US3130040A - Dendritic seed crystals having a critical spacing between three interior twin planes - Google Patents

Dendritic seed crystals having a critical spacing between three interior twin planes Download PDF

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US3130040A
US3130040A US79680A US7968060A US3130040A US 3130040 A US3130040 A US 3130040A US 79680 A US79680 A US 79680A US 7968060 A US7968060 A US 7968060A US 3130040 A US3130040 A US 3130040A
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crystal
melt
crystals
dendritic
seed
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US79680A
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Jr John W Faust
Harold F John
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Priority to US79680A priority Critical patent/US3130040A/en
Priority to GB5330/61A priority patent/GB913678A/en
Priority to CH330161A priority patent/CH412819A/de
Priority to FR856185A priority patent/FR1284358A/fr
Priority to GB44433/61A priority patent/GB951348A/en
Priority to DE19611419738 priority patent/DE1419738A1/de
Priority to FR883563A priority patent/FR80975E/fr
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
    • 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
    • C30B15/36—Single-crystal growth by pulling from a melt, e.g. Czochralski method characterised by the seed, e.g. its crystallographic orientation
    • 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
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/08—Germanium
    • 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
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
    • 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
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
    • C30B29/64—Flat crystals, e.g. plates, strips or discs
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10S117/901—Levitation, reduced gravity, microgravity, space
    • Y10S117/902—Specified orientation, shape, crystallography, or size of seed or substrate
    • 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
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S148/00—Metal treatment
    • Y10S148/107—Melt

