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WO1993005207A1 - Procede de formation de cristallites de diamant et article produit de cette maniere - Google Patents

Procede de formation de cristallites de diamant et article produit de cette maniere Download PDF

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Publication number
WO1993005207A1
WO1993005207A1 PCT/US1992/007439 US9207439W WO9305207A1 WO 1993005207 A1 WO1993005207 A1 WO 1993005207A1 US 9207439 W US9207439 W US 9207439W WO 9305207 A1 WO9305207 A1 WO 9305207A1
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Prior art keywords
nucleating layer
substrate
diamond
carbon
layer
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English (en)
Inventor
R. P. H. Chang
Raymond J. Meilunas
Manfred M. Kappes
Shengzhong Liu
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/02—Pretreatment of the material to be coated
    • C23C16/0272—Deposition of sub-layers, e.g. to promote the adhesion of the main coating
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/26—Deposition of carbon only
    • C23C16/27—Diamond only
    • C23C16/274—Diamond only using microwave discharges
    • 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
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • 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
    • C30B29/04—Diamond

Definitions

  • the present invention relates to formation of a thin diamond layer on a substrate, especially a nondiamond substrate, wherein the nucleation density of diamond crystallites on the substrate is substantially improved.
  • Diamonds are one of the hardest substances known to civilization. But, it also has a plethora of other properties which make it ripe for commercial
  • Diamonds have optical, electrically insulating and heat-transfer capabilities that make it unique. It is an electrical insulator, yet it
  • diamond coated products have potential use in the electronic, military and aerospace, cutting tool, laser, optical and semiconductor
  • diamond film may be used as a protective coating for military and aerospace
  • Diamond coatings may be used as
  • protective coating for laser scanning windows such as at retail-check-out and sunglasses.
  • Cutting tools is another product where diamond coated films can potentially be used. Ceramic cutting tool tips or inserts coated with a diamond film can operate at higher speeds, last longer and cost less to manufacture than conventional tools with carbide or synthetic diamond tips or inserts. Other potential uses include metal cutting tools, automated bonding tools, industrial saws and knives, surgical instruments and microtomes.
  • diamonds could be used to prepare diamond loudspeaker diaphragms for use in loudspeakers.
  • a diamond diaphragm can be prepared by depositing a diamond film on a substrate and then dissolving the substrate.
  • the diamond loudspeaker has properties that exceed that of beryllium, which was known to be the best loudspeaker material heretofore. For instance, the sound propagation speed of the diamond loudspeaker is faster than that of beryllium and its reproducible frequency is greater than that of beryllium
  • Diamond is a very desirable material in the optical industry and in lasers.
  • diamond film coated lens have been used for focusing laser beams.
  • Diamond coated film can be potentially used as a semiconductor. Chips made of single crystal diamond runs faster and cooler than those made of silicon or gallium arsenide.
  • diamond film can be used as thermistors.
  • Thermistors made of polycrystalline diamond film can operate at temperatures much greater than those made up of other material, such as silicon, gallium arsenide or silicon carbide.
  • diamond film Other potential uses for the diamond film include transistors as well as light emitting devices (LED'S).
  • LED'S light emitting devices
  • PECVD PECVD
  • HFCVD hot filament chemical vapor deposition
  • oxygen-acetylene torch PECVD
  • plasma torch techniques PECVD
  • PECVD hot filament chemical vapor deposition
  • HFCVD oxygen-acetylene torch
  • a severe drawback experienced in practicing these thin diamond film deposition processes has involved the need to pretreat nondiamond substrates in a manner to provide a sufficient density of diamond nucleation sites on the substrate surface to enable subsequent growth of a continuous diamond layer.
  • the most common pretreatment developed to-date to achieve the required diamond nucleation density involves
  • abrading pretreatment constitutes a severe processing limitation for many potential applications where the diamond layer will be nucleated and grown on a
  • An object of the present invention is to provide a low pressure diamond deposition method using a novel nucleating layer on a substrate to substantially improve diamond crystallite nucleation and overcome the limitations of the diamond powder abrading technique described hereinabove.
