Crucible for growing crystals

Abstract

The invention relates to a crucible (1) for growing crystals, comprising a crucible cover (2), a crucible base (3), and a crucible wall (4) which extends in the longitudinal central axis (L) of the crucible (1), wherein a growth chamber (5) is delimited within the crucible wall (4) by means of the crucible cover (2) and the crucible base (3). The crucible additionally comprises a crystal mounting (6) which is arranged in an upper region of the crucible (1) and which is designed to receive at least one seed crystal (7), and the crucible (1) is designed to receive a starting material (8) which is provided for depositing on the seed crystal (7) during a growth process. The crucible wall (4) is made of a plurality of wall segments (14), which are arranged one over the other with respect to the longitudinal central axis (L), in a receiving region (13) for the starting material (8).

Description

[0001] Crucibles for growing crystals

[0002] The invention relates to a crucible for growing crystals, in particular SiC crystals, comprising a crucible lid and a crucible base, as well as a crucible wall extending along a longitudinal central axis of the crucible, wherein a growth chamber is defined within the crucible wall by means of the crucible lid and the crucible base. Furthermore, the crucible comprises a crystal holder arranged in an upper region of the crucible and designed to receive at least one seed crystal. The crucible is designed to receive starting material intended for deposition on the seed crystal in a growth process.

[0003] JP2007308355 A discloses a device comprising a crucible for growing SiC crystals. A crystal substrate is arranged on the crucible's top surface and a raw material for growing a crystal is accommodated in the bottom region of the crucible. Furthermore, an upper portion of the crucible wall is tapered with respect to its receiving space toward the crucible lid, which is placed on a lower portion of the crucible in which the raw material is accommodated.

[0004] A disadvantage of such crucibles from the state of the art is that they have to be manufactured in different dimensions for different crystal dimensions to be produced, so that they are suitable for accommodating the crystal substrate as well as a specific amount of raw material.

[0005] The object of the present invention was to overcome the disadvantages of the prior art and to provide a crucible by means of which a user is able to easily adapt the crucible to different crystal dimensions and requirements.

[0006] This object is achieved by a crucible according to the claims.

[0007] The crucible according to the invention is characterized in that the crucible wall, in a receiving area for the starting material, is formed from several wall segments arranged one above the other with respect to the longitudinal center axis. The inventive design makes it possible to design the receiving area of ​​the crucible for the starting material variably, so that its height can be adjusted by varying the wall segments, thereby changing the dimensions of its receiving area and adapting it to different conditions.

[0008] Furthermore, a crucible with wall segments according to the invention can have significantly more complex geometries and components in the receiving area of ​​the starting material, since these can be easily inserted thanks to the modular design.

[0009] A further advantage is that a crucible according to the invention can be more easily reused, since the individual wall segments can be easily replaced as soon as a section of the crucible becomes damaged or deteriorates. This also enables a more economical and environmentally friendly design of the crucible.

[0010] Preferably, the wall segments can be provided with a uniform height relative to the longitudinal center axis. Such a configuration enables simple planning regarding the adapted crucible height, the arrangement of heating elements and other relevant devices for the growth process, as well as the amount of material to be filled.

[0011] An advantageous embodiment provides for the wall segments to have an axial shoulder on at least one end face relative to the longitudinal center axis. Axial shoulders enable stable mounting of the wall segments and also simplify joining them together.

[0012] Furthermore, it may be expedient if the plurality of wall segments are designed identically to one another.

[0013] Another possible design involves every other wall segment being identical, so that the design and arrangement of the wall segments is repeated in pairs. This allows for simpler and more economical production of crucible elements, as well as significantly simplifying the replacement of parts.

[0014] One possible embodiment provides for the wall segments to have an axial shoulder on a respective end face relative to the longitudinal center axis, wherein the axial shoulders of the wall segments are arranged symmetrically to one another. Furthermore, it can be provided that the respective axial shoulders of two superimposed wall segments are formed opposite one another. Thus, the axial shoulders of the two superimposed wall segments can be arranged radially opposite one another, so that each of the axial shoulders has a radial surface, wherein the radial surfaces face one another. In particular, the radial surfaces can touch one another.

