阅读说明：本技术 一种半导体晶体生长装置 (Semiconductor crystal growth device ) 是由 沈伟民 王刚 邓先亮 黄瀚艺 赵言 于 2019-10-17 设计创作，主要内容包括：本发明提供一种半导体晶体生长装置。包括：炉体；坩埚,所述坩埚设置在所述炉体内部,用以容纳硅熔体；提拉装置,所述提拉装置设置在所述炉体顶部,用以从所述硅熔体内提拉出硅晶棒；导流筒,所述导流筒呈桶状并沿竖直方向设置在所述炉体内的所述硅熔体的上方；所述提拉装置提拉所述硅晶棒在竖直方向上穿过所述导流筒；以及磁场施加装置,用以对所述坩埚内的所述硅熔体施加水平方向的磁场；其中,在所述导流筒底部设置有具有向下凸出的台阶,以使所述导流筒底部在所述磁场的方向上与所述硅熔体液面之间的距离小于在垂直于所述磁场的方向上与所述硅熔体液面之间的距离。根据本发明的半导体晶体生长装置,改善了半导体晶体生长的品质。(The invention provides a semiconductor crystal growth apparatus. The method comprises the following steps: a furnace body; a crucible disposed inside the furnace body to contain a silicon melt; a pulling device arranged at the top of the furnace body and used for pulling a silicon crystal bar out of the silicon melt; the guide cylinder is barrel-shaped and is arranged above the silicon melt in the furnace body along the vertical direction; the silicon crystal bar is pulled by the pulling device to penetrate through the guide shell in the vertical direction; and a magnetic field applying device for applying a magnetic field in a horizontal direction to the silicon melt in the crucible; wherein, the bottom of the guide cylinder is provided with a step which protrudes downwards, so that the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction vertical to the magnetic field. According to the semiconductor crystal growth device of the invention, the quality of the semiconductor crystal growth is improved.)

1. A semiconductor crystal growth apparatus, comprising:

a furnace body;

a crucible disposed inside the furnace body to contain a silicon melt;

a pulling device arranged at the top of the furnace body and used for pulling a silicon crystal bar out of the silicon melt;

the guide cylinder is barrel-shaped and is arranged above the silicon melt in the furnace body along the vertical direction, and the silicon crystal rod is pulled by the pulling device to penetrate through the guide cylinder along the vertical direction; and

a magnetic field applying device for applying a magnetic field in a horizontal direction to the silicon melt in the crucible; wherein the content of the first and second substances,

the bottom of the guide cylinder is provided with a step protruding downwards, so that the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction perpendicular to the magnetic field.

2. The semiconductor crystal growth apparatus according to claim 1, wherein the steps are provided on opposite sides of the guide cylinder along the direction of application of the magnetic field.

3. A semiconductor crystal growth apparatus according to claim 2, wherein the step is provided as an arc-like step along a circumferential direction of the draft tube.

4. A semiconductor crystal growth apparatus according to claim 3, wherein the arc-like step corresponds to a central angle in the range of 20 ° -160 °.

5. A semiconductor crystal growth apparatus according to claim 1, wherein the height of the step is in the range of 2-20 mm.

6. The semiconductor crystal growth apparatus of claim 1, wherein the draft tube comprises an inner tube, an outer tube, and an insulating material, wherein a bottom of the outer tube extends below a bottom of the inner tube and is closed with the inner tube bottom to form a cavity between the inner and outer tubes, the insulating material being disposed within the cavity.

7. The semiconductor crystal growth apparatus according to claim 6, wherein the outer cylindrical bottom has a different wall thickness to form a step in which the draft tube bottom protrudes downward.

8. The semiconductor crystal growth apparatus according to claim 6, wherein the insertion member includes a protrusion and an insertion portion, the insertion portion being inserted into the outer cylindrical bottom portion to a position between a portion below the inner cylindrical bottom portion and the inner cylindrical bottom portion, the protrusion extending to cover the outer cylindrical bottom portion.

