US3189415A - Device for crucible-free zone melting - Google Patents

Device for crucible-free zone melting Download PDF

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US3189415A
US3189415A US830026A US83002659A US3189415A US 3189415 A US3189415 A US 3189415A US 830026 A US830026 A US 830026A US 83002659 A US83002659 A US 83002659A US 3189415 A US3189415 A US 3189415A
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rod
housing
melting
opening
coil
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US830026A
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Emeis Reimer
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Siemens Schuckertwerke AG
Siemens AG
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    • CCHEMISTRY; METALLURGY
    • C30CRYSTAL GROWTH
    • C30BSINGLE-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
    • C30B13/00Single-crystal growth by zone-melting; Refining by zone-melting
    • C30B13/28Controlling or regulating
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T117/00Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10T117/10Apparatus
    • Y10T117/1024Apparatus for crystallization from liquid or supercritical state
    • Y10T117/1076Apparatus for crystallization from liquid or supercritical state having means for producing a moving solid-liquid-solid zone

Definitions

  • My invention relates to a device for crucible-free zonemelting of semiconductor rods, particularly silicon rods, within a metallic high-vacuum vessel in which the semiconductor rod is held vertically at both ends while being subjected to zone-melting with the aid of a ring-shaped heater surounding the rod and traveling longitudinally along the rod.
  • the semiconductor rod and the zone heating device are accommodated inside a metal bell of relatively large horizontal inner width which is vac'uum-tightly seated upon a base plate.
  • the 'supports and other devices for holding the rod and the heater are mounted on the base plate, and all bushings and shaft seals required for driving the rod-holding devices and for shifting the zone heater along the rod are located on or in the base plate.
  • the exhaust duct for connecting a vacuum source to the processing chamber is likewise mounted on the base plate. This involves the difi'iculty that foreign particles or material vaporized from the rod may drop into the exhaust duct and may reach the vacuum pump.
  • a vacuum device for crucble-free zone melting of semiconductor rods With a metal housing whose interier forms the/high- Vacuum chamber and which is vertically elongated and has its bottom and top irremovably joined or integral with the vertical side walls. Furthermore, one of the two clamps or other holders for attaching the ends of the semiconductor rod is mounted on the bottom, and the other is mounted on the top of the housing so that the housing itself forms the supporting structure for the top holder.
  • the vacuum chamber in the housing is accessible for servicing through a lateral, sealable opening, and another lateral opening in one of the side walls is provided for connection of the device to the high-vacuum pumping equipment, the latter opening being located in vertically spaced relation from the bottom surface of the housing.
  • the vacuum housing is given prismatic shape and a preferably rectangular horizontal cross section, and one of the vertical side walls is provided with a sealable closure device in form of a hinged door. Another one of the side walls is provided with the exhaust opening and duct for connection to the vacuum pump. Another connection for a pre-vacuum pump, if desired, may be provided on the remaining vertical side wall of the housing.
  • the diameter of the exhaust opening for producing the high vacuum within the processing chamber is not limited by the presence of the other Components, nor is the interior obstructed by any supports for the upper rod holder, and the entire interior of the device is more readily accessible for servicing than is the case in the above-mentioned devices heretofore available.
  • FIG. 1 is a part sectional and perspective View of the device connected with evacuating equipment.
  • FIG. 2 illustrates the same device in a vertical section taken along the line II-II in FIG. 3, the view being from the door side of the device.
  • FIG. 3 is a sectional top View of the device, the section being taken along the line III -III indicated in FIG. 2.
  • the housing 2 of the illustrated device has generally the shape of a vertically elongated prism of rectangular or approximately square cross section.
  • the front wall of the housing is formed by a closure plate 3 which forms a door.
  • the walls of the housing as well as the door are preferably provided with cooling means consisting, for example, of copper tubing (not illustrated) soldered to the walls and door in order to pass a flow of cooling water through the tubing during operation of the device.
  • An inspection window 30 extends approximately over the entire length of the semiconductor rod to be processed and permits observing the zone-melting operation.
  • a duct 4 for'connection to a vacuum pumping device 5 is mounted on the rear wall of the housing and communicates with the interior of the housing through an opening ia of large diameter extending over the predominant portion of the horizontal housing width.
  • the opening 4a and the exhaust duct 4 are located above the bottom surface of the vacuum chamber so that any particles or substances dropping onto the bottom of the device cannot enter into the vacuum equipment.
  • the semiconductor rod 6, for example of silicon, is mounted in the processing chamber by means of two holders 7 and 7a.
