DE102008022882A1 - Producing monocrystalline or polycrystalline semiconductor material using a vertical gradient freeze method, involves introducing lumpy semiconductor raw material into a melting crucible, melting there, and directionally solidifying - Google Patents

Abstract

Producing monocrystalline or polycrystalline semiconductor material using a vertical gradient freeze method, involves introducing lumpy semiconductor raw material (33) into a melting crucible (38), melting there and directionally solidifying, in which temperature profile is established from the upper end to the base of the crucible, the temperature profile being axially displaced in such a way that the phase boundary separating the liquid phase from the crystallized out material migrates, starting from base of the crucible, gradually toward the upper end of the crucible. Producing a monocrystalline or polycrystalline semiconductor material using a vertical gradient freeze method, involves introducing lumpy semiconductor raw material (33) into a melting crucible (38), melting there and directionally solidifying, in which temperature profile is established from the upper end to the base of the melting crucible, the temperature profile being axially displaced in such a way that the phase boundary separating the liquid phase from the crystallized out material migrates, starting from the base of the melting crucible, gradually toward the upper end of the melting crucible, in which method the semiconductor raw material is melted from the upper end of the melting crucible, so that molten material trickles downward and semiconductor raw material, which has not yet melted gradually slumps in the melting crucible and additional semiconductor raw material is replenished to the melting crucible from above onto a zone of semiconductor raw material which has not yet melted or not completely melted, in order at least partly to compensate for a volumetric shrinkage of the semiconductor raw material.

Description

Field of the invention

The The invention relates to a method and a device for crystallizing a semiconductor material, in particular of silicon. A preferred Application relates to the production of monocrystalline or polycrystalline Silicon for applications in photovoltaics.

Background of the invention

As a general rule Solar cells for photovoltaic can be made of single crystal Silicon or polycrystalline silicon are produced. While high-quality solar cells made of silicon single crystals, which is technologically more complex and therefore more expensive, cheaper solar cells are usually made of polycrystalline Made of silicon, which is less expensive and therefore less expensive. Especially in the production of polycrystalline silicon play Therefore, features leading to a reduction in costs and technological Costs for manufacturing lead, a significant role.

Usually is a crucible for the production of silicon with lumpy Silicon filled. During subsequent melting to liquid Silicon, it comes to a significant volume shrinkage, due to the significantly different densities of molten silicon to previously existing bed. Consequently In conventional methods, only a small part of the Crucible volume can be used effectively. From the state of Technique, various measures are known to reduce the volume to compensate.

US 6,743,293 B2 discloses a process for the production of polycrystalline silicon in which a ring-shaped attachment with a corresponding profile is placed on the upper edge of a crucible in order to provide an overall container structure with a larger volume. In the container structure, a silicon bed is introduced. After melting the silicon, the silicon melt fills the entire crucible but not the volume trapped by the annular cap. However, the container construction requires a crystallization unit with a larger volume, in particular a greater height, which is undesirable for energetic reasons. Furthermore, it is difficult to provide a suitable dimensionally stable annular top for reuse.

The Energy for heating and melting the silicon raw material becomes the one about heat conduction and heat radiation first introduced into the crucible, then over Heat conduction and radiation passed on to the melt to become. On the other hand, the melt on the top is mainly over Heat radiation heated directly from the heaters. The heat transfer inside the filled with the melt Crucible also takes place via heat conduction and heat radiation. The material properties, Thermal conductivity and extinction an important Role. In addition, the heat transfer properties determined by the physical properties of the raw material, as it is at the interfaces to a hindrance of heat conduction comes.

Around as cost effective and energy efficient as possible work, it is desired, the volume of the crucible to make it as big as possible, in accordance with it to get big silicon crystals. The great Crucible volume is associated with a longer melting time, because the amount of heat introduced into the crucible through the Size of the absorption of heat effective surface of the melt is limited. A further limitation results from the limitation of the crucible temperature, since the crucible materials can not withstand higher temperatures and the sensitive melt overheats a strong overheating the melting point not unscathed without a contact reaction with the crucible survives.

absorbent Materials can be about the introduction of electromagnetic Heat alternating fields. It can by the appropriate choice the frequency of an adapted to the crucible dimensions penetration depth be chosen so that the melt also in volume can be heated. With strong temperature dependence and at greater height of the crucible However, the electromagnetic heating to near-surface areas limited.

Around to allow a faster melting of the raw material, is the preheating of raw material from the prior art when recharging in the crucible known.

