TW201303091A - Method and device for the directional solidification of a non-metal melt - Google Patents

Abstract

A method for the directional solidification of a non-metal melt (130) which is located in a crucible (120) arranged in the device (100) is proposed, wherein the device (100) has a multiplicity of inductors (110) for generating magnetic fields. By feeding in a first set of phase-shifted alternating currents (I1a, I1b, I1c) at a first frequency (f1), a first travelling field (W1) is generated in the melt (130). By feeding in at least a second set of phase-shifted alternating currents (I2a, I2b, I2c) at a second frequency (f2), a second travelling field (W2) is generated, wherein both travelling fields (W1, W2) move in the same direction, that is counter to the direction of solidification of the melt (130). This achieves a convex curvature of the phase boundary (PG, PG'), which in turn promotes monocrystalline growth and suppresses multicrystalline growth, which in conventional methods may occur in particular in the outer region of the crucible (120).

Description

Non-metal melt directional solidification method and device thereof

The present invention relates to a method according to the first aspect of the patent application and to the device according to claim 15 of the patent application, in particular to a non-metal melt directional solidification method and apparatus therefor.

In the solar industry, the solidification of twins is often carried out to produce solar cells. First, the granular material is melted in a quartz crucible, and then the molten solid is solidified by a vertical temperature gradient to form a crucible ingot and cut into thin hazelnuts. Finally, it is processed into a solar cell.
The ruthenium may be either polycrystalline or monocrystalline. Generally, single crystal germanium solar cells are highly efficient, and polycrystalline germanium sheets are mostly obtained by ingot solidification.
In order to produce a single wafer, a large-capacity single crystal is required, which is obtained by directional solidification of a non-metallic melt, the main production method being the Czochralski method, which is also called the Chekrasal method. Please refer to Wikipedia (http://de.wikipedia.org/wiki/Czochralski-Verfahren) for specific steps in this production method. Compared with the solidified block manufacturing method, the apparatus used in the Clarence method is expensive and high in production cost, but the single crystal material produced by this method has high battery efficiency. In addition, compared with the ingot solidification method, the oxygen content in the crucible is high during the production of the Clarence method, which may cause further degradation of the solar cell.
Therefore, it is necessary to produce a single crystal germanium or a quasi-single crystal germanium by using an ingot solidification method or other better production methods based on the ingot solidification method.
The DE 10 2007 035 756 A1 or WO 2007/084936 A2 patent describes an efficient way to successfully produce single crystal germanium or quasi-single crystal germanium using single crystal seed crystals. At least one single crystal seed crystal is placed in the bottom of the square quartz crucible, and then, as described in the conventional ingot solidification method, the remaining crucible is placed above the single crystal seed crystal in the crucible, and finally the crucible is placed in the heating furnace. The ingot solidifies. The furnace has a different heating zone, i.e., the furnace has one or more top heaters, a surface heater or a bottom heater, and an active heat sink or a passive heat sink is mounted on the bottom of the unit. The temperature of each heating zone in the furnace is different, forming a temperature gradient such that the crucible above the crucible melts and the single crystal zone at the bottom of the crucible remains solid. In the subsequent solidification process, the single crystal region acts as a single crystal seed crystal, grows into a single crystal, and forms a longitudinally moving solid-liquid interface in the solidification direction. Of course, even if there is no single crystal seed crystal, a single crystal can be grown. In this case, it is necessary to nucleate in the groove at the center of the bottom of the crucible. At this time, by controlling the temperature, the crystal nucleus formed in the crucible can be long. crystal.
The temperature gradient affects the convection velocity in the melt because the convection velocity of the melt is primarily determined by the temperature environment. In addition, a fixed magnetic field or a transient magnetic field can also affect the convection speed. In addition, even if the magnetic field strength in the traveling wave field is relatively weak, it can have a large influence on the convection velocity in the melt.
