US3261722A - Process for preparing semiconductor ingots within a depression - Google Patents

Process for preparing semiconductor ingots within a depression Download PDF

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Publication number
US3261722A
US3261722A US326945A US32694563A US3261722A US 3261722 A US3261722 A US 3261722A US 326945 A US326945 A US 326945A US 32694563 A US32694563 A US 32694563A US 3261722 A US3261722 A US 3261722A
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United States
Prior art keywords
melt
depression
semiconductor
block
semiconductor material
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Expired - Lifetime
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US326945A
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English (en)
Inventor
Keller Wolfgang
Spenke Eberhard
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Siemens Schuckertwerke AG
Siemens Corp
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Siemens Corp
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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
    • C30B15/02—Single-crystal growth by pulling from a melt, e.g. Czochralski method adding crystallising materials or reactants forming it in situ to the melt
    • 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
    • Y10S117/90—Apparatus characterized by composition or treatment thereof, e.g. surface finish, surface coating
    • 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
    • Y10T117/1056—Seed pulling including details of precursor replenishment

Definitions

  • FIG. 1 A DEPRESSION 2 Sheets-Sheet 1 Filed NOV. 29, 1963 FIG. 1
  • FIG. 3 PROCESS FOR PREPARING SEMICONDUCTOR INGOTS WITHIN A DEPRESSION 2 Sheets-Sheet 3 Filed Nov. 29. 1963 FIG. 3
  • Such a method comprises melting a semiconduoter in a crucible under a non-reactive atmosphere, dipping a single-crystal seed into the melt surface, and slowly withdrawing the seed. Melt material solidifies on the seed in a crystal orientation determined by the seed and in the shape of a rod larger than the seed. This method was taught by Czochralski.
  • the diameter of the grown semiconductor material can be controlled by regulating the melt temperature, regulating the drawing speed, or both.
  • a small seed monocrystal can be grown to a monocrystal of larger diameter.
  • impurities such as oxygen may diffuse into the melt from the crucible wall.
  • the melt temperature may plastically deform the crucible wall.
  • crucible-free zone melting only permits growing single-crystal rods of small diameter; diameters greater than mm. being obtainable thereby only with considerable difficulty. Producing single crystals of diameters greater than mm. with the zone-melting process is essentially impossible.
  • Another object of the invention is to provide a simple method for growing semiconductor rods of large diameters.
  • a depression in a semiconductor block we form a depression in a semiconductor block and produce in the depression a melt of the same material as the block. We then draw a semiconductor rod upwardly out of the depression in the block.
  • FIG. 1 is a perspective view of an apparatus performing the method of the invention.
  • FIG. 2 is a cross-sectional view of FIG. 1.
  • FIG. 3 is a partially schematic, partially sectional, and partially perspective view of another apparatus performing the method of the invention.
  • a semiconductor block 2 defines :a depression or recess R whose bottom supports a melt 3 of the same semiconductor material.
  • Two high-frequency coils 4 and 5 energized by a generator G, inductively heat the melt.
  • Known means shown as 10, draw a monocrystalline semiconductor rod 6 upwardly from out of the melt through heating coil 5.
  • Rod 6 is started with a monocrystalline seed which first is dipped into the melt so that the entire rod as it is drawn becomes monocrystallinc.
  • a polycrystalline semiconductor rod 7 of the same material as rod 6 is directed downwardly by other known means 11, through the heating coil 4 which melts the bottom of the rod, and into the melt.
  • Both semiconductor rods 6 and '7 have the same diameter in FIGS. 1 and 2.
  • the rod 7 is advanced downwardly with the same speed that the rod 6 is withdrawn, so that the melt mass remains constant.
  • the entering rod 7 may have a smaller or larger diameter than rod 6. In that case, the melt mas-s is maintained constant by regulating the advancing speed of rod 7.
  • the semiconductor material 7 is added to the melt in the form of a powder or granular semiconductor material.
  • the semiconductor rnaterial only after being converted to fiuid form as illustrated for example in FIGS. 1 and 2 where the downwardly advancing rod 7 is melted by induction coil 4 so that the semiconductor material from rod 7 enters the melt in fluid form.
  • the semiconductor rod 6 in FIGS. 1 and 2 has a diameter of approximately 40 mm.
  • the melt in the case of silicon has a semiconductor mass of about grams.
  • the withdrawing speed of the rising rod 6 is 2 to 4 mm. per minute, preferably 3 mm. per minute.
  • the entire operation must be carried on in an inert atmosphere which is provided in the usual manner.
  • the semiconductor block 2 preferably is prepared by grinding semiconductor rods or particles into prism shapes matching each other and, after etching away the grinding traces, assembling the prisms into a single block of suitable size.
  • the block may also be assembled from semiconductor rods prepared by precipitation out of the gaseous phase. Such rods generally have six cornered cross sections and can easily be assembled adjacent to each other.
  • the seams or joints at which the individual pieces engage each other need not be completely tight because the melt, due to capillary forces, will not fiow through the slits if they are not wider than 2 or 3 mm. Larger slits would soon be plugged with hardened semiconductor material from the melt. This hardened material is suflicient itself to hold the pieces together into a single block. Thus the wide slits are advantageous.