DE 32 17 414 C1 discloses the preheating of broken glass when recharging in a melting tank of a glass melting plant. For this purpose, a plate heat exchanger, in the interstices glass shards are constantly refilled. During operation, the same amount of broken glass is fed into the spaces, which is transported away at the lower end of a vibrating conveyor. Through the plate heat exchanger, the exhaust gases obtained during the melting process are conducted at a temperature of about 420 ° C, whereby the glass shards are heated to a temperature of about 245 ° C before. A vertical Be The movability of the plate heat exchanger prevents caking of the broken glass and bridging in the interstices of the plate heat exchanger. The structure is, however, comparatively complex overall.

DE 42 13 481 C1 discloses a corresponding plate heat exchanger, wherein the preheating of the broken glass is preceded by a drying step. For this purpose, in a drying zone in the introduction of the melt by separate supply of hot fuel gas in already cooled Heizgasströmen the moisture is evaporated in the melt.

A corresponding preheating by heat exchanger tubes is from the U.S. Patent 4,353,726 Also known for the Nachchargieren of powdery materials in glass production.

When Alternative to the above methods is in crystallization plants, who work according to the Czochralski method, a continuous or discontinuous refilling of lumpy raw material Known to the volume shrinkage due to the melting of the raw material in the crucible at least partially compensate.

EP 0 315 156 B1 discloses such a crystallizer in which crystalline material is supplied to the crucible via a feed tube. In the feed tube, slowdown means in the form of cross-sectional constrictions or profile bends are provided to reduce a falling rate of the crystalline material. Active preheating of the crystalline material is not disclosed.

EP 1 338 682 A2 discloses a crystallization plant according to the Czochralski method in which crystalline material slips over an inclined tube into the crucible. JP 01-148780 A discloses a corresponding structure. However, complex precautions must be taken to enable the entry of crystalline raw material into the crucible without spatter. This is because spattering of the hot melt in the crystallization plant causes damage to components and impurities that are difficult to remove. Active preheating of the crystalline material is not disclosed.

US 2004/0226504 A1 discloses a sophisticated flap mechanism to suitably reduce the falling rate of the crystalline material upon filling in the crucible. US 2006/0060133 A1 discloses a crystallizer in which crystalline silicon falls down a vertical tube into the crucible. The lower end of the tube is closed by a conical stopper, which gives the crystalline material a radial component of motion. Active preheating of the crystalline material is not disclosed.

JP 07-277874 A discloses the recharging of liquid silicon in the production of single crystal silicon according to the Czochralski method. For this purpose, a silicon raw material rod is melted immediately above the crucible with the aid of a melting heater. The molten silicon flows directly and continuously into the crucible.

JP 2006-188376 A discloses the production of a single crystal material by the Czochralski method, wherein polycrystalline raw material is recharged by fusing a rod-shaped polycrystalline raw material. For this purpose, the rod-shaped raw material is held in a holding body and immersed in a raw material melt in the crucible.

JP 07-118089 A discloses a method for producing a silicon single crystal by the Czochralski method in which granular polycrystalline raw material is introduced into the crucible via a feed tube. In order to prevent SiO 2 formation during recharging, a reducing gas (ie, hydrogen or a hydrogen-inert gas mixture) is blown onto the surface of the silicon melt.

Summary of the invention

In spite of considerable efforts are made in the art Room for improvement, especially with regard to achieving a shorter melting time. According to the invention Thus, a method and an apparatus are provided, which especially with large crucible volume and preferred when using the VGF method (vertical gradient freeze method) when recharging solid, lumpy raw material a shorter one Melting time and more uniform heating of the melt can be achieved.

These and further objects are according to the present Invention by a method according to claim 1, an apparatus according to claim 21 and a use according to claim 20. Further advantageous embodiments are the subject the dependent claims.

