US3460985A - Gas etching followed by gas plating - Google Patents

Gas etching followed by gas plating Download PDF

Info

Publication number
US3460985A
US3460985A US524303A US3460985DA US3460985A US 3460985 A US3460985 A US 3460985A US 524303 A US524303 A US 524303A US 3460985D A US3460985D A US 3460985DA US 3460985 A US3460985 A US 3460985A
Authority
US
United States
Prior art keywords
substrate
gas
reaction
source
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US524303A
Other languages
English (en)
Inventor
Erhard Sirtl
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Application granted granted Critical
Publication of US3460985A publication Critical patent/US3460985A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • 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
    • 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
    • Y10S148/051—Etching
    • 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
    • Y10S148/052—Face to face deposition

Definitions

  • the improvement comprises enforcing the selective reversal of the transport direction by changing the total pressure of the reaction gas mixture in the reaction vessel, and simultaneously maintaining a substantially constant molar mixing ratio of the gas mixture and a constant temperature range of the reaction.
  • silicon as the high purity material
  • iodine as the reaction gas
  • the direction of transport is reversed by changing the total gas pressure from below to above a critical value between about 15 torr and about 85 torr.
  • My invention relates to a method for producing thin crystalline, preferably monocrystalline layers of highly pure materials upon a heated substrate by means of a chemical transport reaction.
  • a reversible transportation ice of material along the direction of a temperature gradient is effected by changing the total pressure of the reaction gas mixture in the reaction vessel while simultaneously maintaining constrainedly a constant molar mixing ratio and a constant temperature range.
  • the invention is predicated upon the recognition that a reversal in transportation of material takes place at a given critical pressure peculiar to the particular chemical transport reaction system being used.
  • This recognition is utilized, for example, by adjusting the total pressure of the reaction gas mixture to a value which, for eliminating material from the substrate surface, is below the critical value peculiar to the transport reaction system, and then maintaining this subcritical pressure value until the desired amount of material is removed from the substrate surface. Thereafter, the growing of a layer on top of the substrate is commenced by changing the total pressure of the reaction gas mixture to a different value above the critical value of the particular transport system, and thereafter maintaining this supercritical pressure constant until the desired layer thickness is attained.
  • the process may be performed by effecting the reversal in transport direction only once, so that first an amount of material is removed from the substrate surface and thereafter an epitaxial layer is grown upon the surface.
  • the reversal in direction of material transportation may also be repeated. This is particularly advantageous if layers of different semiconductor materials or of the same semiconductor material but with respectively different dopants or dopant concentrations, are to be produced.
  • the transport reaction may be performed, in accordance with the sandwich method, between two closely juxtaposed crystal plates or discs of which one constitutes the source material and the other the substrate for the epitaxial layer to be grown.
  • the method of the invention is applicable for transport reactions in which the source material and the substrate are spaced a relatively large distance from each other.
  • Suitable for example are silicon in the system silicon-iodine, titanium in the system titanium-iodine, zirconium in the systems zirconium-chlorine, zirconium-bromine and zirconium-iodine, also vanadium in the system vanadium-iodine, niobium in the systems niobium-chlorine, niobium-bromine, tantalum in the systems tantalum-chlorine, tantalum-bromine and copper in the system Cu OHCl.
  • the values of the critical pressure specific to the chosen transport reaction system can be calculated from the equilibrium constants as well as from the formation enthalpy of the individual reaction partners.
  • the critical pressure for the transport of silicon in the iodine system is 15 torr at 1050 C. 35 torr at 1150 C., and torr at 1250" C.
  • the transport of titanium in the iodine system at 1250 C. becomes reversible at a critical pressure of 20 torr.
