US3342560A - Apparatus for pulling semiconductor crystals - Google Patents

Apparatus for pulling semiconductor crystals Download PDF

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US3342560A
US3342560A US405892A US40589264A US3342560A US 3342560 A US3342560 A US 3342560A US 405892 A US405892 A US 405892A US 40589264 A US40589264 A US 40589264A US 3342560 A US3342560 A US 3342560A
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vessel
crucible
smaller
pulling
larger
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Eckardt Dietrich
Mentzel Friedrich Adolf
Reinke Heinz
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Siemens and Halske AG
Siemens AG
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Siemens AG
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    • 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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/20—Controlling or regulating
    • C30B15/22—Stabilisation or shape controlling of the molten zone near the pulled crystal; Controlling the section of the crystal
    • C30B15/28—Stabilisation or shape controlling of the molten zone near the pulled crystal; Controlling the section of the crystal using weight changes of the crystal or the melt, e.g. flotation methods
    • 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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/02—Single-crystal growth by pulling from a melt, e.g. Czochralski method adding crystallising materials or reactants forming it in situ to the melt
    • 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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/10—Crucibles or containers for supporting the melt
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D11/00—Control of flow ratio
    • G05D11/02—Controlling ratio of two or more flows of fluid or fluent material
    • G05D11/13—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means
    • G05D11/135—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by sensing at least one property of the mixture
    • G05D11/138—Controlling ratio of two or more flows of fluid or fluent material characterised by the use of electric means by sensing at least one property of the mixture by sensing the concentration of the mixture, e.g. measuring pH value
    • 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
    • Y10T117/1004—Apparatus with means for measuring, testing, or sensing
    • Y10T117/1008—Apparatus with means for measuring, testing, or sensing with responsive control means
    • 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
    • Y10T117/1032—Seed pulling
    • Y10T117/1052—Seed pulling including a sectioned crucible [e.g., double crucible, baffle]

Definitions

  • Another object of our invention is to afford the pulling of monocrystalline rods which exhibit a particularly high degree of crystalline perfection, particularly in the sense that the dislocation density is considerably reduced and the distribution of remaining dislocations is more uniform over the cross section and length of the rod, as compared with monocrystal rods pulled by the conventional methods.
  • a further object of the invention is to afford producing a large number of monocrystalline semiconductor bodies or wafers from a pulled crystal rod which, relative to one another, exhibit a lower degree of specimen differences than heretofore usually encountered, thus obtaining a better uniformity of the various semiconductor components produced and reducing the amount of rejects.
  • the molten semiconductor material from which the rod-shaped crystals are to be pulled with the aid of a crystal seed is divided into two different size volumina contained in a relatively large vessel and in a smaller vessel respectively, the vessels being in communication with each other.
  • the crystal is pulled out of the small volume of melt contained in the smaler vessel, and the melt in this vessel is continuously replenished by molten material from the larger vessel which serves as a storage container.
  • An essential feature, in conjunction with the foregoing, is the fact that the volume of the melt contained in the smaller vessel, serving as a crucible, is controlled by applying a constrained relative motion between the two vessels, thus maintaining the volume of melt in the smaller vessel constant or controlling it to change in accordance with a predetermined program.
  • the relative motion is applied by drive means located outside of 'the two vessels.
  • the two vessels are cylindrical and the smaller crucible vessel is located coaxially Within the larger storage Vessel and kept in rotation relative to the larger vessel while being simultaneously displaced in the vertical direction relative to the level of molten material contained in the larger vessel.
  • the concentration of the impurity substance in the two vessels in accordance with the distribution coefficient of the impurity substance in the semiconductor material.
  • This distribution coefficient is defined as the ratio of the impurity concentration. in the solid semiconductor crystal to the impurity concentration in the molten semiconductor material.
  • the distribution coeflicient depends not only upon the properties of the material but also upon the pulling speed at which the crystal is being pulled out of the melt.
  • This so-called effective distribution coefficient is to be taken into account when selecting the impurity concentration in the semiconductor material being used in the process. It is particularly advantageous to select the impurity concentration in the two vessels so that the ratio of the impurity concentration in the smaller vessel to that in the larger vessel corresponds to the reciprocal value of the effective distribution coefiicient.