9. The semiconductor crystal growth apparatus according to claim 8, wherein the protruding portion includes two that are provided on opposite sides on the guide cylinder along the direction of application of the magnetic field, the protruding portion constituting the step.

10. The semiconductor crystal growth apparatus of claim 8, wherein the protrusion is ring-shaped and covers the bottom of the draft tube, the step being provided on the protrusion.

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a semiconductor crystal growth device.

Background

The czochralski method (Cz) is an important method for preparing silicon single crystals for semiconductors and solar energy, in which a high-purity silicon material placed in a crucible is heated and melted by a thermal field composed of a carbon material, and then a single crystal rod is finally obtained by immersing a seed crystal into the melt and passing through a series of processes (seeding, shouldering, isometric, ending and cooling).

In the crystal growth of semiconductor single crystal silicon or solar single crystal silicon using the CZ method, the temperature distribution of the crystal and the melt directly affects the quality and growth rate of the crystal. During the growth of CZ crystal, the micro-impurities are unevenly distributed due to the existence of thermal convection in the melt, and growth streaks are formed. Therefore, how to suppress the thermal convection and temperature fluctuation of the melt during the crystal pulling process is a problem of great concern.

In the crystal growth (MCZ) technology under a magnetic field generating device, a magnetic field is applied to a silicon melt serving as an electric conductor, so that the melt is subjected to a Lorentz force action opposite to the movement direction of the melt, convection in the melt is hindered, viscosity in the melt is increased, impurities such as oxygen, boron, aluminum and the like enter the melt from a quartz crucible and then enter the crystal, finally, the grown silicon crystal can have controlled oxygen content in a wide range from low to high, impurity fringes are reduced, and the method is widely applied to a semiconductor crystal growth process. One typical MCZ technique is the magnetic field crystal growth (HMCZ) technique, which applies a magnetic field to a semiconductor melt and is widely applicable to the growth of large-size, highly-demanding semiconductor crystals.

In the crystal growth (HMCZ) technique under a magnetic field device, a furnace body for crystal growth, a thermal field, a crucible and a silicon crystal are in shape symmetry as much as possible in the circumferential direction, and the temperature distribution in the circumferential direction tends to be uniform through the rotation of the crucible and the crystal. However, the magnetic lines of force of the magnetic field applied in the magnetic field application process pass through the silicon melt in the quartz crucible in parallel from one end to the other end, and the lorentz force generated by the rotating silicon melt is different everywhere in the circumferential direction, so that the flow and temperature distribution of the silicon melt are not uniform in the circumferential direction.

As shown in fig. 1A and 1B, there are shown schematic diagrams of temperature distribution below the interface of a crystal grown by the crystal and a melt in a semiconductor crystal growth apparatus. Fig. 1A shows a graph of test points distributed on a horizontal plane of a silicon melt in a crucible, wherein one point is tested at an angle θ of 45 ° at a distance L of 250mm from the center 25mm below the melt level. Fig. 1B is a graph of a temperature distribution obtained by simulation calculation and test along each point on an angle θ with the X axis in fig. 1A, in which a solid line indicates a temperature distribution profile obtained by simulation calculation and a dot point indicates a temperature distribution profile obtained by a method of test. In FIG. 1A, arrow A shows the direction of rotation of the crucible as counterclockwise rotation and arrow B shows the direction of the magnetic field traversing the crucible diameter along the Y-axis. As can be seen from fig. 1B, in the course of the growth of the semiconductor crystal, whether the data is obtained from the method of simulation calculation or test, it is shown that the temperature under the cross section of the semiconductor crystal and the melt fluctuates in the circumference with the change in angle during the growth of the semiconductor crystal.