  • the two-holders shown to consist of respective chucks with clamping screws 7b, are mounted in Vertical coaxial alignment on respective coaxial shafts 8 and Sa which pass through respective vacuum-tight sealng bushings 8b and 8c of the housing bottom and top to the outside where they are connected with driving and control devices (not shown) which permit displacing the holders longitudinally and/or imparting rotationthereto.
  • the device is further provided with a ring-shaped zone heater consisting of a fiat induction coil 11 mounted on terminal blocks 12 of a shifting device 13 which permits moving the axially narrow heater 11 vertically along the rod 6 in order to mel-t a correspondingly narrow zone of the rod and to displace the molten zone gradually along the rod axis.
  • a semi-cylindrical shield 14 of sheet metal protects the device 13 from heat radiation coming from the molten zone and also from deposition of evaporated material.
  • the heater and the shifting device are mounted along one of the corner areas of the prisma-tic processing chamber.
  • the device 13 comprises several concentric tubes which are separated from each other by evacuated interspaces and also serve for supplying the electric current to the terminal blocks 12 of the heater coil 11.
  • the coil 11 consists of a copper tube which forms part of a coolant circulation system.
  • the coolant passes from the outsideof the housing through i the inner tubila'r portion 1341, thence through one of the I -hollow blocks 12, the tubular coil'll, the other block 12, "and through the cylindr'ical interspace aroundthe tube 13:; back to the outside of the processing device.
  • the 'heat shield 14 isfastenedto the top and bottom of -the vacuumhousing b'y screws and may be provided with water cooling, for; example, with' the aid of'copper 't'ubing (not shown) soldered to the shield'14.
  • a gripper device comprising two vertical "ishaf ts 18. and 18.',- is mounted 'along another edge of' the prisr'naticprecessing chamber, preferably, and as shown, near one ;of thetwo edges remote from thedoor.
  • v v
  • two grippers 15 and 1541 are fastened %hys-means of set screws to the respective vertical sh-afts 18 and 18z,' the two grippe rs being longitudinally' diplace- Q able s o that-they canbe Secured in any desired height.
  • the shaftss and 1841 carry respective spur gears 15 and 19a which are in'mesh with each other and are driven hy a spur gear 2! whose shaft za extends through a rotational 'sealflto the outside where it is actuated by a worm ge'ar; 31 and worm 32 preferably of the self-looking type.
  • lsa are provided i i
  • Thehorizontal spacing of the observation window from the vertical axis of the'rod holders 7,7z,' is preferablyat least five times the immerdiameter of the ring-shaped heater coil 11 in order to prevent the deposition, forming itself on the inside of the observation window due to mat'erial evaporating from the rod, from becoming so dense as to inter-f re with proper observation within too short i I a processing time.
  • the grippen'device facilitates servicing and afiords eliminating one or more operatingsteps, such a-s open- ;ing and closing of the door, inserting a semiconductor rod and evacuating the housing, thus saving a considerable amount of time, for example in a casewhere the rod 6 proper is to be inserted'between two rod pieces' of c'rystal seedspreviously fastened in the respective holders 7 and '7a, and is-then to be fused together with ft-hese seed pieces. 5
  • the rod pieces or seeds can be clamped in the holders and the rod proper can be fastened in'the grippendevice when the door is openl and the zone melting devce, is being 'set up for operation.
  • the door can be enclosed and the housing evaporated, whereafterthefusing operation required for ;oinin'g the'rod 6 with, the end pieces or'seeds can be ef- ,40 jfected with the aid of heater coil 11, and the zone melt- .ing-'proper can'be carried'out without requiring renewed" J ⁇ opening of the doo-r or renewed evacuation of the processingclz aniben I i fl- Asshownirf-FIG. 3 the door-like closure plate 3 cari ;ries' a rubber gask-et zs'which is seated in a swallow-tail 'j gr oove orotherwise fastened to the door.
  • the door is jjoined with the -housing by double-type hinges 2-1 whose ;two hnge axes 'are approxim'ately located in theplan'e of the doorwhenthe door is' closedand tightened. i This ,aifords obtaining a vacuum tight sealingof the door under 'the'etfect 'of the ambient pressure-without encountering' l-ateral -displacement of the'door as a consequence of prese i sure changes.
  • the door is provided wi-t-ha handle 29; 3 L
  • the observation'windcw 30 is, covered by a hard glass pane 23 ofsufficient thickness to withstand all occurring i pressu res.
