WO2017070827A1

WO2017070827A1 - Automatic zone melting crystal growth method and system

Info

Publication number: WO2017070827A1
Application number: PCT/CN2015/092868
Authority: WO
Inventors: 刘和松; 陈辉; 张立杰; 伍月爽; 尚锐刚; 周冰; 杨凯; 高辉
Original assignee: 北京京运通科技股份有限公司; 北京天能运通晶体技术有限公司
Priority date: 2015-10-26
Filing date: 2015-10-26
Publication date: 2017-05-04
Also published as: CN107002276A; CN107002276B

Abstract

The present invention discloses an automatic zone melting crystal growth method and system. The method comprises the following steps: during an automatic diameter increasing stage, if a diameter of a single crystal is greater than a lower base surface diameter of a certain layer of truncated cone-shaped growth region and less than an upper base surface diameter thereof, then determining a growth region of the single crystal to be said layer of truncated cone-shaped growth region, and growing the single crystal in the growth region having a pre-configured growth parameter, wherein the growth parameter at least comprises a polycrystal dropping rate and a heating power; performing, according to a pre-configured function relationship, adjustment to grow the single crystal according to a pre-configured growth angle for the growth region of the single crystal, wherein the growth angle is defined as an included angle between a cone generatrix and a lower base bottom surface; and if the diameter of the single crystal reaches a target value, then switching to an automatic constant diameter growth stage, wherein the current growth region of the single crystal is in a topmost layer of growth region, and the single crystal grows along an axial direction in said growth region. A single crystal grown using the present invention has a predictable shape.

Description

Automatic growth method and system for zone melting crystal

Technical field

The invention relates to a method and a production device for growing a zone melting crystal, in particular to a method and a system for automatically growing a zone melting crystal.

Background technique

In recent years, the process level of zone melting single crystal silicon crystal growth has been greatly improved, and the level of artificially drawn 8-inch single crystal has been obtained. The process of growing single crystal by zone melting method mainly consists of preheating, chemical compounding, seeding, expanding shoulder, equal diameter and closing. For large-size single crystals, the use of full manual method for pulling crystal has significant shortcomings, mainly reflected in the long drawing time of large-size single crystal, and the mass production is difficult; the human influence factor is large, and the growth process is difficult to control; Poor quality consistency.

In order to solve the above problems, a method for automatically producing a single crystal has appeared in the prior art, and automatic growth of the shoulder and equal diameter growth stages can be realized, but the actual growth shape of the single crystal can only be known after the growth is completed, and the single crystal growth is known. A technical problem that the shape cannot be preset.

Summary of the invention

The invention provides an automatic growth method and system for a zone melting crystal, which solves the technical problem that the shape of the grown single crystal is unpredictable compared with the prior art.

In one aspect, the present invention provides an automatic growth method for a zone melting crystal, comprising the steps of:

Manually seeding and expanding the shoulder to form a single crystal; when the diameter of the single crystal is larger than the diameter of the bottom surface of the lowermost truncated growth section of the configured multi-layer truncated cone growth section, switching to the automatic shoulder growth stage;

In the automatic shoulder growth stage, when the diameter of the single crystal is larger than the diameter of the lower bottom surface of a certain circular truncated growth section and smaller than the diameter of the upper bottom surface, the growth interval of the single crystal is the circular truncated growth interval of the layer; a growing interval growth of the configured growth parameter; wherein the growth parameter includes at least a polycrystalline falling speed and a heating power, respectively adjusted according to a configured functional relationship, so that the single crystal grows according to a growth angle in which the growth interval is configured; The growth angle refers to the angle between the round busbar and the lower bottom surface;

When the diameter of the single crystal reaches the target value, it is switched to the automatic equal diameter growth stage. At this time, the growth interval in which the single crystal is located is the growth interval of the uppermost layer, and the single crystal grows in the axial direction in the growth interval.

Preferably, the growth parameter further includes a single crystal falling speed, a single crystal rotating speed, a polycrystalline rotating speed, and a lower melting zone equivalent height, wherein the lower melting zone equivalent height is equal to the liquid volume of the lower melting zone. The height of the cylindrical melting zone.