According to the invention, the semiconductor raw material to be additionally introduced outside the container receiving the melt is heated by targeted introduction of heat to a temperature below the melting temperature of the semiconductor raw material and then heated in the heated state introduced the container. According to the invention, the temperature conditions in the crucible can be better controlled. Because the introduced, almost heated to the melting temperature semiconductor raw material affects the temperature conditions in the crucible only slightly. Thus, any heating method, in particular the entry of electromagnetic radiation from above onto the melt can be used. At the same time, the semiconductor raw material to be introduced can be heated in a controlled manner, which further improves a more precise predefinition of the process parameters. According to the invention a faster melting can be achieved, wherein it is irrelevant according to the invention whether molten or non-molten semiconductor material is or is not already present in the crucible.

expedient the heating of the semiconductor raw material takes place during the transport into the crucible, but outside the Crucible. For this purpose, the semiconductor raw material to be introduced is preferred by means of a conveyor to a heat source moved over. By varying the conveying speed and / or the intensity of the heating can be so easily controls the heating of the semiconductor raw material become.

lower Energy losses occur when the targeted heat input in the semiconductor raw material to be introduced on the inside of a Thermal insulation of the crucible receiving melting furnace he follows. Basically, however, the heat input also in the field of thermal insulation or on their Outside done.

Prefers the heat input is effected by the action of electromagnetic Radiation. For this purpose, the raw material to be introduced is suitably flat spread or distributed, and that to a relatively thin Semiconductor raw material layer whose thickness is sufficient action allows the electromagnetic radiation. To this end can heat radiation or radiation of an optical radiation source, in particular a laser, or microwave radiation or high or Medium frequency radiation on the semiconductor raw material to be introduced act.

To the Transport of the semiconductor raw material is preferably a conveyor which is designed to be the solid, stuffy semiconductor raw material spread or distribute. To this end In particular, a vibrating conveyor with a predetermined width, which is designed so that the semiconductor raw material preferably in a single layer or double layer is spread flat.

According to another embodiment, via the semiconductor raw material during transport through the conveyor, a purge gas sweeps counter to the conveyance direction to free the heated semiconductor raw material from adsorbed H ₂ O and the like. The purge gas used is preferably a suitably heated inert gas, which may also contain hydrogen.

All Particularly preferably, the semiconductor raw material is heated discontinuously according to the invention and placed in the container, depending from the respective level in the crucible. Prefers the crucible is refilled until the melt extends to near the top of the crucible.

LIST OF FIGURES

following the invention will be described by way of example and with reference are described on the accompanying drawings, from which provide further features, advantages and tasks to be solved become. Show it:

1 in a schematic sectional view of an apparatus for producing mono- or polycrystalline silicon according to a first embodiment of the present invention;

2 in a schematic sectional view of an apparatus according to a second embodiment of the invention;

3 in a schematic sectional view of an apparatus according to a third embodiment of the present invention; and

4 in a schematic representation of an apparatus according to a fourth embodiment of the present invention.

In the figures denote identical reference numerals identical or Substantially equal elements or groups of elements.

Detailed description of preferred embodiments

According to the 1 For example, the crystallization plant for producing monocrystalline or polycrystalline silicon comprises a crucible 8th which consists of a quartz crucible which is tightly received in a graphite crucible to sufficiently mechanically support the quartz crucible softened at the melting temperature of the silicon. The quartz crucible extends to the upper edge of the graphite crucible, so that a direct contact of the silicon melt or the solid raw material 5 is excluded with the graphite. The crucible is a commercially available Quark crucible with a footprint of, for example, 550 × 550 mm ² , 720 × 720 mm ² or 880 × 880 mm ² and has an inner coating as a separating layer between SiO _{2 of} the crucible and silicon. Above the crucible 8th is a ceiling heater 7a provided whose base area is greater than or equal to the base of the crucible 8th is. At the side surfaces of the crucible 8th are several flat heating elements 7b at a small distance to the side surfaces of the crucible 8th arranged. Here is the distance between the heating elements of the jacket heater 7b and the side walls of the crucible 8th constant over the entire circumference of the crucible.

Below the crucible 8th is a cooling plate 9 arranged, which is flowed through by a coolant. Between the crucible 8th and the cooling plate 9 a crucible mounting plate is arranged (not shown). In the VGF crystallization process, all are heaters 7a . 7b temperature-controlled. For this purpose, the surface temperatures of the heaters 7a . 7b detected by thermocouples or pyrometers at a suitable location and entered into a control unit, which is connected to the heaters 7a . 7b applied voltage controls or regulates suitable. More specifically, in the fixed crucible VGF method, an axial temperature gradient is established. The temperature profile is shifted by varying the heater temperatures so that the phase boundary separating the liquid phase from the crystallized silicon gradually migrates from the bottom of the crucible to the top of the crucible. This leads to a directed, columnar solidification of the liquid silicon to polycrystalline silicon. The temperature control is carried out so that in the crucible 8th as even as possible isotherms are formed.