  • the loosely assembled block 2 may be held together in an insulating support structure.
  • the support may be removed after adherence of the block pieces, or it may also be permitted to remain around the block 2.
  • the block pieces may also be made to form a single block prior to the beginning of the crystal growing process by radiant heating.
  • the two heating coils 4 are located just above the block so as to produce on the upper surface below the induction heating coils a melt comprised of two sections.
  • a monocrystal seed is now dipped into the melt and withdrawn slowly in the known manner. Molten material solidifies on the seed as it is withdrawn. The solidified material forms a large single crystal. It also lowers the melt level so that the coils 4, 5 can be lowered to melt more block material. This is continued until the conditions existing in FIGS. 1 and 2 are approximated.
  • the semiconductor material for formation of the semiconductor rod 6 is extracted only from one side of the melt whereas polycrystalline semiconductor material to be converted is introduced from the rod 7 at the other side of the melt.
  • the block 2 and the heating coils 4, 5- can then remain at rest.
  • the recess in which the melt rests can be produced in another way for example by mechanical removal or by providing for it while assembling the individual constituents out of which the block 2 is constructed.
  • FIGS. 1 and 2 can produce monocrystalline semiconductor rods, particularly silicon rods of diameters greater than 35 mm.
  • Drawing semiconductor rod 6 out through the induction heating coil 5 and introducing semiconductor rod 7 through induction heating coil 4 reliably provides equal heating.
  • the withdrawn ingot if desired, can be rotated about its axis by means 10 at a speed of 10 to 150 r.p.rn., preferably 40 r.p.m., to achieve thereby a symmetrical growth.
  • the induction coil heating power approximates 5 kilowatts.
  • the pieced-together block may also be assembled in a crucible C which loosely supports the pieces and which limits heat losses.
  • the crucible preferably is comprised of graphite or quartz.
  • the crucible C may also heat the semiconductor material to some extent throughout the crystal growing operation. This permits keeping the heat introduced by the heating coils 4, 5 comparatively small. These coils then melt the semiconductor material whereas the external crucible heating merely helps maintain the semiconductor material at a high temperature, for silicon, over a thousand degrees, for example 1200 C. However, it is essential that the block 2 remain solid at its outside at all times. Thus care must be taken to avoid heating the semiconductor material at the crucible wall to its melting point. At such high temperature diffusion of impurities greatly increases, and in the case of a graphite crucible holding a silicon block a chemical reaction forming silicon carbide results. The melt 3 itself must at all times be surrounded by the block of solid semiconductor material. The method of FIG. 3 otherwise corresponds to that of FIGS. 1 and 2 as to performance and results achieved.
  • the above-mentioned semiconductor rods prepared by precipitation out of the gaseous phase, from which the block 2 is assembled have hexagonal cross sections and are referred to as hexrods.
  • Method of producing a monocrystalline semiconductor member which comprises forming a depression in the top of a block of semiconductor material, inductively heating the bottom of the depression from a heat source within the depression to a temperature at which a semiconductor melt is formed in the interior of the block, drawing a portion of the semiconductor material out of the melt so that it COOls and solidifies to a monocrystalline rod having a diameter greater than 25 mm., feeding a mass of polycrystalline semiconductor material from above through the depression to the melt at the bottom of the depression for replacing the portion of semiconductor material drawn therefrom, and simultaneously inductively heating the mass of polycrystalline semiconductor material to its melting temperature as it is being fed through the depression.
  • Method of producing a monocrystalline semiconductor member which comprises forming a depression in the top of a block of semiconductor material, heating the block from a heat source outside the depression to a temperature below its melting point, additionally inductively heating the bottom of the depression from a heat source within the depression to a temperature at which a semiconductor melt is formed in the interior of the block, drawing a portion of the semiconductor material out of the melt so that it cools and solidifies to a monocrystalline rod having a diameter greater than 25 mm., feeding a specific mass of polycrystalline semiconductor material from above through the depression to the melt at the bottom of the depression for replacing the portion of semiconductor material drawn therefrom, and simultaneously inductively heating the mass of polycrystalline semiconductor material to its melting temperature as it is being fed through the depression.
  • Method of producing a monocrystalline semiconductor member which comprises forming a cavity in the top of a block of semiconductor material, inductively heating the bottom of the cavity from a heat source Within the cavity to a temperature at which a semiconductor melt is formed in the interior of the block, drawing a mass of the semiconductor material out of the melt at a rate at which it cools and solidifies to a monocrystalline rod, feeding a rod of polycrystalline semiconductor material from above through the cavity to the melt at the bottom of the cavity at a rate for replacing the mass of semiconductor material drawn therefrom, and simultaneously inductively heating the rod of polycrystalline semiconductor material to its melting temperature as it is being fed through the cavity.