  • the larger vessel is supplied with a melt Whose impurity concentration is equal to the concentration of the donors or acceptors built into the resulting crystal.
  • the two vessels are mounted preferably in concentric relation to the pulling axis.
  • the relatively small crucible vessel is connected with a vertical shaft which passes through the bottom of the larger storage vessel, both vessels having essentially the shape of an upwardly open cup.
  • the shaft is coupled with a drive for imparting rotational movement to the crucible vessel, and with another drive for displacing this vessel in the vertical direction.
  • the surrounding larger vessel may remain immovable during operation of the apparatus.
  • Suitable coupling means are preferably provided in order to permit separately or simultaneously rotating and vertically displacing the crucible vessel.
  • the movements, particularly the rotation, are preferably controlled to maintain in the smaller vessel a temperature distribution favorable to the formation of a monocrystal. This is done especially by maintaining the thermal center point substantially coincident with the geometrical center of the melt in the smaller vessel.
  • the pulling operation is controlled by continuously sensing or measuring the change in weight of the small crucible vessel resulting from the change in volume of melt contained in the crucible vessel.
  • the resulting measuring signals are used, through suitable control or regulating devices, preferably of electrical type, to correspondingly control the pulling operation by the amount and in the sense required for adjusting or substantially preserving a predetermined volume of melt in the crucible vessel.
  • the volumetric change of the melt contained in the crucible vessel, as manifested by the resulting change in weight is sensed by a force gauge, for example a spring scale or similar device.
  • the control may be effected by providing the springscale device or other force gauge with an electric control contact which acts through an amplifying control system upon the above-mentioned drive for changing the vertical position of the crucible vessel.
  • the control contact essentially functions to define a fixed position for the upper rim of the crucible vessel above the level of the melt contained in the amount of melt in the crucible vessel. is regulated to a desired constant value.
  • the control contact is preferably made adjustable. It then depends upon the adjustment of the control contact being kept fixed or varied the larger storage vessel, so that whether the volume of melt is regulated to remain constant or is varied in accordance with a given control program. It is particularly advantageous that the resulting control or equalization in volume can thus be effected continuously.
  • the two vessels communicate with each other for permitting molten material from the larger storage vessel to continuously replenish the material being consumed in the smaller crucible vessel by the crystalpulling operation.
  • the communication preferably consists of at least one bore traversing the vertical side wall of the smaller vessel.
  • a single capillary bore suffices in a crucible vessel of graphite, this bore being preferably tangential to the interior cup space of the crucible vessel so that the external opening of the bore leads the internal opening during the above-mentioned rotational movement of the crucible vessel.
  • FIG. 1 shows in vertical section a crystal pulling apparatus together with a schematically illustrated system of drive means for the appertaining crucible vessel.
  • FIG. 2 is a vertical section of the same apparatus and shows schematically a different system of drive and control means.
  • FIG. 3 is a vertical section through the crucible vessel in apparatus according to FIGS. 1 and 2, the section being taken along the line III-III in FIG. 4.
  • FIG. 4 is a plan view corresponding to FIG. 3.
  • FIG. 5 shows a different crystal pulling apparatus in vertical section together with a drive and control system identical with the one according to FIG. 2.
  • the illustrated apparatus is equipped with an axially elongated, tubular cylinder 1 of quartz whose interior constitutes a crystal pulling chamber 2 closed at both ends by cover plates 3 and 4 which are provided with respective valve-controlled inlet and outlet nipples 5 and 6 for protective gas, such as argon, nitrogen or hydrogen.
  • protective gas such as argon, nitrogen or hydrogen.
  • argon argon
  • nitrogen argon
  • a pull spindle 7 passes from above through a central opening in the cover plate 3 and carries a crystal seed 17.
  • a closable tube 8, also mounted in the cover plate 3 has a laterally curved lower end and can be turned about its own axis so that dopants or other impurity substance can be selectively supplied into a cup-shaped storage vessel 9 or into a smaller vessel 10- serving as a crucible for the crystal pulling operation proper.
  • the two vessels consist of graphite for example.
  • the storage vessel 9 is supported on the plate 4 and remains stationary during operation of the apparatus.