Definitions

  • This invention relates to the process of producing crystals of solid materials and, in paticular, to dendritic semiconductor crystals.
  • crystals of many solid materials are produced by preparing a melt of the solid material, contacting the surface of the melt with a previously prepared crystal of the material and slowly withdrawing the previously prepared crystal, usually at the rate of the order of an inch an hour, whereby to produce a desired grown crystal member. It has been the invariable practice in this process to maintain the melt during the crystal-growing process at a temperature slightly above the melting point of the solid material.
  • An object of the present invention is to provide a process for growing dendritic crystals of a semiconductor material having a precisely controllable thickness and a predetermined internal twin plane structure by seeding a supercooled melt of the semiconductor material with a seed crystal having a predetermined and preselected internal twin plane structure which is carried over into the grown dendrite.
  • Another object of the present invention is to provide seed crystals to enable the drawing of fiat dendritic crystals of a semiconductor material which crystallizes in the diamond cubic lattice structure from a melt of the material which seed crystals have three twin planes extending therethrough, one twin plane being spaced from 0.1 to microns, from a central twin plane and a second twin being spaced from 0.1 to 30 microns from the central twin plane, the spacing and configuration of the twin planes being carried over into the dendrite from the seed crystal.
  • FIG. 1 is a view in elevation, partly in cross section, of a crystal growing apparatus used in accordance with the teachings of this invention.
  • FIG. 2 is a greatly enlarged fragmentary view of a dendritic crystal having three twin planes.
  • a melt of the material to be grown into a flat dendritic crystal is prepared at a temperature slightly above the melting temperature thereof.
  • the surface of the melt is contacted with at least a tip of a previously prepared seed crystal having three internal twin planes disposed a preselected distance apart at the interior thereof, the three internal twin planes extend entirely across that tip of the seed which conacts the melt, as will be detailed hereinafter, the seed crystal being oriented with a 211 direction vertical to the melt surface.
  • the seed crystal is dipped into the surface of the melt a sufiicient period of time to cause wetting of the lower surface of the seed, usually a period of time a few seconds to a minute is adequate, and, then, the melt is supercooled rapidly following which the seed crystal is withdrawn with respect to the melt at a speed of the order of from one to ten inches a minute. Under some conditions, considerably slower pulling speeds than an inch per minute can be employed, for example 0.2 inch per minute. Pulling speeds of from 4 to 8 inches per minute have given particularly good results, though greater speeds of up to 25 inches per minute may be employed.
  • the degree of supercooling and the rate of pulling can be readily so correlated that the seed crystal withdrawn from the melt comprises solidified melt material thereon of a precisely desired thickness, having the desired crystallographic orientation and having the internal twin plane structure of the seed crystal continued therethrough.
  • a detailed description of the preferred seed crystal structure will be set forth hereinafter.
  • the present invention is particularly applicable to solid materials crystallizing in the diamond cubic lattice structure.
  • examples of such materials are the elements silicon and germanium.
  • stoichiometric compounds having an average of four valence electrons per atom respond satisfactorily to the crystal growing process.
  • Such compounds which have been processed with excellent results comprise substantially equal molar proportions of an element from group HI of the periodic table, and particularly aluminum, gallium and indium, combined with an element from group V of the periodic table, and particularly phosphorus, arsenic and antimony.
  • Compounds comprising stoichiometric proportions of group II and group VI elements, for example, ZnSe and ZnS can be processed.
  • the apparatus comprises a base 12 carrying a support 14 for a crucible 16 of a suitable refractory material such as graphite to hold a melt of the material from which flat dendritic crystals having predetermined crystal orientation and internal twin plane structure are to be drawn.
  • Molten material 18, for example, germanium is maintained within the crucible 16 in the molten state by a suitable heating means such, for example, as an induction heating coil 20 disposed about the crucible.
  • Controls are employed to supply an alternating electrical current to the induction coil 20 to maintain a closely controllable temperature in the body of the melt 18.
  • the temperature should be readily controllable to provide a temperature in the melt a few degrees above the melting point and also to reduce heat input so that the temperature drops in a few seconds, for example in to seconds to a temperature at least one degree below the melting temperature and preferably to supercool the melt from 5 to (3., or lower.
  • a cover 22 closely fitting the top of the crucible 16 may be pro vided in order to maintain a low thermal gradient above the top of the melt.
  • a preferred seed crystal 26 Passing through an aperture 24 in the cover 22 is a preferred seed crystal 26, having three internal twin planes spaced a predetermined distance apart such that one twin is from 0.1 to 5 microns, and preferably from .25 to 4 microns, from the central twin, and the other twin is disposed on the other side of the central twin and spaced from 0.1 to 30 microns, and preferably from 0.25 to 15 microns, therefrom.
  • the seed is oriented crystallographically as will be disclosed in detail hereinafter.
  • the crystal 26 is fastened to a pulling rod 28 by means of a screw 30 or the like.
  • the pulling rod 28 is actuated by suitable mechanism to control its upward movement at a desired uniform rate, ordinarily in excess of one inch per minute.
  • a protective enclosure 32 of glass or other suitable material is disposed about the crucible with a cover 34 closing the top thereof except for an aperture 36 through which the pulling rod 28 passes.
  • a suitable protective atmosphere entering through a conduit 40 and, if necessary, a vent 42 may be provided for circulating a current of such protective atmosphere.
  • the protective atmosphere may comprise a noble gas such as helium or argon, or a reducing gas such as hydrogen or mixtures of hydrogen and nitrogen, or nitrogen or the like or mixtures of two or more gases.
  • the space around the crucible may be evacuated to a high vacuum in order to produce crystals of materials free from any gases.
  • a separately heated vessel containing the component may be disposed in the enclosure 32 to maintain therein a vapor of such compound at a partial pressure sufficient to prevent impoverishing the melt or the grown crystals with respect to the component.
  • an atmosphere of arsenic may be provided when crystals of gallium arsenide are being pulled.
  • the enclosure 32 may be suitably heated, for example, by an electrically heated cover, to maintain the walls thereof at a temperature above the temperature of the separately heated vessel containing the arsenic in order to prevent condensation of arsenic thereon.
  • FIG. 2 of the drawing there is illustrated, in greatly enlarged view, a section of a seed crystal 26 having three internal twin planes. Similar seed crystals may be obtained in various ways, for example, by supercooling a melt of the solid semiconductor material to a temperature at which a portion thereof solidifies at which time some dendritic crystals having three internal twin planes with a preferred spacing will be formed and may be removed from the melt. While these crystals may not be uniform, on the surfaces as shown in FIG. 2, they are suitable for seed purposes. Also one can cutfrom a large crystal a section suitable for use as a seed crystal. However, seed crystals are available from previously grown dendrites and such seeds will be normally used in practicing the process.