Preferably, in the automatic shoulder growth stage, the functional relationship that the polycrystalline falling speed has been configured is specifically:

Where V _poly is the polycrystalline falling speed, V _mono is the single crystal falling speed, D is the measured diameter of the polycrystal, d is the diameter of the single crystal, ρ _l is the liquid density of the crystal, ρ _s is the solid density of the crystal, h _Lqd is the equivalent height of the lower melting zone, and θ is the configured growth angle of the growth zone in which the single crystal is located.

Preferably, in the automatic equal diameter growth stage, the polycrystalline falling speed is adjusted according to the configured function relationship, and the functional relationship is specifically:

Where V _poly is the polycrystalline falling speed, V _mono is the single crystal falling speed, D is the measured diameter of the polycrystalline, and d is the diameter of the single crystal.

Preferably, in the automatic shoulder growth phase, the functional relationship P = f(d) of the heating power is obtained by a curve fitting technique, wherein P is the heating power and d is the diameter of the single crystal.

Preferably, the curve fitting technique employs a polynomial as a fitting function.

Preferably, the curve fitting technique employs a least squares fitting method.

In another aspect, the present invention also provides an automatic growth system for a zone melting crystal, comprising:

a diameter measuring device for measuring the diameter of a single crystal;

Polycrystalline drop servo motor for controlling the falling speed of the polycrystalline material rod;

a high frequency heating device for heating the crystal;

a programmable logic controller for storing the configured multi-layer truncated cone growth interval and the configured growth angle of each growth interval, wherein the growth angle refers to an angle between the truncated bus bar and the lower bottom surface; and is also used for storage a function of the configured polycrystalline falling speed, and a heating power function relationship;

The programmable logic controller is further configured to switch to an automatic shoulder growth stage after the diameter of the single crystal is larger than the diameter of the bottom surface of the configured lowermost truncated growth section; and is also used in the automatic shoulder growth stage. When the diameter of the single crystal is larger than the diameter of the lower surface of the growth section of a certain circular trough and smaller than the diameter of the upper surface, the growth interval of the single crystal is determined as the growth range of the truncated cone, and is controlled according to the growth parameters of the growth interval. Single crystal growth, wherein at least controlling the polycrystalline falling servo motor causes the polycrystalline falling speed to be adjusted according to a configured function relationship, while controlling the high frequency heating device such that the heating power is adjusted according to a configured function relationship; When the diameter reaches the target value, it switches to the automatic equal diameter growth stage to control the growth of the single crystal in the axial direction.

Preferably, the diameter measuring device is further used to determine the diameter of the polycrystalline material rod;

The programmable logic controller is further configured to control the polycrystalline falling servo motor, and in the automatic shoulder growth stage, the function relationship of the polycrystalline falling speed has been configured as follows:

Wherein, V _poly polycrystalline lowering speed, V _mono monocrystalline lowering speed, D is the measured diameter polycrystalline, d is the diameter of a single crystal, ρ _l is the density of the liquid crystal, ρ _s is the solid state density crystals, h _Lqd is the equivalent height of the lower melting zone, and θ is the configured growth angle of the growth zone in which the single crystal is located.

The programmable logic controller is further configured to control the servo motor and, in an automatic equal diameter growth phase, the polycrystalline falling speed is adjusted according to a configured function relationship, and the function relationship of the polycrystalline falling speed configured is specifically

Preferably, the curve fitting technique uses a polynomial as a fitting function.

Preferably, the curve fitting technique employs a least squares fitting method.

In the automatic growth method and system for the zone melting crystal of the present invention, in the automatic shoulder growth stage, the single crystal grows in the growth interval of the configured growth parameters, and the polycrystal falling speed and heating power in the growth parameters are respectively configured according to the configuration. The functional relationship adjustment causes the single crystal to grow in accordance with the growth angle at which the growth interval is disposed, so that the actual growth shape of the single crystal is predictable. Compared with the prior art, the automatic growth method of the zone melting crystal of the present invention and the actual shape of the single crystal grown by the system are predictable, and the shape of the single crystal can be conveniently formed to reduce the waste of raw materials. At the same time, the manual operation is reduced, and the stability of the single crystal quality is enhanced.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

Figure 1 is a schematic view showing the preparation of crystals by a suspension zone melting method;

2 is a schematic view showing a configuration of a multi-layered truncated cone growth section and a growth angle of each truncated cone growth section in the automatic growth method of the zone melting crystal of the present invention;

3 is a schematic view of a single-crystal truncated cone growth section shown in FIG. 2 and a growth angle grown single crystal in each truncated cone growth section;

4 is a schematic view showing the preparation of crystals by the automatic growth method of the zone melting crystal of the present invention;

Fig. 5 is a flow chart showing the method of automatically growing a zone melting crystal of the present invention.