  • the crucible vessel 10 is mounted on a centrally located vertical shaft 11 by means of which the crucible vessel can be kept in rotation and also vertically displaced relative to the larger vessel 9.
  • the shaft 11 is connected with a vertical drive 1 2. and with a rotationa drive 13 through suitable transmission means schematically shown at 14 in FIG. 1.
  • the drive 13 alfords maintaining the crucible vessel 10 in continuous rotation.
  • the drive 12 permits raising the crucible vessel 10 to a top position at the beginning of the crystal pulling operation and thereafter gradually lowering the vessel as the pulling operation proceeds and the molten semiconductor material becomes progressively depleted.
  • respective gasket rings 15 are disposed between the quartz tube 1 and the cover plates 3 and 4. Suitable as gasket material are heat-resistant substances such as silicone rubber.
  • the melt located in the small crucible vessel 10 communicates with the molten material contained in the larger vessel 9.
  • the crucible vessel 10 is provided with a capillary bore 16 (FIGS. 1, 3, 4) which extends in a substantialy tangential direction to the inner peripheral wall of the crucible vessel close to the inner bottom thereof.
  • the direction of the bore 16 is such that the flow of semiconductor material from the larger into the smaller vessel 10 is aided by the rotation of the vessel 10. This is achieved for example by having the direction of the bore from the inner wall of the crucible vessel to the outer wall extend substantially in the direction of rotation imparted to the vessel 10.
  • the desired volume equalization of the melt in the crucible vessel 10 with the molten material contained in the storage vessel 9 is achieved during rotation of the crucible vessel in a particularly favorable manner. Furthermore, the continuous replenishment of semiconductor material is secured until the pulling process is terminated when the crucible vessel 10, at the end of its downward travel, becomes seated upon the bottom of the storage vessel 9.
  • the heating of the semiconductor material for melting it and maitaining it in molten condition may be effected in the conventional manner, such as my an electric resistance heater winding mounted on the peripheral surface of the storage vessel 9 or preferably by an electric induction heater winding which may surround either the vessel 9 within the quartz cylinder 1 or may be mounted around the quartz cylinder in coaxial relation to the vessels 9 and 10.
  • the volume of the storage vessel 9 should be much larger than that of the crucible vessel 10, namely so that the volumetric ratio is larger than 5:1. For example, in the illustrated embodiments, this volumetric ratio is approximately 20:1. Since the yield increases with the volumetric ratio of the storage container 9 to the crucible vessel 10, such choice of a large volumetric ratio affords attaining more than yield of monocrystalline material having a controlled impurity content.
  • FIG. 1 The foregoing description of the apparatus shown in FIG. 1 may be identical with the correspondingly denoted components in FIGS. 2 and 5, and will be further described in a later place.
  • a ballast weight 18 is attached to the crucible shaft 11 and is rated to cause the crucible vessel 10 to be lowered and immersed in the molten material contained in the storage vessel 9.
  • the force gauge or spring-scale device 19 is provided with control means, such as an electric contact, which controls an amplifying controller 20 to actuate the vertical drive 12 in the direction and by the amount required to maintain the crucible vessel 10 thus immersed in the molten material of the storage vessel relative to the level of the molten material.
  • control means such as an electric contact
  • an amplifying controller 20 controls an amplifying controller 20 to actuate the vertical drive 12 in the direction and by the amount required to maintain the crucible vessel 10 thus immersed in the molten material of the storage vessel relative to the level of the molten material.
  • the crucible vessel 10 is gradually lowered as the crystal pulling operation proceeds. This results in obtaining monocrystalliue rod continuously growing in length, until the crucible vessel becomes seated upon the bottom of the storage vessel 9.
  • the crucible vessel 10 is kept in rotation by the rotational drive 13 acting through the transmission means 14 upon the shaft 11.
  • the two vessels 9 and 10 consisting of graphite, are provided with germanium substantially free of doping substances.
  • the germanium is heated, preferably inductively in the above-mentioned manner, to a temperature of about 950 C. until it is molten in both vessels 9 and 10.
