CA1053545A - Non-crucible zone-melting of a semi-conductor - Google Patents
Non-crucible zone-melting of a semi-conductorInfo
- Publication number
- CA1053545A CA1053545A CA214,337A CA214337A CA1053545A CA 1053545 A CA1053545 A CA 1053545A CA 214337 A CA214337 A CA 214337A CA 1053545 A CA1053545 A CA 1053545A
- Authority
- CA
- Canada
- Prior art keywords
- rod
- semi
- funnel
- conductor
- seed crystal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 34
- 238000004857 zone melting Methods 0.000 title claims abstract description 13
- 239000013078 crystal Substances 0.000 claims abstract description 56
- 229910052710 silicon Inorganic materials 0.000 claims description 16
- 239000010703 silicon Substances 0.000 claims description 16
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 239000006004 Quartz sand Substances 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical class [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052738 indium Inorganic materials 0.000 claims description 4
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 4
- 239000000374 eutectic mixture Substances 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 239000010959 steel Substances 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 8
- 239000000945 filler Substances 0.000 abstract description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 14
- 239000000155 melt Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 206010023204 Joint dislocation Diseases 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000007775 late Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 230000003405 preventing effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B13/00—Single-crystal growth by zone-melting; Refining by zone-melting
- C30B13/28—Controlling or regulating
- C30B13/285—Crystal holders, e.g. chucks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
- Y10T117/10—Apparatus
- Y10T117/1024—Apparatus for crystallization from liquid or supercritical state
- Y10T117/1076—Apparatus for crystallization from liquid or supercritical state having means for producing a moving solid-liquid-solid zone
- Y10T117/1084—Apparatus for crystallization from liquid or supercritical state having means for producing a moving solid-liquid-solid zone having details of a stabilizing feature
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
- Engine Equipment That Uses Special Cycles (AREA)
Abstract
Abstract A method and apparatus for non-crucible zone-melting of a semi-conductor crystal rod, in which method the end of the crystal rod is supported by a funnel-shaped sleeve which is connected to the seed-crystal holder, is axially displaceable, and is provided with a filler, the said funnel-shaped sleeve, in its uppermost position, surrounding the cone area of the said rod.
Description
~05i3S45 This present invention re:lates to a method for non-crucible zone-melting of a semi-corlductor crystal rod which i9 provided at i~s lower end with a melted-on seed crystal, and which is held vertically by both its ends, in which method the end of the rod containing the seed crystal is subsequent-ly supported at a location passed through by the melt-zone, after the said location has re-solidified.
Semi-conductor crystals, especially those made of silicon, are pro-duced~ by non-crucible zone-melting, by melting onto one end of a rod-shaped polycrystalline semi-conductor element a monocrystalline seed crystal of lesser diameter than the semi-conductor element, for example w~th the aid of an induction-heating coil. Subsequently, and starting from the location at which the seed c~ystal was melted on, one or more melt-zones, produced by the same or another induction-heating coil, are moved along the said rod-shaped semi-conductor element. This not only eliminates foreign substances from the semi-conductor element but also converts it into a single crystal.
In the production of semi-conductor elements, the semi-conductor material must be as free as possible from dislocations~ since such dislo-cations may have a highly adverse effect on the electrical properties of the semi-conductor components produced. Moreover, the said dislocations shorten the life of the minority carriers in the semi-conductor material It is known from German Public Inspection Text 1 079 593 to reduce the dislocations arising in the rod-shaped semi-conductor element, at the location where the seed crystal is melted onto it, by constricting the cross section of the semi-conductor rod in the immediate vicinity of the said location, prior to the final passage of the melt-zone therethroughO Any dislocations present in the seedling can then heal up in the resulting thin connecting piece between the seed crystal and the semi-conductor rod.
