APPARATUS FOR HEATING MULTIPLE CRUCIBLES

Abstract

A crucible device includes a heating chamber, at least a first crucible in which a first crystal is growable, and at least a second crucible in which a second crystal is growable. The first crucible and the second crucible are arranged within the heating chamber spaced apart from each other along a horizontal and vertical and any orientational direction. The crucible device further comprises a heating system arranged within the heating chamber, wherein the heating system is configured for adjusting a temperature along the horizontal and vertical and any orientational directions.

Claims

1-20. (canceled)

21. A crucible device (100) for growing crystals, the crucible device (100) comprising a heating chamber (140), at least a first crucible (110) in which a first crystal (111) is growable, at least a second crucible (120) in which a second crystal (121) is growable, wherein the first crucible (110) and the second crucible (120) are arranged within the heating chamber (140) spaced apart from each other along a horizontal direction, a heating system arranged within the heating chamber (140), the heating system is configured for adjusting a temperature, wherein the heating system comprises a thermal resistance isolation arranged in the heating chamber, such that the thermal resistance isolation separates the heating chamber (140) in an upper heating volume and a lower heating volume, the thermal resistance isolation comprises a horizontal thermal resistance sheet (105) extending in a horizontal direction for separating the heating chamber (140) in the upper volume and the lower volume, and wherein at least a first upper section of the first crucible (110) is arranged in the first upper volume and at least a first lower section of the first crucible (110) is arranged in the lower volume.

22. The crucible device (100) according to claim 21, wherein the heating system comprises a heating element (101) extending along the first crucible (110) and the second crucible (120).

23. The crucible device (100) according to claim 22, wherein the heating element (101) is an inner heating ring (201), and wherein the inner heating ring (201) is arranged between the first crucible (110) and the second crucible (120).

24. The crucible device (100) according to claim 21, wherein the heating system comprises a further heating element (102) extending along the first crucible (110) and the second crucible (120).

25. The crucible device (100) according to claim 24, wherein the further heating element (102) is an outer heating ring (202), and wherein the first crucible (110) and the second crucible (120) are arranged inside the outer heating ring (202).

26. The crucible device (100) according to claim 22, wherein the heating element (101) is an inner heating element (101), wherein the heating system comprises a further inner heating element (103) extending along the first crucible (110) and the second crucible (120), wherein the inner heating element (101) and the further inner heating element (103) are arranged above each other and spaced apart from each other, such that a lower volume of the heating chamber (140) is heatable by the inner heating element (101) and an upper volume of the heating chamber (140) is heatable by the further inner heating element (103), and wherein at least a first lower section of the first crucible (110) is arranged in the lower volume and at least a first upper section of the first crucible (110) is arranged in the upper heating volume.

27. The crucible device (100) according to claim 24, wherein the further heating element (102) is an outer heating element (102), wherein the heating system comprises a further outer heating element (104) extending along the first crucible (110) and the second crucible (120), and wherein the further heating element (102) and the further outer heating element (104) are arranged above each other and spaced apart from each other, such that the lower volume of the heating chamber (140) is heatable by the further heating element (102) and the upper volume of the heating chamber (140) is heatable by the further outer heating element (104).

28. The crucible device (100) according to claim 24, wherein at least the further heating element (102) is, in particular vertically, movably arranged within the heating chamber (140).

29. The crucible device (100) according to claim 21, wherein the thermal resistance isolation comprises a vertical thermal resistance sheet (106) being arranged between the first crucible (110) and the second crucible (120) and extending along a vertical direction for separating the heating chamber (140) in a first heating volume and a second heating volume, and wherein the first crucible (110) is arranged in the first heating volume and the second crucible (120) is arranged in the second heating volume.

30. The crucible device (100) according to claim 21, wherein the horizontal thermal resistance sheet (105) is movably, in particular along a vertical direction, arranged within the heating chamber (140), such that the height of the first upper volume and the second lower volume is adjustable.

31. The crucible device (100) according to claim 21, wherein the horizontal thermal resistance sheet (105) comprises at least one through hole (107) through which the first crucible (110) is insertable, and wherein the horizontal thermal resistance sheet (105) comprises in particular a second through hole (107) to which the second crucible (120) is insertable.

32. The crucible device (100) according to claim 21, wherein at least the first crucible (110) is, in particular vertically, movably arranged within the heating chamber (140).