  • the vertical drive 12 is operated and the shaft 11 with the crucible vessel 10 is lifted until the upper rim of vessel 10 is located above the level of the melt in storage vessel 9 a distance corresponding to the desired volume of molten material in the crucible 10.
  • the rotational drive 13 switched on so that during the following crystal pulling operation the crucible vessel 10 remains rotating at a speed between 10 and 100 rotations per minute.
  • the deisred doping substance is supplied through tube 8 to the molten germanium in the crucible vessel 10, the quantity of dopant being in accordance with the desired specific electrical resistance of the monocrystalline material.
  • antimony may thus be employed as doping substance.
  • indium may be employed. Both doping substances have a small effective distribution coefficient in germanium. This has the advantage that relatively large quantities of the impurity substance can be introduced, so that any inaccuracies resulting from the weighing of the amount of impurity substance are largely prevented, or the production of a pre-alloy becomes unnecessary. The same advantage is promoted by the above-mentioned choice of a large volumetric ratio of vessels 9' and 10. The larger this ratio, the less will any inaccuracy with respect to the quantity of impurity substance have any detrimental effect upon the product.
  • the pulling spindle 7 is lowered until the crystal seed 17 dips into the melt contained in the crucible vessel 10. After the optimal temperature is regulated in the conventional manner, a monocrystal commences to grow from the seed. Simultaneously, the pulling spindle 7 is pulled upwardly at the growing rate of the crystal. Simultaneously, the volume of molten material in the crucible vessel 10 tends to decrease. However, the crucible vessel is lowered by the drive 12 as continuously as feasible so that the volume of the crucible melt is continuously replenished by semiconductor material flowing from the storage vessel 9 through the capillary bore 16.
  • the volume of melt in the crucible vessel 10 is kept constant or, if desired, is varied in accordance with a predetermined program.
  • the supply of the replenishing material is promoted by placing the bore 16 so that it extends tangentially to the inner peripheral wall of the "crucible vessel 10 and has its direction substantially coincide with the direction of crucible rotation.
  • the rotation of the crucible vessel 10 also provides for good mixing of the molten semiconductor material so that the impurity substance is uniformly distributed over the entire cross section and the entire length of the crystal being pulled out of the melt. Furthermore, the rotation or the control of the rotational speed affords an advantageous control of the temperature distribution in the melt contained in the crucible vessel. This results in a considerable reduction of the dislocation density.
  • substantially non-doped germanium is sup- .plied to the two graphite vessels 9 and 10 and is molten in both vessels by inductive heating at a temperature of about 950 C.
  • the crucible vessel 10 is weighted by attaching to the shaft 11 the amount of Weight 18 required for immersing the crucible vessel 10 in the molten material contained in the storage vessel 9.
  • this vessel is then lifted by the vertical drive 10 with a given force determined by the force gauge 19.
  • the control system described above then operates to maintain the upper rim of crucible vessel 10 positioned at a given distance above the level of molten material in the storage vessel 9.
  • the rotational drive 13 is started and, during the following stages of the crystal pulling operation, the crucible vessel 10 is kept in rotation, preferably at a speed between 10 and r.p.m.
  • a desired quantity of impurity substance is supplied into the crucible vessel with the aid of the tube 8 as described in the foregoing.
  • the impurity substance may consist of antimony for producing n-type germanium crystals, or of indium for producing p-type crystals, also as already explained.
  • the crystal pulling proper is then commenced and continued in the above-described manner.
  • the level of molten material in the crucible vessel 10 tends to become lower.
  • the resulting change in weight, sensed by force gauge 19, acts through the correspondingly adjusted control contact, or in some other suitable manner, upon the amplifying control systom 20 which controls the vertical drive 12 to lower the crucible vessel 10 the amount required for reestablishing the desired volumetric adjustment.
  • the, volume of melt in the crucible vessel 10 is kept constant or otherwise controlled in accordance with a predetermined program, depending upon whether it is desired to produce monocrystals having a constant specific electrical resistance throughout, or monocrystals whose specific resistance changes along the crystal length in accordance with a given program. It will be apparent that in the described manner, the change of molten volume in the crucible vessel 10 is, in eifect, utilized for a feedback control of the vertical crucible displacement.