According to the Voronkov crystal growth theory, the thermal equilibrium equation of the cross section of the crystal and the liquid surface is as follows,

PS*LQ＝Kc*Gc-Km*Gm。

wherein LQ is the potential of phase transformation from silicon melt to silicon crystal, and Kc and Km respectively represent the heat conduction coefficients of the crystal and the melt; kc, Km and LQ are all physical parameters of silicon materials; PS represents the crystallization speed of the crystal in the stretching direction, which is approximately the pulling speed of the crystal; gc, Gm are the temperature gradients (dT/dZ) of the crystal and melt, respectively, at the interface. Since, during the growth of a semiconductor crystal, the temperature below the interface of the semiconductor crystal and the melt exhibits periodic fluctuations with changes in the circumferential angle, i.e., Gc, Gm, which is the temperature gradient (dT/dZ) of the crystal and the melt at the interface, exhibits fluctuations, the crystallization speed PS of the crystal in the circumferential angle direction exhibits periodic fluctuations, which is disadvantageous for the control of the crystal growth quality.

Therefore, it is necessary to provide a new semiconductor crystal growth apparatus to solve the problems of the prior art.

Disclosure of Invention

In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In order to solve the problems in the prior art, the present invention provides a semiconductor crystal growth apparatus, comprising:

a furnace body;

a crucible disposed inside the furnace body to contain a silicon melt;

a pulling device arranged at the top of the furnace body and used for pulling a silicon crystal bar out of the silicon melt;

the guide cylinder is barrel-shaped and is arranged above the silicon melt in the furnace body along the vertical direction, and the silicon crystal rod is pulled by the pulling device to penetrate through the guide cylinder along the vertical direction; and

a magnetic field applying device for applying a magnetic field in a horizontal direction to the silicon melt in the crucible; wherein the content of the first and second substances,

the bottom of the guide cylinder is provided with a step protruding downwards, so that the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction perpendicular to the magnetic field.

Illustratively, the steps are provided on opposite sides of the guide cylinder along the direction of application of the magnetic field.

Illustratively, the step is provided as an arc-shaped step along the circumferential direction of the guide cylinder.

Illustratively, the range of the central angle corresponding to the arc-shaped step is 20-160 degrees.

Illustratively, the height of the step ranges from 2 to 20 mm.

Illustratively, the draft tube comprises an inner tube, an outer tube and an insulating material, wherein the bottom of the outer tube extends below the bottom of the inner tube and is closed with the bottom of the inner tube to form a cavity between the inner tube and the outer tube, and the insulating material is disposed in the cavity.

Illustratively, the bottom of the outer cylinder has different wall thicknesses to form a step protruding downwards from the bottom of the guide cylinder.

Illustratively, the insertion member includes a protrusion and an insertion portion, the insertion portion being inserted into the outer cylinder bottom to a position between a portion below the inner cylinder bottom and the inner cylinder bottom, the protrusion extending to cover the outer cylinder bottom.

Illustratively, the protrusion includes two protrusions disposed on opposite sides of the guide cylinder along the application direction of the magnetic field, the protrusions constituting the step.

Illustratively, the protruding part is annular and covers the bottom of the guide shell, and the step is arranged on the protruding part.

According to the semiconductor crystal growth device, the distance between the bottom of the guide cylinder and the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the silicon melt in the direction perpendicular to the magnetic field, so that the heat dissipation speed of the silicon melt liquid level in the direction of the magnetic field is larger than the heat dissipation speed of the silicon melt liquid level in the direction perpendicular to the magnetic field, the distribution of the silicon melt temperature below the interface of the silicon crystal rod and the silicon melt is adjusted, the problem of fluctuation of the temperature distribution of the silicon melt below the interface of the semiconductor crystal and the silicon melt liquid level caused by the applied magnetic field in the growth process of the semiconductor crystal can be adjusted, the uniformity of the temperature distribution of the silicon melt is effectively improved, the uniformity of the growth speed of the crystal is improved, and the crystal pulling quality is improved. Meanwhile, the flow structure of the silicon melt is adjusted, so that the flow state of the silicon melt is more uniform along the circumferential direction, the speed uniformity of crystal growth is further improved, and the defects of crystal growth are reduced.