  • Anther object of the present invention is to provide an article comprising a
  • the present invention contemplates a method of forming a diamond layer on at least a portion of a substrate, especially, a nondiamond substrate, wherein diamond nucleation is enhanced by providing on at least a portion of the substrate a nucleating layer comprising a carbon cluster having a geodesic molecular structure (i.e., a molecular structure comprised of an array or grid of polygons) and contacting the nucleating layer with a carbon-bearing gas under temperature and pressure conditions effective to nucleate diamond at the
  • the nucleating layer preferably comprises a fullerene molecule, e.g., C 70 fullerene, having a combination of hexagons and pentagons joined at their vertices.
  • the nucleating layer is deposited (e.g., sublimated, sputtered, etc.) on the substrate to thickness of about 100 to about 2000 angstroms.
  • the nucleating layer may be deposited as a continuous layer on a substrate surface or as one or more discrete regions on the substrate surface so as to selectively nucleate diamond crystallites at the region(s).
  • the carbon-bearing gas comprises a mixture of hydrogen and a hydrocarbon.
  • the carbon-bearing gas preferably comprises a carbon-bearing reducing plasma wherein hydrogen and a hydrocarbon are ionized.
  • the nucleating layer is impinged by particles in a pretreatment operation to promote diamond
  • the pretreatment operation may occur prior to and/or concurrently with a nucleation stage of the diamond deposition process.
  • diamond crystallite nucleation is enhanced by forming on at least a portion of the substrate a
  • nucleating layer comprising a C 70 fullerene, or a portion of its molecular structure, and contacting the nucleating layer and a carbon-bearing plasma while the substrate is electrically biased at a negative potential relative to the plasma to accelerate ions in the plasma to impinge on the nucleating layer to facilitate diamond nucleation.
  • the present invention also contemplates an article comprising a substrate and a diamond layer nucleated and grown on at least a portion of the
  • Figure 1 is a schematic view of a microwave plasma enhanced, low pressure chemical vapor deposition (CVD) apparatus for practicing an embodiment of the method of the invention.
  • CVD chemical vapor deposition
  • Figure 2 is an enlarged schematic view of the substrate holder of the apparatus of Figure 1.
  • Figures 3a, b, c are micrographs of diamond crystallites nucleated and grown on circular nucleating layer dots on a silicon substrate in accordance with Example 1 set forth hereinbelow.
  • the present invention is directed to a method for enhancing diamond nucleation on surfaces.
  • the enhancement of diamond nucleation on surfaces consists of the following
  • Ideal surfaces which meet the above requirements include carbon clusters having a geodesic molecular structure and/or films. Fullerene is a type of carbon cluster having a geodesic molecular structure. These molecules form cages having a central cavity. These molecules can take the stable form of hollow closed nets composed of 12 pentagons and at least one hexagon. In stable
  • Examples include buckminsterfullerene (C 60 ), C 70 fullerene, C 76 fullerene, C 78 fullerene, C 82
  • fullerenes C 96 fullerenes and the like.
  • larger fullerenes in the range between C 96 and C 250 can also be used, for example, C 120 fullerenes, C 240
  • fullerenes include carbon clusters in the C 600 - C 700 range.
  • Another fullerene that could be used include buckytubes, i.e., fullerenes containing micron long concentric needle-like tubes in which the hexagons are arranged in a helical pattern. See, Iijima, S.,
  • the preferred carbon clusters are those even-numbered fullerenes having from 60 to about 520 carbon atoms. More preferred are those wherein the number of carbon atoms range from 60 to about 120, and especially preferred in the carbon cluster ranging from 60 to about 100 carbon atoms.
  • the buckytubes are also preferred.
  • microwave plasma enhanced chemical vapor deposition (CVD) apparatus for practicing one embodiment of the method of the invention.
  • the microwave plasma enhanced CVD apparatus is described by R. Meilunas and R.P.H. Chang in Proceedings of the 2nd ICEM Conference,
  • microwave energy at a frequency of 2.45 GHz is transmitted from a 1 KW
  • a water cooled circulator 20 is positioned between the microwave generator 10 and the vacuum chamber 12 to protect the generator from any unwanted reflected power transmitted back from the vacuum chamber 12. Any reflected power is diverted by the circulator 20 to a water cooled dummy load 22.