  • the yield of useful material from a monocrystalline rod pulled in accordance with the invention is increased by increasing the ratio of storagevessel volume to crucible-vessel volume.
  • a further increase in yield is obtainable by greatly delaying the increase in impurity concentration toward the end of the pulling process. This can be done, for example, by employing a storage vessel whose lower portion has a considerably smaller diameter than the upper portion, the height of the lower portion being approximately equal to that of the crucible vessel, and the inner width of the lower portion of smaller diameter being slightly larger than the outer width of the crucible vessel.
  • the annular clearance between the outer periphery of the crucible vessel and the inner periphery of the storage vessel in its lower portion of reduced diameter is made so small that the molten material just remains capable of flowing through the clearance and through the above-mentioned bore into the crucible vessel when the latter approaches the bottom of the storage vessel.
  • this clearance only slightly larger than 1 mm.
  • FIG. 5 A particularly favorable yield is obtained with the aid of apparatus as shown in FIG. 5, which incorporates the various improvement features mentioned in the foregoing.
  • this apparatus corresponds to the one shown in FIGS. 1 and 2 and is equipped with a control drive system of the type shown in FIG. 2.
  • the storage vessel 9 has a lower portion whose diameter is much smaller than that of the upper portion and also has considerably smaller axial height.
  • the diameter of the lower portion is only slightly larger than the outer diameter of the crucible vessel 10 so that a slight clearance gap 22 remains around the outer circumferential surface of the crucible vessel 10 when the latter has reached its lowermost position shown in FIG. 5.
  • the lateral capillary bore 16, being located slightly above the inner bottom of the crucible vessel 10, thus opens into the annular clearance gap 22, and the latter is made just large enough to permit a continuous flow of material from the upper vessel through the clearance 22 and the bore 16 into the crucible vessel 10 during the downward travel of the latter until it reaches the illustrated lowermost position.
  • the amount of melt contained in the storage vessel 9 can be almost fully consumed in the crucible vessel 10 by the crystal pulling operation, thus almost completely converting the molten material originally contained in the storage vessel 9 to monocrystalline constitution, and controlling the impurity concentration along the entire length of the resulting monocrystalline rod to remain constant or correspond to a predetermined program.
  • the much wider upper portion of the storage vessel 9 permits giving it any desired large volume in comparison with the small volume of the crucible vessel 10, the increase in impurity concentration occurs only in the terminating interval of the pulling time and at a rather steep rate of change, so that only a slight portion of the resulting rod, such as to becomes unsuitable for the subsequent production of semiconductor components.
  • the rotation of the crucible vessel provides for good mixing of the material contained therein and consequently secures a uniform distribution of the impurity atoms over the entire length and cross section of the crystal being pulled.
  • the rotational motion also provides for a favorable temperature distribution of the melt contained in the crucible vessel with the result of greatly reducing the dislocation density.
  • the monocrystalline rods produced in this manner by the method of the invention are distinguished not only by a particularly uniform distribution of the donors or acceptors in the semiconductor material and hence by a substantially constant specific resistance over the pulled length, but they also excel by a particularly high degree of crystalline perfection due to the just-mentioned favorable temperature distribution in the crucible.
  • We have found that the density of any remaining dislocations is very greatly reduced in comparison with monocrystalline rods pulled from a melt in accordance with the conventional methods, and that the distribution of such dislocations over the cross section is also more uniform.
  • monocrystalline germanium rods of 500 mm. length and about 30 mm. diameter in which the variations of the specific resistance along 90% of the pulled length amounted to only +-l0% relative to an accurately adjustable median value, and in which the dislocation density was 1000 to 3000 per cm.
  • control and drive components 12 to 14 and 18 to 20 are not essential to the invention proper and that these components may be given any of a great variety of configurations and types well known and available in the art.
  • the example of these components schematically shown in FIG. 6 is presented only as illustrative of one of these available possibilities, the details of this example being not essential to the invention proper with the exception of those already mentioned and described in the foregoing.
  • the drive and control system according to FIG. 6 may correspond to the one shown in FIG. 2 (or FIG. 5).
