GB2079175A - Growing crystals - Google Patents

Growing crystals Download PDF

Info

Publication number
GB2079175A
GB2079175A GB8117039A GB8117039A GB2079175A GB 2079175 A GB2079175 A GB 2079175A GB 8117039 A GB8117039 A GB 8117039A GB 8117039 A GB8117039 A GB 8117039A GB 2079175 A GB2079175 A GB 2079175A
Authority
GB
United Kingdom
Prior art keywords
crystal
crystals
quartz
seed
grown
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.)
Granted
Application number
GB8117039A
Other versions
GB2079175B (en
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.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
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 General Electric Co PLC filed Critical General Electric Co PLC
Priority to GB8117039A priority Critical patent/GB2079175B/en
Publication of GB2079175A publication Critical patent/GB2079175A/en
Application granted granted Critical
Publication of GB2079175B publication Critical patent/GB2079175B/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
    • 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
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/18—Quartz

Abstract

According to this invention a process for forming a crystal of a substance comprises securing surfaces of two crystals (1) together with the axes of the crystals aligned and depositing said substance onto the joined crystals thereby causing them to grow into a single crystal substantially or entirely surrounding the registering regions (2) of said surfaces. A resultant crystal may be sectioned to provide large, single crystals (3) not containing a bonded region.