[0015] It should be noted that the two wall segments arranged one above the other refer to two adjacent wall segments which are arranged directly one after the other with respect to the longitudinal central axis (with respect to possible further wall segments).

[0016] An advantage of such a design is the possibility of forming the wall segments in a T-shape. This allows for a particularly stable crucible wall design and implements a more complex or obstructive flow path geometry with regard to the undesired escape of gases from the crucible. Furthermore, the mechanical stability of the wall segments can be improved, particularly in the case of thermal expansion, since the possible T-shapes, which are arranged opposite one another with respect to the superimposed wall segments, can support each other.

[0017] Furthermore, by means of such a geometric design, additional elements can be attached or formed on the wall segments, which can be arranged within the crucible.

[0018] Furthermore, it can be provided that the respective axial shoulders of superimposed wall segments are tapered relative to one another. Thus, the thickness of the axial shoulders of the wall segments can be designed to decrease from the respective wall segment toward an adjacent wall segment. In this regard, a respective radial surface of the axial shoulders can have a bevel, wherein the respective radial surfaces of two opposing shoulders face each other.

[0019] One possible embodiment provides that at least one of the wall segments has a different wall thickness than the other wall segments, so that a crucible wall thickness of the crucible wall in the region of the wall segment with the different wall thickness also varies. By means of such a configuration, it is possible to achieve different process conditions in the region of this wall segment than in the other wall segments, so that, for example, a temperature can be specifically controlled in this region via the wall thickness using, for example, an inductive heater. In this way, the starting material located within this wall can be specifically heated earlier or later. This can be controlled more effectively, in particular if the material in this region is to be transferred into the gas phase at a specific time in the process, e.g. for a doping process.

[0020] In a possible further development, it can be provided that at least one wall segment has a radial shoulder relative to the longitudinal central axis. Preferably, the wall segment can have a projection in the interior of the crucible. The radial shoulder can be designed in the form of individual elements (interrupted in the circumferential direction) or else in the form of a circumferential or annular web. Preferably, a surface of the shoulder facing the crucible lid can be designed perpendicular to the longitudinal central axis. By means of radial shoulders, bearing arrangements for crucible elements can be created in a wide variety of areas of the crucible with regard to a modular structure, for example if special crucible elements could not be placed in a conventional crucible due to their inner diameter or their geometry, thus creating a significantly greater range of design options for a crucible.

[0021] In an advantageous embodiment, it can be provided that at least one receiving element for receiving the starting material is arranged in the crucible, wherein the receiving element extends radially from the crucible wall in the direction of the longitudinal central axis. The receiving element can preferably have an opening in the region of the crucible center or longitudinal central axis and can be designed, for example, in the shape of an annular disk. The receiving elements can preferably have a reduced thickness in the direction of the longitudinal central axis and / or be inclined in the direction of the crucible lid (starting from the crucible wall towards the center), so that they have an improved load-bearing capacity for the starting material.

[0022] With an inclined bottom surface, a gas flow from the underlying starting material can be directed more effectively toward the crucible center. Furthermore, a previously mentioned opening in the region of the longitudinal center axis also promotes a gas flow toward the crucible center. This type of flow promotes a convex shape of the growing crystal, which has a beneficial effect on polytype stability and defect density. A possible refinement provides for the receiving element to be arranged on the radial shoulder.

[0023] In a further possible embodiment, it can be provided that the receiving element is formed in one piece with one of the wall segments.

[0024] Furthermore, it can be provided that the receiving elements comprise boundary walls for the starting material, which are arranged radially inwardly on the receiving elements and extend from the receiving element toward the crucible lid. Furthermore, the boundary wall can be formed integrally with the receiving element or as a separate component.