According to German Patent 1 128 413, for example, rod-shaped silicon monocrystals completely free of dislocations are produced in that, 105~545 with non-crucible zone-melting, the melt-zone passes repeatedly throu~h a vertical silicon rod held by its end~, the said rod having, melted onto its lower end a monocrystalline seed crystal of a cross section substantially less than that of the said silicon rod; in that all passes through the melt-zone begin at the seed crystal; and in that the said melt-zone passes through the seed crystal at a velocity of between 7 and 15 mm/min. During its final passage through the melt-zone zone, the cross section of the si'icon rod~ at the transition between the seed crystal and the rod itself, is constricted by temporarily moving the ends of the rod apart at a velocity higher than 25 tO mm/min., the velocity of the melt-zone decreasing constantly from this con-striction until the full cross section of the silicon rod is reached. Fin-ally the melt zone is passed through the silicon rod at a velocity of less than 7 mm/min It has been found that in producing monocrystalline semi-conductor rods of large diameter by non-crucible zone-melting, the rod-shaped single crystal, which grows onto the seed crystal during the final zone pass, tends to vibrate because of the thin connecting piece between it and the seed cry-stal. This is particularly so if thick7 monocrystalline semi-conductor rods are to be produced, for example, by upsetting during non-crucible melt-ing. These vibrations cause dislocations and defects in the single crystal of the material solidifying from the melt zone during the final passage of the zone through the semi-conductor rod. These vibrations even lead frequent-ly to dripping of the melt out of the melt-zone, and even to breakage of the thin connecting piece between the seed crystal and the semi-conductor rod, and thus to an interruption of the zone-melting process.
It is therefore the purpose of the invention to improve the known zone-melting process, and to prevent the occurrence of these vibrations dur-ing the final passage of the melt zone through the semi-conductor crystal rod~
This invention relates to a device for non-crucible zone-melting of a semi-conductor crystal rod which is provided at its lower end with a melted-on seed crystal and which is held vertically by both its ends, said device having two vertical, approximately coaxial holders for the semi-conductor rod, characterized in that the holder for the end of the rod carrying the seed crystal is surrounded by a funnel-shaped sleeve which is rotatable and is axially displaceable in relation to the area of the said rod which area is cone-shaped, lying above the seed crystal, the said f~nnel-shaped sleeve being provided with means of supporting the said rod in the cone-shaped area thereof.
Although it is already known in the case of non-crucible zone-melt-ing of a crystalline rod onto one end of which a seed crystal is melted, to provide this end of the rod with supports located at the edge of an axially displaceable sleeve which encloses the holder with the seed crystal, this arrangement does not provide a satisfactory solution to the problem of pre-venting vibration during the processing of very thick (above 30 mm diameter), dislocation-free, semi-conductor crystal rods, since the said supports are not in uniform contact with the circular cone of the rod. This instability frequently leads to additional vibration which counteracts, or even elimin-ates, the effect of the supports.
The invention takes another direction, solving the problem inquestion by using, as a support, a funnel-shaped sleeve which is connected to the seed-crystal holder, which is rotatable and axially displaceable, and which in its uppermost position surrounds the cone area of the rod lying above the seed crystal, the said funnel-sleeve being provided with a means for supporting the rod in the cone area thereof.
According to another development of the concept of the invention, provision is made to fill the funnel-sleeve, either with granular silicon, quartz sand, or a liquid metal, preferably lead or indium, which solidifies in the said funnel-sleeve. The said filling may, however, be in the form of a heap of densely packed metal spheres.
This filling of granular silicon, quartz sand, or metal provides ~-t ~ -3-10535~5 a reliable and easily arranged support which prevents the occurrence of vibration during the production of dislocation-free crystal rods having seed crystals at their lower ends.
According to another particularly satisfactory example of embodi-ment of the teaching of the invention, provision is made, at the upper edge of the funnel-sleeve, for the fitting of inserts of extremely pure metal, for -3a-~ ,, ... . . . . . . .
10~i3545 example aluminum, the said inserts melting upon coming into contact with the cone area of the hot rodg and forming a eutectic mixture. As compared with the arrangement described in German nisclosure Text 15.19.901, this present arrangement results in the equalization of all irregularities on the periphery of the rod occurring during alloying.
It is within the scope of this present invention that support be provided by the raised funnel-sleeve when the melt~zone passing through the rod is at least 10 cm away from the said funnel-sleeve when the latter is in its uppermost position.