  • the shaft 11 of the crucible vessel 10 carries a fixedly mounted shoulder ring 181 upon which a number of slotted weighting rings 182, 183 are stacked. These rings jointly constitute the ballast weight denoted as a whole by 18.
  • the upper portion of shaft 11 is displaceable vertically with respect to its lower portion 11a whose vertical position is fixed.
  • the displaceable upper portion of shaft 11 rests upon a helical spring 192 of a force gauge 19 of the spring-scale type and is non-rotatably guided in a sleeve 191 in which the spring 192 is mounted.
  • the sleeve 191 rotatable together with the lower shaft portion 11a and is in rigid connection with the lower portion 11a of the shaft thus being prevented from moving upwardly or downwardly.
  • the shaft 11 carries a fixedly mounted, grooved ring 193 straddled by a lever 194 which is pivoted at 195 to the stationary frame structure of the apparatus and carries an insulating pin 196.
  • the pin 196 moves downward and closes the lower contact of a control switch 197.
  • the pin 196 moves upward and closes the upper contact of switch 197.
  • the amplifying control system 20 shown schematically in FIG.
  • the control switch 197 can be vertically adjusted to a desired position by means of a spindle 198 and a wheel or gear 199.
  • the control system operates to regulate the process for constant volume of melt in the crucible vessel and thus for constant specific resistance throughout the useful length of the resulting mono-crystalline rod.
  • the gear 199 is operated during the pulling operation in accordance with a given program, the volume of melt in the crucible vessel and consequently the resistance properties of the resulting rod are changed accordingly.
  • the lower shaft portion 11a has a fixed shoulder ring 141 which is supported on a bearing mounted on a sleeve 142.
  • the sleeve 142 is in threaded engagement with a gear 144 which is rotatable but not axially displaceable. Consequently, rotation of gear 144 causes lifting or lowering of the sleeve 142 which is prevented from rotating by having a lateral pin 143 engaged in a vertical guide of the stationary supporting structure. Rotation is imparted to the gear 144 by a pinion and a gear 146 driven from the rotor 121 of the above-mentioned motor 12.
  • the lower portion 11a of the shaft is in sliding engagement with a gear 131 which is rotatable but not axially displaceable and is driven through a pinion 134 from the motor of the rotational drive 13.
  • the gear 131 has a key engaging a longitudinal slot 132 of the shaft 11.
  • Apparatus for pulling semiconductor crystals comprising crystal pulling means defining a vertical axis, two upwardly open cup-shaped vessels of different volumetric sizes respectively for containing different amounts of molten semiconductor material, said two vessels being mounted coaxially beneath said pulling means and said smaller vessel being located inside said larger vessel, said larger vessel being stationary and said smaller vessel being rotatable, rotational drive means connected to said smaller vessel for maintaining it in rotation during crystal pulling operation, said larger vessel having a bottom recess of smaller diameter than in the upper portion of said vessel, said recess having a depth approximately equal to the height of said smaller vessel and a diameter adapted with clearance to the diameter of said smaller vessel so as to permit said smaller vessel to be lowered into said recess.
  • said smaller vessel having a shaft extending downwardly through the bottom of said larger vessel, said vertical displacement control means and said rotational drive means being coupled to said shaft.
  • Apparatus for pulling semiconductor crystals comprising crystal pulling means defining a vertical axis, two upwardly open cup-shaped vessels of different volumetric sizes respectively for containing different amounts of molten semiconductor material, said two vessels being mounted coaxially beneath said pulling means and said smaller vessel being located inside said larger vessel and being vertically displaceable relative to said larger vessel, rotational drive means connected to said smaller vessel for maintaining it in rotation during crystal pulling operation, force guage means connected to said smaller vessel and responsive to the weight of the melt contained in said smaller vessel, and a vertical displacement drive connected with said smaller vessel and controlled by said force gauge means for varying the vertical portion of said smaller vessel so as to control the volume of melt contained therein during crystal pulling.
  • said force gauge means comprising an electric control contact, and amplifying control means connecting said control with said vertical drive for controlling the latter.
  • control contact having adjusting means for varying the setting of said contact in accordance with a desired control operation.
  • said smaller vessel having a bore in its lateral wall, and said clearance being substantially the minimum required for replenishing the melt in said smaller vessel through said clearance and bore.