33. The crucible device (100) according to claim 21, wherein at least the first crucible (110) is rotatably arranged within the heating chamber (140).

34. The crucible device (100) according to claim 21, further comprising a rotary table on which the first crucible (110) and the second crucible (120) are arranged, wherein the rotary table is rotatable with respect to the heating system.

35. The crucible device (100) according to claim 21, wherein the heating chamber (140) comprises a plurality of viewports (108) through which respective sensors, in particular temperature sensors, are protruding within the heating chamber (140).

36. The crucible device (100) according to claim 21, wherein at least the first crucible (110) comprises a tube line (109) which is guided through the heating chamber (140) for supplying source material within the first crucible (110) and/or for draining off source material out of the first crucible (110).

37. The crucible device (100) according to claim 36, wherein the tube line (109) is coupled to a bottom of the first crucible (110), wherein the first crucible (110) comprises in particular a seed fixing section for fixing a seed crystal, and wherein the seed fixing section is located at a top section of the crucible.

38. A method for growing crystals, the method comprising adjusting a temperature within a heating chamber (140) along a horizontal and vertical and/or any orientational direction by a heating system arranged within the heating chamber (140), wherein at least a first crucible (110) in which a first crystal (111) is growable and a second crucible (120) in which a second crystal (121) is growable are arranged within the heating chamber (140) spaced apart from each other along a horizontal direction, wherein the heating system comprises a thermal resistance isolation arranged in the heating chamber, such that the thermal resistance isolation separates the heating chamber (140) in an upper heating volume and a lower heating volume, the thermal resistance isolation comprises a horizontal thermal resistance sheet (105) extending in a horizontal direction for separating the heating chamber (140) in the upper volume and the lower volume, and wherein at least a first upper section of the first crucible (110) is arranged in the first upper volume and at least a first lower section of the first crucible (110) is arranged in the lower volume.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0050] The aspects defined above and further aspects of the present invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment. The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

[0051] FIG. 1 shows a schematic view of a crucible device according to an exemplary embodiment of the present invention.

[0052] FIG. 2 shows a top view of a crucible device according to an exemplary embodiment of the present invention.

[0053] FIG. 3 shows thermal diagram of the crucible device according to FIG. 2.

[0054] FIG. 4 shows thermal diagram of the crucible device according to FIG. 1.

[0055] FIG. 5 shows a crucible comprising a porous element in a tube line according to an exemplary embodiment of the present invention.

[0056] FIG. 6 shows a schematic view of a crucible device comprising four heating elements having different power density according to an exemplary embodiment of the present invention.

[0057] FIG. 7 shows a thermal diagram of a crucible device shown in FIG. 6 according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0058] The illustrations in the drawings are schematic. It is noted that in different figures similar or identical elements are provided with the same reference signs.

[0059] FIG. 1 shows a schematic view of a crucible device 100 for growing crystals 111, 112 according to an exemplary embodiment of the present invention. The crucible device 100 comprises a heating chamber 140, at least a first crucible 110 in which a first crystal 111 is growable, and at least a second crucible 120 in which a second crystal 121 is growable. The first crucible 110 and the second crucible 120 are arranged within the heating chamber 140 spaced apart from each other along a horizontal direction. The crucible device 100 further comprises a heating system arranged within the heating chamber 140, wherein the heating system is configured for adjusting a temperature along the horizontal and vertical and any orientational directions.

[0060] The crucible device 100 is a furnace comprising the heating chamber 140 which provides a heatable accommodation space for the crucibles 110, 120. The heating system heats the inner volume of the crucibles 110, 120 until a desired temperature is reached. The temperature which may be provided inside the inner volume of the heating chamber 140 and the crucibles 110, 120, respectively, may be 100° C. to 1400° C., preferably to approximately 2200° C. or more.

[0061] The heating system comprises specifically respective heating elements 101, 102, 103, 104 which are spaced apart from each other along the horizontal and vertical and any orientational directions such that specific horizontally vertically and any orientationally spaced locations inside the heating chamber 140 can be heated, in particular individually with respect to each other, such that a desired temperature gradient along the horizontal and vertical and any orientational directions can be adjusted. The heating elements 101, 102, 103, 104 may be RF (radio frequency) heaters, resistive heaters and heating generators. Furthermore, heating element may be formed by an inlet injecting hot medium, such as high temperature gas. The heating elements 101, 102, 103, 104 may form single heating blocks which are arranged at the specific location inside the heating chamber 140. Furthermore, as shown in detail in FIG. 2, the heating elements 101, 102, 103, 104 may form long heating arrays/lines having for example a linear or circular extension.