Description

SPECIFICATION An improved process for growing crystals This invention relates to processes for growing large, single crystals of substances of which suitably sized seed crystals are difficult to obtain.
The invention relates especially but not exclusively to the production of quartz crystals.
A demand exists, for certain filter applications, for a supply of long lengths (e.g. 30 cm.) of single crystal quartz. Natural crystals of good quality and of the required length suitable for use as seeds for synthetic crystals are scarce and expensive.
Moreover since quartz has the property that overgrowth on a seed crystal is always of a shorter dimension than the seed, the lengths of quartz crystals produced synthetically by existing techniques have been limited.
According to this invention a process for forming a crystal of a substance comprises the steps of securing a crystal face of a first seed crystal to the crystal face of a second seed crystal with the axes of the two crystals aligned and depositing the said substance onto the joined crystals thereby causing them to grow into a single crystal substantially or entirely enclosing the registering regions of said crystal faces.
Large single crystals of substances may be grown by this process. A resultant crystal may be sectioned to provide large, single crystals not containing a bonded region.
The process may be modified so that a multiplicity of suitably aligned seed crystals may be bonded together and grown into a single crystal.
The bonding material preferably comprises a metal having the property that two layers of the metal each deposited onto a surface of a respective crystal may be fused together by heating the layers while pressed together.
The metal used for bonding seed crystals is preferably gold.
The invention may be better understood from the following example of an embodiment in accordance with the invention with reference to Figures 1 and 2 of the accompanying drawings.
Figure 1 shows two quartz seed crystals bonded together for use in growing a crystal according to the invention, and Figure 2 shows the crystals iilustrated in Figure 1 after they have been grown into a single crystal.
With reference to Figure 1 , two quartz seed crystals 1 are bonded together as follows. The portion of each crystal which is to be bonded to the other is coated to a thickness of 200 Angstroms with a nickel-chromium alloy by vapour deposition of the latter onto the said portion. The coating of nickel-chromium alloy provides a firm foundation for a layer of gold 2 which is evaporated onto the nickel-chromium layer to a depth of 2000 Angstroms and then electroplated to a thickness of 10 to 1 5 microns.
The two crystals 1 are clamped together with the gold plated regions pressed together under a pressure of 100 pounds per square inch with the axes of the crystals aligned. The assembly is placed in a furnace and heated to 3000C for 2 hours. The gold layers fuse together at this temperature thereby bonding the crystals.
Subsequent overgrowth of the joined crystals in an autoclave in a 3 molar solution of sodium hydroxide saturated with respect to SiO2 as used in growing quartz crystals by existing techniques, at a temperature of 300-4000C (preferably 3500C, with a temperature gradient of 500 C) and a pressure of between 1000 and 2000 atmospheres (preferably approximately 1000 atmospheres) for six weeks produces a single large quartz crystal as shown in Figure 2. Such a crystal has a greater overall length than a crystal grown from a single seed. Quartz wafers with a correspondingly greater length may be cut from such a crystal e.g. as shown at 3. Alternatively a crystal produced by a method according to the invention may be cut so that the metal bonding layer 2 is retained in the crystal.Quartz crystals containing an almost completely embedded metal strip to which electrical contact can be made have applications as resonators.
This invention includes crystals grown by a method according to the invention.
1. A process for forming a crystal of a substance comprising the steps of securing a face of a first seed crystal to the face of a second seed crystal with the axes of the two crystals aligned and depositing the said substance onto the joined crystals thereby causing them to grow into a single crystal substantially or entirely enclosing the registering regions of said crystal faces.
2. A process according to Claim 1 in which the said faces are directly secured to each other by a bonding material.
3. A process according to Claim 2 in which the bonding material comprises a metal or alloy.
4. A process according to Claim 3 in which the bonding of the crystals is effected by depositing a layer of the said metal or alloy on to a region of a surface of each said crystal, pressing the two deposited layers together and heating to fuse the two layers and form a bond between them.
5. A process according to Claim 3 or Claim 4 in which the metal or alloy is deposited onto the said faces by vapour deposition.
6. A process according to Claim 4 in which a layer of gold is deposited onto a layer of nickel chromium alloy initially deposited onto the said faces.
7. A process according to any preceding claim in which the said faces overlap.
8. A process according to any preceding claim in which a multiplicity of seed crystals are facially secured to one another.
9. A crystal grown by a method according to any preceding claim.
10. A quartz crystal grown by a method according to any of Claims 1 to 8.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An improved process for growing crystals This invention relates to processes for growing large, single crystals of substances of which suitably sized seed crystals are difficult to obtain. The invention relates especially but not exclusively to the production of quartz crystals. A demand exists, for certain filter applications, for a supply of long lengths (e.g. 30 cm.) of single crystal quartz. Natural crystals of good quality and of the required length suitable for use as seeds for synthetic crystals are scarce and expensive. Moreover since quartz has the property that overgrowth on a seed crystal is always of a shorter dimension than the seed, the lengths of quartz crystals produced synthetically by existing techniques have been limited. According to this invention a process for forming a crystal of a substance comprises the steps of securing a crystal face of a first seed crystal to the crystal face of a second seed crystal with the axes of the two crystals aligned and depositing the said substance onto the joined crystals thereby causing them to grow into a single crystal substantially or entirely enclosing the registering regions of said crystal faces. Large single crystals of substances may be grown by this process. A resultant crystal may be sectioned to provide large, single crystals not containing a bonded region. The process may be modified so that a multiplicity of suitably aligned seed crystals may be bonded together and grown into a single crystal. The bonding material preferably comprises a metal having the property that two layers of the metal each deposited onto a surface of a respective crystal may be fused together by heating the layers while pressed together. The metal used for bonding seed crystals is preferably gold. The invention may be better understood from the following example of an embodiment in accordance with the invention with reference to Figures 1 and 2 of the accompanying drawings. Figure 1 shows two quartz seed crystals bonded together for use in growing a crystal according to the invention, and Figure 2 shows the crystals iilustrated in Figure 1 after they have been grown into a single crystal. With reference to Figure 1 , two quartz seed crystals 1 are bonded together as follows. The portion of each crystal which is to be bonded to the other is coated to a thickness of 200 Angstroms with a nickel-chromium alloy by vapour deposition of the latter onto the said portion. The coating of nickel-chromium alloy provides a firm foundation for a layer of gold 2 which is evaporated onto the nickel-chromium layer to a depth of 2000 Angstroms and then electroplated to a thickness of 10 to 1 5 microns. The two crystals 1 are clamped together with the gold plated regions pressed together under a pressure of 100 pounds per square inch with the axes of the crystals aligned. The assembly is placed in a furnace and heated to 3000C for 2 hours. The gold layers fuse together at this temperature thereby bonding the crystals. Subsequent overgrowth of the joined crystals in an autoclave in a 3 molar solution of sodium hydroxide saturated with respect to SiO2 as used in growing quartz crystals by existing techniques, at a temperature of 300-4000C (preferably 3500C, with a temperature gradient of 500 C) and a pressure of between 1000 and 2000 atmospheres (preferably approximately 1000 atmospheres) for six weeks produces a single large quartz crystal as shown in Figure 2. Such a crystal has a greater overall length than a crystal grown from a single seed. Quartz wafers with a correspondingly greater length may be cut from such a crystal e.g. as shown at 3. Alternatively a crystal produced by a method according to the invention may be cut so that the metal bonding layer 2 is retained in the crystal.Quartz crystals containing an almost completely embedded metal strip to which electrical contact can be made have applications as resonators. This invention includes crystals grown by a method according to the invention. CLAIMS
1. A process for forming a crystal of a substance comprising the steps of securing a face of a first seed crystal to the face of a second seed crystal with the axes of the two crystals aligned and depositing the said substance onto the joined crystals thereby causing them to grow into a single crystal substantially or entirely enclosing the registering regions of said crystal faces.
2. A process according to Claim 1 in which the said faces are directly secured to each other by a bonding material.
3. A process according to Claim 2 in which the bonding material comprises a metal or alloy.
4. A process according to Claim 3 in which the bonding of the crystals is effected by depositing a layer of the said metal or alloy on to a region of a surface of each said crystal, pressing the two deposited layers together and heating to fuse the two layers and form a bond between them.
5. A process according to Claim 3 or Claim 4 in which the metal or alloy is deposited onto the said faces by vapour deposition.
6. A process according to Claim 4 in which a layer of gold is deposited onto a layer of nickel chromium alloy initially deposited onto the said faces.
7. A process according to any preceding claim in which the said faces overlap.
8. A process according to any preceding claim in which a multiplicity of seed crystals are facially secured to one another.
9. A crystal grown by a method according to any preceding claim.
10. A quartz crystal grown by a method according to any of Claims 1 to 8.
11. A quartz crystal grown by a method according to any of Claims 1 to 8 at a temperature of 300 to 4000C and a pressure of between 1000 and 2000 atmospheres.
12. A quartz crystal containing a partially embedded metal strip grown by a method according to any of Claims 3 to 6.
13. A crystal grown by a method according to any of Claims 2 to 8 substantially as shown in Figure 2 of the accompanying drawings.
14. A method of growing a quartz crystal carried out substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
GB8117039A 1980-06-26 1981-06-03 Growing crystals Expired GB2079175B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8117039A GB2079175B (en) 1980-06-26 1981-06-03 Growing crystals