Description of the reference signs:

10 polycrystalline raw material rods, 20 heating equipment, 31 upper melting zone, 32 lower melting zone, 40 seed crystals.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in Figure 1, the preparation of crystals by suspension zone melting is carried out in a sealed reaction chamber filled with argon. First, the cylindrical polycrystalline material rod 10 is vertically placed in a high temperature reaction chamber, and the end of the polycrystalline material rod is melted by the high frequency heating device 20 to produce a melting zone, wherein the melting zone portion is located above the high frequency heating device. For the upper melting zone 31, the portion of the melting zone located below the high frequency heating device is the lower melting zone 32; then the seed crystal 40 is melted into the already melted region, and the melt will be suspended in the seed by the surface tension of the molten crystal. Between the crystal and the polycrystalline raw material rod; thereafter, the high frequency heating device is slowly raised upward to melt the polycrystalline raw material rod above the molten crystal. At this time, the molten crystal near one end of the seed crystal starts to solidify, forming the same crystal orientation as the seed crystal. When the high frequency heating device sweeps across the entire polycrystalline material rod, it is converted into a single crystal ingot.

The automatic growth method of the zone melting crystal of the present invention is an automatic growth method using a suspension zone melting method, and the object to be achieved is to ensure the crystallization (ie, no crystal transformation occurs, resulting in failure of single crystal growth to become polycrystalline). Under the conditions, in the automatic shoulder growth stage and the automatic equal diameter growth stage, the single crystal can grow in a set shape. In order to achieve this goal, the set shape of the single crystal should first be set; then, the growth parameters in the single crystal growth process are controlled to achieve the actual growth shape of the single crystal in accordance with the set shape of the single crystal. In order to realize that the actual growth shape of the single crystal is consistent with the shape of the single crystal, it is necessary to control a plurality of growth parameters in the single crystal growth process of the crystal prepared by the suspension zone melting method, including the single crystal falling speed, the single crystal rotation speed, and the like. Crystal falling speed, polycrystalline rotating speed, heating power and equivalent melting zone equivalent height, wherein the lower melting zone equivalent height refers to the height of the cylindrical melting zone equal to the volume of the lower melting zone liquid. The growth parameters closely related to the actual growth shape of the crystal include the heating power, and the relationship between the polycrystalline falling speed and the single crystal falling speed. Therefore, it is necessary to precisely control the relationship between the heating power, the polycrystalline falling speed, and the single crystal falling speed.

Before the single crystal is grown by the automatic growth method of the zone melting crystal, firstly, it is necessary to set the set shape of the single crystal, and specifically includes: setting a plurality of coaxial and stacked circular truncated growth intervals and growth angles of each growth interval, The diameter of the bottom surface of each growth interval is larger than the diameter of the lower bottom surface, and the bottom surface of each growth interval is used as the upper layer The lower bottom surface of the long section; wherein, the growth angle refers to the angle between the round busbar and the lower bottom surface, and the diameter of the bottom surface of the uppermost growth section is larger than the target diameter; that is, by configuring the multi-layer truncated cone growth interval and configuring each growth interval The growth angle defines a set shape of the single crystal; the bottom surface of the truncated cone growth section is the lower bottom surface, and the upper bottom surface is the upper bottom surface;

The automatic growth method of the zone melting crystal is given below. When a single crystal silicon having a diameter of 8 inches (1 inch = 25.4 mm, wherein mm is a millimeter) is grown, an 18-layer truncated cone growth interval and growth angles of the respective growth intervals are arranged to define An example of the set shape of the single crystal, it should be noted that in the present embodiment, the method of automatically growing the region-melting crystal grows single crystal silicon for example only, and the method for automatically growing the crystal-melting crystal is not limited to growing single crystal silicon. It can also be other single crystal crystals. The number of growth intervals set is 18, which are 40-80mm, 80-85mm, 85-95mm, 95-110mm, 110-130mm, 130-140mm, 140-150mm, 150-160mm, 160-165mm, 165-175mm. , 175 ~ 183mm, 183 ~ 186mm, 186 ~ 190mm, 190 ~ 194mm, 194 ~ 198mm, 198 ~ 200mm, 200 ~ 202mm, 202 ~ 204.0mm, the growth angle of the growth interval is 72 °, 78 °, 81 °, 78°, 77°, 77°, 78°, 79°, 80°, 80.5°, 81°, 83°, 85°, 86°, 87°, 88°, 89°, 90°; 90° means single crystal Growing in the axial direction, the diameter of the single crystal no longer needs to be increased; as for the number of growth intervals, the more the number, the smoother the crystal surface grown according to the growth angle of the growth interval;