  • a four stub tuner 24 is employed to impedance match the deposition system to the generator 10, thereby
  • the mode converter 14 is employed to alter the electric and magnetic fields from the rectangular mode to a circular mode such that the electric field lines of the
  • propagating microwave energy are circularly symmetrical relative to the longitudinal axis of the vacuum chamber 12, thereby centering the plasma P in the vacuum chamber 12.
  • the microwave energy is transferred into a deposition region DP of the vacuum chamber 12 through a high purity quartz window 26 mounted on a flange 12a of the vacuum chamber 12.
  • the deposition region DP of the vacuum chamber 12 has dimensions matched to the
  • ultra-high purity hydrogen gas and ultra-high purity hydrocarbon (e.g., methane) gas are supplied to the deposition region DP via a common conduit 33 communicating with respective gas supply conduits 34, 36.
  • the gas supply conduits 34, 36 extend from conventional gas sources 38, 40 (e.g., ultra-high purity hydrogen and methane gas cylinders).
  • Hydrogen flow and hydrocarbon flow to the deposition region DP are controlled by a mass flow controller (not shown) in the respective supply conduits 34, 36.
  • the metered gas flows are mixed in the common conduit 33 to provide desired hydrogen/methane gas mixture ratios in the deposition region DP during the nucleation stage and the growth stage of the plasma enhanced CVD process as will be described hereinbelow.
  • a vacuum pump 42 is actuated to evacuate the chamber 12 to a base pressure of about 2 x 10 -6 torr.
  • the vacuum pump 42 communicates to the chamber 12 via a pressure control valve 44, such as a gate valve, in a conduit 46.
  • a thin diamond layer is formed on a suitable substrate 50 which is located on a substrate holder mechanism 53 that includes a tubular quartz substrate support 54 and an annular graphite cover 56 overlying the substrate 50 at the upper end 54a of the support 54.
  • the support upper end 54a is sealed in a flat, gas-tight manner to provide a support platform for the substrate 50 and to prevent ingress of contaminating gases from the ambient atmosphere external of the vacuum chamber 12.
  • the cover 56 is biased downwardly by a plurality of springs 58 (two shown) connected between quartz rods 59 on the underside of the collar 56 and the bottom wall 12b of the vacuum chamber 12.
  • the collar 56 thereby clamps the substrate 50 on the sealed upper end of the support 54.
  • the quartz rods 59 electrically isolate the substrate 50 and the cover 56 from ground potential.
  • the substrate support 54 is movable by a linear position 61 to enable desired positioning of the substrate surface relative to the plasma P.
  • a strip 63 of platinum foil is clamped between the substrate 50 and the cover 56 in electrical contact therewith in order to electrically bias the substrate relative to the plasma P in accordance with a feature of the invention to be described hereinbelow.
  • the foil strip 63 is spot welded to a platinum wire 62 which is connected to and passes through a vacuum feedthrough 64 in the chamber wall 12c.
  • the wire 62 is connected to the negative terminal of an external direct current voltage source 66 as shown in Figure 1.
  • the other terminal of the voltage source 66 as well as the vacuum chamber wall 12b are connected to ground as also shown in Figure 1.
  • a wire mesh microwave attenuation tube (not shown) is employed about the foil strip 63 and wire 62 between the cover 56 and the feedthrough 64.
  • the attenuation tube has a diameter below the cutoff
  • the attenuation tube thus functions to attenuate any complex waveform that might travel out of the deposition region DP down the electrical connection (foil strip 63 and wire 62).
  • a novel nucleating layer 60 is provided on the substrate surface to substantially enhance the density of diamond crystallites nucleated on the substrate.
  • the nucleating layer 60 can be deposited on a discrete region or portion of the substrate surface where diamond is to be selectively nucleated and grown. Alternately, the nucleating layer 60 can be deposited as a continuous layer on the substrate surface to form a corresponding continuous diamond layer or film on the surface; for example, for use a protective layer on the substrate.