The WO 2010/060802 A2 patent describes a traveling wave field with overlapping settings with at least two different frequencies, and the first wave field passes through the melt from bottom to top, while the second wave field passes through the melt from top to bottom. liquid. Specifically, the traveling wave field is a dual-frequency magnetic field with one frequency moving above the melt or crucible and the other frequency moving below the solution or crucible. Accordingly, the tantalum nitride layer can be protected by the lower convection velocity at the edge of the melt. Preferably, a relatively high frequency and low frequency magnetic field is generated, and the resulting Lorentz force and convection velocity are small in the edge region while the volume force remains unchanged. This measure is mainly used to protect the ruthenium wall coating and therefore does not improve the production of single crystal ingots or quasi-single crystal ingots.
The DE 10 2006 020 234 A1 patent describes a device for solidifying a non-metallic melt having a longitudinally moving traveling wave field in which the frequencies of all the inductor currents are identical.
The DE 103 49 339 A1 patent describes a crystal growth furnace with a heater which is simultaneously a sensor for generating a traveling wave field, which is connected to a three-phase AC power source to form a wave field. The traveling wave field has only one frequency.
The WO 2011/076157 A1 patent also describes a method of solidifying a non-metallic melt which controls the convection velocity of the melt by means of a line of waves. In order to achieve uniform mixing in the solid-liquid interface, the Lorentz force cannot be symmetrically distributed.
To this end, methods for directional solidification of non-metallic melts have been developed, in particular ingot solidification. At least one single crystal seed crystal is disposed at the bottom of the crucible, and the molten solid is solidified from the position of the seed crystal, and a solid liquid interface that moves longitudinally is formed in the solidification direction.
In addition, in the non-metallic melt, at least one wave field is formed through the innumerable inductors to reduce the convection velocity of the melt near the crucible wall and to protect the crucible plating.
The production of single crystal germanium is often carried out by ingot solidification, whereby a single crystal germanium produced usually has a single crystal region in its center, but is surrounded by a large polycrystalline region around its center, and some polycrystalline particles are very Fine, in which several crystal twin particles often appear, so only 10% of the wafers produced are obtained from the single crystal region (Photon, May 2005), and other wafers either have polycrystalline regions or are completely It consists of polycrystals. Due to the difference in the structure of the structure, the subsequent treatment of the single crystal region and the polycrystalline region is also different. Therefore, the subsequent processing cost of the single crystal crucible obtained by the solidification method is much higher than that of the conventional ingot solidification method.
For this reason, it is necessary to continuously improve the production method to completely eliminate the polycrystalline region or to limit the polycrystalline region to the edge region of the bismuth ingot (because the edge of the bismuth ingot is generally thrown away), thereby saving production costs.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method of solidifying a non-metallic melt in a certain direction, and more particularly to provide an ingot solidification method for producing a niobium ingot to improve the defects of the above production method. Through the non-metallic melt directional solidification method of the present invention, the growth of a single crystal can be promoted, and no or only a small amount of polycrystals are present at the edge of the crucible, and the generation of crystal twin particles is reduced. Since single crystal germanium ingots and single crystal germanium ingots require high purity in their edge regions, the method and apparatus of the present invention are particularly suitable for the manufacture of single crystal germanium ingots or single crystal germanium ingots.

In order to achieve the above object, it is achieved by the manufacturing method described in the first aspect of the patent application of the present invention and the manufacturing apparatus according to the fifteenth aspect of the patent application.

Preferably, the inductor is powered by at least one set of phase-shifted alternating current having a settable frequency to generate at least one single-frequency traveling wave field in the molten metal, so that the solid-liquid interface forms a curved surface, and the curved surface faces The solidification direction is convex, and the molten metal flows in the opposite direction of the solidification direction under the action of the at least one wave field, and the frequency of the traveling wave field can be set to 50 Hz.

Since the single crystal seed crystal cannot be placed flush into the crucible, the polycrystalline domain is bound to form in the edge region. In addition, during the solidification process, the crystallites appear on the crucible wall, and the crystallites grow obliquely. The single crystal domain, which in turn affects the growth of the single crystal, is such that the polycrystalline region resembling a single crystal germanium is mainly formed during the nucleation process near the crucible wall.