For convenience of illustration, in FIG. 2, only the four-stage truncated cone growth interval is taken as an example, and the truncated cone growth interval is indicated by a broken line, and is set in the range of d ₀ to d ₁ , and the growth angle of the single crystal in the growth interval is θ _1; in the interval d ₁ ~ d _2, the growth angle of the single crystal growing section is θ _2; in d ₂ ~ d ₃ range, the growth angle of the single crystal growing section is θ _3, in d ₃ In the interval of -d ₄ , the growth angle of the single crystal in the growth interval is θ ₄ = 90°, and the set shape of the single crystal according to the growth interval and the growth angle of each growth interval is as shown by the solid line in FIG. 3 , wherein The lowermost column is the seed crystal;

Thereafter, the process personnel set the set value of the single crystal falling speed, the single crystal rotating speed, the polycrystalline rotating speed, and the lower melting zone equivalent height in the growth parameters of each of the growth intervals by the craftsman based on experience or conventional crystal pulling data. , wherein, as shown in FIG. 4, the lower melting zone equivalent height h _lqd is the height of the cylindrical molten zone equal to the liquid volume of the lower melting zone; for example, the polycrystalline rotating speed is 0.18 in the growth interval of 160.0 to 165.0 mm. Rpm, the single crystal rotation speed is 13.5 rpm, the single crystal falling speed is 2.5 mm/min, and the lower melting zone equivalent height is 7 mm; that is, the growth rate of the single crystal in the growth parameter is set for each growth interval, and the single crystal rotation speed is Polycrystalline rotation speed and equivalent height of the lower melting zone;

Then, according to the pre-stored heating power and the corresponding single crystal diameter data record, the curve heating technique is used to obtain the heating power as a function of the single crystal diameter; wherein the pre-stored heating power and the corresponding single crystal diameter data are obtained. The record is the historical data of the heating power recorded by the computer and the corresponding single crystal diameter during the artificial extension process; that is, the growth parameter also includes the heating power, which is a function relationship of the heating power configuration;

Finally, a functional relationship is configured for the polycrystalline falling speed; by configuring the heating power function relationship and the polycrystalline falling speed configuration function relationship, the single crystal is grown according to the growth angle that has been configured in the growth interval.

The following is a method for preparing a crystal by a zone melting method: a step of growing a single crystal having a diameter of 8 inches (1 inch = 25.4 mm, wherein mm is a millimeter) at an equal diameter: as shown in FIG.

Manually seeding and expanding the shoulder to form a single crystal; when the diameter of the single crystal is larger than the diameter of the bottom surface of the lowermost truncated cone growth section of the configured multi-layer truncated cone growth section, the surface is switched to the automatic shoulder growth stage;

In the automatic shoulder growth stage, when the diameter of the single crystal is larger than the diameter of the lower bottom surface of a certain circular truncated growth section and smaller than the diameter of the upper bottom surface, the growth interval of the single crystal is the circular truncated growth interval of the layer, that is, when the single crystal When the diameter is greater than 40 mm and less than 80 mm, the growth interval of the single crystal is the lowermost growth interval; when the diameter of the single crystal is greater than 80 mm and less than 85 mm, the growth interval of the single crystal is the sub-lower growth interval; and so on; The single crystal grows in the growth interval of the configured growth parameter; wherein the growth parameter includes at least the polycrystal falling speed and the heating power, and the growth of the single crystal according to the configured growth interval is adjusted according to the configured function relationship, respectively. Angle growth; wherein the growth angle refers to the angle between the round busbar and the lower bottom surface;

When the diameter of the single crystal reaches the target value of 8 inches, it is switched to the automatic equal diameter growth stage. At this time, the growth interval of the single crystal is the uppermost growth interval, and the single crystal grows in the axial direction in the uppermost growth interval.