In one device having two vertical, approximately coaxial holders for the semi-conductor rod, which achieves the purpose of the invention in a particularly satisfactory way, the holder for the end of the rod carrying the seed crystal is surrounded by a funnel-shaped sleeve which is rotatable and axially displaceable as far as the cone area of the rod, the said funnel-sleeve being provided5 in the said area, with means for supporting the said rod in that area. The support means used in this connection are granular silicon, quartz sand, melted and resolidified metal such as lead or indium, or metal spheres, which are placed in the said funnel sleeve by means of a filling device. It is also possible for the support means to be in the form of an aluminum insert which forms, with the rod, a eutectic mixture in the cone area thereof, The invention and the advantages thereof are described in greater detail hereinafter by means of the examples of embodiment illustrated in Figures 1 - 3 of the drawing.
Figure 1 is a section through the device in the vicinity of the lower rod support, showing diagrammaticall~r the new device for the non-crucible zone-melting of a semi-conductor crystal rod, before the end of the rod is supported, whereas Figures 2 and 3 show the arrangement of Figure 1 while it is acting 1053~4S
as a support.
In Fig~re 1, a monocrystalline seed crystal ~ is secured in a holder 3. The said seed crystal is connected to the lower end of a semi-conductor crystal rod 4 made, for example, of silicon. A melt-zone 6, pro-duced by an induction-heating coil 5, is moved, as a result of relative motion between semi-conductor crystal rod 4 and the said induction-heating coil, axially through the said semi-conductor crystal rod, starting at the location where the seed crystal is melted onto the said rod. A funnel-shaped sleeve 7, made of titanium, silicon, or graphite, surrounds rod holder 3, and is adapted to move axially in relation thereto, being operated by an external drive means (not shown in the drawing). The said funnel-sleeve rotates with rod-holder 3 and rests upon a pin 8 fitted to a rod 9 arranged within rod holder 3 and adapted to move axially, the said pin being located in a guide slot 10 in rod holder 3. ~eference numeral 11 indicates the bottom of the chamber provided for the non-crucible zone-melting opera-tion. For the sake of clarity, the necessary seals have been omitted from the drawing.
Figure 1 shows the passage of the melt-zone before the end of the rod is supported. The said end is grown, as a single crystal free of dislocations, onto thin connecting piece 12, the so-called bottleneck, pre-viously produced by melting the area between semi-conductor crystal rod 4 and seed crystal 2 and by separating the said rod from the said crystal in an axial direction. Since both the semi-conductor crystal rod and the seed crystal rotate about their axes, there is a danger of the end of the said rod connected to bottleneck 12 starting to vibrate if the melt-zone has receded too far away from the melt-location between seed crystal 2 and semi-conductor crystal rod 4.
In the case of silicon rods of about 40 mm in diameter, this is so, for example, when the melt-zone is about 70 cm from thin connecting piece 12. The amplitude of the vibration is often so high that the process has to 11)5~545 be interrupted.
Before melt-zone 6 has reached the critical distance from bottle-neck 12 for the occurrence of vibrations, funnel-sleeve 7 is pushed upwards by means of rod 9 until it surrounds the cone area of semi~conductor crystal rod 4 lying above seed crystal 2 - as shown in Figures 2 and 3. The sup-port process starts when funnel-sleeve 7 is filled with the stabilizing agent.
In Figure 2, the said support means is in the form of a funnel-sleeve 7 filled with quartz sand 13 from a filler tube 14. It is also pos-sible to use, instead of quartz sand 13, granular silicon, steel spheres, oreven liquid lead or indium, the latter solidifying in the said funnel sleeve.
As may be seen in Figure 2, it is no longer possible for semi-conductor cry-stal rod 4 seated on bottleneck 12 to vibrate. The lower part of rod ~ ad-jacent seed crystal 2 and bottleneck 12 is aiready so cold that no more dis-locations are formed. The reference numerals are the same as in Figure 1.