  • the nucleating layer 60 is effective to enhance diamond crystallite nucleation on a variety of nondiamond substrate materials including, but not limited to, metals such as Mo, semiconductors such as silicon, and insulators such as silicon dioxide.
  • the nucleating layer 60 deposited on the substrate surface comprises a carbon cluster containing a geodesic molecular structure.
  • the nucleating layer 60 deposited on the substrate surface preferably comprises a C 70 fullerene whose molecular structure comprises, as is known, a combination of hexagonal molecular units (or faces) and pentagonal molecular units (faces) arranged in a pattern or array and joined at vertices of the units to form a hollow, oblong ball-shaped molecule. Carbon atoms are located at the vertices of the joined hexagons and the pentagons.
  • the molecular structure of the C 7 0 fullerene is characterized and illustrated in Popular Science, August, 1991, pp. 52-57 and 87 as well as other
  • the C 70 fullerene is obtained from carbon soot prepared in accordance with a known preparation
  • the nucleating layer may also comprise a C 60 fullerene whose molecular structure comprises, as is also known, a combination of hexagonal molecular units (or faces) and pentagonal molecular units (or faces) arranged and joined at vertices of the units to form a hollow, spherical ballshaped molecule wherein the carbon atoms are located at the vertices of the joined hexagons and pentagons.
  • the molecular structure of the C 60 fullerene is also known, a combination of hexagonal molecular units (or faces) and pentagonal molecular units (or faces) arranged and joined at vertices of the units to form a hollow, spherical ballshaped molecule wherein the carbon atoms are located at the vertices of the joined hexagons and pentagons.
  • the molecular structure of the C 60 fullerene is also
  • the C 60 fullerene is prepared in the same manner described hereinabove for the C 70 fullerene.
  • Other members of the fullerene family of molecules such as C 72 , C 76 , C 84 , C 90 , C 92 , C 96 and like, that exhibit an appropriate ordered molecular structure, stability in air, and ability to withstand, at least to some degree, the environment in which plasma enhanced CVD is conducted may also find use as a nucleating layer in practicing the invention.
  • fullerenes may be prepared as described above for the C 70 fullerenes.
  • the various fullerenes are separated by column
  • mixtures of C 60 , C 70 and other fullerenes may be employed as the nucleating layer 60.
  • the carbon soot referred to hereinabove in the production of C 70 fullerene may itself (i.e., the soot) be used as the nucleating layer.
  • the invention envisions the substitution and/or addition of one or more elements and/or radicals at one or some of the carbon atom positions of a carbon cluster molecule, e.g., C 70 fullerene, so as to enhance its efficacy as a nucleating layer in the low pressure CVD process.
  • silicon may be substituted for one or more of the carbon atoms of the C 70 fullerene molecule or other fullerene molecules.
  • oxygen, hydrogen or halogen e.g., fluorine
  • Metal complexes of carbon clusters e.g., alkali metal, Group VIII metals (e.g., platinum, palladium, nickel and the like) and other metal complexes of carbon clusters, e.g., alkali metal, Group VIII metals (e.g., platinum, palladium, nickel and the like) and other metal complexes of carbon clusters, e.g., alkali metal, Group VIII metals (e.g., platinum, palladium, nickel and the like) and other
  • metallofullerenes such as lanthanum or scandium
  • fulleroids in which dipolar molecules are added to the fullerene can also be used.
  • fulleroids include 4, 4-dibromodiphenyl fulleroid, bis-(4- bromophenyl)fulleroid, bis-4-n-dimethylaminophenyl fulleroids, bis-(4-methoxyphenyl)fulleroids, bis-4- methylphenyl) fulleroids and the like.
  • the nucleating layer 60 may be deposited on the substrate surface by various techniques.
  • an appropriate quantity of the carbon cluster e.g., C 70 or C 60 fullerene material, can be positioned in a conventional sublimation chamber at 10 -6 torr and heated by a hot filament to a sufficiently high
  • the substrate surface appropriately located relative to the fullerene material in the chamber.
  • the substrate surface is typically located about two (2) inches above and facing the heated fullerene material in the sublimation chamber so that evaporated material deposits on the substrate surface as a thin layer.