In the method for preparing crystals by the zone melting method of the present invention, in the automatic shoulder growth stage, the single crystal grows in the growth interval of the configured growth parameters, and the polycrystal falling speed and heating power in the growth parameters are respectively configured according to the configuration. The adjustment of the functional relationship causes the single crystal to grow according to the growth angle at which the growth interval is arranged, so that the actual growth shape of the single crystal is close to the set shape of the single crystal, and the actual growth shape of the single crystal is predictable. In the prior art, it is impossible to predict what shape a single crystal is obtained during the growth of a single crystal. Compared with the prior art, the actual shape of the single crystal grown by the automatic growth method of the zone melting crystal of the present invention is predictable, and the shape of the single crystal can be conveniently formed to reduce the waste of the raw material. The reduced manual operation enhances the stability of the single crystal quality.

Specifically, in the automatic shoulder growth stage, the function relationship of the polycrystalline falling speed has been configured as follows:

Where V _poly is the polycrystalline falling speed, V _mono is the single crystal falling speed, D is the measured diameter of the polycrystal, d is the diameter of the single crystal, ρ _l is the liquid density of the crystal, ρ _s is the solid density of the crystal, h _Lqd is the equivalent height of the lower melting zone, and θ is the growth angle of the single crystal that has been configured in the current growth interval, that is, the polycrystalline falling speed is closely matched with the single crystal falling speed and the configured growth angle. The polycrystalline falling speed is a control parameter closely related to the crystal growth shape. By controlling the polycrystalline falling speed, precise control of the crystal growth shape can be achieved.

In the automatic shoulder growth phase, the functional relationship P = f(d) of the heating power is obtained by curve fitting technique, where P is the heating power and d is the diameter of the single crystal. Heating power is closely related to the actual growth shape of the crystal The growth parameters require fine control, and in the relationship between the heating power obtained by the curve fitting technique and the diameter of the single crystal, the heating power continuously changes with the diameter of the single crystal, which facilitates the fine control of the heating power.

Specifically, the curve fitting technique may use a polynomial as a fitting function.

Specifically, the curve fitting technique may adopt a least squares fitting method.

Further, in the present embodiment, the heating power of the single crystal obtained by curve fitting is a function of the diameter of the single crystal: P = f (d) = - 2.871 × 10 ^-8 d ⁴ + 1.273 × 10 ^-5 d ³ -2.089×10 ^-3 d ² +0.4116d+29.76; wherein P is the heating power and d is the diameter of the single crystal.

Specifically, in the automatic equal diameter growth stage, the polycrystalline falling speed is adjusted according to the configured function relationship, and the function relationship of the polycrystalline falling speed has been configured as follows:

The polycrystalline falling speed is a control parameter closely related to the crystal growth shape. By controlling the polycrystalline falling speed, precise control of the crystal growth shape can be achieved.

Finally, when the length of the single crystal reaches the target value, the automatic equal diameter growth stage is ended, and the finishing is performed manually.

An automatic growth system for a zone melting crystal of the present invention comprises:

a diameter measuring device for measuring the diameter of a single crystal;

a high frequency heating device for heating the crystal;

The automatic growth system of the zone melting crystal of the present invention, in the automatic shoulder growth stage, when the diameter of the single crystal is larger than the diameter of the lower bottom surface of a certain circular truncated growth section and smaller than the diameter of the upper bottom surface, the programmable logic controller judges the single The growth interval of the crystal is the circular growth zone of the layer, controlling the growth of the single crystal in the growth interval of the configured growth parameters, and controlling at least the polycrystalline falling servo motor so that the polycrystalline falling speed is adjusted according to the configured function relationship. Simultaneously controlling the heating device so that the heating power is adjusted according to the configured function relationship, so that the single crystal grows according to the growth interval in which it is placed. Growth; thus, the actual growth shape of the single crystal is predictable. In the prior art, it is impossible to predict what shape a single crystal is obtained during the growth of a single crystal. Compared with the prior art, the actual shape of the single crystal grown by the automatic growth system of the zone melting crystal of the present invention is predictable, and the shape of the single crystal can be conveniently formed to reduce the waste of the raw material. The reduced manual operation enhances the stability of the single crystal quality.