[0025] Furthermore, the boundary wall can be formed from a shaped solid body made of a material with the same or similar (chemical) composition as the starting material. For example, it can be formed from a pressed or sintered starting material (e.g., SiC), which is converted into the gas phase during the process together with the starting material stored on the receiving elements. The purity of the material preferably corresponds to that of the starting material. Furthermore, the density of the solid body can increase toward the receiving element, so that a deeper section is less reactive, ensuring stability relative to the stored starting material.

[0026] An advantageous embodiment provides that the wall segments each have a thread, wherein the wall segments are screwed together by means of the thread

[0027] It can also be advantageous to place a heat-resistant lubricant between the individual wall segments during the growth process. For example, graphite powder or graphite in a lubricious form can be introduced between the connecting areas of the wall segments, thus facilitating joining of the wall segments and creating a seal between the parts—and allowing the wall segments to be separated again after a growth process.

[0028] It may also be provided to arrange a graphite adhesive or graphitizing sugar solutions such as glucose syrup between the wall segments. A possible further development provides for at least one of the wall segments to have a different material composition and / or density than the other wall segment(s). By means of such a design, targeted, modified process conditions can be achieved in the area of ​​the wall segment, similar to the previously mentioned advantages of variable wall thicknesses, whereby the wall segments can be geometrically identical. For the sake of completeness, it should be mentioned that preferably essentially the same material (e.g., graphite) is used, and the wall segments exhibit slight differences in their process state. As an example, but not limited to, a density difference of 0.01–0.1 g / cm 3or a different thermal conductivity of, for example, 0.1 - 1 W / mK (at process temperature) is conceivable, as well as different electrical resistances for the inductive heating (e.g. 3xl0 4 Ohm.m).

[0029] For a better understanding of the invention, it is explained in more detail using the following figures.

[0030] They show in a highly simplified, schematic representation:

[0031] Fig. 1 A device for producing crystals with a crucible accommodated therein;

[0032] Fig. 2 shows an embodiment of a crucible according to the invention with individual wall segments;

[0033] Fig. 3 shows an embodiment of the wall segments in exploded view;

[0034] Fig. 4 shows another embodiment of a crucible;

[0035] Fig. 5 shows a possible embodiment of the wall segments.

[0036] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the position information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these position information must be applied analogously to the new position in the event of a change in position.

[0037] Fig. 1 shows a device for producing single crystals by means of vapor deposition. The device 9 comprises an evacuable chamber 10, with a crucible 1 according to the preamble accommodated therein (whereby a crucible according to the invention can also be accommodated therein in this way). An underside of the crucible lid 2 can form a crystal holder 6 of the crucible 1 and is designed to attach (at least) one seed crystal 7. In a bottom region of the crucible 1, delimited by the crucible wall 4 and the crucible bottom 3, there is a starting material 8, which is intended for crystal growth on the seed crystal 7 and is used up during the growth or breeding process.

[0038] The transition of the starting material into the gas phase is achieved by heating it with at least one heater 11. According to this exemplary embodiment, the heating of the starting material 8 and the crucible 1 by the heater 11 occurs inductively. The crucible 1 arranged in the chamber 10 can also be enclosed by insulation 12 for thermal insulation. The insulation 12 simultaneously prevents heat loss from the crucible 1 and achieves a heat distribution in the interior of the crucible 1 that is favorable for the crystal growth process on the seed crystal 7.

[0039] The material for the chamber 10 is preferably a glass material, in particular quartz glass. The crucible 1 and the insulation 12 surrounding it are preferably made of graphite, with the insulation 12 being formed by a graphite felt or the like.

[0040] When the starting material 8 is heated, its atoms or molecules pass into the gas phase. They can diffuse into the interior of the crucible 1 via the gas phase and deposit on the seed crystal 7, thereby causing crystal growth. The aim is to form a single crystal that is as free of defects as possible. The quality of the crystal forming on the seed crystal 7 depends predominantly on the temperature gradient between the starting material 8 and the seed crystal 7, and also, among other things, on the evaporation rate of the starting material 8. The latter, in turn, depends on the form in which the starting material 8 is made available in the crucible 1. It can prove advantageous if the starting material 8 is formed from a mixture of a powdered raw material and a raw material in the form of lumps.Alternatively, this can also be in the form of particles (especially silicon carbide) with a very limited size distribution.

[0041] Fig. 2 shows a possible embodiment of a crucible 1 according to the invention, in particular for growing SiC crystals.

[0042] The crucible 1 comprises a crucible lid 2, a crucible bottom 3, and a crucible wall 4 extending with respect to a longitudinal central axis L. By means of the crucible lid 2 and the crucible bottom 3, a growth chamber 5 is delimited within the crucible wall 4.

[0043] Furthermore, the crucible 1 has a crystal holder 6, wherein the crystal holder 6 is arranged in the region of the crucible lid 2 and is designed to receive at least one seed crystal 7 and the crucible 1 is designed to receive starting material 8 which is intended for deposition on the seed crystal 7 in a growth process.

[0044] According to the invention, the crucible wall 4 is formed in a receiving area 13 for the starting material 8 from a plurality of wall segments 14 arranged one above the other with respect to the longitudinal center axis L. An arrangement of the wall segments 14 "one above the other" preferably means a load-transmitting arrangement.

[0045] The wall segments 14 can preferably be arranged in alignment with the outer surface of the crucible 1 or the crucible wall 4. Furthermore, this can also be provided with respect to the inner surface of the crucible wall 4.

[0046] Furthermore, the wall segments 14 can have an axial shoulder 17 on at least one end face 16 relative to the longitudinal center axis L. As illustrated, these shoulders 17 are preferably complementary between the end faces 16 of adjacent wall segments 14. The axial shoulders 17 can be designed in the form of a step, as illustrated, or can have other complementary shapes designed to engage with the opposite end face 16, e.g., roof-shaped. Furthermore, engagement elements or threads for connecting the wall segments 14 can also be formed on the axial shoulders 17.

[0047] As also shown, the crucible base 3 can have a complementary shape for accommodating the wall segments 14, e.g., a similar shoulder. Furthermore, regardless of the embodiment, it can be provided that the wall segments 14 have a uniform height 15 with respect to their axial extension relative to the longitudinal center axis L. As can also be seen from Fig. 2, in one possible embodiment, it can be provided that the wall segments 14 are identical to one another.

[0048] With regard to that region of the crucible wall 4 in which the crucible lid 2 is arranged, or also the crystal holder 6 (and which is preferably not intended for storing the starting material), the crucible wall 4 can have a segment which is designed differently from the wall segments 14 of the receiving region 13, as can be seen from Fig. 2 and Fig. 4.

[0049] At an upper end of the receiving area 13, a cover element 20 can preferably be provided, which can prevent a vertical flow of the material in the gas phase from the receiving area in the direction of the crucible lid 2 in the area of ​​the crucible wall 4.

[0050] In the center of the crucible, there can also be arranged a boundary wall 21, e.g. in the form of a porous or gas-permeable body, which is preferably hollow-cylindrical and made of the crucible material. Furthermore, the boundary wall 21 serves to form a cavity in the region of the longitudinal center axis L, wherein no starting material 8 is arranged within the cavity and thus a radial barrier for the starting material 8 is formed by the boundary wall 21 and within the boundary wall 21 a gas stream can flow from the crucible bottom 3 in the direction of the crucible lid 2 during the growth process. As shown in Fig. 2, the boundary wall 21 can also consist of individual body segments 22, which preferably have an extension height corresponding to the height 15 of the wall segments 14 with respect to the longitudinal center axis L. Furthermore, these can have the same orhave a similar geometric shape to the wall segments, particularly with regard to the axial shoulders. As indicated by dashed lines, an annular groove can be provided in the crucible base 3, for example, to accommodate the body segments 22.

[0051] In one possible embodiment, it can also be provided that the entire crucible wall 4 is formed from wall segments 14 according to the invention, as indicated in Fig. 3, wherein the wall segments are shown in an exploded view. As can be seen from Figs. 3 and 4, the wall segments 14 can furthermore have an axial shoulder 17 on a respective end face 16 with respect to the longitudinal center axis L, wherein the axial shoulders 17 of the wall segments 14 are preferably arranged symmetrically to one another (opposite on the base body).

[0052] In addition, the axial shoulders 17 of each two (directly or adjacent) wall segments 14 arranged one above the other can be formed opposite one another. Furthermore, in the illustrated embodiment of the wall segments 14, the respective axial shoulders 17 of successive wall segments 14 alternately form part of the inner wall of the crucible (axial shoulders of a first wall segment) and part of the outer wall of the crucible (axial shoulders of a second wall segment), whereby the axial shoulders 17 of two wall segments 14 together can form a crucible wall thickness. In particular, these wall segments 14 can be T-shaped with respect to their cross-section, which shape enables particularly stable mounting.

[0053] With regard to this embodiment, it can be provided that a respective axial shoulder of the two wall segments arranged one above the other has a radial surface, such that a first axial shoulder has a first radial surface, and a second axial shoulder, which is arranged opposite the first shoulder, has a second radial surface, wherein the first and second radial surfaces face one another. In particular, the radial surfaces can touch one another. With regard to the first radial surface and second radial surface, there can preferably be two (cylindrical) jacket surfaces, wherein one of the two radial surfaces is a radially inner jacket surface and the other is a radially outer jacket surface.

[0054] Furthermore, the wall segments 14 can each have a thread, whereby the wall segments 14 can be screwed together by means of the thread. In this regard, Fig. 3 shows a possible arrangement of a thread 24, for example, on two facing regions of two superimposed or directly adjacent wall segments 14. As can be seen, the thread can be formed on the respective axial shoulders 17.

[0055] In Fig. 3, regardless of the design, a possible radial shoulder 18 is schematically indicated by dashed lines on two different wall segments 14, which extends from the wall segments 14 towards the longitudinal central axis L. Such a radial shoulder 18 can preferably be designed in a step-like manner. The radial shoulders 18 can be provided for receiving or supporting various elements within the crucible, e.g. cover elements for directing the gas flow towards the center of the crucible. As mentioned at the beginning, the radial shoulders can be continuous, in the form of an annular web or the like, but also as individual elements which extend only slightly in the circumferential direction.

[0056] Regardless of the illustrated embodiment, it can also be provided that the axial shoulders have a beveled configuration on their radial surfaces facing a respective axial shoulder of the adjacent wall segment. Thus, the axial shoulders can be conical in a connecting region. In this regard, the mutually facing radial surfaces of the axial shoulders of two superimposed wall segments can be beveled, with the respective thickness of the axial shoulders decreasing along the longitudinal center axis L of the wall segments in the direction of the adjacent wall segment.

[0057] In this regard, a respective oblique arrangement of two mutually facing shoulders is indicated in Fig. 3 by means of the dashed bevels 28.

[0058] For the sake of completeness, it should be mentioned that the bevels 28 can preferably have the same inclination or complementary angles.

[0059] According to the embodiment shown in Fig. 4, it can be provided that the radial shoulders 18 are designed as an extension of the base body of the wall segments 14 (with the exception of the axial shoulders), so that the wall segments 14 with the radial shoulders 18 are thicker in terms of their radial width than the wall segments 14 without radial shoulders. Furthermore, the radial shoulders 18 can also be designed to run obliquely, e.g. conically as is also indicated by dashed lines in Figs. 3 and 4, so that, for example, an inner diameter of the shoulders becomes larger in the direction of the crucible bottom. Furthermore, the radial shoulders 18 can be designed in the form of partial elements and arranged around a circumference, e.g. offset from one another by an angular amount, e.g. 2 webs offset by 180° or 3 webs offset by 120° in the circumferential direction.

[0060] Regardless of the embodiment, it can be provided that a receiving element 19 for storing the starting material 8 is arranged on at least one radial shoulder 18. As can be seen, several wall segments 14 with radial shoulders 18 arranged thereon can be provided, so that several receiving elements 19 for receiving the starting material 8, or for receiving different compositions and versions of the starting material 8, are provided in the crucible 1.

[0061] As can also be seen from Fig. 4, boundary walls 21 for the starting material 8 can be provided on the receiving elements 19 in the radial direction to the longitudinal center axis L, which boundary walls are designed, for example, in the form of hollow cylindrical bodies. As also indicated by dashed lines, the boundary walls 21 can be conical or, with respect to their extension from the receiving element 19 to the crucible lid 2, can be inclined in the direction of the longitudinal center axis L or even in the direction of the crucible wall 4. The boundary walls 21 can also be formed integrally with the receiving elements 19. With respect to an inclination to the longitudinal center axis L, a larger receiving volume for the starting material 8 on the receiving elements 19 is possible, as well as a promotion of the gas flow towards the center. Furthermore, the boundary walls 21 preferably have a uniform height, in particular with respect to a uniform height 15.

[0062] In addition, a wall thickness of the boundary wall 21 can be designed such that it becomes smaller in the direction of the crucible lid, preferably uniformly.

[0063] Furthermore, it can be provided that the boundary wall 21 is formed from a shaped solid body, wherein the solid body consists of a material that has the same or similar (chemical) composition as the starting material 8, so that it can dissolve in the growth process.

[0064] In a further development, it can also be provided that the receiving elements 19 are formed integrally with the wall segments 14, as shown in Fig. 5. Irrespective of this, the respective receiving elements 19 can have a uniform radial distance 23 from the longitudinal center axis L, or else different distances 23, as shown. The geometric shape of the receiving elements 19 can be designed in the form of a uniform extension, or else inclined or tapered in the direction of the longitudinal center axis L, so that their thickness decreases. The individual boundary walls can also have different inclinations to the longitudinal center axis L.Furthermore, also independently of the embodiment shown, it can be provided that a surface 25 facing the crucible lid 2 and / or a surface 26 facing away from the crucible lid 2 of at least one of the receiving elements 19 is inclined, wherein the respective surface 25, 26, starting from the crucible wall 4 in the direction of the longitudinal center axis L, is inclined towards the crucible lid 2 as indicated by the surfaces 25, 26 in Figs. 4 and 5. In the case of an inclination of both surfaces, a thickness of the receiving element 19 can be constant in this regard or can also become smaller towards the longitudinal center axis L.

[0065] The wall segments 14 themselves can be T-shaped as in Figures 3 and 4, but they can also have other shapes, e.g. corresponding to the shape shown in Fig.

[0066] 2 and also formed integrally with the receiving elements 19. As can also be seen from Figs. 3 and 4, it can be provided that every second wall segment 14 is formed identically, so that they can be arranged in pairs.

[0067] In addition, a mentioned cover element 20 can also be formed in one piece with the wall segments 14.

[0068] Preferably, it can also be provided that the wall segments 14 have a constant inner and outer diameter (with the exception of the receiving elements or radial shoulders), as can be seen from the figures.

[0069] As further indicated by dashed lines in Figs. 4 and 5, it can also be provided that at least one of the wall segments 14 has an inner and / or outer diameter that differs from the other wall segments, so that a wall thickness 27 of the respective wall segment 14 and a crucible wall thickness formed thereby is different from the wall thicknesses of the other wall segments or the remaining crucible wall 4. As mentioned at the beginning, slightly different process conditions can be created in the respective regions.

[0070] As mentioned at the beginning, the material of the wall segments can also be designed differently.

[0071] Figures 4 and 5 show further and possibly independent embodiments of the crucible, wherein the same reference numerals or component designations are used for the same parts as in the preceding figures 2 and 3. To avoid unnecessary repetition, reference is made to the detailed description in the preceding figures.

[0072] With regard to the various illustrated embodiments of the wall segments 14, it can also be provided that a heat-resistant lubricant is arranged between the wall segments 14 (or end faces 16), as mentioned above. This can preferably be provided between the axial shoulders of two wall segments 14 relative to each other. Furthermore, it can also be applied to a previously mentioned thread.