Figure 3 shows another solution for the support problem. In this case inserts 15, made of high-purity aluminum, are fitted by means of holders to the inner edge of funnel-sleeve 7. When the said funnel-sleeve is raised, the said inserts make gentle contact with the cone of rod 4 and become al-loyed to the still semi-conductor material, e.g. silicon. As the melt-zone continues to move upwards, the alloyed area around the periphery of the rod cools down~ and a firm joint is formed which prevents vibration. In this arrangement, it is important that the temperature of the contact point be correctly selected. The remaining reference numerals are as in Figures 1 and
Semi-conductor crystals, especially those made of silicon, are pro-duced~ by non-crucible zone-melting, by melting onto one end of a rod-shaped polycrystalline semi-conductor element a monocrystalline seed crystal of lesser diameter than the semi-conductor element, for example w~th the aid of an induction-heating coil. Subsequently, and starting from the location at which the seed c~ystal was melted on, one or more melt-zones, produced by the same or another induction-heating coil, are moved along the said rod-shaped semi-conductor element. This not only eliminates foreign substances from the semi-conductor element but also converts it into a single crystal.
In the production of semi-conductor elements, the semi-conductor material must be as free as possible from dislocations~ since such dislo-cations may have a highly adverse effect on the electrical properties of the semi-conductor components produced. Moreover, the said dislocations shorten the life of the minority carriers in the semi-conductor material It is known from German Public Inspection Text 1 079 593 to reduce the dislocations arising in the rod-shaped semi-conductor element, at the location where the seed crystal is melted onto it, by constricting the cross section of the semi-conductor rod in the immediate vicinity of the said location, prior to the final passage of the melt-zone therethroughO Any dislocations present in the seedling can then heal up in the resulting thin connecting piece between the seed crystal and the semi-conductor rod.
According to German Patent 1 128 413, for example, rod-shaped silicon monocrystals completely free of dislocations are produced in that, 105~545 with non-crucible zone-melting, the melt-zone passes repeatedly throu~h a vertical silicon rod held by its end~, the said rod having, melted onto its lower end a monocrystalline seed crystal of a cross section substantially less than that of the said silicon rod; in that all passes through the melt-zone begin at the seed crystal; and in that the said melt-zone passes through the seed crystal at a velocity of between 7 and 15 mm/min. During its final passage through the melt-zone zone, the cross section of the si'icon rod~ at the transition between the seed crystal and the rod itself, is constricted by temporarily moving the ends of the rod apart at a velocity higher than 25 tO mm/min., the velocity of the melt-zone decreasing constantly from this con-striction until the full cross section of the silicon rod is reached. Fin-ally the melt zone is passed through the silicon rod at a velocity of less than 7 mm/min It has been found that in producing monocrystalline semi-conductor rods of large diameter by non-crucible zone-melting, the rod-shaped single crystal, which grows onto the seed crystal during the final zone pass, tends to vibrate because of the thin connecting piece between it and the seed cry-stal. This is particularly so if thick7 monocrystalline semi-conductor rods are to be produced, for example, by upsetting during non-crucible melt-ing. These vibrations cause dislocations and defects in the single crystal of the material solidifying from the melt zone during the final passage of the zone through the semi-conductor rod. These vibrations even lead frequent-ly to dripping of the melt out of the melt-zone, and even to breakage of the thin connecting piece between the seed crystal and the semi-conductor rod, and thus to an interruption of the zone-melting process.
It is therefore the purpose of the invention to improve the known zone-melting process, and to prevent the occurrence of these vibrations dur-ing the final passage of the melt zone through the semi-conductor crystal rod~
This invention relates to a device for non-crucible zone-melting of a semi-conductor crystal rod which is provided at its lower end with a melted-on seed crystal and which is held vertically by both its ends, said device having two vertical, approximately coaxial holders for the semi-conductor rod, characterized in that the holder for the end of the rod carrying the seed crystal is surrounded by a funnel-shaped sleeve which is rotatable and is axially displaceable in relation to the area of the said rod which area is cone-shaped, lying above the seed crystal, the said f~nnel-shaped sleeve being provided with means of supporting the said rod in the cone-shaped area thereof.
Although it is already known in the case of non-crucible zone-melt-ing of a crystalline rod onto one end of which a seed crystal is melted, to provide this end of the rod with supports located at the edge of an axially displaceable sleeve which encloses the holder with the seed crystal, this arrangement does not provide a satisfactory solution to the problem of pre-venting vibration during the processing of very thick (above 30 mm diameter), dislocation-free, semi-conductor crystal rods, since the said supports are not in uniform contact with the circular cone of the rod. This instability frequently leads to additional vibration which counteracts, or even elimin-ates, the effect of the supports.
The invention takes another direction, solving the problem inquestion by using, as a support, a funnel-shaped sleeve which is connected to the seed-crystal holder, which is rotatable and axially displaceable, and which in its uppermost position surrounds the cone area of the rod lying above the seed crystal, the said funnel-sleeve being provided with a means for supporting the rod in the cone area thereof.
According to another development of the concept of the invention, provision is made to fill the funnel-sleeve, either with granular silicon, quartz sand, or a liquid metal, preferably lead or indium, which solidifies in the said funnel-sleeve. The said filling may, however, be in the form of a heap of densely packed metal spheres.
This filling of granular silicon, quartz sand, or metal provides ~-t ~ -3-10535~5 a reliable and easily arranged support which prevents the occurrence of vibration during the production of dislocation-free crystal rods having seed crystals at their lower ends.
According to another particularly satisfactory example of embodi-ment of the teaching of the invention, provision is made, at the upper edge of the funnel-sleeve, for the fitting of inserts of extremely pure metal, for -3a-~ ,, ... . . . . . . .
10~i3545 example aluminum, the said inserts melting upon coming into contact with the cone area of the hot rodg and forming a eutectic mixture. As compared with the arrangement described in German nisclosure Text 15.19.901, this present arrangement results in the equalization of all irregularities on the periphery of the rod occurring during alloying.
It is within the scope of this present invention that support be provided by the raised funnel-sleeve when the melt~zone passing through the rod is at least 10 cm away from the said funnel-sleeve when the latter is in its uppermost position.
In one device having two vertical, approximately coaxial holders for the semi-conductor rod, which achieves the purpose of the invention in a particularly satisfactory way, the holder for the end of the rod carrying the seed crystal is surrounded by a funnel-shaped sleeve which is rotatable and axially displaceable as far as the cone area of the rod, the said funnel-sleeve being provided5 in the said area, with means for supporting the said rod in that area. The support means used in this connection are granular silicon, quartz sand, melted and resolidified metal such as lead or indium, or metal spheres, which are placed in the said funnel sleeve by means of a filling device. It is also possible for the support means to be in the form of an aluminum insert which forms, with the rod, a eutectic mixture in the cone area thereof, The invention and the advantages thereof are described in greater detail hereinafter by means of the examples of embodiment illustrated in Figures 1 - 3 of the drawing.
Figure 1 is a section through the device in the vicinity of the lower rod support, showing diagrammaticall~r the new device for the non-crucible zone-melting of a semi-conductor crystal rod, before the end of the rod is supported, whereas Figures 2 and 3 show the arrangement of Figure 1 while it is acting 1053~4S
as a support.
In Fig~re 1, a monocrystalline seed crystal ~ is secured in a holder 3. The said seed crystal is connected to the lower end of a semi-conductor crystal rod 4 made, for example, of silicon. A melt-zone 6, pro-duced by an induction-heating coil 5, is moved, as a result of relative motion between semi-conductor crystal rod 4 and the said induction-heating coil, axially through the said semi-conductor crystal rod, starting at the location where the seed crystal is melted onto the said rod. A funnel-shaped sleeve 7, made of titanium, silicon, or graphite, surrounds rod holder 3, and is adapted to move axially in relation thereto, being operated by an external drive means (not shown in the drawing). The said funnel-sleeve rotates with rod-holder 3 and rests upon a pin 8 fitted to a rod 9 arranged within rod holder 3 and adapted to move axially, the said pin being located in a guide slot 10 in rod holder 3. ~eference numeral 11 indicates the bottom of the chamber provided for the non-crucible zone-melting opera-tion. For the sake of clarity, the necessary seals have been omitted from the drawing.
Figure 1 shows the passage of the melt-zone before the end of the rod is supported. The said end is grown, as a single crystal free of dislocations, onto thin connecting piece 12, the so-called bottleneck, pre-viously produced by melting the area between semi-conductor crystal rod 4 and seed crystal 2 and by separating the said rod from the said crystal in an axial direction. Since both the semi-conductor crystal rod and the seed crystal rotate about their axes, there is a danger of the end of the said rod connected to bottleneck 12 starting to vibrate if the melt-zone has receded too far away from the melt-location between seed crystal 2 and semi-conductor crystal rod 4.
In the case of silicon rods of about 40 mm in diameter, this is so, for example, when the melt-zone is about 70 cm from thin connecting piece 12. The amplitude of the vibration is often so high that the process has to 11)5~545 be interrupted.
Before melt-zone 6 has reached the critical distance from bottle-neck 12 for the occurrence of vibrations, funnel-sleeve 7 is pushed upwards by means of rod 9 until it surrounds the cone area of semi~conductor crystal rod 4 lying above seed crystal 2 - as shown in Figures 2 and 3. The sup-port process starts when funnel-sleeve 7 is filled with the stabilizing agent.
In Figure 2, the said support means is in the form of a funnel-sleeve 7 filled with quartz sand 13 from a filler tube 14. It is also pos-sible to use, instead of quartz sand 13, granular silicon, steel spheres, oreven liquid lead or indium, the latter solidifying in the said funnel sleeve.
As may be seen in Figure 2, it is no longer possible for semi-conductor cry-stal rod 4 seated on bottleneck 12 to vibrate. The lower part of rod ~ ad-jacent seed crystal 2 and bottleneck 12 is aiready so cold that no more dis-locations are formed. The reference numerals are the same as in Figure 1.
Figure 3 shows another solution for the support problem. In this case inserts 15, made of high-purity aluminum, are fitted by means of holders to the inner edge of funnel-sleeve 7. When the said funnel-sleeve is raised, the said inserts make gentle contact with the cone of rod 4 and become al-loyed to the still semi-conductor material, e.g. silicon. As the melt-zone continues to move upwards, the alloyed area around the periphery of the rod cools down~ and a firm joint is formed which prevents vibration. In this arrangement, it is important that the temperature of the contact point be correctly selected. The remaining reference numerals are as in Figures 1 and
2.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for non-crucible zone-melting of a semi-conductor crystal rod which is provided at its lower end with a melted-on seed crystal and which is held vertically by both its ends, said device having two vertical, approximately coaxial holders for the semi-conductor rod, characterized in that the holder for the end of the rod carrying the seed crystal is surrounded by a funnel-shaped sleeve which is rotatable and is axially displaceable in relation to the area of the said rod which area is cone-shaped, lying above the seed crystal, the said funnel-shaped sleeve being provided with means of supporting the said rod in the cone-shaped area thereof.
2. A device according to claim 1, characterized in that the support means consist of granular silicon, quartz sand, melted and re-solidified metals, or metal spheres, the said means being placed in the said funnel-shaped sleeve by means of a filling device.
3. A device according to claim 2 wherein said metal is lead or indium.
4. A device according to claim 1, characterized in that the support is in the form of an aluminum insert which forms a eutectic mixture with the rod in the cone-shaped area thereof.