  • the seed crystal of FIG. 2 is a portion of a previously grown dendrite which is to be used as a seed.
  • the seed crystal 26 comprises two relatively flat parallel faces 50 and 52 with three intermediate interior twin planes 54, 56 and 58 extending therethrough. Examination will show that the crystallographic structure of the preferred seed on both faces 50 and 52 is that indicated by the crystallographic direction arrows at the right and left faces, respectively, of the figure. It will be noted that the horizontal directions perpendicular to the flat faces 50 and 52 and parallel to the melt surfaces are 1l1 The direction of growth of the dendritic crystal will be in a 21l crystallographic direction.
  • the faces 50 and 52 of the dendritic crystal 26 were to be etched preferentially to the ⁇ 111 ⁇ planes with a silver nitrate-nitric acid etch, most other nitric acid etches or a potassium ferricyanide etch, they will both exhibit equilateral triangular etch pits 60 whose vertices 62 will point upwardly while their bases will be parallel to the surface of the melt. If the faces 50 and 52 are etched with a superoxol etch or a hydrogen peroxide etch, somewhat rounded pits having a roughly triangular shape are formed.
  • the etch pits on both faces 56 and 52 of seed crystal 26, formed by etching with a silver nitrate-nitric acid etch, a suitable nitric acid etch or a potassium ferricyanide etch have their vertices 60 pointing upwardly.
  • a non-twinned crystal or a crystal containing two twin planes or any even number thereof will exhibit triangular etch pits on one face whose vertices will be pointing opposite to the direction of the vertices on the other face assuming of course that both faces are etched with an etchant from the same class.
  • the spacing or lamellae between the successive adjacent twin planes 54, 56 and 58 ordinarily is not uniform in the best seed crystals.
  • the lamellar spacing, such as A between the twin planes 54 and 56, and B between twin planes 56 and 58, is of the order of microns; that is from less than one micron to approximately 30 microns.
  • a good seed crystal should contain three internal twin planes, the lamella between one set of two adjacent twin planes should be thin enough to prevent wrongdirection growth, but not so narrow as to interfere with initial seeding by terminating too readily.
  • a suitable lamella is one having a width of from 0.1 micron to 5 microns and preferably from 0.25 micron to 4 microns.
  • the lamella between the other set of adjacent twin planes should not be so wide as to interfere with growth, or to be unusually receptive to grain boundary degeneration, a suitable lamella is one having a width of from 0.1 micron to 30 microns and preferably from 0.25 micron to 15 microns.
  • the best seed crystal is one having three twin planes which are separated by lamellae of about 1.7 and about 5 microns respectively.
  • a seed crystal having an unsuitable three twin configuration particularly with spacing outside the ranges given, is introduced into the melt in the manner previously described a plurality of dendrites may grow in an uncontrollable fashion and in several or all of the allowed crystallographic directions. Some of such dendrites would lose one twin plane. If a dentrite is grown from a seed in which the narrow twin spacing exceeds 5 microns, one of the (111) faces will have a central stripe of dislocations and will not be suitable for device fabrication.
  • a dendrite when properly seeded with a seed having three twins separated by lamellae of the preferred width preserves the twin planes and their spacing as in the seed throughout its own subsequent growth, barring an accident. This spacing is not appreciably altered by growth or thermal conditions.
  • all the twin planes in a good seed crystal extend entirely through the seed.
  • the seed behaves as if no such twin plane is present at all insofar as pulling dendrites from the melt is concerned. If two of the three tw n planes in a dendrite containing three twin planes are completely enclosed within a crystal, then satisfactory dendrites will not grow. If the crystal is cut, melted back, fractured, or otherwise treated to expose all three twin planes at at least one edge or one surface contacting the melt, then satisfactory dendrites can be pulled therewith.
  • One technique for determining the number of twin planes present in a dendrite comprises scribing a line transverse of the length of the dendrite, bending the dendrite at the scribed line to how it away from the scribed line until it fractures thereat, and, without polishing or otherwise working on the fractured face, examining it under a microscope at a magnification of at least 100x, and preferably 200x to 500x.
  • the fracturing results in relatively flat faces developing at successive lamellae at different angles to each other which stand out distinctly under illumination. Also, preferentially etching of a polished cross section, preferably cross sections lapped at an angle to the fiat face, so as to selectively distinguish the lamellae from each other, will enable the separate twin planes to be clearly distinguished.
  • the direction of withdrawal of the seed crystal 26 having three twin planes from the melt 18 must be with the direction of the vertices 58 of the etch pits being upward and the bases being substantially parallel to the surface of the melt.
  • This statement of course applies to etch pits formed employing a silver nitrate-nitric acid etch, a nitric acid etch or a potassium ferricyanide etch.
  • the seed crystal is not from a dendrite, and does not have a fiat (111) surface, then the direction of its crystal axes should be determined at the twin plane faces where the proper 211 orientation may be established. When so withdrawn, the melt will solidify at the bottom of the crystal in a satisfactory prolongation thereof.
  • the melt When a relatively cold flat seed crystal has been introduced into the melt which is at a temperature of only a few degrees above the melting point of the material, the melt will dissolve the tip of the seed crystal. However, there will be a meniscus-like contact between the seed crystal and the body of the melt. Such contact should be maintained by keeping the temperature of the melt close to the melting point of the material.
  • spikes appear to grow at the rate of approximately two millimeters per second.
  • the seed crystal pulling mechanism is energized to pull the crystal from the melt at the desired rates. The initiation of pulling is timed to the appearance and growth of the spikes for best results.
  • the seed crystal is disposed so that one edge is nearer the thermal center of the melt crucible than is the other edge, it is possible to increase briefly either the pulling rate or the temperature of the melt, and under these variations the dendritic crystal furthest away from the thermal center or in a hotter region will usually stop growing and thereafter only a single dendritic crystal will be attached to and grow from the seed. Also, if the double dendritic crystal attached to the original seed crystal is introduced into the same or another melt slightly above the melting temperature and after supercooling the melt, on pulling the double dendritic crystal from the surface, there will be formed two diamond-shaped areas attached to the double dendrites and four dendritic crystals will be pulled, two attached to each of the original dendrites.
  • the seed crystal 26 were to be pulled at a slowly increasing rate just as supercooling of the crucible is being efifected by reducing the heat input, so that at the end of about 5 to 10 seconds the full pulling rate is being applied, then only one dendritic crystal will usually be attached to the seed crystal.
  • the seed crystal need not be flat. It may be of any suitable size or shape as long as its crystal orientation and twin plane configuration corresponds to that shown in FIG. 2. Usually a portion of a previously grown dendritic crystal having the desired twin plane configuration will be quite satisfactory for use as a seed and ordinarily a portion of such a dendrite will be used as the seed crystal.