[0073] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0074] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0075] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0076] For the sake of clarity, it should be noted that some elements have been shown not to scale and / or enlarged and / or reduced in size to improve understanding of the structure.

[0077] crucible

[0078] Crucible lid Crucible bottom Crucible wall

[0079] Growing chamber Crystal holder Seed crystal Starting material Device Chamber

[0080] Heating Insulation Recording area Wall segment Height

[0081] Front side axial shoulder radial shoulder receiving element cover element boundary wall

[0082] Body segments distance

[0083] Thread facing surface opposite surface wall thickness chamfer

Claims

Patent claims 1. Crucible (1) for growing crystals comprising; - a crucible lid (2) and a crucible bottom (3), and - a crucible wall (4), wherein the crucible wall (4) extends with respect to a longitudinal central axis (L) of the crucible (1) and a growth chamber (5) is delimited within the crucible wall (4) by means of the crucible lid (2) and the crucible bottom (3); - a crystal holder (6), wherein the crystal holder (6) is arranged in an upper region of the crucible (1) and is provided for receiving at least one seed crystal (7); and wherein the crucible (1) is designed to receive starting material (8) which is provided for deposition on the seed crystal (7) in a growth process; characterized in that the crucible wall (4) is formed in a receiving region (13) for the starting material (8) from a plurality of wall segments (14) arranged one above the other with respect to the longitudinal central axis (L).

2. Crucible (1) according to claim 1, characterized in that the wall segments (14) have a uniform height (15) with respect to the longitudinal central axis (L).

3. Crucible (1) according to claim 1 or 2, characterized in that the wall segments (14) have an axial shoulder (17) on at least one end face (16) with respect to the longitudinal center axis (L).

4. Crucible (1) according to one of claims 1 to 3, characterized in that the plurality of wall segments (14) are identical to one another.

5. Crucible (1) according to one of claims 1 to 3, characterized in that the wall segments (14) have an axial shoulder (17) on a respective end face (16) with respect to the longitudinal center axis (L), wherein the axial shoulders (17) of the wall segments (14) are arranged symmetrically to one another.

6. Crucible (1) according to claim 5, characterized in that the respective axial shoulders (17) of two wall segments (14) arranged one above the other are formed opposite one another.

7. Crucible (1) according to one of claims 1 to 6, characterized in that at least one of the wall segments (14) has a different wall thickness than the other wall segment(s), so that a crucible wall thickness of the crucible wall in the region of the wall segment (14) also varies with the different wall thickness.

8. Crucible (1) according to one of claims 1 to 7, characterized in that at least one wall segment (14) has a radial shoulder (18) relative to the longitudinal central axis (L).

9. Crucible (1) according to one of claims 1 to 8, characterized in that at least one receiving element (19) for receiving the starting material (8) is arranged in the crucible (1), wherein the receiving element (19) extends radially from the crucible wall (4) in the direction of the longitudinal central axis (L).

10. Crucible according to claim 8 and 9, characterized in that the receiving element (19) is arranged on the radial shoulder (18).

11. Crucible (1) according to claim 9, characterized in that the receiving element (19) is formed in one piece with one of the wall segments (14).

12. Crucible (1) according to one of claims 9 to 11, characterized in that the receiving element (19) has a boundary wall (21) for the starting material (8), wherein the boundary wall (21) extends from the receiving element (19) in the direction of the crucible lid (2).

13. Crucible (1) according to one of claims 1 to 12, characterized in that the wall segments (14) each have a thread to one another, wherein the wall segments (14) are screwed together by means of the thread.

14. Crucible (1) according to one of claims 1 to 13, characterized in that a lubricant which is heat-resistant with respect to the growth process is arranged between the individual wall segments (14).

15. Crucible (1) according to one of claims 1 to 14, characterized in that at least one of the wall segments (14) has a different material composition and / or density than the other wall segment(s) (14).

Images