Specifically, the growth parameter further includes a single crystal falling speed, a single crystal rotating speed, a polycrystalline rotating speed, and a lower melting zone equivalent height, wherein the lower melting zone equivalent height is equal to the liquid volume of the lower melting zone. The height of the cylindrical melting zone; the growth rate of the single crystal in the growth parameters of each of the growth intervals, the rotation speed of the single crystal, the rotation speed of the polycrystal, and the equivalent of the lower melting zone, based on experience or previous crystal pulling data by the craftsman Height setting value.

Specifically, the diameter measuring device is further configured to determine a diameter of the polycrystalline material rod;

Where V _poly is the polycrystalline falling speed, V _mono is the single crystal falling speed, D is the measured diameter of the polycrystal, d is the diameter of the single crystal, ρ _l is the liquid density of the crystal, ρ _s is the solid density of the crystal, h _Lqd is the equivalent height of the lower melting zone, and θ is the growth angle of the growth interval in which the single crystal is placed, that is, the polycrystalline falling speed is closely matched with the single crystal falling speed and the configured growth angle. The polycrystalline falling speed is a control parameter closely related to the crystal growth shape. By controlling the polycrystalline falling speed, precise control of the crystal growth shape can be achieved.

Further, the system for preparing crystals by zone melting method includes other servo motors and motors involved in motion, such as single crystal falling servo motors and single crystal falling motors, single crystal rotating servo motors and single crystal rotating motors, polycrystalline rotating servo motors and In a polycrystalline rotating machine or the like, a moving servo motor controls the speed of the corresponding motion by controlling a motor corresponding to the motion, such as a single crystal rotating servo motor for controlling the single crystal rotating speed by controlling the single crystal rotating motor.

Specifically, the programmable logic controller is further configured to control the servo motor and, in an automatic equal diameter growth phase, the polycrystalline falling speed is adjusted according to a configured function relationship, and the polycrystalline falling speed has a configured function relationship. Specifically

In the automatic shoulder growth phase, the heating power configured function relationship P = f(d) is obtained by a curve fitting technique, where P is the heating power and d is the diameter of the single crystal. The heating power is a growth parameter closely related to the actual growth shape of the crystal, which requires fine control. In the relationship between the heating power obtained by the curve fitting technique and the diameter of the single crystal, the heating power continuously changes with the diameter of the single crystal. It is convenient to achieve fine control of heating power.

Specifically, the curve fitting technique adopts a least squares fitting method.

Specifically, the curve fitting technique uses a polynomial as a fitting function.

It is apparent that those skilled in the art can make various modifications and variations to the embodiments of the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

An automatic growth method for a zone melting crystal, comprising the steps of:

Manually seeding and expanding the shoulder to form a single crystal; when the diameter of the single crystal is larger than the diameter of the bottom surface of the lowermost truncated growth section of the configured multi-layer truncated cone growth section, switching to the automatic shoulder growth stage;

In the automatic shoulder growth stage, when the diameter of the single crystal is larger than the diameter of the lower bottom surface of a certain circular truncated growth section and smaller than the diameter of the upper bottom surface, the growth interval of the single crystal is the circular truncated growth interval of the layer; a growing interval growth of the configured growth parameter; wherein the growth parameter includes at least a polycrystalline falling speed and a heating power, respectively adjusted according to a configured functional relationship, so that the single crystal grows according to a growth angle in which the growth interval is configured; The growth angle refers to the angle between the round busbar and the lower bottom surface;