  • the pulled dendritic crystal need have no direct relation to the seed crystal as far as size is concerned.
  • the pulled dendritic crystal will have a size and shape depending on the pulling conditions.
  • the melts of the materials may be supercooled as much as 30 to 40 C. below their melting point.
  • supercooling of from to 15 C. has given best results with germanium and indium antimonide, for example.
  • a greater degree of supercooling requires higher rates of crystal withdrawal from the melt as well as requiring more precise control of the speed of pulling.
  • Germanium and indium antimonide dendritic crystals have been satisfactorily pulled at rates of from 4 inches to 12 inches per minute from melts supercooled 5 C. to 15 C.
  • these crystals have had a highly uniform thickness selected from the range of from 3 to 20 mils and a selected width of from 1 to 4 millimeters.
  • the length of these crystals is limited solely by the pulling apparatus employed. No difiiculty has been experienced in pulling crystals of, for example, 300 feet in length in a slightly modified crystal pulling furnace as normally used in the art.
  • the pulled dendritic crystals will have a thickness of the order of from 1 to 25 mils and the width across the flat faces may be from 20 mils to 200 mils and even wider.
  • the surface at the flat faces will exhibit essentially perfect (1 11) orientation.
  • the grown deudritic crystals of this invention will be essentially twinned crystals which are not of single crystal structure. Properly grown crystals will have faces that comprise flat areas on either side which are parallel and planar within a wavelength, of sodium light, per centimeter of length.
  • dendritic crystals While the dendritic crystals will exhibit some degree of edge serration, dendritic crystals have been obtained with fairly uniform edges having a minimum of ragged appearance.
  • the serrated edges comprise only a small portion of the crystals and can be readily removed or left intact in dice since they do not affect the properties of the central or main body portion of the dendrites.
  • the flat dendritic crystals of the present invention are relatively flexible, and crystals of a thickness of 7 mils may be bent on a radius of the order of 4 inches or even less without breaking. Consequently, crystals may be continuously drawn from the melt and wound on a cylinder of a radius of this order in continuous lengths, as desired. The thinner crystals obviously can be wound to a smaller radius than crystals of greater thickness.
  • the grown dendritic crystals of the present invention have surfaces of such perfection that, in the case of semiconductor materials they may be employed for semiconductor applications simply by applying to the faces thereof desired alloys or solders without any intermediate polishing, lapping or etching. In fact, in general, etching results in a degradation of the perfection of the crystal face. In all cases the crystal surfaces have a perfect (111) orientation as grown. For making such devices as diodes, transistors, photodiodes and other similar semiconductor devices, the (111) surfaces are a particularly desired orientation.
  • a further advantage of the present invention is that dice for semiconductor and other applications may be prepared from the grown dendritic crystals by a very simple operation which does not require the use of sawing, ultrasonic cavitation, or other involved cutting processes.
  • To prepare a desired convex polygonal shape from a fiat dendritic crystal it is only necessary to score the surface lightly with a diamond, for example, and upon a slight flexing,
  • the dendrite will break along the score mark, thereby leaving the desired shape die.
  • Example I In apparatus similar to FIG. 1, a graphite crucible containing a quantity of germanium is heated by the induction coil to a temperature several degrees above the melting point of germanium, the temperature being about 938 C., until the entire quantity forms a molten pool.
  • a dendritic seed crystal having three interior twin planes spaced 5 microns and 1.7 microns apart respectively extending entirely therethrough and oriented as in FIG. 2 of the drawing, held vertically in a holder is lowered until its lower end touches the surface of the molten germanium. The contact with the molten germanium is maintained until a small portion of the end of the dendritic seed crystal has melted.
  • the temperature of the melt is lowered rapidly in a matter of 5 seconds by reducing current to the coil 20, to a temperature 8 below the melting point of the germanium so that the melt is supercooled (about 928 C.).
  • the germanium seed crystal is pulled upwardly at a rate of 7 inches per minute.
  • Two dendritic crystals were attached to the seed and each was of a thickness of 7 mils and was approximately 2 mm. in width.
  • the grown dendritic crystals had substantially flat and highly parallel faces from end to end with (111) orientation.
  • the germanium dendritic crystals so grown were found to have no surface imperfections except for a number of microscopic steps differing by about 50 angstroms and were of a quality suitable for semiconductor applications.
  • the resultant dendrite, thus grown had three twin planes extending throughout its length which were spaced 5 microns and 1.7 microns apart respectively.
  • dendrites were pulled successfully using seeds having three twin planes wherein the lamellar spacing between twin successive planes was in the range of from 0.1 to 4 microns, for one and from 0.1 to 15 for the other.
  • Example II The procedure of Example I was repeated except that the seed employed had three interior twin planes spaced 30 microns and 1.7 microns apart respectively extending entirely through the seed.
  • the resulting dendrite was found to have some grain boundary degeneration along the edges. A section of this dendrite could not be used as a seed until the degenerate regions were removed. This illustrates the fact that the 30 micron spacing is at about the limit for the spacing between twin planes.
  • a dendritic seed crystal of a material crystallizing in the diamond cubic lattice structure having three interior twin planes extending entirely therethrough, said interior twin planes being spaced from 0.1 to 5 microns and from 0.1 to 30 microns apart, respectively.
  • a dendritic seed crystal of a material crystallizing in the diamond cubic lattice structure having three in- 9 terior twin planes extending entirely therethrough, said interior twin planes being parallel to each other and being spaced from 0.5 to 4 microns and from 0.5 to 15 microns apart, respectively.
  • a dendritic seed crystal of a material crystallizing in the diamond cubic lattice structure having two relatively fiat parallel faces, and with three interior twin planes extending entirely therethrough, said interior twin planes being parallel to the relatively fiat parallel faces and said interior twin planes being spaced 5 microns and 1.7 microns apart, respectively.
  • a dendritic crystal of a semiconductor material crystallizing in the diamond cubic lattice structure having two relatively fiat parallel faces comprised of ⁇ 111 ⁇ planes, and having three interior twin planes extending entirely therethrough relatively parallel to the parallel faces, said twin planes being spaced from 0.1 to 5 microns and 0.1 to 30 microns apart, respectively.
  • a dendritic crystal of a semiconductor material crystallizing in the diamond cubic lattice structure having two relatively fiat parallel faces comprised of ⁇ 111 ⁇ planes, and having three interior twin planes extending entirely therethrough relatively parallel to the parallel faces, said twin planes being spaced from 0.5 to 4 microns and 0.5 to 15 microns apart, respectively.
  • a dendritic crystal of a semiconductor material crystallizing in the diamond cubic lattice structure having two relatively flat parallel faces comprised of 111 ⁇ planes and having three interior twin planes extending entirely therethrough relatively parallel to the parallel faces, said twin planes being spaced 5 microns and 1.7 microns apart, respectively.