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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)
  • Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
US326945A 1962-12-12 1963-11-29 Process for preparing semiconductor ingots within a depression Expired - Lifetime US3261722A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES82821A DE1243641B (de) 1962-12-12 1962-12-12 Verfahren zur Herstellung von Halbleiterstaeben durch Ziehen aus der Schmelze

Publications (1)

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US3261722A true US3261722A (en) 1966-07-19

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US (1) US3261722A (OSRAM)
BE (1) BE641091A (OSRAM)
CH (1) CH420071A (OSRAM)
DE (1) DE1243641B (OSRAM)
GB (1) GB1059960A (OSRAM)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3470039A (en) * 1966-12-21 1969-09-30 Texas Instruments Inc Continuous junction growth
US3607114A (en) * 1969-10-13 1971-09-21 Siemens Ag Apparatus for producing a monocrystalline rod, particularly of semiconductor material
US3622282A (en) * 1966-12-30 1971-11-23 Siemens Ag Method for producing a monocrystalline rod by crucible-free floating zone melting
US3776703A (en) * 1970-11-30 1973-12-04 Texas Instruments Inc Method of growing 1-0-0 orientation high perfection single crystal silicon by adjusting a focus coil
FR2567918A1 (fr) * 1984-07-20 1986-01-24 Wedtech Corp Procede d'evaporation et de fonte du silicium et dispositif pour sa mise en oeuvre
US4575401A (en) * 1984-06-07 1986-03-11 Wedtech Corp Method of and apparatus for the drawing of bars of monocrystalline silicon
US4650540A (en) * 1975-07-09 1987-03-17 Milton Stoll Methods and apparatus for producing coherent or monolithic elements
US5958133A (en) * 1996-01-29 1999-09-28 General Signal Corporation Material handling system for growing high-purity crystals

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2793103A (en) * 1954-02-24 1957-05-21 Siemens Ag Method for producing rod-shaped bodies of crystalline material
US2858199A (en) * 1954-10-15 1958-10-28 Itt Crystal production
US2890139A (en) * 1956-12-10 1959-06-09 Shockley William Semi-conductive material purification method and apparatus
US2914397A (en) * 1952-08-01 1959-11-24 Int Standard Electric Corp Refining processes for semiconductor materials
US2977258A (en) * 1958-04-09 1961-03-28 Philco Corp Production of semiconductors and the like
US2979386A (en) * 1956-08-02 1961-04-11 Shockley William Crystal growing apparatus
US2999737A (en) * 1954-06-13 1961-09-12 Siemens And Halske Ag Berlin A Production of highly pure single crystal semiconductor rods
US3084037A (en) * 1960-01-08 1963-04-02 Temescal Metallurgical Corp Gaseous ion purification process
US3160497A (en) * 1962-11-15 1964-12-08 Loung Pai Yen Method of melting refractory metals using a double heating process

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE973231C (de) * 1953-01-20 1959-12-24 Telefunken Gmbh Verfahren zur Herstellung von Einkristallen durch Ziehen aus einer Schmelze

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914397A (en) * 1952-08-01 1959-11-24 Int Standard Electric Corp Refining processes for semiconductor materials
US2793103A (en) * 1954-02-24 1957-05-21 Siemens Ag Method for producing rod-shaped bodies of crystalline material
US2999737A (en) * 1954-06-13 1961-09-12 Siemens And Halske Ag Berlin A Production of highly pure single crystal semiconductor rods
US2858199A (en) * 1954-10-15 1958-10-28 Itt Crystal production
US2979386A (en) * 1956-08-02 1961-04-11 Shockley William Crystal growing apparatus
US2890139A (en) * 1956-12-10 1959-06-09 Shockley William Semi-conductive material purification method and apparatus
US2977258A (en) * 1958-04-09 1961-03-28 Philco Corp Production of semiconductors and the like
US3084037A (en) * 1960-01-08 1963-04-02 Temescal Metallurgical Corp Gaseous ion purification process
US3160497A (en) * 1962-11-15 1964-12-08 Loung Pai Yen Method of melting refractory metals using a double heating process

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3470039A (en) * 1966-12-21 1969-09-30 Texas Instruments Inc Continuous junction growth
US3622282A (en) * 1966-12-30 1971-11-23 Siemens Ag Method for producing a monocrystalline rod by crucible-free floating zone melting
US3607114A (en) * 1969-10-13 1971-09-21 Siemens Ag Apparatus for producing a monocrystalline rod, particularly of semiconductor material
US3776703A (en) * 1970-11-30 1973-12-04 Texas Instruments Inc Method of growing 1-0-0 orientation high perfection single crystal silicon by adjusting a focus coil
US4650540A (en) * 1975-07-09 1987-03-17 Milton Stoll Methods and apparatus for producing coherent or monolithic elements
US4575401A (en) * 1984-06-07 1986-03-11 Wedtech Corp Method of and apparatus for the drawing of bars of monocrystalline silicon
FR2567918A1 (fr) * 1984-07-20 1986-01-24 Wedtech Corp Procede d'evaporation et de fonte du silicium et dispositif pour sa mise en oeuvre
US5958133A (en) * 1996-01-29 1999-09-28 General Signal Corporation Material handling system for growing high-purity crystals

Also Published As

Publication number Publication date
BE641091A (OSRAM) 1964-06-11
DE1243641B (de) 1967-07-06
CH420071A (de) 1966-09-15
GB1059960A (en) 1967-02-22

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