In addition, crystal twin particles are formed at the edges of the single crystal domain, and the crystal twin particles are directly nucleated near the single crystal in the deep cold zone. Less convective motion and uniform mixing of the melt will cause the solid-liquid interface to accumulate impure melt and eventually cause the zone solidification temperature to decrease, thereby forming a cryogenic zone, a process that often occurs in macroscopic projections with regional grooves. In the solid-liquid interface area, usually near the wall of the crucible. Therefore, uniform mixing of the solid-liquid interface is ensured during the formation of the single crystal germanium, and at least a slightly convex solid-liquid interface is formed in the critical region.

By increasing the bit error density, a small amount of polycrystalline regions are formed in the single crystal germanium, which leads to dislocation joints, because in this case, polycrystalline regions are occasionally formed spontaneously.

The inventors of the present invention considered that the formation process of the above-mentioned crystal twin particles and the nucleation process occurring on the crucible wall cause formation and expansion of twin crystals and polycrystalline regions, which are effectively suppressed by the directional solidification method of the present invention.

Maintaining the solid-liquid interface bulging during the entire solidification process prevents the crystallites from penetrating into the center of the ingot, although this phenomenon can be achieved by precise temperature control, but it has been proved that at least one wave field of the present invention is in many Aspects are more advantageous, and the traveling wave field acts in the opposite direction of the solidification direction of the melt edge.

Adjusting the solid-liquid interface through the traveling wave field is significantly more accurate than the temperature control. The at least one wave field is symmetrically distributed with the Laurentz force density relative to the horizontal axis (X-axis). In fact, during the temperature control process, the convexity of the solid-liquid interface becomes smaller as the height of the bismuth ingot increases, because the thermal conductivity of the solidified crystal is significantly inferior to the thermal conductivity of the melt.

Another embodiment of the present invention has two traveling wave fields, each of which has a different frequency, and the frequencies pass through the molten metal in the same direction. Specifically, the two traveling wave fields pass through the molten metal in the opposite direction of the solidifying direction. In this way, on the one hand, convection can be increased, and on the other hand, the curved surface of the solid-liquid interface can be better adjusted, and the curved surface protrudes in the solidification direction. The high-frequency component (first frequency) mainly acts near the edge, and by selecting an appropriate current intensity, the solid-liquid interface can be obviously symmetrically curved, and the mixture can be uniformly mixed near the wall. At the same time, the second low frequency (second frequency) is used to generate a volumetric force. Through the first frequency and the second frequency, it is ensured that the solid-liquid interface remains convex over the entire crystal surface, and convection is increased to ensure uniform mixing to effectively prevent the formation of the deep-cooling zone.

The method of the invention is particularly suitable for use in turbid liquids in directional solidification furnaces.

The method of the invention has the following advantages:

The inductor of the present invention extends longitudinally in the crucible, and at least two inductors are installed in at least two regions of the melt. The inductors have different heights when viewed from the bottom of the crucible, and the upper inductor is located above the melt, at least A central or lower sensor is located in the middle or lower portion of the melt and supplies power to the inductor with alternating current, such that the amplitude of the alternating current passing through the upper and middle or lower portions of the inductor is different.

Preferably, the amplitude of the alternating current through the upper inductor is greater than the amplitude of the alternating current through the middle or lower inductor.

Of course, it is also possible to install three inductors, which are respectively located at the upper, middle and lower portions of the melt, and supply the inductor with alternating current. The amplitude of the alternating current of the upper inductor is greater than the amplitude of the alternating current of the middle and lower inductors.

Preferably, the amplitudes of the alternating currents through the upper, middle and lower inductors are different, the amplitude of the alternating current gradually decreases from top to bottom, or the amplitude of the alternating current through the upper inductor is greater than the amplitude of the alternating current passing through the lower inductor, and passes through the central inductor. The AC has the largest amplitude.

Preferably, the inductors are powered by a first set of phase-shifted alternating currents having a first settable frequency and a second set of phase-shifted alternating currents having a second settable frequency to form a traveling wave field, such that It is possible to form a solid-liquid interface curved surface at the edge of the crucible and the inside of the crucible, the curved surface protruding toward the solidification direction, preferably, the first frequency is at least twice the second frequency, the first frequency is at least 250 Hz, and the second frequency is at most It is 50Hz.