Drawings

The following drawings of the invention are included to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In the drawings:

FIGS. 1A and 1B are schematic views showing a temperature distribution below an interface between a crystal grown on a crystal and a melt in a semiconductor crystal growth apparatus;

FIG. 2 is a schematic view of a semiconductor crystal growth apparatus;

FIG. 3 is a schematic view showing the arrangement of the positions of the crucible, guide cylinder and silicon ingot in the cross section in the semiconductor crystal growth apparatus according to one embodiment of the present invention;

FIG. 4 is a schematic view of the variation of the distance between the bottom of the draft tube of the semiconductor crystal growing apparatus and the liquid level of the silicon melt as a function of the angle α in FIG. 3 according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a guide shell in a semiconductor growth device according to an embodiment of the invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.

In the following description, for a thorough understanding of the present invention, a detailed description will be given to illustrate a semiconductor crystal growth apparatus according to the present invention. It will be apparent that the invention may be practiced without limitation to specific details that are within the skill of one of ordinary skill in the semiconductor arts. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.

It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Exemplary embodiments according to the present invention will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same elements are denoted by the same reference numerals, and thus the description thereof will be omitted.

Referring to fig. 2, a schematic structural diagram of a semiconductor crystal growing apparatus is shown, the semiconductor crystal growing apparatus includes a furnace body 1, a crucible 11 is arranged in the furnace body 1, a heater 12 for heating the crucible 11 is arranged outside the crucible 11, silicon melt 13 is contained in the crucible 11, the crucible 11 is composed of a graphite crucible and a quartz crucible sleeved in the graphite crucible, and the graphite crucible is heated by the heater to melt polycrystalline silicon material in the quartz crucible into the silicon melt. Wherein each quartz crucible is used for one batch semiconductor growth process and each graphite crucible is used for multiple batch semiconductor growth processes.

A pulling device 14 is arranged at the top of the furnace body 1, under the driving of the pulling device 14, the seed crystal pulls the silicon crystal rod 10 from the liquid level of the silicon melt, and a heat shield device is arranged around the silicon crystal rod 10, exemplarily, as shown in fig. 1, the heat shield device comprises a guide cylinder 16, the guide cylinder 16 is arranged in a barrel shape, and is used as the heat shield device to separate a quartz crucible and the heat radiation of the silicon melt in the crucible to the crystal surface in the crystal growth process, to increase the cooling speed and the axial temperature gradient of the crystal rod, to increase the crystal growth quantity, on the one hand, to influence the heat field distribution on the silicon melt surface, to avoid the too large difference of the axial temperature gradients at the center and the edge of the crystal rod, and to ensure the stable growth between the crystal rod and the liquid level of the silicon melt; meanwhile, the guide cylinder is also used for guiding the inert gas introduced from the upper part of the crystal growth furnace to enable the inert gas to pass through the surface of the silicon melt at a larger flow speed, so that the effect of controlling the oxygen content and the impurity content in the crystal is achieved. During the growth of a semiconductor crystal, the silicon crystal rod 10 passes vertically upwards through the guide cylinder 16 under the drive of the pulling device 14.

In order to realize the stable growth of the silicon crystal rod, a driving device 15 for driving the crucible 11 to rotate and move up and down is further arranged at the bottom of the furnace body 1, and the driving device 15 drives the crucible 11 to keep rotating in the crystal pulling process so as to reduce the thermal asymmetry of the silicon melt and enable the silicon crystal column to grow in an equal diameter.

In order to obstruct the convection of the silicon melt, increase the viscosity of the silicon melt, reduce the impurities such as oxygen, boron, aluminum and the like from entering the melt from the quartz crucible and further entering the crystal, finally enable the grown silicon crystal to have the controlled oxygen content ranging from low to high, and reduce the impurity stripes, the semiconductor growing device also comprises a magnetic field applying device 17 arranged outside the furnace body and used for applying a magnetic field to the silicon melt in the crucible.