  • the pane 23 is vacuum-tightlysealedby means a of a 'gasket 22 preferably of rubber
  • An exterior protective sheet' Z'f of transparent and splinter-proof glass plasfltc', or'glassplastic'compositiom is mounted on spacer tubes 26 at some distance from the hard-gl ass pane 23,
  • Theprotective sheet 27 consists preferably; of; ⁇ polymethylmetharylate known under the ⁇ trade j %name Plexiglas.
  • another thinner glass pane 24 is removably inserted on the inner' side of -a trap may be mounted on the top of the housing 2 so as to' suspend therefrom.
  • the trap tube 'being closed' at the 'bottom toward the interior off the processing charnber, may have its upper, open end passing vacuum-tightly' :through the top of the housing ,so 'that it can be filled from the outside with coolant, for example liquid air.
  • a device for crucible-free zone melting of silicon V and other semiconductor rods comprising a' stationary metal housing of generally pr isrnatic and verticallyelom i gated shape forming a vacuum ,charnber 'and ,having fectangular vertical side walls and respective horizontal-- top and ,bottom parts'irrernovably 'joined with said Walls, two serniconductor-rod holders mounted on'sa'd respective 'top and bottom parts .in vertical and coa rial' alig i ment on an axis substantially coinci'dent with the vertical r center axis of said 'housing for .holding therespective ends of theirod to be processed, a ring-shap'ed'induction r heater surrounding the vertical rod-'holder axis and being displaceable in the axial direction, the vertical front wall I i' of said housing having an accessiopening for servicing saidchamben said access opening having
  • Theau xiliary pane '23 is held'by means of a( i 'spreding spring 2 5 so that-it can re'adily-be removed, or r exchahged-forcleaning,purposes-
  • the inner pane 24 may also'be attached by other means, suchas" by one or &more leafsprirgsattached by screws-to the dooL
  • the sheet-27 may-be given a dark coloring so that no protective goggles are needed fo observingthe melting operation;
  • said.rod-shaped jdrive means -for said heater extending t vertically between said center axis and one of the verticalrear edges of saidhousing 2.
  • a tubular cooling trap may be rno unted' in one of the ber for said opening
  • a device for crucible-free zone melting of silicon and other semiconductor rods comprising a stationary metal housing of vertically elongated shape forming a vacuum chamber and having vertical side Walls and having a top and a bottom irremovably joined with said side walls, two semiconductor-rod holders mounted on said top and said bottom respectively in vertical and coaXial alignment for holding the respective ends of the rod to be processed, the axis of said holders being substantially coincident with the vertical center axis of said housing, a ring-shaped induction heater surrounding said rod-holder aXis and being displaceable along said axis a distance constituting a major portion of the height of said chamber, vertically displaceable means in said chamber for supporting and moving said heater along said distance the vertical front wall of said housing having an access opening extending vertically fxom one of said holders to the other for servicing said chamber, a sealable closure plate covering said access opening during zone-melting operation and having a Vertically elongated observation window eXtending over substantially the entire vertical displacement path
  • said housing having the shape of a Vertically elongated prism with rectangular cross section, said closure plate having substantially the same size as said vertical front wall of said housing, and said heater supporting means extending through said bottom part to the outside of said housing and along a rear vertical edge of said chamber at a place substantially between said rear edge and said rod-holder axs.

Description

June 15, 1965 R. EMEIS &
DEVICE FOR CRUCIBLE-FREE ZONE MELTING Filed July 28, 1959 v 3 Sheets-Sheet 1 June 15, 1965 R. EMEIS DEVICE FOR CRUCIBLE-FREE ZONE MELTING 5 SheetS-Shet 3 Filed July 28, 1959 United States Parent O DEVICE FOR CRUClBLE-FREE ZONE MELTING Reimer Emeis, Ebermannstadt, Upper Franconia, Germany, assignor to Siemens-Schuckertwerke Aktiengesellschaft, Erlangen, Germany, a corporation of Germany Filed July 28, 1959, Ser. No. 830,()26 Claims priority, application Germany, July 30, 1958, S 59,210 4 Claims. (Cl. 23--273) My invention relates to a device for crucible-free zonemelting of semiconductor rods, particularly silicon rods, within a metallic high-vacuum vessel in which the semiconductor rod is held vertically at both ends while being subjected to zone-melting with the aid of a ring-shaped heater surounding the rod and traveling longitudinally along the rod. r
In a known device for crucible-free zone melting in high vacuum, the semiconductor rod and the zone heating device are accommodated inside a metal bell of relatively large horizontal inner width which is vac'uum-tightly seated upon a base plate. The 'supports and other devices for holding the rod and the heater are mounted on the base plate, and all bushings and shaft seals required for driving the rod-holding devices and for shifting the zone heater along the rod are located on or in the base plate. The exhaust duct for connecting a vacuum source to the processing chamber is likewise mounted on the base plate. This involves the difi'iculty that foreign particles or material vaporized from the rod may drop into the exhaust duct and may reach the vacuum pump. Another difiiculty is the fact that the above-mentiored parts, all mounted on the base plate, impose a severe limitation upon the diametrical size of the duct opening so that a relatively long period of time is needed, when starting the operation, for producing the high vacuum. Furthermore, for exchanging a semiconductor rod or servicing the auxiliary devices within the chamber, the bell must be lifted of the base plate by a hoisting device.