Here, the coat heater 7b be designed to a temperature gradient from the top to the bottom of the crucible 8th build. For this purpose, the heating elements can also be subdivided into two or more segments arranged vertically one above the other, which have a heating power decreasing from the upper edge to the lower end of the crucible. The arranged at the same height level segments lead to the formation of planar, horizontal isotherms and thus to form a flat, horizontal phase boundary.

Of the Crucible preferably has a polygonal cross-section, in particular a rectangular or square Cross-section. In this way, the waste for the production of the usual polygonal, in particular rectangular or square, Solar cells for photovoltaics are minimized.

The entire crystallization plant is of a preferably pressure-resistant or gas-tight envelope (not shown) surrounded, so that built inside an inert or reducing inert gas atmosphere can be.

According to the 1 protrudes a conveyor 2 through the thermal insulation 6 through into the interior of the furnace into refillable solid, lumpy raw material 3 from the bottom of the storage and dosing tank 1 in the crucible 8th to promote. According to the invention, the solid, lumpy raw material 3 heated during transport by targeted heat input to a temperature below the melting temperature of the raw material. The heated raw material then falls from the front end of the conveyor 2 following gravity into the crucible 8th down.

According to the 1 is used for heating a tube furnace, which is used in the field of thermal insulation 6 arranged heating elements 4 is formed and the conveyor 2 surrounds in sections. The conveyor itself is called Rüttelrinne 2 formed in a known manner and made for example of CFC or silicon carbide (SiC). The vibrating trough 2 at the same time spreads the raw material to be introduced flat, so that the heat input in the area of the tube furnace 4 can be done in the already extensively spread raw material. In this case, the raw material is preferably conveyed flat as a single or double layer, wherein the thickness of the single or double layer is preferably smaller than the penetration depth of electromagnetic radiation into the raw material to be introduced. According to the 1 sweeps over the on the vibrating trough 2 transported solid, lumpy raw material a purge gas 13 in countercurrent, and that downstream of the heating device 4 to free the preheated raw material from adsorbed H ₂ O and other residual gases.

In the embodiment according to the 2 the heat input takes place by irradiation with a CO ₂ laser beam 10 that's over a window 11 and a beam guide in the conveyor 2 is coupled. A suitable imaging optics provides for a suitable expansion or imaging of the laser beam onto that on the conveyor 2 flat spread raw material. The conveyor 2 is designed as Rüttelrinne.

In the embodiment according to the 3 Heat is transferred by microwave radiation from a magnetron 12 over a waveguide 11 in the from the conveyor 2 subsidized raw material is coupled.

In a variant of the fourth embodiment form, as in the 4 shown, the distance between the center of the crucible 8th and the front end of the conveyor 2 by horizontal displacement of the conveyor 2 be shortened when introducing the raw material. In this way, splashes and mechanical damage of an inner coating of the crucible 8th effectively prevented. According to the 4 the heat input for preheating the additionally introduced raw material via the ceiling heater.

By guiding the purge gas 13 in countercurrent to the raw material to be replenished, which can also be optionally switched on and off again, the auxiliary heating can be partially dispensed with at a low flow rate or maximum heat output.

As will be readily apparent to one skilled in the art, any other conveyor means which are sufficiently temperature stable and capable of conveying fillable raw material into the crucible may be used in the crystallization unit of the present invention. Preference is given to materials with low electrical conductivity, the silicon is not contaminated, such as silicon nitride (Si ₃ N ₄ ) or the already mentioned CFC or SiC.

following is the operation of the crystallization plant according to the invention on the basis of preferred embodiments closer to be discribed.

Embodiment 1

With Help of a temperature sensor becomes the surface temperature the silicon bed in the crucible continuously detected. Thus, it can be determined that and when the melting temperature of silicon is reached. Depending on the heating power for heating the crucible The silicon packing collapses more or less quickly. The Silicon fill melts from the surface ago. A predetermined period of time after reaching the melting temperature of silicon becomes additional with the aid of the conveyor Silicon raw material introduced into the crucible. The delivery rate is suitable depending on the actual Heating power set. The actually in the crucible introduced amount of silicon raw material is using the sensor detected. The silicon bed sank continuously the crucible together. The entry of the additional Silicon raw material can be continuous or in predetermined Time intervals and dosage amounts take place, in each case according to the actual heating power. The additional silicon raw material is by selective heat input to a temperature little heated below the melting temperature of silicon, so the melt in the crucible only slightly cools and quickly back to the intended operating temperature can be brought.