The alternating current having the second frequency has one or several second amplitudes, and the alternating current having the first frequency has one or several first amplitudes, the first amplitude being 20% greater than the second amplitude.

In addition, the sensor located in the 纵向 extends longitudinally, an upper sensor is located in the upper part of the melt, at least one middle sensor is located in the middle of the molten metal, and the lower sensor is located in the lower part of the molten metal, and the alternating current having the first frequency or the second frequency is The inductor is powered so that the amplitude of the alternating current through the upper, middle and lower sensors is different. The inductor is powered by an alternating current having a second frequency such that the amplitude of the alternating current passing through the upper inductor is greater than the amplitude of the alternating current passing through the central or lower inductor.

Preferably, the alternating current amplitude having the second frequency is between 10 amps and 800 amps, and the alternating current amplitude having the first frequency is between 12.5 amps and 1000 amps.

It is also possible to install two sets of sensors in the crucible, one of which is powered by an alternating current having a first frequency and the other of which is powered by an alternating current having a second frequency.

In order to heat the melt, a heating current is supplied to the inductor, which is composed of direct current and alternating current, wherein the share of the alternating current reaches a minimum specified value, that is, 10%, and the alternating current should have at least one frequency in order to generate at least one wave field. Especially a second frequency.

The first group and the second group of phase-shifted alternating currents are unequal phase-shifted alternating current.

Specific embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in the figure, the solidification apparatus 100 of the present invention or the crystallization apparatus for directional solidification of the non-metal melt 130 of the present invention is located in a crucible. The melt 130 is a crucible melt and the crucible is a square quartz crucible. A plurality of inductors 110 are mounted on the crucible 120 to induce a magnetic field in the melt 130 through an alternating current power supply. Forming at least a traveling wave field having a frequency of at least 50 Hz, the traveling wave field passing through the molten metal in the longitudinal direction or in the direction of solidification, affecting the edge region of the molten metal, so that the interface PG between the liquid phase and the solid phase has A convex surface.

In the present embodiment, two traveling wavefields W1 and W2 are formed, the frequencies of which are different, but the directions are the same. Preferably, the two traveling wave fields extend longitudinally from top to bottom, that is, in the opposite direction of the solidification direction.

For example, three inductors 110a to 110c are sequentially mounted in the longitudinal direction, and power is supplied to the inductors 110a to 110c by means of a first set of phase shifting alternating currents I1a.I1b and I1c and a second set of phase shifting alternating currents I2a, I2b and I2c. The first frequency f1 of a set of phase-shifted alternating currents I1a.I1b and I1c is 400 Hz, and the second low frequency f of the second set of phase-shifted alternating currents I2a, I2b and I2c is 220 Hz.

The above alternating magnetic fields W1 and W2 are stacked to form a dual-frequency traveling wave field, which passes through the solidified molten metal 130 from top to bottom, and adjusts the parameters of the frequencies f1 and f2 and the parameters of the current amplitude to make the solid-liquid interface PG The surface remains in the expected convex state. As shown in the change of the solid-liquid interface, as the crystal grows, the solid-liquid interface moves from bottom to top, that is, in the solidification direction.

In the general manufacturing method, there is no single-frequency, dual-frequency or multi-frequency traveling wave field, and therefore, when the crystal growth rate is more than 5 mm per hour, a concave interface suddenly appears. By adjusting the temperature, it is difficult to effectively improve this phenomenon. Since the temperature is affected by the thermal conductivity of the crucible, the thermal conductivity of the crystal, and the convection of the melt, it is difficult or almost impossible to obtain the desired melt edge interface by adjusting the temperature. Therefore, in the solidified melt, the single crystal region may become smaller and smaller, and if the ingot is higher, the single crystal region located above the ingot may be completely squeezed out.

In contrast to the general manufacturing method, according to the manufacturing method of the present invention, the content of polycrystals and crystal twin particles in a single crystal germanium can be effectively controlled, and the production cost can be lowered. With the traveling wave field (see figures W1 and W2), the ingot can maintain a convex solid-liquid interface at any height, especially in the edge region, thus ensuring that particles that may appear during the nucleation process in the crucible can The crucible is quickly removed, and in addition, the formation of the cryogenic zone and the twin particles of the crystal can be prevented by the method of the present invention. In this embodiment, a dual frequency magnetic field is generated, the frequency of which is different, but the direction is the same. The high frequency mainly acts near the edge of the crucible. By selecting the appropriate current intensity, the solid-liquid interface near the crucible wall can be completely inwardly bent, and at the same time, a volume force is generated by the second low frequency.

As the crystallization height increases, the bottom cooling effect becomes less and less obvious. In order to compensate for this defect, the effect of the low frequency component on the upper part of the melt should be further strengthened. Therefore, the current intensity of the upper coil generating the magnetic field is higher than that of the lower coil. The strength, in this way, can be compensated for by the strengthening of the Lorentz force in the upper part of the melt. The current intensity of the high frequency component remains constant throughout the ingot height. Through the combination of the magnetic field elements, the crystallization of the ingot can be achieved from the position of the single crystal seed crystal through the cross section of the ingot and the height of the ingot.

By selecting the current intensity parameter and the frequency parameter, the convexity of the solid-liquid interface can be accurately controlled. For example, by adjusting the frequencies f1 and f2, the convection velocity of the rim edge can be relatively large and the convection direction can be made downward. At the same time, it is also possible to ensure that the flow rate to the inside of the melt is greater than 0.01 to 2 cm/sec. By parameterizing the frequency from the extended direction and the phase shift through the inductor, the amplitude and geometry can effectively adjust the direction of the Lorentz force density and the influence of flow rate or convection. In order to generate a traveling wave field, the inductor must be supplied with a higher current, up to 1000 amps, and the inductor can be heated due to ohmic losses. In order to prevent the heat energy from being removed by means of heat dissipation, the inductor can also be used as a heating element, so that the melt heating can be effectively controlled. It would be more beneficial to supply a DC heating current to the alternating current that produces the traveling wave field. The AC and DC ratios can be adjusted according to the production process.

The spatial distribution of the Lorentz force density is important for the solid-liquid interface to form a convex surface, and the spatial distribution of the Lorentz force density is formed by the alternating currents I1a to I1c and I2a to I2c. It has been shown that a convex surface can be formed at the edge of the interface by means of a single-frequency traveling wave field. At this time, the alternating currents I1a to I1c having the first frequency f1 have different current intensities, and the current intensity mainly depends on the sensors 110a to 110b. Installation height. The current intensity of the upper inductor 110a is higher than the current intensity of the lower inductors 110b and 110c. As shown in Table 1, the current intensity of the alternating current I1a to I1c when the first frequency is 400 Hz, in which the second frequency or the second alternating current I2a - I2c need not be input, that is:
│I1a│ > │I1b│ > │I1c│ and │I2a│ = │I2b│ = │I2c│ = 0

Table 1 (single frequency traveling wave field: first frequency f1 = 400 Hz, second frequency f2 = 0)

As shown in Table 2, the first frequency is 300 Hz, and the second frequency is 20 Hz. At this time, the alternating current current having the first frequency f1 is the same, both are 200 amps, and the alternating current currents having the second frequency f2 are not equal. The minimum is 400 amps, which is:
│I1a│ = │I1b│ = │I1c│= 200 A and │I2a│ > │I2b│ > │I2c│

Table 2 (Double frequency traveling wave field: first frequency f1 = 300 Hz, second frequency f2 = 20 Hz)

In addition, the current intensity of the high-frequency alternating current I1a – I1c can also be different. The parameter values of the current intensity are listed in Table 3, namely:
│I1a│ < │I1b│ < │I1c│ and │I2a│ > │I2b│ > │I2c│

Table 3 (Double frequency traveling wave field: first frequency f1 = 300 Hz, second frequency f2 = 20 Hz)

As shown in Table 3, the intensity of the alternating current I1a - I1c input to the high frequency f1 increases from top to bottom, and the current of the alternating current I2a - I2c input to the low frequency f2 rises from the bottom to the top.

When the inductor or coil is energized, there is a phase difference between the coils, and the longitudinal installation of the inductor is only part of a longitudinally extending linear mode that flows different phase-shift currents between the segments.

Through the magnetic fields W1 and W2 of the present invention, a convex solid-liquid interface PG or PG' is formed, which can also promote single crystal growth at the edge of the crucible, and effectively suppress and eliminate polycrystalline growth, and the interface convexity is transmitted through the Lorentz force. The density is adjusted to adjust, and the Lorentz force density is affected by the current intensity and frequency.

The apparatus of the present invention can also be used in a square melting crucible, and the coil can also be placed square along the edge of the crucible, even if this does not affect the formation of the magnetic field. The sensor can also be inserted longitudinally, preferably by applying a set of sensors and inputting dual frequencies for the set of sensors. Of course, it is also possible to set a set of sensors for each frequency. The inductor can also be used as a heating device for which direct current is input, in which case the alternating current having the frequencies f1 and f2 accounts for at least 10% of the heating current. Therefore, the apparatus of the present invention can be used to effectively solidify non-metallic melts, especially ruthenium melts, and can also control the longitudinal growth of single crystal ruthenium or single crystal ruthenium.

100. . . Device for carrying out the production process (melt furnace)

110. . . Sensor (horizontal coil)

110a-110c. . . Inductor coil

120. . .坩埚 (quartz glass crucible with inner plating)

130. . . Melt

140. . . Single crystal seed crystal

I1a~I1c. . . First set of phase shifted alternating current

I2a~I2c. . . Second set of phase shifting alternating current

W1, W2. . . First or second row of wave fields (the same direction and opposite to the direction of solidification)

F1, f2. . . First or second frequency of traveling wave field W1 or W2

PG, PG'. . . Solid-liquid interface

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a crystallization apparatus for directional solidification of a non-metallic melt according to the present invention.

100. . . Device for carrying out the production process (melt furnace)

110. . . Sensor (horizontal coil)

110a~110c. . . Inductor coil

120. . .坩埚 (quartz glass crucible with inner plating)

130. . . Melt

140. . . Single crystal seed crystal

I1a-I1c. . . First set of phase shifted alternating current

I2a-I2c. . . Second set of phase shifting alternating current

W1, W2. . . First or second row of wave fields (the same direction, opposite to the direction of solidification)

F1, f2. . . First or second frequency of traveling wave field W1 or W2

Claims (16)