[0062] The heating chamber 140 may comprise an insulating material 115, such that the inner volume of the heating chamber 140 is thermally isolated. In the heating chamber 140 of the crucible device 100 at least two or a plurality of first and second crucibles 110, 120, 130 can be arranged. The plurality of crucibles 110, 120, 130 may be arranged along a linear, translatory arrangement direction. Furthermore, the plurality of crucibles 110, 120, 130 may be arranged along a circular arrangement direction (see FIG. 2).

[0063] Each crucible 110, 120 comprises an inner volume in which the crystal growing takes place. Inside the crucible 110, 120, a seed element may be placed. The seed element is made of a desired single crystal material, such as sapphire. Furthermore, a source material 117, which provide a reaction fluid of a desired crystal material, e.g. high purity SiC powder, is put into the inner volume of the crucible 110, 120. The reaction fluid may be injected by tube lines 109 comprising for example nozzles or a porous element 116.

[0064] The seed crystal may be fixed to the respective fixing region inside the crucible 110, 120 for example by clamping means and/or by gluing with adhesive materials. As shown in FIG. 1, the first crystal 111 and the second crystal 121 are fixed at top sections 112, 122 of the respective first and second crucibles 110, 120, such that the crystals 111, 121 growth from the top section 112, 122 to a respective bottom section of the respective crucible 110, 120.

[0065] The heating system comprise for example an inner heating element 101 and a further inner heating element 103 extending along the first crucible 110 and the second crucible 120. The inner heating element 101 and the further inner heating element 103 are arranged above each other and spaced apart from each other, such that a lower volume v1 of the heating chamber 140 is heatable by the inner heating element 101 and an upper volume v2 of the heating chamber 140 is heatable by the further inner heating element 103. At least a lower section of the crucibles 110, 120 is arranged in the lower volume v1 and at least an upper section of the crucibles 110, 120 is arranged in the upper heating volume v2.

[0066] Hence, the inner heating element 101 and the further inner heating element 103 are arranged above each other along a vertical direction, such that a vertical temperature gradient is adjustable.

[0067] Specifically, the growth surface of the crystals 111, 121 change its vertical position within the crucible 110, 120 due to the growing of the crystal 111, 121. Hence, the temperature at the respective growth surface can be exactly adjusted considering the vertical location of the growth surface. For example, at the region of the growth surface, different temperature may be adjusted with respect to an upper or lower location with respect to the growth surface. However, it is also possible to provide different vertical heating zones within the crucible 120, 130.

[0068] According to further exemplary embodiment, the further heating element is an outer heating element 102, wherein the heating system comprises a further outer heating element 104 extending along the first crucible 110 and the second crucible 120 and wherein the outer heating element 102 and the further outer heating element 104 are arranged above each other and spaced apart from each other, such that the lower volume v1 of the heating chamber 140 is heatable by the outer heating element 102 and the upper volume v2 of the heating chamber 140 is heatable by the further outer heating element 104.

[0069] Hence, the outer heating element 102 and the further outer heating element 104 are arranged above each other along a vertical direction, such that a vertical temperature gradient is adjustable. Between the lower heating elements 101, 102 and the upper heating elements 103, 104, a plurality of further intermediate heating elements may be arranged in order to provide different temperature sections along the vertical direction.

[0070] The heating elements 101, 102, 103, 104 may be, in particular vertically, movably arranged within the heating chamber 140. Hence, the temperature gradient may be adjusted very precisely. For example, the heating elements 101, 102, 103, 104 can be adjusted along the horizontal direction, such that the (horizontal) distance of the heating elements 101, 102, 103, 104 to the respective crucible 110, 120 is adjustable. Additionally or alternatively, the heating elements 101, 102, 103, 104 are adjustable along a vertical direction, such that the heating elements 101, 102, 103, 104 is arrangeable between for example a top 112, 122 and the bottom of the crucible 110, 120 and the plurality of crucibles 130, respectively.