  • said smaller vessel having a downwardly tapering frust0- conical shape
  • said larger vessel having a downwardly tapering inner shape generally adapted to that of said smaller vessel.
  • said larger vessel having a downwardly tapering inner space and having an upwardly tapering wall thickness.
  • said smaller vessel having a lateral bore extending near the vessel bottom from the interior to the outside for communication with said larger vessel, said bore being substantially tangential to the inner periphery of said smaller vessel and extending therefrom substantially in the direction of rotation of said smaller vessel.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
US405892A 1963-10-28 1964-10-22 Apparatus for pulling semiconductor crystals Expired - Lifetime US3342560A (en)

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US (1) US3342560A (xx)
CH (1) CH440227A (xx)
DE (3) DE1444541C3 (xx)
GB (1) GB1029769A (xx)
NL (1) NL6410933A (xx)
SE (1) SE302446B (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3637439A (en) * 1968-11-13 1972-01-25 Metallurgie Hoboken Process and apparatus for pulling single crystals of germanium
US4050905A (en) * 1975-05-27 1977-09-27 The Harshaw Chemical Company Growth of doped crystals
US5129986A (en) * 1989-11-16 1992-07-14 Shin-Etsu Handotai Co., Ltd. Method for controlling specific resistance of single crystal and an apparatus therefor
US5131974A (en) * 1989-11-16 1992-07-21 Shin-Etsu Handotai Co., Ltd. Method of controlling oxygen concentration in single crystal and an apparatus therefor
US5215620A (en) * 1989-09-19 1993-06-01 Shin-Etsu Handotai Co. Ltd. Method for pulling a silicon single crystal by imposing a periodic rotation rate on a constant rotation rate
US5593498A (en) * 1995-06-09 1997-01-14 Memc Electronic Materials, Inc. Apparatus for rotating a crucible of a crystal pulling machine
US6059876A (en) * 1997-02-06 2000-05-09 William H. Robinson Method and apparatus for growing crystals
EP3011083A1 (en) * 2013-06-21 2016-04-27 South Dakota Board of Regents Method of growing germanium crystals

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727839A (en) * 1950-06-15 1955-12-20 Bell Telephone Labor Inc Method of producing semiconductive bodies
US2809136A (en) * 1954-03-10 1957-10-08 Sylvania Electric Prod Apparatus and method of preparing crystals of silicon germanium group
US2876147A (en) * 1953-02-14 1959-03-03 Siemens Ag Method of and apparatus for producing semiconductor material
US2892739A (en) * 1954-10-01 1959-06-30 Honeywell Regulator Co Crystal growing procedure
US2908004A (en) * 1957-05-10 1959-10-06 Levinson John Temperature control for crystal pulling
US2944875A (en) * 1953-07-13 1960-07-12 Raytheon Co Crystal-growing apparatus and methods
DE1101775B (de) * 1953-05-18 1961-03-09 Int Standard Electric Corp Vorrichtung zum Ziehen von Einkristallen mit vorbestimmter konstanter Fremdstoffkonzentration
US2977258A (en) * 1958-04-09 1961-03-28 Philco Corp Production of semiconductors and the like
US3002824A (en) * 1956-11-28 1961-10-03 Philips Corp Method and apparatus for the manufacture of crystalline semiconductors
US3033660A (en) * 1959-05-05 1962-05-08 Philips Corp Method and apparatus for drawing crystals from a melt
FR1302043A (fr) * 1961-08-09 1962-08-24 Union Carbide Corp Appareil pour provoquer la croissance de compositions homogènes solides
US3067139A (en) * 1956-11-28 1962-12-04 Philips Corp Method for treating materials having a high surface tension in the molten state in a crucible
US3194691A (en) * 1959-09-18 1965-07-13 Philips Corp Method of manufacturing rod-shaped crystals of semi-conductor material
US3198606A (en) * 1961-01-23 1965-08-03 Ibm Apparatus for growing crystals