A method for directionally solidifying a non-metal melt (130), the melt (130) being located in a crucible (120) having at least one single crystal seed crystal (140) at the bottom of the crucible (120), and the molten metal (130) The position of the single crystal seed crystal (140) begins to solidify and forms a longitudinally moving solid-liquid interface (PG, PG') in the solidification direction (Y), which is characterized by:
Providing at least one first group of phase-shifted alternating currents having a settable frequency (f1) by means of an inductor (110), that is, generating a line of waves (W1) through the plurality of inductors (110) in the molten metal (130) So that a curved surface of a solid-liquid interface (PG, PG') can be formed at least at the edge of the crucible (120), the curved surface protruding toward the solidification direction (Y);
The molten metal (130) can flow relative to the solidification direction (Y) under the action of at least one wave field (W1), and the preset frequency (f1) can be at least 50 Hz. The method of claim 1, wherein the inductor (110) of the crucible (120) extends longitudinally, wherein at least two inductors (110a, 110b) are located in at least two regions of the melt (130), And the inductors are mounted at different heights from the bottom of the crucible, the upper inductor (110a) is located above the melt (130), and at least one middle or at least the lower inductor (110b, 110c) is located in the middle of the melt (130) Or below, and providing alternating current (I1a, I1b) to the inductor (110), respectively, and making the alternating current amplitudes through the upper and middle or lower inductors (110a, 110b) different. The method of claim 2, wherein the amplitude of the alternating current passing through the upper inductor (110a) is greater than the amplitude of the alternating current passing through the central or lower inductor (110b). The method of claim 2, wherein three inductors (110a, 110b, 110c) are installed, respectively located at the upper, middle and lower portions of the melt (130), with alternating current (I1a, I1b, I1c) The inductor (110) is powered, and the amplitude of the alternating current of the upper inductor (110a) is greater than the amplitude of the alternating current of the middle and lower inductors (110b, 110c). The method of claim 1, wherein two traveling wave fields (W1, W2) are generated in the melt (130) through a plurality of inductors (110), having a first settable frequency (f1) a first set of phase-shifted alternating currents (I1a, I1b, I1c) and a second set of phase-shifted alternating currents (I2a, I2b, I2c) having a second settable frequency (f2) for powering the inductor (110), such that A curved surface is formed inside and at the edge of the crucible (120), and the curved surface protrudes toward the solidification direction (Y). The method of claim 5, wherein the first frequency (f1) is at least twice the second frequency (f2), and the first frequency (f1) is at least 250 Hz and the second frequency is at most 50 Hz. The method of claim 1, wherein the alternating current (I2a, I2b, I2c) having the second frequency (f2) has one or several second amplitudes, and the alternating current having the first frequency (f1) (I1a) , I1b, I1c) has one or several first amplitudes, and the first amplitude is at least greater than 20% of the second amplitude. The method of claim 1, wherein the inductor (110) is longitudinally extended on the crucible (120), and the upper inductor (110a) is located above the melt (130), at least a central inductor ( 110b) is located in the middle of the melt (130), the lower inductor (110c) is located in the lower part of the melt (130), and is powered by the alternating current (I1a, I1b, I1c; I2a, I2b, I2c) for the inductor (110), alternating current (I1a, I1b, I1c; I2a, I2b, I2c) have a first frequency (f1) and a second frequency (f2), and the amplitudes of the alternating currents through the upper, middle and lower inductors (110a, 110b, 110c) are different . The method of claim 8, wherein the alternating current (I2a, I2b, I2c) having the second frequency (f2) is used to supply the inductor (110), and the alternating current amplitude of the upper inductor (110a) is obtained. Greater than the AC amplitude through the middle and lower sensors (110b, 110c). The method of claim 5, wherein the alternating current (I2a, I2b, I2c) having the second frequency (f2) has an amplitude between 10 amps and 800 amps, and the alternating current having the first frequency (f1) (I1a, I1b, I1c) amplitudes between 12.5 amps and 1000 amps. The method of claim 1, wherein two sets of inductors (110) are mounted on the crucible (120), and one of the inductors (110) is supplied with an alternating current having a first frequency (f1) (I1a). , I1b, I1c), supplying an alternating current (I2a, I2b, I2c) having a second frequency (f2) to another set of inductors (110). The method of claim 1, wherein in order to heat the molten metal (130), a heating current is input to the inductor (110), and the electrothermal current is composed of alternating current and direct current. The method of claim 12, wherein the alternating current accounts for at least 10% of the heating current, and the alternating current has at least one frequency, preferably two frequencies (f1, f2) to generate at least one line of waves. Field (W1, W2). The method of claim 1, wherein the first group and/or the second group of phase shifting alternating currents have different phase differences. A device for directionally solidifying a non-metal melt (130) having a crucible (120), a crucible (120) containing a melt (130), and at least one single crystal seed crystal (140) in the crucible (120), The molten metal (130) solidifies from the single crystal seed crystal (140) and forms a solid-liquid interface (PG, PG') that moves longitudinally in the solidification direction (Y), and is characterized by:
The device houses a plurality of inductors (110) on the crucible (120), and supplies the inductor (110) with at least one set of phase-shifted alternating current (I1a, I1b, I1c) having a settable frequency (f1) to enable the melt Forming at least one wave field (W1) in (130), and forming a curved surface at least at the edge of the crucible (120), the curved surface protruding toward the solidification direction (Y), so that the traveling wave field (W1) can be along The opposite direction of the solidification direction (Y) passes through the melt (130), which has a frequency (f1) of at least 50 Hz. The apparatus of claim 15, wherein the apparatus is used in the method of applying the solidified non-metallic melt (130) described in claims 2 to 14.