Since the magnetic lines of force of the magnetic field applied by the magnetic field applying device 17 pass through the silicon melt in the crucible in parallel from one end to the other end (see the dashed arrow in fig. 2), the lorentz forces generated by the rotating silicon melt are all different in the circumferential direction, and therefore the flow and temperature distribution of the silicon melt are not uniform in the circumferential direction, where the temperature in the magnetic field direction is higher than the direction perpendicular to the magnetic field. The inconsistency of the flow and temperature of the silicon melt is manifested by fluctuation of the temperature of the melt below the cross section of the semiconductor crystal and the melt with the change of the angle, so that the crystallization speed PS of the crystal is fluctuated, and the growth speed of the semiconductor is uneven on the circumference, which is not favorable for controlling the growth quality of the semiconductor crystal.

For this reason, in the semiconductor growth apparatus of the present invention, the draft tube 16 is disposed at different distances from the bottom of the draft tube to the surface of the silicon solution.

Different distances are set between the bottom of the guide cylinder and the liquid level of the silicon solution, the distance between the bottom of the guide cylinder and the liquid level of the silicon solution in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the liquid level of the silicon solution in the direction perpendicular to the magnetic field, the heat radiated from the liquid level of the silicon melt to the guide cylinder is large in the place with the smaller distance, and the heat radiated from the liquid level of the silicon melt to the guide cylinder is small in the place with the larger distance, so that the temperature of the liquid level of the silicon melt at the place with the smaller distance is reduced more than that of the liquid level of the silicon melt at the place with the larger distance, and the problem that the temperature in the applying direction of the magnetic field is higher than that in the applying direction perpendicular to the magnetic field due to. Therefore, the distance between the bottom of the guide cylinder and the silicon crystal rod is set, so that the distribution of the temperature of the silicon melt below the interface of the silicon crystal rod and the silicon melt is adjusted, the fluctuation of the temperature of the silicon melt in the circumferential direction caused by the applied magnetic field can be adjusted, the uniformity of the temperature distribution of the silicon melt is effectively improved, the speed uniformity of crystal growth is improved, and the crystal pulling quality is improved.

Meanwhile, because different distances exist between the bottom of the guide cylinder and the liquid level of the silicon melt, the pressure flow velocity introduced from the top of the furnace body and flowing back to the liquid level of the silicon melt through the guide cylinder is increased at a position with a larger distance, the shearing force of the liquid level of the silicon melt is increased, the pressure flow velocity introduced from the top of the furnace body and flowing back to the liquid level of the silicon melt through the guide cylinder is reduced at a position with a smaller distance, and the shearing force of the liquid level of the silicon melt is reduced. Meanwhile, the oxygen content distribution in the grown semiconductor crystal is uniform by changing the flowing state of the silicon melt, the uniformity of the oxygen content distribution in the crystal is improved, and the defects of crystal growth are reduced.

Specifically, according to the invention, the bottom of the guide cylinder 16 is provided with the step protruding downwards, so that the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide cylinder and the liquid level of the silicon melt in the direction perpendicular to the magnetic field.

According to an example of the present invention, the steps are provided on opposite sides of the guide cylinder along the application direction of the magnetic field. Illustratively, the step is provided as an arc-shaped step along the circumferential direction of the guide shell

Referring to fig. 3, there is shown a schematic view of the arrangement of the bottom surfaces of a crucible, a draft tube and a silicon ingot in a semiconductor crystal growth apparatus according to an embodiment of the present invention. As shown in fig. 3, the draft tube 16 is arranged in a circular barrel shape so that the bottom of the draft tube 16 is circular, wherein, along the direction of application of the magnetic field (as shown by arrow B in fig. 3), steps 1601 and 1602 protruding downward are provided at opposite sides of the guide cylinder 16, the steps 1601 and 1602 are provided at opposite sides of the bottom of the guide cylinder 16 along the direction of the magnetic field, the steps 1601 and 1602 are arc-shaped, so that the distance from the bottom of the draft tube 16 to the liquid level of the silicon melt is smaller than the distance from the bottom of the draft tube 16 to the liquid level of the silicon melt at other positions along the magnetic field direction, the temperature of the liquid level of the silicon melt is reduced more quickly along the magnetic field direction, thereby the defect that the temperature of the silicon melt is higher along the magnetic field direction due to the application of the horizontal magnetic field is overcome, and the temperature of the liquid level of the silicon melt is more uniformly distributed along the circumferential direction of the guide cylinder.