Embodiment 2

With Help of a temperature sensor becomes the surface temperature the silicon bed in the crucible continuously detected. A central controller has previously detected what amount introduced to silicon bed in the crucible has been. Or this amount may be the central controller be entered. Depending on the current heating power and the amount of raw material currently in the crucible becomes a predetermined amount of additional raw material refilled in the crucible. This refilling can be continuous or in multiple, time-delayed steps carried out, to each of which a predetermined amount of additional raw material introduced becomes. The additional silicon raw material is targeted through Heat input to a temperature just below the melting temperature heated by silicon, so that the melt in the crucible only slightly cools and quickly returns to the intended operating temperature brought can be.

Embodiment 3

With Help of a sensor will increase the surface temperature of the Crucible filling continuously recorded and so the timing determined, to which the melting temperature of silicon is reached. A predetermined time after reaching the melting point becomes depending on the actual heating power a predetermined amount of additional raw material in the Refilled crucible. This step will be after predetermined Time intervals, repeated according to the current heat output, until a predetermined level of the crucible is reached. The additional silicon raw material is through targeted heat input to a temperature little heated below the melting temperature of silicon, so the melt in the crucible only slightly cools and quickly brought back to the intended operating temperature can be.

Embodiment 4

With the aid of a temperature sensor, the surface temperature of the crucible filling is continuously monitored. Furthermore, the level of the crucible is continuously monitored by means of a visual inspection system and / or a distance sensor. After dropping the level by a predetermined amount, caused by the volume shrinkage of the silicon bed, a predetermined amount of additional raw material is replenished into the crucible. This step is repeated when the level of the crucible after refilling has dropped again by a second predetermined level. The height by which the level drops between the refilling steps is reduced due to the increasing filling of the crucible. Alternatively, instead of operating in discrete predetermined steps, the replenishment of raw material may also be initiated whenever a predetermined level of the crucible is exceeded. The additional silicon raw material is heated by targeted heat input to a temperature slightly below the melting temperature of silicon, so that the melt in the crucible only slightly cools and can be quickly brought back to the intended operating temperature.

to Process control can be the central control device based on empirical values To fall back on. This concerns in particular the required Time to melt the bed at known Heating power, which among other things also from the thermal insulation of the crucible is dependent. Such experience can be based on previous processes or numerical or physical simulations. The experience can also by monitoring other processes be updated continuously.

As the skilled person will be readily apparent that is suitable inventive method not only for the production polycrystalline silicon according to the VGF method but also for the production of any single crystals, in particular of germanium and calcium fluoride single crystals.

1

reservoir

2

Conveyor

3

granular raw material

4

heating elements

5

melt or solid raw material

6

thermal insulation

7a

ceiling heaters

7b

jacket heater

8th

melting pot

9

cooling plate

10

laser beam

11

execution for laser beam / waveguide

12

magnetron

13

purge

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6743293 B2 [0004]
• - DE 3217414 C1 [0009]
• - DE 4213481 C1 [0010]
• US 4353726 [0011]
• - EP 0315156 B1 [0013]
• - EP 1338682 A2 [0014]
• JP 01-148780A [0014]
• US 2004/0226504 A1 [0015]
• US 2006/0060133 A1 [0015]
• JP 07-277874A [0016]
• - JP 2006-188376 A [0017]
• JP 07-118089 A [0018]

Claims (21)