[0071] Specifically, the inner heating element 101 and the outer heating element 102 are arranged at the bottom sections of the crucibles 110, 120, wherein above the respective inner and outer heating elements 101, 102 respective further inner and outer heating elements 103, 104 are arranged which are adjustable along a vertical direction with respect to the inner and outer heating elements 101, 102 below. Additionally, also the heating elements 101, 102 arranged at the bottom sections of the crucible 110, 120 may be movable along the vertical direction.

[0072] Furthermore, a thermal resistance isolation 105, 106 can be arranged in the heating chamber 140, such that the thermal resistance isolation 105, 106 separates the heating chamber 140 in a first heating volume and a second heating volume.

[0073] The thermal resistance isolation comprises a vertical thermal resistance sheet 106 being arranged between the first crucible 110 and the second crucible 120 and extending along a vertical direction for separating the heating chamber in a first heating volume and a second heating volume, wherein the first crucible 110 is arranged in the first heating volume and the second crucible 120 is arranged in the second heating volume. Hence, by the vertical thermal resistance sheet 106, temperature gradients between for example two adjacent crucibles 110, 120 can be adjusted more precisely.

[0074] Furthermore, the thermal resistance isolation comprises a horizontal thermal resistance sheet 105 extending in a horizontal direction for separating the heating chamber 140 in an upper volume v2 and a lower volume v1, wherein at least a first upper section of the first crucible 110 is arranged in the first upper volume v2 and at least a first lower section of the first crucible 110 is arranged in the lower volume v1. Hence, the temperature of the crucible 110, 120 in the upper volume v2 and the temperature of the crucible 110, 120 in the lower volume v1 can be adjusted more precisely since both volumes v1, v2 are thermally isolated by the horizontal thermal resistance sheet 105.

[0075] The horizontal thermal resistance sheet 105 comprises through holes 107 through which the first crucible 110 and the second crucible 120 are insertable, wherein the horizontal thermal resistance sheet 105. Hence, the horizontal thermal resistance sheet 105 provides only small gaps to the crucibles 110, 120, 130 and for example to the wall of the heating chamber 140, such that a proper thermal isolation between an upper volume v2 and a lower volume v1 separated by the horizontal thermal resistance sheet 105 is provided.

[0076] Specifically, the vertical and/or specifically the horizontal thermal resistance sheet 105, 106 are movable. In particular, the horizontal thermal resistance sheet 105 is movably, in particular along a vertical direction, arranged within the heating chamber 140, such that the height of the first upper volume v2 and the second lower volume v1 is adjustable. The horizontal thermal resistance sheet 105 may be coupled to a vertical guiding rail which is arranged for example at a side wall of the heating chamber 140, such that the horizontal thermal resistance sheet 105 is movable along the vertical guiding rail.

[0077] Furthermore, the first crucible 110 and the second crucible 120 are movably arranged within the heating chamber 140. For example, the crucibles 110, 120 may be arranged onto lifting pistons so that the crucibles 110, 120 and are lifted along the vertical direction in order to be moved in a desired temperature zone within the heating chamber 140.

[0078] Furthermore, the heating chamber comprises 140 comprises a plurality of viewports 108 through which respective sensors, in particular temperature sensors, are protruding within the heating chamber 140.

[0079] Furthermore, the crucibles 110, 120 are coupled to tube lines 109 which are guided through the heating chamber 140 for supplying source material 117 within the crucibles 110, 120 and/or for draining off source material 117 out of the crucibles 110, 120. For example, a plurality of respective tubes lines 109 may be coupled to the respective crucible 110, 120.

[0080] In the specific embodiment shown in FIG. 1, the respective tubes lines 109 are coupled to a respective bottom of the crucibles 110, 120. The crucibles 110, 120 comprise in particular a seed fixing section for fixing a seed crystal at the top section 112, 122.

[0081] FIG. 2 shows a top view of a crucible device 100 according to an exemplary embodiment of the present invention. A plurality of crucibles 110, 120, 130 are arranged circumferentially around the center of the heating chamber 140.

[0082] An inner heating element 101, 103 is formed as an inner heating ring 201. The inner heating ring 201 is arranged between the crucibles 110, 120, 130. The inner heating ring 201 is surrounded by the respective crucibles 110, 120, 130. Hence, the inner region surrounded by the plurality of crucibles 110, 120, 130 can be adjusted with respect to an outer region surrounding the crucibles 110, 120, 130.