It is an object of my invention to eliminate the abovementioned shortcomings and limitation of crucible-free zone melting devices and to provide a processing apparatus which can more readily be serviced, afiords better protection of the vacuum producing equipment, and greatly reduces the starting-up time required for reducing the pressure in the processing chamber to the required high vacuum.
According to my invention, a vacuum device for crucble-free zone melting of semiconductor rods is provided With a metal housing whose interier forms the/high- Vacuum chamber and which is vertically elongated and has its bottom and top irremovably joined or integral with the vertical side walls. Furthermore, one of the two clamps or other holders for attaching the ends of the semiconductor rod is mounted on the bottom, and the other is mounted on the top of the housing so that the housing itself forms the supporting structure for the top holder. The vacuum chamber in the housing is accessible for servicing through a lateral, sealable opening, and another lateral opening in one of the side walls is provided for connection of the device to the high-vacuum pumping equipment, the latter opening being located in vertically spaced relation from the bottom surface of the housing.,
According to another, preferred feature of my invention, the vacuum housing is given prismatic shape and a preferably rectangular horizontal cross section, and one of the vertical side walls is provided with a sealable closure device in form of a hinged door. Another one of the side walls is provided with the exhaust opening and duct for connection to the vacuum pump. Another connection for a pre-vacuum pump, if desired, may be provided on the remaining vertical side wall of the housing.
By vrtue of the above-mentioned features, the diameter of the exhaust opening for producing the high vacuum within the processing chamber is not limited by the presence of the other Components, nor is the interior obstructed by any supports for the upper rod holder, and the entire interior of the device is more readily accessible for servicing than is the case in the above-mentioned devices heretofore available.
The foregoing and more specific objects, advantages and features of my invention will be apparent from, and will be described in, the following with reference to the embodiment of a processing device according to the invention illustrated by way of example on the accompanying drawings in which: i
FIG. 1 is a part sectional and perspective View of the device connected with evacuating equipment.
FIG. 2 illustrates the same device in a vertical section taken along the line II-II in FIG. 3, the view being from the door side of the device.
FIG. 3 is a sectional top View of the device, the section being taken along the line III -III indicated in FIG. 2.
The housing 2 of the illustrated device has generally the shape of a vertically elongated prism of rectangular or approximately square cross section. The front wall of the housing is formed by a closure plate 3 which forms a door. The walls of the housing as well as the door are preferably provided with cooling means consisting, for example, of copper tubing (not illustrated) soldered to the walls and door in order to pass a flow of cooling water through the tubing during operation of the device. An inspection window 30 extends approximately over the entire length of the semiconductor rod to be processed and permits observing the zone-melting operation. A duct 4 for'connection to a vacuum pumping device 5 is mounted on the rear wall of the housing and communicates with the interior of the housing through an opening ia of large diameter extending over the predominant portion of the horizontal housing width. The opening 4a and the exhaust duct 4 are located above the bottom surface of the vacuum chamber so that any particles or substances dropping onto the bottom of the device cannot enter into the vacuum equipment. r v
The semiconductor rod 6, for example of silicon, is mounted in the processing chamber by means of two holders 7 and 7a. The two-holders, shown to consist of respective chucks with clamping screws 7b, are mounted in Vertical coaxial alignment on respective coaxial shafts 8 and Sa which pass through respective vacuum- tight sealng bushings 8b and 8c of the housing bottom and top to the outside where they are connected with driving and control devices (not shown) which permit displacing the holders longitudinally and/or imparting rotationthereto. i
v The device is further provided with a ring-shaped zone heater consisting of a fiat induction coil 11 mounted on terminal blocks 12 of a shifting device 13 which permits moving the axially narrow heater 11 vertically along the rod 6 in order to mel-t a correspondingly narrow zone of the rod and to displace the molten zone gradually along the rod axis. A semi-cylindrical shield 14 of sheet metal protects the device 13 from heat radiation coming from the molten zone and also from deposition of evaporated material.
The heater and the shifting device are mounted along one of the corner areas of the prisma-tic processing chamber. As best apparent from FIG. 2 the device 13 comprises several concentric tubes which are separated from each other by evacuated interspaces and also serve for supplying the electric current to the terminal blocks 12 of the heater coil 11. The coil 11 consists of a copper tube which forms part of a coolant circulation system. The coolant passes from the outsideof the housing through i the inner tubila'r portion 1341, thence through one of the I -hollow blocks 12, the tubular coil'll, the other block 12, "and through the cylindr'ical interspace aroundthe tube 13:; back to the outside of the processing device.
The 'heat shield 14 isfastenedto the top and bottom of -the vacuumhousing b'y screws and may be provided with water cooling, for; example, with' the aid of'copper 't'ubing (not shown) soldered to the shield'14.
I A gripper device, comprising two vertical "ishaf ts 18. and 18.',- is mounted 'along another edge of' the prisr'naticprecessing chamber, preferably, and as shown, near one ;of thetwo edges remote from thedoor. As is best ap: v
parent from FIG. 3 two grippers 15 and 1541 are fastened %hys-means of set screws to the respective vertical sh-afts 18 and 18z,' the two grippe rs being longitudinally' diplace- Q able s o that-they canbe Secured in any desired height.
The shaftss and 1841 carry respective spur gears 15 and 19a which are in'mesh with each other and are driven hy a spur gear 2!) whose shaft za extends through a rotational 'sealflto the outside where it is actuated by a worm ge'ar; 31 and worm 32 preferably of the self-looking type. For protecting the semiconductor rod 6 from being contaminatedflhe ends of the grippers '15, lsa are provided i iThehorizontal spacing of the observation window from the vertical axis of the'rod holders 7,7z,'is preferablyat least five times the immerdiameter of the ring-shaped heater coil 11 in order to prevent the deposition, forming itself on the inside of the observation window due to mat'erial evaporating from the rod, from becoming so dense as to inter-f re with proper observation within too short i I a processing time. t rnines the locations at whichshafts' and Sa, and the' The* just-ment-ioned spac ing deterappertaining vacuum-tight `seals ;bottom of the housing z.
V remaining front corners of the vacuum chamber. Such withtubular pieces l ofheat-resistant and wear-resista nt-material,preferablyrqua-rtz., v i
The grippen'device facilitates servicing and afiords eliminating one or more operatingsteps, such a-s open- ;ing and closing of the door, inserting a semiconductor rod and evacuating the housing, thus saving a considerable amount of time, for example in a casewhere the rod 6 proper is to be inserted'between two rod pieces' of c'rystal seedspreviously fastened in the respective holders 7 and '7a, and is-then to be fused together with ft-hese seed pieces. 5 For such operation the rod pieces or seeds can be clamped in the holders and the rod proper can be fastened in'the grippendevice when the door is openl and the zone melting devce, is being 'set up for operation. Then'the; door can be enclosed and the housing evaporated, whereafterthefusing operation required for ;oinin'g the'rod 6 with, the end pieces or'seeds can be ef- ,40 jfected with the aid of heater coil 11, and the zone melt- .ing-'proper can'be carried'out without requiring renewed" J `{opening of the doo-r or renewed evacuation of the processingclz aniben I i fl- Asshownirf-FIG. 3 the door-like closure plate 3 cari ;ries' a rubber gask-et zs'which is seated in a swallow-tail 'j gr oove orotherwise fastened to the door. The door is jjoined with the -housing by double-type hinges 2-1 whose ;two hnge axes 'are approxim'ately located in theplan'e of the doorwhenthe door is' closedand tightened. i This ,aifords obtaining a vacuum tight sealingof the door under 'the'etfect 'of the ambient pressure-without encountering' l-ateral -displacement of the'door as a consequence of prese i sure changes. The door is provided wi-t-ha handle 29; 3 L The observation'windcw 30 is, covered by a hard glass pane 23 ofsufficient thickness to withstand all occurring i pressu res. The pane 23 is vacuum-tightlysealedby means a of a 'gasket 22 preferably of rubber An exterior protective sheet' Z'f of transparent and splinter-proof glass plasfltc', or'glassplastic'compositiom is mounted on spacer tubes 26 at some distance from the hard-gl ass pane 23,
jleaving an int'erspce preferably ahout equal to thethickness ofgpanez. Theprotective sheet 27 consists preferably; of;` polymethylmetharylate known under the `trade j %name Plexiglas. For protecting the hard-glass pane 23 fronibeng `-`soiled by evaporated material, another thinner glass pane 24 is removably inserted on the inner' side of -a trap may be mounted on the top of the housing 2 so as to' suspend therefrom. The trap tube, 'being closed' at the 'bottom toward the interior off the processing charnber, may have its upper, open end passing vacuum-tightly' :through the top of the housing ,so 'that it can be filled from the outside with coolant, for example liquid air.
' 'It will'be obvious to those skilled in the art, upon study- 'ing the disclosure, that iny invention permits'ofjvarious modications' with respect' to design-and arrangen entof the device Components and hence may be emb odied in apparatus other than particularly statedvand described herein, without departing from the essential features of niy i invention and within the scope of the claims annexed' hereto. A
I claim; i i i 1. A device for crucible-free zone melting of silicon V and other semiconductor rods, comprising a' stationary metal housing of generally pr isrnatic and verticallyelom i gated shape forming a vacuum ,charnber 'and ,having fectangular vertical side walls and respective horizontal-- top and ,bottom parts'irrernovably 'joined with said Walls, two serniconductor-rod holders mounted on'sa'd respective 'top and bottom parts .in vertical and coa rial' alig i ment on an axis substantially coinci'dent with the vertical r center axis of said 'housing for .holding therespective ends of theirod to be processed, a ring-shap'ed'induction r heater surrounding the vertical rod-'holder axis and being displaceable in the axial direction, the vertical front wall I i' of said housing having an accessiopening for servicing saidchamben said access opening havingaheight equal to at least the major part of the maximumaxial displace-i` i ment of said heater a closure meinber'pivotally mounted -on 'said housing in front of said front wall to close said access' opening and scaling meansbetween said housing 'and said closure member, saidclosure' member having j an observation window extendng verticallyover a major` part of the height of said access opening, and comprising ,v a transparent: pressure-withstanding o'ter pane and a I removably mounted inner pane 'to protect said.: outer' pane from, soilage, said housing having an evacuating opening in the vertical reanwall and having an evacuating ;duet communicating .through i said 'opening with' said chamber, ;said latteropening having a width substantially equal 'to that of said chamber and being upwardly-spaced from said bottom part, the lower one of said rod holders being vertically displaceable, two rod-shaped drive'means' for axially displacing said one rod holder and said heate' respectivelY said respective drive meansextending' r through said housing bottom parttQi -'the outside,-and
?the door. Theau xiliary pane '23 is held'by means of a( i 'spreding spring 2 5 so that-it can re'adily-be removed, or r exchahged-forcleaning,purposes- The inner pane 24 may also'be attached by other means, suchas" by one or &more leafsprirgsattached by screws-to the dooL For protecting the observer@ eyesight, the sheet-27 may-be given a dark coloring so that no protective goggles are needed fo observingthe melting operation; i
said.rod-shaped jdrive means -for said heater extending t vertically between said center axis and one of the verticalrear edges of saidhousing 2. In a device for-crucible-freefzone meltng of :neltable rod, `a 'stationaryjhou'sing two holder members in the` housing, means-for relatively displacing the,holder: memberstivertically with respect toeach other, a 'meltf ing coil in .thejhousing means for supportingahd for 'relatively displacingfthe coilvertically of theveni-cel' t aXis of the holder membersj' the improvement thereing the housing V having i an 'access opening having a 'height' substantially at least as great .as'the entire vertical' displa'cement path of 'the meltir g; coil, and a closure mem- A tubular cooling trap may be rno unted' in one of the ber for said opening having an observation window eX- tending over at least the major part of the height of the opening, and two rod-gripping devices in said housing, each including a rotary vertical shaft and a gripper means mounted on the shaft, and means extending through the housing to turn the shats to position the grippers on opposite sides of the rod to hold the rod, so that upon opening the closure member the rod can be placed and held between the holders at the start of the melting operation, and, after closing the closure member and commencing the melting, the grippers can be turned away from the rod to permit the said relative displacement of the melting coil.
3. A device for crucible-free zone melting of silicon and other semiconductor rods, comprising a stationary metal housing of vertically elongated shape forming a vacuum chamber and having vertical side Walls and having a top and a bottom irremovably joined with said side walls, two semiconductor-rod holders mounted on said top and said bottom respectively in vertical and coaXial alignment for holding the respective ends of the rod to be processed, the axis of said holders being substantially coincident with the vertical center axis of said housing, a ring-shaped induction heater surrounding said rod-holder aXis and being displaceable along said axis a distance constituting a major portion of the height of said chamber, vertically displaceable means in said chamber for supporting and moving said heater along said distance the vertical front wall of said housing having an access opening extending vertically fxom one of said holders to the other for servicing said chamber, a sealable closure plate covering said access opening during zone-melting operation and having a Vertically elongated observation window eXtending over substantially the entire vertical displacement path of said induction heater, said cover plate being hinged to said housing and having a vertical hinge aXis for opening movement of said plate in the outward direction away from said access opening, said housing having an evacuatng opening located in the vertical rear wall and having a diameter substantially equal to the width of said chamber, said housing having an evacuating duct communicating through said latter opening with said chamber, and said means for supportin said he-ater extending vertically in the rear portion of said chamber so as to be located behind said rod holders relative to said access opening.