  • the adjustment of the critical pressure can be made by providing for a corresponding negative pressure in the reaction vessel, or by admixing inert gas to the halogen vapor or helagenide vapor which forms part of the reaction gas.
  • Suitable as substrates for the layers to be precipitated are inert materials such as quartz, carbon (pyrographite), silicon carbide, highly refractory oxides. Further applicable are tungsten, tantalum or other metals of a sufliciently high melting point to remain stable at the reaction temperature.
  • the substrates may consist of the material to be precipitated or of materials having the same crystalline lattice structure and approximately the same lattice constant. The crystalline constitution of the precipitated layers largely depends upon the constitution of the substrate material.
  • Layers suitable for use in semiconductor devices may be produced by adding doping materials to the source material or to the reaction gas in the conventional manner.
  • the method according to the invention is favorably applicable for producing semiconductor circuit components such as transistors, rectifiers and the like, as well as for the production of symmetrically conducting circuit components such as ohmic resistors.
  • FIG. 1 shows schematically and in section an apparatus for performing the transport reaction by a sandwich method between two closely adjacent discs of crystalline material
  • FIG. 2 shows schematically and in section an apparatus for converting a polycrystalline material of low purity to a high-purity monocrystalline product.
  • the apparatus according to FIG. 1 comprises a reaction vessel 1 of quartz having a gas inlet and an outlet with respective valves 11 and 12. Mounted inside the vessel is an electric heater 2 whose terminals 3 are located outside of the reaction vessel for connection to a voltage source.
  • the heater may be formed of silicon-coated graphite, for example.
  • Placed on top of the heater 2 is a monocrystalline disc 4 of silicon to serve as source material.
  • a substrate disc 5 on top of the source disc 4 also consists of monocrystalline silicon.
  • the apparatus serves to produce a chemical transport reaction which removes material from the source disc 4 and precipitates it upon the adjacent surface of the substrate 5. An optimal distance between the disc 4 and 5 is secured by a spacer 6 of quartz or silicon.
  • the reaction gas containing iodine vapor, enters the reaction vessel 1 in the direction of the arrow 7 through the valve 11.
  • the iodine reacts with the silicon in accordance with the equation
  • the reaction gas leaves the vessel 1 through the outlet 8 and the valve 12, this being indicated by an arrow 9.
  • the outlet 8 is connected with a vacuum pump which is not illustrated.
  • a vacuum meter 10 is provided for measuring the total pressure inside the reaction vessel.
  • the source disc 4 is heated by means of the heater 2 to a temperature of about 1250 C.
  • the substrate 5, being heated by direct heat transfer from the source 4 is at an about 50 C. lower temperature than the source material.
  • the pressure in the reaction vessel is first set to a value of about torr. At this gas pressure there occurs an elimination of material from the substrate 5.
  • the surface of the substrate is cleaned from any impurities and liberated from any surface damage so that a particularly smooth surface will result.
  • the pressure in the reaction vessel is increased to about 150 torr. This causes the transport direction to reverse so that now semiconductor material from the more highly heated source plate 4 is eliminated and precipitates onto the surface of the substrate 5 where a thin monocrystalline layer is grown.
  • the source disc 4 and the substrate 5 may differ from each other with respect to doping.
  • a substrate 5 of p-type silicon may be provided with an epitaxial layer of n-type silicon, the source disc 4 in this case being n-type material.
  • the source disc and the substrate may also be chosen of material having the same type of conductance and either the same or respectively different electrical conductance values.
  • doping material may be added to the reaction gas serving as the transporting medium.
  • the crystalline discs 4 and 5 are preferably made of materials having the same conductivity (specific resistance).
  • the precipitation of material onto the substrate may be interrupted for a short interval of time, for example between the precipitation of the individual layers.
  • Such temporary interruption may be effected by reducing the total gas pressure in the reaction vessel below the critical value of about torr. At this pressure the transport of material from the source disc 4 to the substrate 5 will cease.
  • concentration of the doping material or by adding respectively different doping materials to the reaction gas layers of respectively different conductivity are produced.
