating structure are not the same.

[0005] Further, the height of lower heating structure is less than the height of middle heating structure, and the height of middle heating structure is less than the height of upper heating structure.

[0006] Further, the height ratio of upper heating structure, middle heating structure and lower heating structure is 4:2:1 or 6:3:2.

[0007] Further, the first electrode foot and the second electrode foot are oppositely arranged.

[0008] Further, the gap between upper heating structure and middle heating structure and the gap between middle heating structure and lower heating structure are the same.

[0009] Further, upper heating structure, middle heating structure and lower heating structure each include a plurality of first and last sequentially connected blades, and the number of blades of upper heating structure, the number of blades of middle heating structure and the number of blades of lower heating structure are consistent.

[0010] Further, the blade is U-shaped or V-shaped.

[0011] Further, the first electrode leg and the second electrode leg are connected with the positive pole and the negative pole of the power supply respectively, and the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel.

[0012] A single crystal furnace system comprises a quartz crucible and a heater for pulling single crystal as described above, the heater is arranged around the periphery of the quartz crucible, and the upper heating structure, the middle heating structure and the lower heating structure are coaxially arranged with the quartz crucible.

[0013] Further, the upper heating structure corresponds to the upper part of the quartz crucible, the middle heating structure corresponds to the middle part of the quartz crucible, and the lower heating structure corresponds to the lower part of the quartz crucible, so as to heat the upper part, the middle part and the lower part of the quartz crucible.

[0014] By adopting the above technical scheme, the heater has the coaxially arranged upper heating structure, middle heating structure and lower heating structure, the upper heating structure, the middle heating structure and the lower heating structure are arranged around the periphery of the quartz crucible, and the upper heating structure, the middle heating structure and the lower heating structure heat the upper part, the middle part and the lower part of the quartz crucible respectively, the height of the upper heating structure, the height of the middle heating structure and the height of the lower heating structure are different along the axial direction of the upper heating structure, so that the resistances of the upper heating structure, the middle heating structure and the lower heating structure are different, the heat generation amounts of the upper heating structure, the middle heating structure and the lower heating structure are different, the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel with the power supply, the heat generation amount distribution in the axial direction of the heater is controlled, so that the protrusion height of the solid-liquid interface during crystal pulling is controlled; when the height of the upper heating structure is greater than the height of the middle heating structure, the height of the middle heating structure is greater than the height of the lower heating structure, the resistance of the upper heating structure is greater than the resistance of the middle heating structure, and the resistance of the middle heating structure is greater than the resistance of the lower heating structure, the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel with the two ends of the power supply through the first electrode leg and the second electrode leg, so that the heat generation amount of the upper heating structure is the smallest, the heat generation amount of the lower heating structure is the largest, the overall heat generation amount of the heater is lowered, the protrusion height of the solid-liquid interface during single crystal pulling is reduced, the solid-liquid interface is flattened, the problem of broken sprue caused by single crystal component undercooling is solved, and the stability of pulling heavy-doped low-resistivity single crystal is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic view of the heater of an embodiment of the utility model;

[0016] Figure 2 is an equivalent circuit structural schematic view of the heater of an embodiment of the utility model;

[0017] Figure 3is a structural schematic view of a single crystal furnace system of an embodiment of the utility model;

[0018] Figure 4 is a structural schematic view of a single crystal furnace system using a heater in the prior art.

[0019] In the figure:

[0020] 1, upper heating structure 2, middle heating structure 3, lower heating structure

[0021] 4, first electrode foot 5, second electrode foot 6, blade

[0022] 7, silicon melt 8, heat flow 9, solid-liquid interface

[0023] 100, heater DETAILED DESCRIPTION

[0024] The utility model will be further explained in connection with the drawings and specific embodiments.

[0025] Figure 1 A structural schematic view of an embodiment of the utility model is shown, and the embodiment relates to a heater for drawing single crystal and a single crystal furnace system, the heater has upper heating structure, middle heating structure and lower heating structure, the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel, the height of the upper heating structure, the height of the middle heating structure and the height of the lower heating structure are not same, the lower heating structure has the maximum heat output, so that the solid-liquid interface protruding height is reduced in the single crystal growth process, and it is beneficial to the drawing of heavy-doped low resistivity single crystal.

[0026] A heater 100 for drawing single crystal, such as Figure 1As shown, the quartz crucible heating device comprises the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 arranged coaxially, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are arranged in sequence along the top-to-bottom direction of the quartz crucible, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are used for heating the quartz crucible, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected with the first electrode leg 4 and the second electrode leg 5 respectively, that is, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected with the first electrode leg 4, and at the same time, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected with the second electrode leg 5, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected in parallel, along the axial direction of the upper heating structure 1, the height of the upper heating structure 1, the height of the middle heating structure 2 and the height of the lower heating structure 3 are not the same, so that the heat generation of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 is not the same, thereby controlling the increase of the heating amount of the middle and lower parts of the quartz crucible, thereby reducing the convex height of the solid-liquid interface 9 when the single crystal is drawn.

[0027] Specifically, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are annular structures, which are adapted to the shape of the circumferential side wall of the quartz crucible, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 can be arranged around the circumferential side of the quartz crucible to heat the quartz crucible. The diameter of the upper heating structure 1, the diameter of the middle heating structure 2 and the diameter of the lower heating structure 3 are the same, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are located on the same circumferential surface, and the diameter of the upper heating structure 1 is greater than the outer diameter of the quartz crucible, the upper heating structure 1 is arranged coaxially with the quartz crucible, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are at the same distance from the outer circumferential side of the quartz crucible, and the distance of heat transfer is the same.

[0028] Specifically, the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 each comprise a plurality of blades 6 connected in sequence, for example, the upper heating structure 1 comprises n blades 6, the first blade 6 is connected with the second blade 6, the second blade 6 is connected with the third blade 6, and so on, the n-1 blade 6 is connected with the n blade 6, and the n blade 6 is connected with the first blade 6, each blade 6 is connected with one blade 6 on both sides to form an annular upper heating structure 1. The number of blades 6 of the upper heating structure 1, the number of blades 6 of the middle heating structure 2 and the number of blades 6 of the lower heating structure 3 are consistent, and in some embodiments, the number of blades 6 of the upper heating structure 1, the number of blades 6 of the middle heating structure 2 and the number of blades 6 of the lower heating structure 3 are preferably 24-36.

[0029] The above-mentioned blade 6 is U-shaped or V-shaped, and comprises a first connecting portion and a second connecting portion connected to each other, and the connection between the first connecting portion and the second connecting portion is U-shaped or V-shaped. The structure of the blade 6 is a prior art, which will not be described in detail here.

[0030] In the upper heating structure 1, the plurality of blades 6 are located on the same circumferential surface, the corresponding axial one ends of the plurality of blades 6 are located on the same circle, and the corresponding axial other ends of the plurality of blades 6 are also located on the same circle, that is, the height of each blade 6 along the axial direction of the upper heating structure 1 is the same; in the middle heating structure 2, the plurality of blades 6 are located on the same circumferential surface, the corresponding axial one ends of the plurality of blades 6 are located on the same circle, and the corresponding axial other ends of the plurality of blades 6 are also located on the same circle, that is, the height of each blade 6 along the axial direction of the middle heating structure 2 is the same; in the lower heating structure 3, the plurality of blades 6 are located on the same circumferential surface, the corresponding axial one ends of the plurality of blades 6 are located on the same circle, and the corresponding axial other ends of the plurality of blades 6 are also located on the same circle, that is, the height of each blade 6 along the axial direction of the lower heating structure 3 is the same.

[0031] In some embodiments, preferably, the height of the lower heating structure 3 is less than the height of the middle heating structure 2, and the resistance of the lower heating structure 3 is less than the resistance of the middle heating structure 2, and the height of the middle heating structure 2 is less than the height of the upper heating structure 1, and the resistance of the upper heating structure 1 is greater than the resistance of the middle heating structure 2.

[0032] In some embodiments, preferably, the ratio of the height of the upper heating structure 1, the height of the middle heating structure 2 and the height of the lower heating structure 3 is 4:2:1 or 6:3:2, and the ratio of the height of the upper heating structure 1, the height of the middle heating structure 2 and the height of the lower heating structure 3 is selected according to actual needs, which will not be specifically required here.

[0033] The gap between the upper heating structure 1 and the middle heating structure 2 and the gap between the middle heating structure 2 and the lower heating structure 3 are the same along the axial direction of the upper heating structure 1, or the gap between the upper heating structure 1 and the middle heating structure 2 and the gap between the middle heating structure 2 and the lower heating structure 3 are not the same, for example, the gap between the upper heating structure 1 and the middle heating structure 2 is greater than the gap between the middle heating structure 2 and the lower heating structure 3, or the gap between the upper heating structure 1 and the middle heating structure 2 is less than the gap between the middle heating structure 2 and the lower heating structure 3, the size of the gap between the upper heating structure 1 and the middle heating structure 2 and the gap between the middle heating structure 2 and the lower heating structure 3 is selected according to actual needs. In some embodiments, preferably, the gap between the upper heating structure 1 and the middle heating structure 2 and the gap between the middle heating structure 2 and the lower heating structure 3 are the same.

[0034] The first electrode pin 4 is connected to the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3, and the corresponding positions of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 on the same straight line are connected to the first electrode pin 4, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected to the first electrode pin 4 respectively, and the corresponding positions of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 on the other same straight line are connected to the second electrode pin 5, so that the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected to the second electrode pin 5 respectively.

[0035] In some embodiments, preferably, the first electrode pin 4 and the second electrode pin 5 are arranged opposite to each other, and the first electrode pin 4 and the second electrode pin 5 are located at two ends of the same diameter of the heater.

[0036] The first electrode pin 4 and the second electrode pin 5 are connected to the positive and negative poles of the power supply respectively to form a loop, and the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected in parallel to the positive and negative poles of the power supply.

[0037] In some embodiments, preferably, the power supply can be a direct current power supply.

[0038] It is set that the resistance of the upper heating structure 1 is R1, the resistance of the middle heating structure 2 is R2, and the resistance of the lower heating structure 3 is R3, then R1>R2>R3, since the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are connected in parallel, the equivalent circuit of the heater 100 is as shown in Figure 2 Therefore, according to the heat calculation formula Q=I 2R, the heat quantity Q1 of the upper heating structure 1, the heat quantity Q2 of the middle heating structure 2 and the heat quantity Q3 of the lower heating structure 3 can be calculated. According to the calculation, Q1 < Q2 < Q3, the heat quantity of the upper heating structure 1 is the smallest, the heat quantity of the middle heating structure 2 is in the middle, and the heat quantity of the lower heating structure 3 is the largest. The overall heat quantity of the heater is moved downward, and the heat quantity of the middle and lower part of the heater is larger than that of the upper part.

[0039] As shown in Figure 3 , the heater 100 is used to heat the silicon raw material in the quartz crucible. The heat flow 8 of the heater 100 passes through the silicon melt 7 and is transmitted to the lower part of the solid-liquid interface 9, so that the shape of the solid-liquid interface 9 is slightly convex to the silicon melt 7, and the convex height is 0-5mm, as shown in Figure 4 , when the existing heater is used to heat the silicon raw material in the quartz crucible, the convex height of the solid-liquid interface 9 is 10-30mm. Compared with the existing heater for heating the silicon raw material in the quartz crucible, the convex height of the solid-liquid interface 9 is reduced, and the solid-liquid interface 9 is obviously flattened, which is beneficial to the drawing of the heavy-doped low-resistance single crystal.

[0040] A single crystal furnace system, comprising a quartz crucible and a heater 100 for drawing single crystal as claimed above. The heater 100 is arranged around the periphery of the quartz crucible. The upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are coaxially arranged with the quartz crucible. The first electrode leg 4 and the second electrode leg 5 are respectively connected with the electrode column at the bottom of the single crystal furnace.

[0041] The upper heating structure 1 corresponds to the upper part of the quartz crucible and heats the upper part of the quartz crucible. The middle heating structure 2 corresponds to the middle part of the quartz crucible and heats the middle part of the quartz crucible. The lower heating structure 3 corresponds to the lower part of the quartz crucible and heats the lower part of the quartz crucible. The arrangement of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 comprehensively heats the quartz crucible along the axial direction of the quartz crucible. According to the different resistances of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3, the heat quantities of the upper heating structure 1, the middle heating structure 2 and the lower heating structure 3 are different, so as to control the heat quantities at different positions along the axial direction of the quartz crucible, thereby controlling the convex height of the solid-liquid interface during crystal drawing.

[0042] The height of the lower heating structure 3 is smaller than that of the middle heating structure 2, so the resistance of the lower heating structure 3 is smaller than that of the middle heating structure 2. The height of the middle heating structure 2 is smaller than that of the upper heating structure 1, so the resistance of the upper heating structure 1 is larger than that of the middle heating structure 2. Therefore, the heat quantity of the upper heating structure 1 is the smallest, the heat quantity of the middle heating structure 2 is in the middle, and the heat quantity of the lower heating structure 3 is the largest, thereby reducing the convex height of the solid-liquid interface during crystal drawing.