5. A device according to claims 1, 2 or 4, characterized in that the funnel-shaped sleeve is made of metal.
6. A device according to claims 1, 2 or 4, characterized in that the funnel-shaped sleeve is made of titanium, steel, silicon or graphite.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2358300A DE2358300C3 (en) | 1973-11-22 | 1973-11-22 | Device for holding a semiconductor crystal rod vertically during crucible-free zone melting |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1053545A true CA1053545A (en) | 1979-05-01 |
Family
ID=5898815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA214,337A Expired CA1053545A (en) | 1973-11-22 | 1974-11-21 | Non-crucible zone-melting of a semi-conductor |
Country Status (7)
| Country | Link |
|---|---|
| US (2) | US3923468A (en) |
| JP (1) | JPS5337803B2 (en) |
| BE (1) | BE816506A (en) |
| CA (1) | CA1053545A (en) |
| DE (1) | DE2358300C3 (en) |
| IT (1) | IT1025571B (en) |
| PL (1) | PL95739B1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4045278A (en) * | 1973-11-22 | 1977-08-30 | Siemens Aktiengesellschaft | Method and apparatus for floating melt zone of semiconductor crystal rods |
| DE2455173C3 (en) * | 1974-11-21 | 1979-01-18 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Device for vertical holding of the rod end containing the seed crystal during crucible-free zone melting |
| DE2529366A1 (en) * | 1975-07-01 | 1977-01-20 | Wacker Chemitronic | DEVICE FOR SUPPORTING A CRYSTALLINE ROD |
| DE2652199C3 (en) * | 1976-11-16 | 1982-05-19 | Wacker-Chemitronic Gesellschaft für Elektronik-Grundstoffe mbH, 8263 Burghausen | Device for supporting the crystal rod during crucible-free zone pulling |
| JP3376877B2 (en) * | 1997-09-02 | 2003-02-10 | 信越半導体株式会社 | Seed crystal holder |
| DE112017004008B4 (en) | 2016-08-10 | 2021-08-26 | Sumco Corporation | Single crystal manufacturing method and apparatus |
| CN112429282B (en) * | 2020-11-10 | 2022-04-12 | 常州嘉业智能装备科技有限公司 | Funnel for multiple filling |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2989378A (en) * | 1956-10-16 | 1961-06-20 | Int Standard Electric Corp | Producing silicon of high purity |
| GB848382A (en) * | 1957-11-28 | 1960-09-14 | Siemens Ag | Improvements in or relating to the production of mono-crystalline bodies |
| NL235481A (en) * | 1958-02-19 | |||
| NL240421A (en) * | 1958-07-30 | |||
| US3134700A (en) * | 1959-04-22 | 1964-05-26 | Siemens Ag | Dislocation removal by a last pass starting at a location displaced from the original seed into the grown crystal |
| US3179593A (en) * | 1960-09-28 | 1965-04-20 | Siemens Ag | Method for producing monocrystalline semiconductor material |
| NL260045A (en) * | 1961-01-13 | |||
| US3159408A (en) * | 1961-10-05 | 1964-12-01 | Grace W R & Co | Chuck |
| BE626374A (en) * | 1961-12-22 | |||
| DE1519901A1 (en) * | 1966-09-23 | 1970-02-12 | Siemens Ag | Method for crucible-free zone melting of a crystalline rod |
| DE1619993A1 (en) * | 1967-03-03 | 1971-07-01 | Siemens Ag | Process for growing a rod-shaped single crystal from semiconductor material by crucible-free zone melting |
| US3494742A (en) * | 1968-12-23 | 1970-02-10 | Western Electric Co | Apparatus for float zone melting fusible material |
| DE2059360A1 (en) * | 1970-12-02 | 1972-06-08 | Siemens Ag | Process for the production of homogeneous bars from semiconductor material |
-
1973
- 1973-11-22 DE DE2358300A patent/DE2358300C3/en not_active Expired
-
1974
- 1974-06-18 BE BE145571A patent/BE816506A/en unknown
- 1974-10-21 JP JP12128774A patent/JPS5337803B2/ja not_active Expired
- 1974-11-11 IT IT29278/74A patent/IT1025571B/en active
- 1974-11-18 PL PL1974175723A patent/PL95739B1/en unknown
- 1974-11-20 US US525641A patent/US3923468A/en not_active Expired - Lifetime
- 1974-11-21 CA CA214,337A patent/CA1053545A/en not_active Expired
-
1977
- 1977-03-17 US US05/778,587 patent/USRE30863E/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE2358300C3 (en) | 1978-07-20 |
| USRE30863E (en) | 1982-02-09 |
| PL95739B1 (en) | 1977-11-30 |
| BE816506A (en) | 1974-10-16 |
| JPS5084171A (en) | 1975-07-07 |
| US3923468A (en) | 1975-12-02 |
| JPS5337803B2 (en) | 1978-10-12 |
| DE2358300B2 (en) | 1977-12-01 |
| DE2358300A1 (en) | 1975-06-05 |
| IT1025571B (en) | 1978-08-30 |
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