  • the thickness of the individual layers can then be adjusted by correspondingly selecting the duration of the precipitating process.
  • a source 14 of halogen or halogenide it is preferable to heat a source 14 of halogen or halogenide to a different temperature.
  • the source 14 can be closed by means of a valve 13. In some cases it is necessary to also heat the other vessel walls in order to prevent condensation of the vapors at undesired localities.
  • the apparatus represented in FIG. 2 is particularly advantageous if a material of a relatively low purity, available for example in polycrystalline form, is to be precipitated in hyperpure and monocrystalline form.
  • thin layers of titanium can be produced in this manner.
  • the transportation of the titanium is likewise effected in the iodine system, using Til as reaction gas for example.
  • the gaseous TiI reacts with the titanium and forms Til; in accordance with the equation At a temperature of about 1250 C., there first occurs a removal of titanium under formation of Til the total pressure of the reaction gas in the reaction vessel being kept below a critical value of 20 torr, for example at 10 torr.
  • the pressure in the reaction vessel is increased to a value above approximately 50 torr.
  • Til is dissociated into Til and Ti, and the titanium simultaneously precipitates in solid constitution.
  • the precipitated layer grows in monocrystalline or polycrystalline form.
  • reaction vessel Used as reaction vessel is an elongated tube 21 of quartz having a gas inlet 22 at one end and a gas outlet 23 at the opposite end.
  • the tube is surrounded by two electric furnaces 24 and 25.
  • the furnace 24 and 25 are adjusted to respectively different temperatures.
  • a single furnace may also be used if it permits maintaining an adjustable temperature gradient.
  • the reaction gas, for example vaporous TiI is supplied in the direction of the arrow 26 through a valve 27.
  • the residual gases are withdrawn through the outlet 23 and a valve 28 in the direction of the arrow 29 by means of a vacuum pump (not illustrated).
  • the valves 27 and 28 permit closing and sealing the reaction vessel.
  • the gas pressure in the reaction vessel is measured by a manometer 30.
  • Lumps 31 of raw titanium, used as source material, are heated by furnace 24 to a temperature of about 1250 C.
  • the substrate 32 is maintained by means of the furnace 25 at a temperature about 40 C. lower than that of the source material.
  • the pressure of the reaction gas (T11 is adjusted to about 5 to 10 torr. At this gas pressure there occurs an elimination of material from the substrate 32 by transport-reaction etching.
  • the gas pressure in the reaction vessel is raised to above the critical pressure of about 20 torr (at 1250 C.), so that now the source material (raw titanium) 31 is converted to gaseous TiI
  • the source material (raw titanium) 31 is converted to gaseous TiI
  • the precipitating titanium forms a grown thin layer of crystalline or monocrystalline constitution.
  • the apparatus is to be equipped with an additional source of halogen or halogenide corresponding to the source 14 shown in FIG. 1.
  • the above-described process can be repeated several times so that the purity degree of the resulting titanium can be greatly increased in this manner.
  • various other materials can be processed by an analogous transport reaction, for example zirconium, vanadium, niobium, tantalum or copper.
  • the constitution of the precipitated layers greatly depends upon the crystalline constitution of the substrate being employed. That is, a monocrystalline substrate as a rule is required if the precipitated layer is to grow as a monocrystal.
  • said substrate is a monocrystal, and which comprises setting the total gas pressure in said vessel to a value below the critical pressure of the chemical transport system being used, maintaining the gas pressure at said subcritical value until a damage layer is removed from said substrate, and thereafter changing the total gas pressure to a supercritical value for growing an epitaxial layer on the substrate.
  • the method according to claim 10, which comprises heating and maintaining the silicon source plate at about 1250 C. and the substrate at about 1000 C., setting the total gas pressure to a low value which is less than the critical value of 85 torr to etch the substrate surface, and thereafter setting the total gas pressure to a high value above 85 torr for growing an epitaxial layer on the substrate.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Chemical Vapour Deposition (AREA)
US524303A 1965-02-05 1966-02-01 Gas etching followed by gas plating Expired - Lifetime US3460985A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES0095336 1965-02-05