Process for crystallizing a semiconductor material, in particular silicon, comprising the steps of: providing a container ( 8th ) for receiving a melt ( 5 ) of the semiconductor material; Introduction of solid, lumpy semiconductor raw material into the container ( 8th ); Melting of the raw material ( 3 ) to the melt ( 5 ) of the semiconductor material; and crystallizing the melt ( 5 ) to a single- or polycrystalline semiconductor material, in particular silicon; further comprising the step of additionally introducing semiconductor raw material ( 3 ) in the container ( 8th comprising the steps of: heating the semiconductor raw material outside the container by selective heat input to a temperature below the melting temperature of the semiconductor raw material; and introducing the semiconductor raw material in the heated state into the container. Method according to claim 1, wherein the targeted heat input on the inside of a thermal insulation ( 6 ) of the container ( 8th ) receiving melting furnace takes place. The method of claim 1 or 2, wherein the targeted Heat input by the action of electromagnetic radiation he follows. The method of claim 3, wherein the electromagnetic radiation is selectively formed by imaging thermal radiation or radiation from an optical radiation source ( 10 ), in particular a laser, or by application of microwave radiation or high-frequency or medium-frequency radiation to the semiconductor raw material ( 3 ) acts to heat it. Method according to one of the preceding claims, wherein the solid, lumpy semiconductor raw material ( 3 ) during transport through a conveyor ( 2 ) is spread flat and the targeted heat input takes place in the already flat-spreading semiconductor raw material. The method of claim 5, wherein the solid, lumpy Semiconductor raw material during transport to a Single or double layer, preferably to a single layer, flat is spread. Method according to claim 5 or 6, wherein the conveyor device ( 2 ) the semiconductor raw material ( 3 ) from the lower end of a semiconductor raw material storage and dosing container ( 1 ) into a container ( 8th ) receiving melting furnace promotes. Method according to claim 7, wherein a front end of the conveyor ( 2 ) before introducing the semiconductor raw material ( 3 ) by a thermal insulation ( 6 ) of the melting furnace is passed through into the interior of the melting furnace. The method of claims 5 to 8, wherein during transport through the conveyor ( 2 ) a purge gas ( 13 ) in opposite directions over the semiconductor raw material ( 3 ) to free the heated semiconductor raw material from adsorbed H ₂ O. Method according to one of claims 5 to 9, wherein for introducing the semiconductor raw material, a front end of the conveyor ( 2 ) by horizontal displacement of the conveyor ( 2 ) so to the center of the container ( 8th ) is moved, that a preheating of the semiconductor raw material is performed by a ceiling heater. Method according to one of the preceding claims, wherein the semiconductor raw material and / or the melt in the container from above and / or laterally via a ceiling heater ( 7a ) and / or by means of flat, spaced from the side walls of the container heating elements ( 7b ) and the melt is solidified by an axial temperature profile which is shifted in a controlled manner to the monocrystalline or polycrystalline semiconductor material, in particular to the monocrystalline or polycrystalline silicon. Method according to one of the preceding claims, wherein the semiconductor raw material ( 3 ) is heated discontinuously and introduced into the container. Method according to one of the preceding claims, wherein a surface temperature of the semiconductor raw material in the container ( 8th ) is continuously detected and the predetermined semiconductor material is continuously introduced into the container at a rate corresponding to the heating power for a predetermined period of time or immediately after reaching the melting temperature of the semiconductor raw material. A method according to any one of claims 1 to 12, wherein a surface temperature of said semiconductor raw material in said container ( 8th ) is continuously detected, and a predetermined amount of additional semiconductor raw material is replenished into the container depending on the heating power and the amount of the semiconductor raw material currently in the container. A method according to any one of claims 1 to 12, wherein a surface temperature of said semiconductor raw material in said container ( 8th ) is continuously detected to determine a time at which the melting temperature of the semiconductor raw material is reached, and wherein a predetermined amount of time after the time depending on the heating power, a predetermined amount of additional semiconductor raw material is replenished in the container. Method according to one of claims 1 to 12, wherein a level of the container ( 8th ) is continuously monitored and after a decrease in the level by a predetermined amount, which is dependent on the current level, a predetermined amount of additional semiconductor raw material is refilled into the container. The method of claim 16, wherein the level monitored by distance measurement, in particular laser distance measurement becomes. Method according to one of claims 14 to 17, wherein the step of refilling is repeated until the container ( 8th ) is filled near its upper edge with a semiconductor melt. Method according to one of claims 13 to 18, wherein the introduced semiconductor raw material during refilling over the cross section of the container ( 8th ) is evened out. Use of the method according to one of Claims 1 to 19 crystallized silicon in photovoltaics. Device for crystallizing a semiconductor material, in particular of silicon, comprising: a container ( 8th ) for receiving a melt ( 5 ) of the semiconductor material; a heating device ( 7a . 7b ) for heating the container ( 8th ) to a temperature above the melting temperature of the semiconductor material; and a grant ( 2 ) for introducing solid, lumpy semiconductor raw material ( 3 ) in the container, wherein the conveying means is adapted to the solid, particulate semiconductor raw material during melting or after melting of the semiconductor raw material in the container ( 8th ) to the melt ( 5 ), characterized in that the subsidy ( 2 ) a heating device ( 4 ; 10 to 12 ), so that the solid, lumpy semiconductor raw material ( 3 ) is heated outside the container by targeted heat input to a temperature below the melting temperature of the semiconductor raw material and the semiconductor raw material in the heated state in the container ( 8th ) can be introduced.