[0043] The single crystal furnace system is used for drawing heavily doped low resistivity single crystals, and the resistivity of the single crystal is low, and the resistivity of the arsenic doped single crystal is less than or equal to 0.0025 Ω.cm, and the resistivity of the phosphorus doped single crystal is less than or equal to 0.0011 Ω.cm.

[0044] According to the technical scheme, the heater has coaxially arranged upper heating structure, middle heating structure and lower heating structure, the upper heating structure, the middle heating structure and the lower heating structure are arranged around the lateral side of the quartz crucible, and heat the upper part, the middle part and the lower part of the quartz crucible respectively, the height of the upper heating structure, the height of the middle heating structure and the height of the lower heating structure are different along the axial direction of the upper heating structure, so that the resistances of the upper heating structure, the middle heating structure and the lower heating structure are different, the heat generation amounts of the upper heating structure, the middle heating structure and the lower heating structure are different, the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel with the power supply, the heat generation amount distribution in the axial direction of the heater is controlled, so that the protrusion height of the solid-liquid interface during crystal drawing is controlled; when the height of the upper heating structure is greater than the height of the middle heating structure, the height of the middle heating structure is greater than the height of the lower heating structure, the resistance of the upper heating structure is greater than the resistance of the middle heating structure, and the resistance of the middle heating structure is greater than the resistance of the lower heating structure, the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel at both ends of the power supply through the first electrode leg and the second electrode leg, so that the heat generation amount of the upper heating structure is the smallest, the heat generation amount of the lower heating structure is the largest, the overall heat generation amount of the heater is lowered, the protrusion height of the solid-liquid interface during single crystal drawing can be reduced, the solid-liquid interface is flattened, the problem of broken sprue caused by component undercooling of the single crystal is solved, and the stability of drawing the heavily doped low resistivity single crystal is ensured.

[0045] The above embodiment of the utility model is described in detail, but the content is only the preferred embodiment of the utility model, and cannot be considered as limiting the scope of the utility model. Any equivalent change and improvement within the scope of the utility model application shall still belong to the patent coverage range of the utility model.

Claims

1. A heater for pulling a single crystal, characterized by: The upper heating structure, the middle heating structure and the lower heating structure are coaxially arranged, and the upper heating structure, the middle heating structure and the lower heating structure are sequentially arranged from the top to the bottom of the quartz crucible.

2. The heater for pulling a single crystal according to claim 1, characterized by: The height of the lower heating structure is less than the height of the middle heating structure, and the height of the middle heating structure is less than the height of the upper heating structure.

3. The heater for pulling a single crystal according to claim 1 or 2, characterized by: The ratio of the height of the upper heating structure, the height of the middle heating structure and the height of the lower heating structure is 4:2:1 or 6:3:

2.

4. The heater for pulling a single crystal according to claim 3, characterized by: The first electrode foot and the second electrode foot are oppositely arranged.

5. The heater for pulling a single crystal according to claim 4, characterized by: The gap between the upper heating structure and the middle heating structure is the same as the gap between the middle heating structure and the lower heating structure.

6. The heater for pulling a single crystal according to claim 1 or 2 or 4 or 5, characterized by: The upper heating structure, the middle heating structure and the lower heating structure each include a plurality of blades connected in sequence.

7. The heater for pulling a single crystal according to claim 6, wherein: The blade is U-shaped or V-shaped.

8. The heater for pulling a single crystal according to claim 1, characterized by: The first electrode foot and the second electrode foot are respectively connected to the positive electrode and the negative electrode of the power supply, and the upper heating structure, the middle heating structure and the lower heating structure are connected in parallel.

9. A single crystal furnace system, characterized by: The heater for pulling single crystal includes a quartz crucible and the heater for pulling single crystal according to any one of claims 1-8, and the heater is arranged around the quartz crucible, and the upper heating structure, the middle heating structure and the lower heating structure are coaxially arranged with the quartz crucible.

10. The single crystal furnace system of claim 9, wherein: The upper heating structure corresponds to the upper part of the quartz crucible, and the upper part of the quartz crucible is heated, the middle heating structure corresponds to the middle part of the quartz crucible, and the middle part of the quartz crucible is heated, and the lower heating structure corresponds to the lower part of the quartz crucible, and the lower part of the quartz crucible is heated.

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