It should be understood that the steps provided at the two opposite sides of the bottom of the guiding cylinder along the direction of the magnetic field in the present embodiment are only exemplary, and those skilled in the art will understand that any step provided at the bottom of the guiding cylinder can make the distance between the guiding cylinder and the silicon crystal bar in the direction of applying the magnetic field greater than the distance between the guiding cylinder and the silicon crystal bar in the direction perpendicular to the magnetic field, so as to achieve the technical effects of the present invention.

Illustratively, the range of the central angle corresponding to the arc-shaped step is 20-160 degrees.

Illustratively, the height of the step ranges from 2 to 20 mm.

Referring to fig. 4, a schematic diagram showing variation of a distance between a bottom of a draft tube of a semiconductor crystal growing apparatus and a liquid level of a silicon melt according to an embodiment of the present invention as a function of an angle α in fig. 3 is shown, wherein a vertical axis represents the distance between the bottom of the draft tube and the liquid level of the silicon melt, and a horizontal axis represents variation of a position of the bottom of the draft tube as a function of the angle α in fig. 3. The distance between the bottom of the guide cylinder and the liquid level of the silicon melt is smaller when alpha is 90 DEG and 270 DEG than when alpha is 0 DEG and 180 DEG, wherein the bottom of the guide cylinder is positioned in the direction of the magnetic field when alpha is 90 DEG and 270 DEG (as shown by arrow B in figure 3), and the bottom of the guide cylinder is positioned perpendicular to the direction of the magnetic field when alpha is 0 DEG and 180 deg. Wherein, the difference H between the distance H0 between the bottom of the guide shell and the liquid level of the silicon melt when alpha is 0 DEG and the distances H0 and H90 between the bottom of the guide shell and the liquid level of the silicon melt when alpha is 90 DEG is the height of the step, and the range is 2-20 mm. As the arc-shaped steps are arranged along the circumference, the corresponding central angle W ranges from 20 degrees to 160 degrees. Because the bottom of the guide shell is arranged in a step shape, a fillet is applied to the joint of the steps, and exemplarily, the radius range of the fillet is 1-5 mm.

According to one example of the present invention, a draft tube includes an inner tube, an outer tube, and a heat insulating material, wherein a bottom of the outer tube extends below a bottom of the inner tube and is closed with the bottom of the inner tube to form a cavity between the inner tube and the outer tube, and the heat insulating material is disposed within the cavity.

The bottom of the outer cylinder is provided with different wall thicknesses so as to form a step protruding downwards from the bottom of the guide cylinder. Referring to fig. 4, a schematic structural view of a guide shell according to an embodiment of the present invention is shown. Wherein the draft tube 16 includes an inner tube 161, an outer tube 163, and a thermal insulation material 163 disposed between the inner tube 161 and the outer tube 162, wherein a bottom of the outer tube 162 extends below a bottom of the inner tube 161 and is closed with the bottom of the inner tube 161 to form a cavity between the inner tube 161 and the outer tube 162 that accommodates the thermal insulation material 163. The guide shell is of a structure comprising an inner shell, an outer shell and a heat insulating material, so that the installation of the guide shell can be simplified. Illustratively, the material of the inner and outer barrels is provided as graphite, and the heat insulating material includes fiberglass, asbestos, rock wool, silicate, aerogel blanket, vacuum plate, and the like.

The bottom of the outer cylinder is provided with the steps with different wall thicknesses so as to form the downward protrusion of the bottom of the guide cylinder, and the steps of the guide cylinder are arranged only through the arrangement of the outer cylinder, so that the manufacturing process of the steps is simplified, and the production cost is reduced.