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  • 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)
US79680A 1960-03-21 1960-12-30 Dendritic seed crystals having a critical spacing between three interior twin planes Expired - Lifetime US3130040A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US79680A US3130040A (en) 1960-03-21 1960-12-30 Dendritic seed crystals having a critical spacing between three interior twin planes
GB5330/61A GB913678A (en) 1960-03-21 1961-02-13 Process for producing dendritic crystals of semiconductor materials
CH330161A CH412819A (de) 1960-03-21 1961-03-20 Verfahren zur Züchtung dendritischer Halbleiterkristalle
FR856185A FR1284358A (fr) 1960-03-21 1961-03-20 Procédé de préparation de cristaux dendritiques de semi-conducteurs
GB44433/61A GB951348A (en) 1960-03-21 1961-12-12 Pulling dendritic crystals
DE19611419738 DE1419738A1 (de) 1960-03-21 1961-12-21 Verfahren zum Zuechten von duennen,flachen dendritischen Einkristallen
FR883563A FR80975E (fr) 1960-03-21 1961-12-29 Procédé de préparation de cristaux dendritiques de semi-conducteurs

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Application Number Priority Date Filing Date Title
US1638460A 1960-03-21 1960-03-21
US79680A US3130040A (en) 1960-03-21 1960-12-30 Dendritic seed crystals having a critical spacing between three interior twin planes

