Classifications

• • 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
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/305—Sulfides, selenides, or tellurides
• • 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
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/305—Sulfides, selenides, or tellurides
  • C23C16/306—AII BVI compounds, where A is Zn, Cd or Hg and B is S, Se or Te
• • 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
  • C23C16/06—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 metallic material
  • C23C16/16—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 metallic material from metal carbonyl compounds
• • 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
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• • 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
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
  • H10P14/24—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials using chemical vapour deposition [CVD]

Definitions

• This invention relates generally to the field of semiconductor, photovoltaic, flat panel or LCD-TFT device fabrication.
• Phase change materials are used in standard bulk silicon technologies to form the memory elements of nonvolatile memory devices. Phase change materials exhibit at least two different states, one being amorphous and the other(s) crystalline. The amorphous state is characterized by the absence of crystallinity or the lack of long range order, as opposed to crystallized states, which are characterized by a long range order. Accordingly, the order in a unit ceil, which is repeated a large number of times, is representative of the whole material.
• Each memory cell in a nonvolatile memory device may be considered as a variable resistor that reversibly changes between higher and lower resistivity states corresponding to the amorphous state and the crystalline state of the phase change material.
• the states can be identified because each state can be characterized by a conductivity difference of several orders of magnitude.
• the phase changes of the memory element are performed by direct heating of the phase change material with high programming currents.
• bipolar transistors are used to deliver high programming currents by directly heating the phase change material. The high current produces direct heating of the phase change material, which can cause the phase change material to degrade over repeated programming operations, thereby reducing memory device performance.
• the materials of practical use today most contain germanium.
• the most extensively studied material is Ge 2 Sb 2 Te 5 .
• the deposition can be conventionally performed by plasma vapor deposition (PVD) techniques such as sputtering, chemica! vapor deposition (CVD) and atomic layer deposition (ALD) and related techniques including pulse-CVD, remote plasma CVD 1 plasma assisted CVD, plasma enhanced ALD, a variety of materials are now being studied in order to overcome the challenges of deposition in complex structures, including those consisting of trenches.
• PVD plasma vapor deposition
• CVD chemica! vapor deposition
• ALD atomic layer deposition
• pulse-CVD remote plasma CVD 1 plasma assisted CVD
• plasma enhanced ALD plasma enhanced ALD
• germanium-antimony-tellurium (GST) material raises some difficulties, however. For example, many germanium containing precursors are insufficiently thermally stable for a reproducible process.
• a method for depositing a tellurium or GST type film on a substrate comprises providing a reactor, and at least one substrate disposed in the reactor.
• a tellurium containing precursor is provided, where the precursor has one of the following general formulas: (XR 1 R 2 R 3 )Te(XR 4 R 5 R 6 ) (I)
• each of Ri -6 is independently selected from among: H, a C1-C6 aikyl, a C1-C6 alkoxy, a C1 -C6 alkylsilyl, a C1-C6 perfluorocarbon, a C1-C6 aikytsiloxy, a C1 -C6 alkyiamino, an alkyisilylamino, and an aminoamido;
• X is carbon, silicon or germanium;
• n and m are integers selected from 0, 1 , and 2; in formulas (Ha) and (lib), y is an integer selected from 2, 3 and 4; in formula (Hc), y is an integer selected from 1 , 2 and 3.
• the tellurium containing precursor is introduced into the reactor.
• the reactor is maintained at a temperature of at least 100 0 C, and at
• a tellurium precursor comprises a precursor with one of the following general formulas:
• X is carbon, silicon or germanium;
• n and m are integers selected from 0, 1 , and 2; in formulas (Na) and (lib), y is an integer selected from 2, 3 and 4; in formula (lie), y is an integer selected from 1 , 2 and 3.
• inventions of the current invention may include, without limitation, one or more of the following features: maintaining the reactor at a temperature between about 100 0 C and about 500°C, and preferably between about 15O 0 C and about 350 0 C; maintaining the reactor at a pressure between about 1 Pa and about 10 5 Pa, and preferably between about 25 Pa and about 10 3
• the reducing gas is at (east one of: hydrogen; ammonia; siiane; disilane; trisiiane; hydrogen radicals; and mixtures thereof: the teilurium precursor and the reducing gas are introduced into the chamber either substantially simultaneously or sequentially; the teiiurium precursor and the reducing gas are introduced into the chamber substantially simultaneously and the chamber is configured for chemical vapor deposition; the tellurium precursor and the reducing gas are introduced into the chamber sequentially and the chamber is configured for atomic layer deposition; a tellurium containing thin fi!m coated substrate; introducing at least one germanium containing precursor and at least one antimony containing precursor; and depositing at least part of the germanium and antimony containing precursors onto the substrate to form a germanium, tellurium and antimony (GST) containing film; and the telluium precursor is at least one of: Te(GeM ⁇ 3)2; Te(GeEt ⁇ ) 2 ;
• Te(GeiPr 3 ) 2 Te(GetBu 3 ) 2 ; Te(GetBuMe 2 ) 2 ; Te(SiMe 3 ) 2 ;
• alkyi group refers to saturated functional groups containing exclusively carbon and hydrogen atoms.
• alkyl group may refer to linear, branched, or cyclic alkyl groups. Examples of linear alkyl groups include without limitation, methyl groups, ethyl groups, propyl groups, butyl groups, etc. Examples of branched alkyls groups include without limitation, f-butyl. Examples of cyclic alkyl groups include without limitation, cyclopropyl groups, cyclopentyl groups, cyclohexyl groups, etc.
• Me refers to a methyl group
• Et refers to an ethyl group
• tBu refers to a tertiary butyl group
• iPr refers to an isopropyl group.
• R groups independently selected relative to other R groups bearing different subscripts or superscripts, but is also independently selected relative to any additional species of that same R group.
• R groups may, but need not be identical to each other or to R 2 or to R 3 .
• values of R groups are independent of each other when used in different formulas.
• Figure 1 illustrates a thermo-gravimetric analysis of several tellurium precursors, according to embodiments of the current invention.
• embodiments of the current invention relate to methods and compositions for the deposition of tellurium and GST type films on a substrate.
• the tellurium precursor comprises a precursor with one of the following general formulas:
• each of Ri -6 Is independently selected from among: H, a C1-C6 alkyl, a C1-C6 alkoxy, a C1 -C6 alkylsilyl, a C1 -C6 perfluorocarbon, a C1-C6 alkylsiloxy, a C1 -C6 alkylamino, an aikylsiiyiamino, and an aminoamido;
• X is carbon, silicon or germanium;
• n and m are integers selected from 0, 1 , and 2; in formulas (Ha) and (Mb), y is an integer selected from 2, 3 and 4; in formula (Mc), y is an integer selected from 1 , 2 and 3.
• tellurium precursor has the general formula (I)
• the precursors are linear and can be shown schematically as:
• precursors covered by formula (I) include, but are not limited to: Te(GeMe 3 ) 2 ; Te(GeEt 3 ) 2 ; Te(GeiPr 3 ) 2 ; Te(GetBu 3 ) 2 ; Te(GetBuMe 2 )z; Te(SiMe 3 J 2 ; Te(SiEt 3 ) 2 ; Te(SuPr 3 J 2 ; Te(SitBu 3 ) 2 ; Te(SitBuMe 2 )2; Te(Ge(SiMe 3 ) 3 ) 2 ; Te(Si(SiMe 3 ) 3 ) 2 ; Te(GeMe 3 )(Si(SiMe 3 ) 3 ); and
• precursors covered by general formuias (Ma), (lib) and (lie) include, but are not limited to: ((GeMe 2 )Te-) 3 ; ((GeEt 2 )Te-J 3 ; ((GeMeEt)Te-) 3 ;
• the tellurium precursor has the general formula (INJ)
• the precursors can be shown schematically as:
• Embodiments of the tellurium precursor may be synthesized in various ways. Examples of synthesis of the tellurium precursor include, but are not limited to synthesis schemes 1 - 5 as shown below:
• the disclosed precursors may be deposited to form a thin film using any deposition methods known to those of skill in the art.
• suitable deposition methods include without limitation, conventional CVD 1 atomic layer deposition (ALD), and pulsed chemical vapor deposition (P-CVD).
• ALD atomic layer deposition
• P-CVD pulsed chemical vapor deposition
• a thermal CVD deposition is preferred.
• a precursor in vapor form is introduced into a reactor.
• the precursor in vapor form may be produced by vaporizing a liquid precursor solution, through a conventional vaporization step such as direct vaporization, distillation, or by bubbling an inert gas (e.g. N 2 , He, Ar, etc.) into the precursor solution and providing the inert gas plus precursor mixture as a precursor vapor solution to the reactor. Bubbling with an inert gas may a!so remove any dissolved oxygen present in the precursor solution.
• an inert gas e.g. N 2 , He, Ar, etc.
• the reactor contains one or more substrates on to which the thin films will be deposited.
• the one or more substrates may be any suitable substrate used in semiconductor, photovoltaic, flat panel, or LCD-TFT device manufacturing.
• suitable substrates include without limitation, silicon substrates, silica substrates, silicon nitride substrates, silicon oxy nitride substrates, tungsten substrates, or combinations thereof. Additionally, substrates comprising tungsten or noble metals (e.g. platinum, palladium, rhodium, or gold) may be used.
• Substrates may contain one or more additional layers of materials, which may be present from a previous manufacturing step. Dielectric and conductive layers are examples of these.
• the reactor or deposition chamber may be a heated vessel which has at least one or more substrates disposed within.
• the reactor has an outlet, which may be connected to a vacuum pump to allow by products to be removed from the chamber, or to aliow the pressure within the reactor to be modified or regulated.
• the temperature in the chamber is normally maintained at a suitable temperature for the type of deposition process which is to be performed. In some cases, the chamber may be maintained at a lower temperature, for instance when the substrates themselves are heated directly, or where another energy source (e.g. plasma or radio frequency source) is provided to aid in the deposition.
• another energy source e.g. plasma or radio frequency source
• reactors include, without limitation, a cold-wall type reactor, a hot-wall type reactor, a single-wafer reactor, a multi-wafer reactor, or other types of deposition systems under conditions suitable to cause the precursors to react and form the layers.
• deposition may take place for a varying length of time. Generally, deposition may be allowed to continue as long as desired to produce a film with the necessary properties.
• Typicai fiim thicknesses may vary from several hundred angstroms to several hundreds of microns, depending on the specific deposition process.
• the deposition chamber is maintained at a temperature greater than about 100 0 C. In some embodiments, the temperature is maintained between about 100 0 C and about 500 0 C, preferably, between about 15O 0 C. Likewise, the pressure in the deposition chamber is maintained at a pressure between about 1 Pa and about 10 5 Pa, and preferably between about 25 Pa, and about 10 3 Pa.
• a reducing gas is aiso introduced into the reaction chamber.
• the reducing gas may be one of hydrogen; ammonia; siiane; disilane; trisilane; hydrogen radicals; and mixtures thereof.
• the germanium precursor and the reducing gas may be introduced to the reaction chamber substantially simuitaneously.
• the germanium precursor and the reducing gas may be introduced sequentially, and in some cases, there may be an inert gas purge introduced between the precursor and reducing gas.
• germanium and antimony may also be provided and deposited on the substrate.
• germanium, tellurium, and antimony containing precursors By providing germanium, tellurium, and antimony containing precursors, a chalcogenide glass type film may be formed on the substrate, for instance, GeTe-Sb 2 Te 3 Or Ge 2 Sb 2 Te 5
• the precursor and any optional reactants or precursors may be introduced sequentially (as in ALD) or simuitaneously (as in CVD) into the reaction chamber.
• the reaction chamber is purged with an inert gas between the introduction of the precursor and the introduction of the reactant.
• the reactant and the precursor may be mixed together to form a reactant/precursor mixture, and then introduced to the reactor in mixture form.
• the precursor vapor solution and the reaction gas may be pulsed sequentially or simultaneously (e.g. pulsed CVD) into the reactor.
• Each pulse of precursor may last for a time period ranging from about 0.01 seconds to about 10 seconds, alternatively from about 0.3 seconds to about 3 seconds, alternatively from about 0.5 seconds to about 2 seconds.
• the reaction gas may also be pulsed into the reactor. In such embodiments, the pulse of each gas may last for a time period ranging from about 0.01 seconds to about 10 seconds, alternatively from about 0.3 seconds to about 3 seconds, alternatively from about 0.5 seconds to about 2 seconds.
• thermo-gravimetric analyses were performed in an inert atmosphere in order to avoid reaction of the molecules with air and moisture (same atmosphere encountered in the deposition process). The experiments were performed at atmospheric pressure.
• Te(SitBuMe 2 ) 2 is ranked second in terms of volatility, with a full evaporation at around 24O 0 C.
• Te(SiiPr 3 ) 2 and Te(GeiPr 3 ) 2 exhibited roughly the same evaporation pattern, Te(GeiPr3)2 being slightly less volatile, which may be due to the heavy weight of germanium vs. silicon.
• the volatility and evaporation patterns of ail these molecules fit to the criteria of CVD/ ALD molecules.

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• 2009
  • 2009-05-29 US US12/475,204 patent/US8101237B2/en active Active
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