When the diameter of the single crystal reaches the target value, it is switched to the automatic equal diameter growth stage. At this time, the growth interval in which the single crystal is located is the growth interval of the uppermost layer, and the single crystal grows in the axial direction in the growth interval.
The method according to claim 1, wherein the growth parameter further comprises a single crystal falling speed, a single crystal rotating speed, a polycrystalline rotating speed, and a lower melting zone equivalent height, wherein The equivalent height of the melt zone refers to the height of the cylindrical melt zone equal to the volume of the liquid in the lower melt zone.
The method for automatically growing a zone melting crystal according to claim 2, wherein in the automatic shoulder growth stage, the functional relationship of the polycrystalline falling speed has been configured as follows:
Where V poly is the polycrystalline falling speed, V mono is the single crystal falling speed, D is the measured diameter of the polycrystal, d is the diameter of the single crystal, ρ l is the liquid density of the crystal, ρ s is the solid density of the crystal, h Lqd is the equivalent height of the lower melting zone, and θ is the configured growth angle of the growth zone in which the single crystal is located.
The method for automatically growing a zone melting crystal according to claim 1, wherein in the automatic equal diameter growth stage, the polycrystalline falling speed is adjusted according to a configured function relationship, and the functional relationship is specifically:
Where V poly is the polycrystalline falling speed, V mono is the single crystal falling speed, D is the measured diameter of the polycrystalline, and d is the diameter of the single crystal.
The method for automatically growing a zone melting crystal according to claim 1, wherein in the automatic shoulder growth phase, the function relationship P*f(d) of the heating power is obtained by using a curve fitting technique, wherein P is the heating power and d is the diameter of the single crystal.
The method of automatically growing a zone-melting crystal according to claim 5, wherein the curve fitting technique employs a polynomial as a fitting function.
The method of automatically growing a zone melting crystal according to claim 5, wherein the curve fitting technique employs a least squares fitting method.
An automatic growth system for a zone melting crystal, comprising:

a diameter measuring device for measuring the diameter of a single crystal;

Polycrystalline drop servo motor for controlling the falling speed of the polycrystalline material rod;

a high frequency heating device for heating the crystal;

a programmable logic controller for storing the configured multi-layer truncated cone growth interval and the configured growth angle of each growth interval, wherein the growth angle refers to an angle between the truncated bus bar and the lower bottom surface; and is also used for storage a function of the configured polycrystalline falling speed, and a heating power function relationship;

The programmable logic controller is further configured to switch to an automatic shoulder growth stage after the diameter of the single crystal is larger than the diameter of the bottom surface of the configured lowermost truncated growth section; and is also used in the automatic shoulder growth stage. When the diameter of the single crystal is larger than the diameter of the lower surface of the growth section of a certain circular trough and smaller than the diameter of the upper surface, the growth interval of the single crystal is determined as the growth range of the truncated cone, and is controlled according to the growth parameters of the growth interval. Single crystal growth, wherein at least controlling the polycrystalline falling servo motor causes the polycrystalline falling speed to be adjusted according to a configured function relationship, while controlling the high frequency heating device such that the heating power is adjusted according to a configured function relationship; When the diameter reaches the target value, it switches to the automatic equal diameter growth stage to control the growth of the single crystal in the axial direction.
The automatic growth system for a zone melting crystal according to claim 8, wherein the growth parameter further comprises a single crystal falling speed, a single crystal rotating speed, a polycrystalline rotating speed, and a lower melting zone equivalent height, wherein The equivalent height of the melt zone refers to the height of the cylindrical melt zone equal to the volume of the liquid in the lower melt zone.
The automatic growth system for a zone melting crystal according to claim 9, wherein said diameter measuring device is further for measuring a diameter of a polycrystalline raw material rod;

The programmable logic controller is further configured to control the polycrystalline falling servo motor, and in the automatic shoulder growth stage, the function relationship of the polycrystalline falling speed has been configured as follows:
Where V poly is the polycrystalline falling speed, V mono is the single crystal falling speed, D is the measured diameter of the polycrystal, d is the diameter of the single crystal, ρ l is the liquid density of the crystal, ρ s is the solid density of the crystal, h Lqd is the equivalent height of the lower melting zone, and θ is the configured growth angle of the growth zone in which the single crystal is located.
The automatic growth system for a zone melting crystal according to claim 8, wherein said diameter measuring device is further for measuring a diameter of a polycrystalline material rod;

The programmable logic controller is further configured to control the servo motor and, in an automatic equal diameter growth phase, the polycrystalline falling speed is adjusted according to a configured function relationship, and the function relationship of the polycrystalline falling speed configured is specifically
Where V poly is the polycrystalline falling speed, V mono is the single crystal falling speed, D is the measured diameter of the polycrystalline, and d is the diameter of the single crystal.
The automatic growth system for a zone melting crystal according to claim 8, wherein in the automatic shoulder growth phase, the functional relationship P=f(d) of the heating power is obtained by a curve fitting technique, wherein P is the heating power and d is the diameter of the single crystal.
The automatic growth system for a zone melting crystal according to claim 12, wherein said curve fitting technique employs a polynomial as a fitting function.
The automatic growth system for a zone melting crystal according to claim 12, wherein said curve fitting technique employs a least squares fitting method.