  • the nucleating layer deposited on the substrate surface will have a thickness of about 100 to about 2000 angstroms. A specific thickness of the nucleating layer used in practicing the invention are described in the Examples set forth hereinbelow.
  • the nucleating layer may be formed in the vacuum chamber 12 and deposited on the substrate surface in the deposition region DP shown in Figure 1.
  • a graphite source (not shown) may be positioned in the vacuum chamber 12 so as to be impinged by a laser beam or particle (ion) beam
  • a suitable beam generator (not shown) also disposed in the vacuum chamber 12.
  • the beam is impinged on the graphite source under conditions to sputter carbon atoms therefrom for recombination as fullerene molecules that are deposited onto the substrate surface.
  • This sputtering technique is advantageous to eliminate the need to deposit the nucleating layer 60 in a
  • the nucleating layer may be deposited as one or more discrete regions on the substrate surface or as a continuous layer thereon. The capability of depositing the nucleating layer at
  • the diamond nucleated at one or more of these discrete regions can be grown to form an integrated circuit component, such as an interconnect, heat sink, etc. at appropriate locations on a semiconductor wafer or other microelectronic device substrate.
  • Nucleation and growth of diamond at the nucleating layer are effected by contacting the plasma P established in the deposition region DP of the vacuum chamber 12 and the nucleating layer under conditions of temperature, pressure, gas mixture composition, gas flow rate, etc. selected to this end.
  • a pretreatment of the nucleating layer to promote diamond nucleation is conducted concurrently with a nucleation stage of the low pressure CVD process.
  • the pretreatment/nucleation stage is conducted using a plasma P rich in hydrocarbon as compared to the plasma used during the growth stage of the CVD process .
  • deposition region DP during the pretreatment/nucleation stage comprises about 3-20 volume % and more preferably 5-15 volume % methane and the balance hydrogen.
  • the gas mixture is supplied at 100 seem (standard cubic
  • a typical gas mixture supplied to the deposition region DP during the growth stage comprises about 1 volume % and the balance
  • the gas mixture is supplied at about 100 sccm to a 100 torr total pressure in the chamber 12.
  • the substrate 50 typically is heated by direct interaction with the plasma P and microwave induction heating to a temperature of about 30°C to 500°C during the
  • pretreatment/nucleation stage and to about 700°C to about 950°C during the growth stage.
  • a separate heating device may be employed in the chamber 12 to heat the substrate to the desired temperature.
  • the substrate is electrically biased to accelerate
  • hydrocarbon-rich plasma P to impinge on the nucleating layer 60 while it is in contact with the plasma.
  • the substrate 50 is biased negatively from about 100 to about 300 volts relative to the plasma (and ground potential) by the voltage source 66 shown in Figure 1.
  • the impinging positive ions from the plasma P are believed to cleave carbon-carbon bonds of the nucleating layer and thereby create sites for gas phase carbon species to nucleate, although Applicants do no wish to be bound by this explanation.
  • Diamond appears to selectively nucleate at the nucleating layer at some time following initial cation impact.
  • the nucleating layer remains in contact with the plasma for a period of time to initiate sufficient diamond crystallite nucleation to enable subsequent growth to a continuous diamond layer.
  • a typical duration of the pretreatment/nucleation stage is on the order of several minutes (e.g., about 5-15 minutes).
  • carbon or hydrocarbyl ions from an ion source in the chamber 12 may be used.
  • Other alternative methods include inert ions (such as argon, neon, helium, etc.), laser beam, electron beam, or energetic neutral carbon/or inert gas beams in a medium of carbon carrying gas such as CH 4 or CH 4 during pretreatment.
  • the growth stage is conducted for a time period (e.g., 60 minutes) to form a continuous
  • the grown diamond layer exhibits a grain size less than approximately one (1) micron.
  • a shadow mask can be used, if desired, to lithographically define the areas where C 70 is
  • the areas comprise circular dots each 200 microns in diameter.
  • Pretreatment/Nucleation Each silicon substrate with the C 70 film thereon was loaded into the plasma enhanced chemical vapor deposition machine described above for nucleation and growth. To activate the film for diamond nucleation, a pretreatment of positive ion bombardment by biasing (at 200 volts) the substrate with respect to the plasma was applied. During the pretreatment, which typically was conducted for 15 minutes, the gas
  • composition was 10% CH 4 in H 2 of 15 torr total pressure, microwave power 400 Watts and a gas flow rate of 100 seem.
  • the substrate temperature was 400°C.
  • Diamond crystallite growth was then initiated in region DP on the pretreated/nucleation substrate in a growth stage lasting about 60 minutes using standard conditions; e.g., substrate temperature 900°C; 1% CH 4 in H 2 ; total pressure of 100 Torr; microwave power 800 Watts; gas flow rate of 100 seem.
  • Figures 3a, 3b, 3c are micrographs at different magnifications of continuous diamond film growth observed at the circular nucleating dots on a silicon substrate surface.
  • Figure 3d the Raman spectra of the diamond film that was grown is shown. The selective nucleation and growth of diamond at the nucleating dots (as compared to the silicon substrate) is evident.
  • Example 1 substrate and for pretreatment/nucleation and growth of diamond were used as described for Example 1. Diamond nucleation and growth similar to that described for Example 1 were observed.
  • a molybdenum substrate was used in this example. Removal of the molybdenum oxide surface prior to C 70 sublimation is optional. The same conditions for sublimation of the C 70 nucleating film and for pretreatment/nucleation and growth of diamond were used as described in Example 1. Diamond nucleation and growth similar to that described for Example 1 were observed.
  • a C 60 nucleating layer was sublimated on a silicon substrate in a manner described hereinabove.
  • the same conditions for pretreatment/ nucleation and growth of diamond were used as in Example 1.
  • Diamond nucleation and growth on the C 60 dots was observed to be a few orders of magnitude less than that observed in Example 1.
  • the aforementioned carbon soot comprising a mixture of C 70 , C 60 and possibly other fullerenes was employed as the nucleating layer.
  • the same conditions of pretreatment/nucleation and growth of diamond were used as in Example 1.
  • Diamond nucleation and growth on the circular dots was observed to be a few orders of magnitude less than that observed in Example 1.
  • an alternate embodiment of the invention envisions pretreating the nucleating layer 60 prior to conducting the low pressure CVD process such that only a portion of the fullerene molecular structure remains on the substrate as a nucleating layer.
  • a nucleating layer 60 comprising, or having an outer region comprising, a fractional portion of the fullerene molecule (for example, C 60 , C 84 and more preferably C 70 , and the like) may be formed by ion beam, laser beam or intense
  • the pretreated substrate is then placed in the vacuum chamber 12 for nucleation and growth of diamond at the nucleating layer by the plasma enhanced CVD process described hereinabove with or without negative substrate biasing during the nucleation stage of the process.
  • carbon cluster having a geodesic molecular structure is intended to include the aforementioned C 70 fullerene, C 60 fullerene, other fullerenes or carbon clusters having a molecular structure comprised of an array or grid of polygons and that are effective to enhance diamond nucleation in low pressure diamond deposition processes, as well as mixtures of such molecules (e.g., the aforementioned carbon soot).
  • the term is also intended to include portions of such molecules that, for example, may remain on the substrate surface after the pretreatments described in the preceding paragraph.
  • the term is intended to include substitution/ addition modified forms of such molecules, or portions thereof, wherein one or more elements and/or radicals are substituted and/or added at one or some carbon atoms positions of the molecular structure.
  • reducing gas refers to the presence of hydrogen gas.
  • Gas refers to a molecule or atom in the gaseous state at standard temperatures and pressures. It also includes those molecules or atoms which are volatile liquids at 1 atm pressure and room temperature. It includes the neutral molecule or atom as well as the plasma. The neutral molecule or atom, as defined herein, refers to the molecule or atom in the unexcited state (i.e., the molecule or atom itself).
  • neutral molecules or atoms also include, however, the excited molecules or atoms, (the molecule or atom in an excited state) and radicals thereof. It also includes the charged species and electrons (ions) of the unexcited or excited molecules or atoms.
  • Pulsma refers to a neutral mixture of positively and negatively charged particle interacting with an electromagnetic field.
  • carbon bearing gas as used herein is intended to comprise carbon containing molecules or atoms which are gases at standard temperatures and pressures or which are volatile liquids at 1 atm
  • the carbon containing molecules or atoms are hydrocarbons or oxygen containing hydrocarbons or the halogenated containing hydrocarbons.
  • the volatile liquids are preferably organic solvents, for example, hydrocarbon as well as aromatic solvents, ethers, esters, hexanes, alcohols and fluorinated and chlorinated hydrocarbons.
  • the carbon containing molecule or atom is a gas at standard pressure and temperature. It is more preferable that the carbon containing molecule or atom is a hydrocarbon, and more preferably aliphatic. It is most preferable that the carbon containing molecule or atom is a
  • containing molecule or atom contain no more than 10 carbon atoms and most preferably no more than 8 carbon atoms and most preferably no more than 4 carbon atoms.
  • Examples include carbon monoxide, carbon dioxide, hydrocarbons, (e.g., methane, ethane, propane, butane, pentane, hexane, heptanes, octanes, cyclopentane, cyclohexane, petroleum ether and the like), halogenated hydrocarbons, (e.g., carbon tetrachloride, carbon tetrafluoride, methylene, chloride, methylene fluoride, chloroform, fluoroform, methyl chloride, methyl
  • alcohols e.g., methanol, ethanol, propanol, butanol, and the like
  • ethers
  • ketones e.g., acetone, and the like
  • ester e.g., methyl acetate, ethyl acetate, and the like
  • aromatics e.g., benzene, toluene, ethyl
  • benzene and the like
  • carbon dioxide and carbon monoxide.
  • Preferred examples include the hydrocarbons, especially those containing 1-4 carbon atoms, the halogenated hydrocarbons, especially the methyl
  • halogenated compounds especially the methyl and ethyl alcohols, ethers, carbon dioxide and carbon monoxide. More preferred examples include the
  • hydrocarbons which are gases at standard temperature and pressure and carbon monoxide and carbon dioxide. The most preferred are the hydrocarbons which are gases at STP.
  • carbon bearing plasma is intended to include the charged species of the carbon bearing gas as defined herein.
  • the invention has been described hereinabove as being practiced using a plasma enhanced, low pressure CVD apparatus/process, the invention is not so limited and may be practiced using other thin diamond film deposition apparatus/processes including, but not limited to, hot filament CVD, non-plasma enhanced CVD, gas torch, plasma torch and laser ablation.

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Abstract

Procédé permettant de former une couche de diamant sur un substrat, plus spécifiquement sur un substrat qui n'est pas lui-même du diamant. Dans ce procédé on améliore la formation des germes cristallins de diamant en créant une couche de nucléation comprenant un agglomérat de fullerène ou de carbone présentant une structure moléculaire géodésique sur le substrat. On met ensuite en contact la couche de nucléation et un plasma ou un autre gaz contenant du carbone, dans des conditions de température et de pression efficaces pour former des germes cristallins de diamant sur la couche de nucléation. Pendant cette mise en contact, le substrat est polarisé négativement par rapport au plasma pour envoyer les ions positivement chargés du plasma sur la couche de nucléation afin de stimuler la formation de cristallites de diamant.
PCT/US1992/007439 1991-09-03 1992-09-03 Procede de formation de cristallites de diamant et article produit de cette maniere Ceased WO1993005207A1 (fr)

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US753,736 1991-09-03

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2270326A (en) * 1992-09-03 1994-03-09 Kobe Steel Europ Ltd Growth of diamond films on silicon substrates with application of bias to substrate; tessellated patterns
WO1994027323A1 (fr) * 1993-05-06 1994-11-24 Kobe Steel Europe Limited Preparation de surfaces de silicium nucleees
WO1994026953A1 (fr) * 1993-05-17 1994-11-24 North Carolina State University Procede de fabrication de films de diamant orientes
US5449531A (en) * 1992-11-09 1995-09-12 North Carolina State University Method of fabricating oriented diamond films on nondiamond substrates and related structures
EP0692552A1 (fr) * 1994-07-11 1996-01-17 Southwest Research Institute Méthode assistée par faisceau d'ions pour la production d'un revêtement en carbone dur amorphe
GB2300424A (en) * 1995-05-01 1996-11-06 Kobe Steel Europ Ltd Diamond growth on ion implanted surfaces
EP0650465A4 (fr) * 1993-03-23 1997-05-21 Dieter M Gruen Conversion de fullerenes en diamant.
EP0890705A3 (fr) * 1997-07-09 1999-05-06 Baker Hughes Incorporated Trépan de forage avec élément de coupe ayant une surface de coupe en diamant nanocristallin
CN116445885A (zh) * 2023-03-06 2023-07-18 浙江工业大学 纳米金刚石片竖立组装的高迁移率n型薄膜及其制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0320657A1 (fr) * 1987-12-17 1989-06-21 General Electric Company Procédé de croissance de diamant
EP0343846A2 (fr) * 1988-05-27 1989-11-29 Xerox Corporation Procédé de fabrication de diamant polycristallin
US5006203A (en) * 1988-08-12 1991-04-09 Texas Instruments Incorporated Diamond growth method
GB2240114A (en) * 1990-01-18 1991-07-24 Stc Plc Film nucleation process for growing diamond film
US5132105A (en) * 1990-02-02 1992-07-21 Quantametrics, Inc. Materials with diamond-like properties and method and means for manufacturing them

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0320657A1 (fr) * 1987-12-17 1989-06-21 General Electric Company Procédé de croissance de diamant
EP0343846A2 (fr) * 1988-05-27 1989-11-29 Xerox Corporation Procédé de fabrication de diamant polycristallin
US5006203A (en) * 1988-08-12 1991-04-09 Texas Instruments Incorporated Diamond growth method
GB2240114A (en) * 1990-01-18 1991-07-24 Stc Plc Film nucleation process for growing diamond film
US5132105A (en) * 1990-02-02 1992-07-21 Quantametrics, Inc. Materials with diamond-like properties and method and means for manufacturing them

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
APPLIED PHYSICS LETTERS. vol. 59, no. 26, 23 December 1991, NEW YORK US pages 3461 - 3463 MEILUNAS ET AL 'nucleation of diamond films on surfaces using carbon clusters' *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2270326A (en) * 1992-09-03 1994-03-09 Kobe Steel Europ Ltd Growth of diamond films on silicon substrates with application of bias to substrate; tessellated patterns
GB2270326B (en) * 1992-09-03 1996-10-09 Kobe Steel Europ Ltd Preparation of diamond films on silicon substrates
US5449531A (en) * 1992-11-09 1995-09-12 North Carolina State University Method of fabricating oriented diamond films on nondiamond substrates and related structures
US5849413A (en) * 1992-11-09 1998-12-15 North Carolina State University Oriented diamond film structures on nondiamond substrates
EP0650465A4 (fr) * 1993-03-23 1997-05-21 Dieter M Gruen Conversion de fullerenes en diamant.
WO1994027323A1 (fr) * 1993-05-06 1994-11-24 Kobe Steel Europe Limited Preparation de surfaces de silicium nucleees
WO1994026953A1 (fr) * 1993-05-17 1994-11-24 North Carolina State University Procede de fabrication de films de diamant orientes
EP0692552A1 (fr) * 1994-07-11 1996-01-17 Southwest Research Institute Méthode assistée par faisceau d'ions pour la production d'un revêtement en carbone dur amorphe
GB2300424A (en) * 1995-05-01 1996-11-06 Kobe Steel Europ Ltd Diamond growth on ion implanted surfaces
EP0890705A3 (fr) * 1997-07-09 1999-05-06 Baker Hughes Incorporated Trépan de forage avec élément de coupe ayant une surface de coupe en diamant nanocristallin
US5954147A (en) * 1997-07-09 1999-09-21 Baker Hughes Incorporated Earth boring bits with nanocrystalline diamond enhanced elements
CN116445885A (zh) * 2023-03-06 2023-07-18 浙江工业大学 纳米金刚石片竖立组装的高迁移率n型薄膜及其制备方法

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