According to one example of the invention, the guide shell comprises an adjusting device for adjusting the distance between the bottom of the guide shell and the liquid level of the silicon melt. The distance between the bottom of the guide shell and the liquid level of the silicon melt is changed by adding an adjusting device, so that the manufacturing process of the guide shell can be simplified on the basis of the structure of the existing guide shell.

With continued reference to fig. 4, illustratively, the adjustment device includes an insertion member 18, the insertion member 18 including a protrusion 181 and an insertion portion 182, the insertion portion 182 being inserted into a position between a portion of the bottom of the outer barrel 162 extending below the bottom of the inner barrel 161 and the bottom of the inner barrel 161, the protrusion 181 extending to cover the bottom of the outer barrel 162.

Because the existing draft tube is generally set to be a conical barrel shape, the bottom of the draft tube is generally set to be circular in cross section, and the draft tube is set to be an insertion part included between the inner barrel and the outer barrel, the shape of the bottom of the draft tube can be flexibly adjusted by adjusting the structure and the shape of the insertion part under the condition of not changing the structure of the existing draft tube so as to adjust the distance between the bottom of the draft tube and the liquid level of the silicon melt; therefore, the effect of the invention is achieved by arranging the adjusting device with the inserting part under the condition of not changing the existing semiconductor growing device. Meanwhile, the insertion part can be manufactured in a modularized mode and replaced, so that the method is suitable for semiconductor crystal growth processes of different sizes, and further cost is saved.

Meanwhile, the inserting part is inserted into the position between the bottom of the outer barrel and the bottom of the inner barrel, so that the heat conduction from the outer barrel to the inner barrel is effectively reduced, the temperature of the inner barrel is reduced, the radiation heat transfer from the inner barrel to the crystal bar is further reduced, the difference value of the axial temperature gradients of the center and the periphery of the crystal bar is effectively reduced, and the crystal pulling quality is improved. Illustratively, the adjusting device is made of a material with low thermal conductivity, such as SiC ceramic, quartz, etc.

For example, the adjusting device may be provided in segments, such as two segments provided on the guide shell along the direction of the magnetic field, so that the protrusions form steps; the baffle can also be arranged along the circumference of the bottom of the guide shell, for example, the baffle is arranged as a circular ring, and the protruding part is provided with a step.

It is to be understood that the arrangement of the adjusting means in segments or in a ring is merely exemplary, and any adjusting means capable of adjusting the distance between the bottom of the draft tube inner cylinder and the silicon ingot is suitable for use in the present invention.

The above is an exemplary description of the semiconductor crystal growth apparatus according to the present invention, which, the distance between the bottom of the guide shell and the silicon melt in the direction of the magnetic field is smaller than the distance between the bottom of the guide shell and the silicon melt in the direction perpendicular to the magnetic field, so that the heat dissipation speed of the liquid level of the silicon melt in the direction of the magnetic field is higher than that of the liquid level of the silicon melt in the direction vertical to the magnetic field, thereby regulating the temperature distribution of the silicon melt below the interface of the silicon crystal bar and the silicon melt, and adjusting the temperature distribution of the silicon melt in the growth process of the semiconductor crystal, because of the problem of the fluctuation of the temperature distribution of the silicon melt below the interface of the semiconductor crystal and the liquid level of the silicon melt caused by the applied magnetic field, the uniformity of the temperature distribution of the silicon melt is effectively improved, thereby improving the speed uniformity of crystal growth and improving the crystal pulling quality. Meanwhile, the flow structure of the silicon melt is adjusted, so that the flow state of the silicon melt is more uniform along the circumferential direction, the speed uniformity of crystal growth is further improved, and the defects of crystal growth are reduced.

The present invention has been illustrated by the above embodiments, but it should be understood that the above embodiments are for illustrative and descriptive purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications may be made in accordance with the teachings of the present invention, which variations and modifications are within the scope of the present invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.