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CH (1) CH412819A (de)
DE (1) DE1419738A1 (de)
FR (2) FR1284358A (de)
GB (2) GB913678A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3278342A (en) * 1963-10-14 1966-10-11 Westinghouse Electric Corp Method of growing crystalline members completely within the solution melt
US3427211A (en) * 1965-07-28 1969-02-11 Ibm Process of making gallium phosphide dendritic crystals with grown in p-n light emitting junctions
US3547708A (en) * 1967-01-13 1970-12-15 Ibm Surface finish and dimension controlled and parallel faceted semiconductor crystals and growing process
DE2547905A1 (de) * 1975-10-25 1977-04-28 Hoechst Ag Lichtempfindliches kopiermaterial
US4121965A (en) * 1976-07-16 1978-10-24 The United States Of America As Represented By The Administrator Of The National Aeronautics & Space Administration Method of controlling defect orientation in silicon crystal ribbon growth
US4140570A (en) * 1973-11-19 1979-02-20 Texas Instruments Incorporated Method of growing single crystal silicon by the Czochralski method which eliminates the need for post growth annealing for resistivity stabilization
US4239583A (en) * 1979-06-07 1980-12-16 Mobil Tyco Solar Energy Corporation Method and apparatus for crystal growth control

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB769426A (en) * 1953-08-05 1957-03-06 Ass Elect Ind Improvements relating to the manufacture of crystalline material
US3031403A (en) * 1958-08-28 1962-04-24 Westinghouse Electric Corp Process for producing crystals and the products thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB769426A (en) * 1953-08-05 1957-03-06 Ass Elect Ind Improvements relating to the manufacture of crystalline material
US3031403A (en) * 1958-08-28 1962-04-24 Westinghouse Electric Corp Process for producing crystals and the products thereof

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3278342A (en) * 1963-10-14 1966-10-11 Westinghouse Electric Corp Method of growing crystalline members completely within the solution melt
US3427211A (en) * 1965-07-28 1969-02-11 Ibm Process of making gallium phosphide dendritic crystals with grown in p-n light emitting junctions
US3547708A (en) * 1967-01-13 1970-12-15 Ibm Surface finish and dimension controlled and parallel faceted semiconductor crystals and growing process
US4140570A (en) * 1973-11-19 1979-02-20 Texas Instruments Incorporated Method of growing single crystal silicon by the Czochralski method which eliminates the need for post growth annealing for resistivity stabilization
DE2547905A1 (de) * 1975-10-25 1977-04-28 Hoechst Ag Lichtempfindliches kopiermaterial
DE2547905C2 (de) 1975-10-25 1985-11-21 Hoechst Ag, 6230 Frankfurt Lichtempfindliches Aufzeichnungsmaterial
US4121965A (en) * 1976-07-16 1978-10-24 The United States Of America As Represented By The Administrator Of The National Aeronautics & Space Administration Method of controlling defect orientation in silicon crystal ribbon growth
US4239583A (en) * 1979-06-07 1980-12-16 Mobil Tyco Solar Energy Corporation Method and apparatus for crystal growth control

Also Published As

Publication number Publication date
CH412819A (de) 1966-05-15
GB951348A (en) 1964-03-04
FR80975E (fr) 1963-07-12
DE1419738A1 (de) 1969-07-31
GB913678A (en) 1962-12-28
FR1284358A (fr) 1962-02-09

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