Publications (1)

Publication Number Publication Date
US3460985A true US3460985A (en) 1969-08-12

Family

ID=7519299

Family Applications (1)

Application Number Title Priority Date Filing Date
US524303A Expired - Lifetime US3460985A (en) 1965-02-05 1966-02-01 Gas etching followed by gas plating

Country Status (7)

Country Link
US (1) US3460985A (de)
AT (1) AT257692B (de)
CH (1) CH480449A (de)
DE (1) DE1519865A1 (de)
GB (1) GB1077456A (de)
NL (1) NL6601478A (de)
SE (1) SE309576B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5108543A (en) * 1984-11-07 1992-04-28 Hitachi, Ltd. Method of surface treatment

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2195663B (en) * 1986-08-15 1990-08-22 Nippon Telegraph & Telephone Chemical vapour deposition method and apparatus therefor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3168422A (en) * 1960-05-09 1965-02-02 Merck & Co Inc Process of flushing unwanted residue from a vapor deposition system in which silicon is being deposited
US3316130A (en) * 1963-05-07 1967-04-25 Gen Electric Epitaxial growth of semiconductor devices

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3168422A (en) * 1960-05-09 1965-02-02 Merck & Co Inc Process of flushing unwanted residue from a vapor deposition system in which silicon is being deposited
US3316130A (en) * 1963-05-07 1967-04-25 Gen Electric Epitaxial growth of semiconductor devices

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5108543A (en) * 1984-11-07 1992-04-28 Hitachi, Ltd. Method of surface treatment

Also Published As

Publication number Publication date
GB1077456A (en) 1967-07-26
DE1519865A1 (de) 1970-02-26
CH480449A (de) 1969-10-31
NL6601478A (de) 1966-08-08
SE309576B (de) 1969-03-31
AT257692B (de) 1967-10-25

Similar Documents

Publication Publication Date Title
US3511727A (en) Vapor phase etching and polishing of semiconductors
Theuerer Epitaxial silicon films by the hydrogen reduction of SiCl4
US4504521A (en) LPCVD Deposition of tantalum silicide
JPS6364993A (ja) 元素半導体単結晶薄膜の成長方法
JPS6051847B2 (ja) 酸化層の形成方法
US3316130A (en) Epitaxial growth of semiconductor devices
US3476640A (en) Smooth surfaced polycrystals
US3140965A (en) Vapor deposition onto stacked semiconductor wafers followed by particular cooling
US3941647A (en) Method of producing epitaxially semiconductor layers
US3348984A (en) Method of growing doped crystalline layers of semiconductor material upon crystalline semiconductor bodies
US3460985A (en) Gas etching followed by gas plating
Minagwa et al. Epitaxial Growth of α-SiC from the Vapor Phase
JPS6255688B2 (de)
US3372671A (en) Apparatus for producing vapor growth of silicon crystals
US3926715A (en) Method of epitactic precipitation of inorganic material
US3574006A (en) Method of producing semiconductor layers by precipitation from the gaseous phase
US3235418A (en) Method for producing crystalline layers of high-boiling substances from the gaseous phase
US3341374A (en) Process of pyrolytically growing epitaxial semiconductor layers upon heated semiconductor substrates
US3428500A (en) Process of epitaxial deposition on one side of a substrate with simultaneous vapor etching of the opposite side
US3200001A (en) Method for producing extremely planar semiconductor surfaces
US3340110A (en) Method for producing semiconductor devices
JP3657036B2 (ja) 炭化ケイ素薄膜および炭化ケイ素薄膜積層基板の製造方法
US3290181A (en) Method of producing pure semiconductor material by chemical transport reaction using h2s/h2 system
US3271209A (en) Method of eliminating semiconductor material precipitated upon a heater in epitaxial production of semiconductor members
Bloem et al. Epitaxial Growth of Silicon by CVD in a Hot‐Wall Furnace