4. In a Zone-melting device according to claim 3, said housing having the shape of a Vertically elongated prism with rectangular cross section, said closure plate having substantially the same size as said vertical front wall of said housing, and said heater supporting means extending through said bottom part to the outside of said housing and along a rear vertical edge of said chamber at a place substantially between said rear edge and said rod-holder axs.
References Cited by the Examiner UNITED STATES PATENTS 2,745,13 1 5/56 Auwarter.
2,870,309 1/59 Capita 23-301 2,876,147 3/59 Kniepkamp 23-30l 2,902,350 9/59 i Jenny 23 301 2,904,663 9/ 59 Emeis et al 23-273 2,972,525 2/ 61 Emeis.
OTHER REFERENCES Buehler Rev. Scient Inst., Vol. 28 (June 1957), pages 453-460, Q/184/RS.
Keck Review of Scient. Inst., Vol. 25, No. 4, pp. 331- 334, April 1954.
Marshall et al.: Journal of Scientic Instruments, Vol. 35, April 1958, pp. 121-125.
NORMAN YUDKOF-F, Pr'mary Examiner.
MAURICE A. BRINDISI, GEORGE D. MITCHELL,
Exam'ners.

Claims (1)

  1. 2. IN A DEVICE FOR CRUCIBLE-FREE ZONE MELTING OF A MELTABLE ROD, A STATIONARY HOUSING, TWO HOLDER MEMBERS IN THE HOUSING, MEANS FOR RELATIELY DISPLACING THE HOLDER MEMBERS VERTICALLY WITH RESPECT TO EACH OTHER, A MELTING COIL IN THE HOUSING, MEANS FOR SUPPORTING AND FOR RELATIVELY DISPLACING THE COIL VERTICALLY OF THE VERTICAL AXIS OF THE HOLDER MEMBERS; THE IMPROVEMENT THEREIN, THE HOUSING HAVING AN ACCESS OPENING HAVING A HEIGHT SUBSTANTIALLY AT LEAST AS GREAT AS THE ENTIRE VERTICAL DISPLACEMENT PATH OF THE MELTING COIL, AND A CLOSURE MEMBER FOR SAID OPENING HAVING AN OBSERVATION WINDOW EXTENDING OVER AT LEAST THE MAJOR PART OF THE HEIGHT OF THE OPENING, AND TWO ROD-GRIPPING DEVICES IN SAID HOUSING, EACH INCLUDING A ROTARY VERTICAL SHAFT AND A GRIPPER MEANS MOUNTED ON THE SHAFT, AND MEANS EXTENDING THROUGH THE HOUSING TO TURN THE SHAFTS TO POSITION THE GRIPPERS ON OPPOSITE SIDES OF THE ROD TO HOLD THE ROD, SO THAT UPON OPENING THE CLOSURE MEMBER THE ROD CAN BE PLACED AND HELD BETWEEN THE HOLDERS AT THE START OF THE MELTING OPERATION, AND, AFTER CLOSING THE CLOSURE MEMBER AND COMMENCING THE MELTING, THE GRIPPERS CAN BE TURNED AWAY FROM THE ROD TO PERMIT THE SAID RELATIVE DISPLACEMENT OF THE MELTING COIL.
US830026A 1958-07-30 1959-07-28 Device for crucible-free zone melting Expired - Lifetime US3189415A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3607110A (en) * 1967-03-11 1971-09-21 Siemens Ag Vacuum apparatus for excluding carbon impurities from a silicon body
US3630684A (en) * 1966-09-24 1971-12-28 Siemens Ag Device for heater movement in crucible-free zone melting a crystalline rod
US3650700A (en) * 1968-01-16 1972-03-21 Siemens Ag Device for crucible-free zone melting having sealing means for a sliding member
US3901499A (en) * 1973-05-07 1975-08-26 Siemens Ag Mounting device for crystalline rods
US3923468A (en) * 1973-11-22 1975-12-02 Siemens Ag Method for crucible-free zone melting of semiconductor crystal rods
US3986837A (en) * 1973-03-08 1976-10-19 Nikkei Kako Kabushiki Kaisha Method of and apparatus for manufacturing single crystal compound semiconductor
US3989468A (en) * 1973-11-22 1976-11-02 Siemens Aktiengesellschaft Apparatus for crucible-free zone melting of semiconductor crystal rods
US3994690A (en) * 1974-02-15 1976-11-30 Elphiac Universal apparatus for elaborating semiconductive monocrystals
US4078897A (en) * 1975-04-11 1978-03-14 Leybold-Heraeus Gmbh & Co. Kg Apparatus for producing monocrystals
USRE29824E (en) * 1973-11-22 1978-11-07 Siemens Aktiengesellschaft Apparatus for crucible-free zone melting of semiconductor crystal rods
US4186173A (en) * 1975-04-11 1980-01-29 Leybold-Heraeus Gmbh & Co. Kg Apparatus for producing monocrystals

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US2745131A (en) * 1950-03-22 1956-05-15 Alois Vogt Device for the cleaning of sight glasses allowing inspection of high vacuum rooms
US2870309A (en) * 1957-06-11 1959-01-20 Emil R Capita Zone purification device
US2876147A (en) * 1953-02-14 1959-03-03 Siemens Ag Method of and apparatus for producing semiconductor material
US2902350A (en) * 1954-12-21 1959-09-01 Rca Corp Method for single crystal growth
US2904663A (en) * 1957-11-15 1959-09-15 Siemens Ag Apparatus for zone melting of semiconductor material
US2972525A (en) * 1953-02-26 1961-02-21 Siemens Ag Crucible-free zone melting method and apparatus for producing and processing a rod-shaped body of crystalline substance, particularly semiconductor substance

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BE525102A (en) * 1952-12-17 1900-01-01
US2792317A (en) * 1954-01-28 1957-05-14 Westinghouse Electric Corp Method of producing multiple p-n junctions
US2809905A (en) * 1955-12-20 1957-10-15 Nat Res Dev Melting and refining metals

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2745131A (en) * 1950-03-22 1956-05-15 Alois Vogt Device for the cleaning of sight glasses allowing inspection of high vacuum rooms
US2876147A (en) * 1953-02-14 1959-03-03 Siemens Ag Method of and apparatus for producing semiconductor material
US2972525A (en) * 1953-02-26 1961-02-21 Siemens Ag Crucible-free zone melting method and apparatus for producing and processing a rod-shaped body of crystalline substance, particularly semiconductor substance
US2902350A (en) * 1954-12-21 1959-09-01 Rca Corp Method for single crystal growth
US2870309A (en) * 1957-06-11 1959-01-20 Emil R Capita Zone purification device
US2904663A (en) * 1957-11-15 1959-09-15 Siemens Ag Apparatus for zone melting of semiconductor material

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3630684A (en) * 1966-09-24 1971-12-28 Siemens Ag Device for heater movement in crucible-free zone melting a crystalline rod
US3607110A (en) * 1967-03-11 1971-09-21 Siemens Ag Vacuum apparatus for excluding carbon impurities from a silicon body
US3650700A (en) * 1968-01-16 1972-03-21 Siemens Ag Device for crucible-free zone melting having sealing means for a sliding member
US3986837A (en) * 1973-03-08 1976-10-19 Nikkei Kako Kabushiki Kaisha Method of and apparatus for manufacturing single crystal compound semiconductor
US3901499A (en) * 1973-05-07 1975-08-26 Siemens Ag Mounting device for crystalline rods
US3923468A (en) * 1973-11-22 1975-12-02 Siemens Ag Method for crucible-free zone melting of semiconductor crystal rods
US3989468A (en) * 1973-11-22 1976-11-02 Siemens Aktiengesellschaft Apparatus for crucible-free zone melting of semiconductor crystal rods
USRE29824E (en) * 1973-11-22 1978-11-07 Siemens Aktiengesellschaft Apparatus for crucible-free zone melting of semiconductor crystal rods
US3994690A (en) * 1974-02-15 1976-11-30 Elphiac Universal apparatus for elaborating semiconductive monocrystals
US4078897A (en) * 1975-04-11 1978-03-14 Leybold-Heraeus Gmbh & Co. Kg Apparatus for producing monocrystals
US4186173A (en) * 1975-04-11 1980-01-29 Leybold-Heraeus Gmbh & Co. Kg Apparatus for producing monocrystals

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FR1231481A (en) 1960-09-29
NL240421A (en)
BE581195A (en)
CH375527A (en) 1964-02-29
GB917635A (en) 1963-02-06
DE1151669B (en) 1963-07-18

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