US3241925A (en) * 1960-08-19 1966-03-22 Union Carbide Corp Apparatus for growing solid homogeneous compositions

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2727839A (en) * 1950-06-15 1955-12-20 Bell Telephone Labor Inc Method of producing semiconductive bodies
US2876147A (en) * 1953-02-14 1959-03-03 Siemens Ag Method of and apparatus for producing semiconductor material
DE1101775B (de) * 1953-05-18 1961-03-09 Int Standard Electric Corp Vorrichtung zum Ziehen von Einkristallen mit vorbestimmter konstanter Fremdstoffkonzentration
US2944875A (en) * 1953-07-13 1960-07-12 Raytheon Co Crystal-growing apparatus and methods
US2809136A (en) * 1954-03-10 1957-10-08 Sylvania Electric Prod Apparatus and method of preparing crystals of silicon germanium group
US2892739A (en) * 1954-10-01 1959-06-30 Honeywell Regulator Co Crystal growing procedure
US3002824A (en) * 1956-11-28 1961-10-03 Philips Corp Method and apparatus for the manufacture of crystalline semiconductors
US3067139A (en) * 1956-11-28 1962-12-04 Philips Corp Method for treating materials having a high surface tension in the molten state in a crucible
US2908004A (en) * 1957-05-10 1959-10-06 Levinson John Temperature control for crystal pulling
US2977258A (en) * 1958-04-09 1961-03-28 Philco Corp Production of semiconductors and the like
US3033660A (en) * 1959-05-05 1962-05-08 Philips Corp Method and apparatus for drawing crystals from a melt
US3194691A (en) * 1959-09-18 1965-07-13 Philips Corp Method of manufacturing rod-shaped crystals of semi-conductor material
US3241925A (en) * 1960-08-19 1966-03-22 Union Carbide Corp Apparatus for growing solid homogeneous compositions
US3198606A (en) * 1961-01-23 1965-08-03 Ibm Apparatus for growing crystals
FR1302043A (fr) * 1961-08-09 1962-08-24 Union Carbide Corp Appareil pour provoquer la croissance de compositions homogènes solides

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3637439A (en) * 1968-11-13 1972-01-25 Metallurgie Hoboken Process and apparatus for pulling single crystals of germanium
US4050905A (en) * 1975-05-27 1977-09-27 The Harshaw Chemical Company Growth of doped crystals
US5215620A (en) * 1989-09-19 1993-06-01 Shin-Etsu Handotai Co. Ltd. Method for pulling a silicon single crystal by imposing a periodic rotation rate on a constant rotation rate
US5129986A (en) * 1989-11-16 1992-07-14 Shin-Etsu Handotai Co., Ltd. Method for controlling specific resistance of single crystal and an apparatus therefor
US5131974A (en) * 1989-11-16 1992-07-21 Shin-Etsu Handotai Co., Ltd. Method of controlling oxygen concentration in single crystal and an apparatus therefor
US5593498A (en) * 1995-06-09 1997-01-14 Memc Electronic Materials, Inc. Apparatus for rotating a crucible of a crystal pulling machine
US5766341A (en) * 1995-06-09 1998-06-16 Memc Electric Materials, Inc. Method for rotating a crucible of a crystal pulling machine
US6059876A (en) * 1997-02-06 2000-05-09 William H. Robinson Method and apparatus for growing crystals
EP3011083A1 (en) * 2013-06-21 2016-04-27 South Dakota Board of Regents Method of growing germanium crystals
CN105723019A (zh) * 2013-06-21 2016-06-29 南达科他州评议委员会 生长锗晶体的方法
EP3011083A4 (en) * 2013-06-21 2017-03-29 South Dakota Board of Regents Method of growing germanium crystals
US10125431B2 (en) 2013-06-21 2018-11-13 South Dakota Board Of Regents Method of growing germanium crystals

Also Published As

Publication number Publication date
DE1444541C3 (de) 1974-01-31
SE302446B (xx) 1968-07-22
DE1544250B2 (de) 1973-12-20
DE1251721B (de) 1967-10-12
DE1544250C3 (de) 1974-08-01
DE1544250A1 (de) 1970-02-26
DE1444541B2 (de) 1973-06-20
CH440227A (de) 1967-07-31
DE1444541A1 (de) 1970-02-19
NL6410933A (xx) 1965-04-29
GB1029769A (en) 1966-05-18

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