[0083] Furthermore, a further heating element 102, 104 can be formed as an outer heating ring 202. The crucibles 110, 120, 130 are arranged between the inner heating ring 201 and the outer heating ring 202. The inner sides of the crucibles 110, 120, 130 are directed to the inner heating ring 201 and the outer side of the crucibles 110, 120, 130 are directed to the outer heating ring 202.

[0084] The inner heating ring 201 and the outer heating ring 202 are for example resistive heating elements or heating ring tubes which are flushed by heating medium.

[0085] For example, a plurality of inner and/or outer heating rings 201, 202 may be arranged above each other. The plurality of heating rings 201, 202 are movable with respect to each other along the vertical direction. Furthermore, the inner or outer heating rings 201, 202 may adjust its diameters in order to adjust the distance between the crucibles 110, 120, 130.

[0086] FIG. 3 shows thermal diagram of the crucible device according to FIG. 2. the inner heating ring 201 and the outer heating ring 202 are adjusted in such a manner, that the region between the inner ring 201 and the outer ring 202 and almost constant temperature is provided, such that all crucibles 110, 120, 130 may have a similar temperature. Specifically, a uniform temperature profile along the horizontal direction can be adjusted.

[0087] FIG. 4 shows thermal diagram of the crucible device 100 according to FIG. 1. The heating elements 101, 102, 103, 104 may be adjusted individually, such that each temperature element 101, 102, 103, 104 radiates a predefined thermal energy into the inner volume of the heating chamber 140. Specifically, in the exemplary embodiment, the lower volume v1 is adjusted with a higher temperature by the heating elements 101, 102 with respect to the upper volume v2 which is adjusted by the further heating elements 103, 104. The temperatures of both volume v1, v2 can be separated furthermore by the horizontal thermal resistance sheet 105.

[0088] FIG. 5 shows a crucible 110 comprising a porous element 116 in a tube line 109 according to an exemplary embodiment of the present invention. In a crucible 110, a crystal growth 111 takes place at the top section 112. The source material 117 is filled within the crucible 110. Specifically, the source material 117 is vaporized and the particles of the source material growth on surfaces of the first crystal 111 and the seed crystal, respectively. Specifically, at the end of the tube line 109, a porous element 116 can be installed. Hence, the vaporization of the source material 117 may be improved by pressing the source material 117 through the porous element 116.

[0089] FIG. 6 shows a schematic view of a crucible device 100 comprising four heating elements 101, 102, 103, 104 having different power densities. For example, an inner heating element 101 (such as an inner heating ring 201) passes the crucible 110 on the bottom section on the right side. At an opposing left side, an outer heating element 102 (such as an altar heating ring 202) passes the crucible 110. Accordingly, at the top section 112 of the crucible 110, respective inner and outer heating elements 103, 104 (which may also be ring shaped) are arranged at respective inner and outer side of the crucible 110.

[0090] Hence, on four sections (the upper section and lower section at the first side and the upper and lower section of an opposing second side) of the crucible 110 specific temperatures may be adjusted, such that a very specific and detailed temperature profile within the crucible volume is adjustable. In order to provide for example an almost uniform temperature profile within the crucible 110, the button heating elements 101, 102 may be adjusted with more heating power with respect to the heating elements 103, 104 at the top section 112 of the crucible 110.

[0091] FIG. 7 shows a thermal diagram of a crucible device shown in FIG. 6. as can be seen from the isothermal lines running through the crucible 110, the temperature in a center section of the crucible 110, in which the crystal growth takes place, varies between 2200° C. and 2280° C.

[0092] This small temperature difference in the growth direction and uniform temperature profile along the crystal surface in such high temperature regions supports a homogeneous and hence a proper crystal growth of a respective crystal 111 within the inner volume of the crucible 110.

[0093] It should be noted that the term “comprising” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

[0094] 100 crucible device

[0095] 101 inner heating element

[0096] 102 outer heating element

[0097] 103 further inner heating element

[0098] 104 further outer heating element

[0099] 105 horizontal thermal resistance sheet

[0100] 106 vertical thermal resistance sheet

[0101] 107 through hole

[0102] 108 viewport

[0103] 109 tube line

[0104] 110 first crucible

[0105] 111 first crystal

[0106] 112 top section

[0107] 115 isolation

[0108] 116 porous element

[0109] 117 source material

[0110] 120 second crucible

[0111] 121 second crystal

[0112] 122 top section

[0113] 140 heating chamber

[0114] 201 inner heating ring

[0115] 202 outer heating ring