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8021023 1980-06-26
GB8117039A GB2079175B (en) 1980-06-26 1981-06-03 Growing crystals

Publications (2)

Publication Number Publication Date
GB2079175A true GB2079175A (en) 1982-01-20
GB2079175B GB2079175B (en) 1983-12-07

Family

ID=26276013

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8117039A Expired GB2079175B (en) 1980-06-26 1981-06-03 Growing crystals

Country Status (1)

Country Link
GB (1) GB2079175B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4475980A (en) * 1982-06-01 1984-10-09 United Technologies Corporation Solid state production of multiple single crystal articles
EP0515288A1 (en) * 1991-05-24 1992-11-25 France Telecom Process for the hydrothermal growth of crystals using seeds obtained by assembling flat sheets
US5205872A (en) * 1988-12-10 1993-04-27 Kawasaki Steel Corporation Method of producing crystal bodies having controlled crystalline orientation

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4475980A (en) * 1982-06-01 1984-10-09 United Technologies Corporation Solid state production of multiple single crystal articles
US5205872A (en) * 1988-12-10 1993-04-27 Kawasaki Steel Corporation Method of producing crystal bodies having controlled crystalline orientation
US5487794A (en) * 1988-12-10 1996-01-30 Kawasaki Steel Corporation Method of producing crystal bodies having controlled crystalline orientation
EP0515288A1 (en) * 1991-05-24 1992-11-25 France Telecom Process for the hydrothermal growth of crystals using seeds obtained by assembling flat sheets
FR2676753A1 (en) * 1991-05-24 1992-11-27 France Telecom METHOD FOR INCREASING THE DIMENSIONS OF CRYSTALS THAT CAN BE DETERMINED BY HYDROTHERMAL GROWTH, USING A GERM OBTAINED BY ASSEMBLING CRYSTALLINE BLADES.
US5377615A (en) * 1991-05-24 1995-01-03 France Telecom Process for increasing the dimensions of crystals which can be produced by hydrothermal growth, using a seed obtained by crystalline plate assembly

Also Published As

Publication number Publication date
GB2079175B (en) 1983-12-07

Similar Documents

Publication Publication Date Title
US3206698A (en) Electro-mechanical delay line having ferroelectric transducer bonded to solid delay medium
US3590467A (en) Method for bonding a crystal to a solid delay medium
DE2951470A1 (en) ACOUSTIC SURFACE WAVES (AOFW) - PRESSURE SENSORS AND ASSOCIATED CONSTRUCTION
KR20010021494A (en) Thermal mismatch compensation to produce free standing substrates by epitaxial deposition
US4018374A (en) Method for forming a bond between sapphire and glass
FR2395327A1 (en) METHOD OF APPLYING A DEPOSIT ON A GRAPHITE BODY AND DEVICE INTENDED FOR IMPLEMENTING THIS PROCESS
US4381214A (en) Process for growing crystals
US4278195A (en) Method for low temperature bonding of silicon and silicon on sapphire and spinel to nickel and nickel steel and apparatus using such _a bonding technique
US4645117A (en) Bonding metal to ceramic
JPH03274271A (en) Thin diamond film-coated member
GB2079175A (en) Growing crystals
US4073675A (en) Waveguiding epitaxial LiNbO3 films
JPS6129920B2 (en)
JPS61151097A (en) Production of diamond thin film with smooth surface
JPH03286522A (en) Growth method of si crystal
US4191788A (en) Method to reduce breakage of V-grooved <100> silicon substrate
US4869420A (en) Method of diffusion bonding and densifying material of a heater element for an electron beam tube
JPS61159124A (en) Production of temperature sensor
US4851057A (en) Method of diffusion bonding and densifying material
WO1987004854A3 (en) Liquid epitaxial process for producing three-dimensional semiconductor structures
FR2840730A1 (en) Monocrystalline semiconductor substrate manufacturing method for laser diode, involves forming nucleation layer that acts as barrier for diffusion of thermally dissociated elements from gallium arsenide intermediate support
JPS60180886A (en) Pattern-transferring method
SU1137092A1 (en) Method for connecting ceramics with metal
US4717067A (en) Diffusion bonded structure and method of making
RU2068026C1 (en) Method to produce oriented monocrystalline films of magnetic materials

Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee