WO2004030046A1 - Method of producing lithium tantalate substrate for surface acoustic wave element - Google Patents

Method of producing lithium tantalate substrate for surface acoustic wave element Download PDF

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Publication number
WO2004030046A1
WO2004030046A1 PCT/KR2003/001958 KR0301958W WO2004030046A1 WO 2004030046 A1 WO2004030046 A1 WO 2004030046A1 KR 0301958 W KR0301958 W KR 0301958W WO 2004030046 A1 WO2004030046 A1 WO 2004030046A1
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Prior art keywords
lithium tantalate
substrate
single crystal
tantalate single
reduction
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Application number
PCT/KR2003/001958
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French (fr)
Inventor
Soo-Byong Chea
Yoon-Seong Kim
Han-Gyun Kim
Jin-Ki Kang
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Iljin Diamond Co., Ltd.
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Priority to JP2004539629A priority Critical patent/JP2005535555A/en
Priority to AU2003267833A priority patent/AU2003267833A1/en
Publication of WO2004030046A1 publication Critical patent/WO2004030046A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/08—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of resonators or networks using surface acoustic waves
    • 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
    • C30B29/22—Complex oxides
    • C30B29/30—Niobates; Vanadates; Tantalates
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02818—Means for compensation or elimination of undesirable effects
    • H03H9/02921—Measures for preventing electric discharge due to pyroelectricity

Definitions

  • the present invention relates to a method of producing a lithium tantalate single crystal substrate, and more particularly, to a method of producing a lithium tantalate single crystal substrate for a surface acoustic wave element, which is removed static electricity of the substrate surface by increasing an electric conductivity of the single crystal substrate from reduction of the lithium tantalate single crystal substrate above a
  • a lithium tantalate single crystal is widely used in a variety of a surface acoustic wave signal processing device, an infrared sensor, an optical switching device, an optical memory, and etc because the lithium tantalate single crystal has excellent piezoelectric
  • the process for producing the surface acoustic wave device has some problems including a spark generation by discharging static charge which is charged at both lateral surfaces of the lithium tantalate substrate. This phenomenon is caused by a superconductivity of the lithium tantalate.
  • the lithium tantalate which is an electrical insulating material, it needs a lot of time to be an electrical neutral state by moving of the static charge on the surface ofthe lithium tantalate.
  • a spark may be easily generated by discharging the static charge.
  • the static electricity by the static charge of the lithium tantalate substrate may cause mal-operation of a manufacturing apparatus for a surface acoustic wave device and the substrate is strongly attached to the manufacturing apparatus so that the substrate may be damaged because of a mechanical stress, thereby lowering a working stability.
  • a spark generated by discharging of the static charge attached on the substrate may damage the substrate or the device formed on the substrate or at the substrate, furthermore, may cause failure of an apparatus for manufacturing the device by an electric shock.
  • a signal line width of the device is decreased from several tens micro-meters to several micro-meters.
  • the signal line having a fine width is disconnected by small amount of discharge generated by a local static charge difference of the substrate surface, thereby shortening a device life-span.
  • a method for manufacturing a device on a substrate is used after forming a conducting metal film on an opposite side of a device manufacturing side ofthe substrate and removing a static electricity by grounding or after discharging for long time by electrical connecting of the both sides of the substrate.
  • the method needs additional steps for forming the conducting metal film and removing the conducting metal film after manufacturing the device or increases a manufacturing cost due to increase ofthe processing time. Further, even if the method is used, the shortening of the device life-span caused by small amount of discharge generated by a local static charge difference on the substrate surface cannot be effectively solved.
  • a process for improving a static electricity characteristic of the substrate includes a step of rapidly moving static charge on a substrate by increasing an electric conductivity of a lithium tantalate single crystal substrate which is polarized.
  • a representative example is disclosed in US Patent No. 6,319,430 Bl. Referring to US Patent No. 6,319,430 Bl, a lithium niobate or lithium tantalate substrate is heated up to under a Curie temperature for maintaining a poling state and reduced, so that an electric conductivity of the single crystal substrate is increased. When the lithium niobate or lithium tantalate substrate is reduced under a reduction atmosphere, an electric conductivity is increased because an electronic density is increased due to variation of an oxidation state.
  • a method of producing a lithium tantalate single crystal substrate for a surface acoustic wave device which includes the steps of: reducing a lithium tantalate single crystal ingot or substrate by heating above a
  • Tc Curie temperature ofthe lithium tantalate single crystal ingot or substrate under a reduction atmosphere; poling treatment of the lithium tantalate single crystal ingot or substrate under a reduction atmosphere or an inert atmosphere; and producing the surface acoustic wave device substrate by processing the lithium tantalate single crystal ingot or substrate.
  • a volume specific resistance ofthe reduced lithium tantalate single crystal ingot or substrate is preferably about 10 -10 ⁇ • cm.
  • the conventional reduction method cannot be effectively used. Further, a reduction rate of the conventional method is low, as well as it is very difficult to obtain a lithium tantalate single crystal having a volume specific resistance below about
  • the reduction rate of the lithium tantalate single crystal is rapidly increased and the poling state is also maintained.
  • a conventional poling process is performed by increasing a reaction temperature above a Curie temperature under an air atmosphere and applying an electric field on both sides of the single crystal substrate.
  • the poling treatment is performed under a reduction atmosphere or at least an inert atmosphere to increase a reduction rate and to maintain the poling state because a reduction state is removed by a re-oxidation reaction when the poling treatment of the reduced lithium tantalate is performed by a heat treatment under an air atmosphere like the conventional process.
  • the reduction temperature is preferably over about 605 ° C which is a Curie temperature of lithium tantalate and under about 1650 °C which is a melting point of lithium tantalate.
  • a reduction atmosphere for a reduction heat treatment or a poling treatment is controlled by at least one of a gas and a solid selected from a group consisting of a reduction gas, such as hydrogen, carbon monoxide, steam, and the like, or a reduction solid, such as a graphite, a carbon black, and the like.
  • an inert atmosphere is controlled by an inert gas including nitrogen and argon, or vacuum.
  • a variation of an electric conductivity of the reduced lithium tantalate single crystal can be known by measuring a volume specific resistance by using a high resistance meter.
  • the volume specific resistance of a non-reduced lithium tantalate single crystal is about 10 14 to about 10 15 ⁇ • cm and the volume specific resistance is decreased as increasing of a degree of reduction.
  • the volume specific resistance is below about 10 ⁇ ⁇ • cm to be free from static electricity at a surface of a lithium tantalate substrate.
  • the volume specific resistance is preferably below about 10 10 ⁇ • cm. If the volume specific resistance is below about 10 8 ⁇ • cm, a mechanical strength of the lithium tantalate single crystal is weakened, therefore a bottom limit of the volume specific resistance is preferably above about 10 ⁇ • cm.
  • a color ofthe single crystal is changed into dark gray or black, and the black color is much darker with increasing of a reduction degree.
  • Table 1 shows volume specific resistances measured by a high resistance meter for lithium tantalate substrates reduced by using hydrogen as a reducing agent below a Curie temperature after performing a poling treatment like a conventional treatment. [Table 1 ]
  • Table 2 shows volume specific resistances measured by a high resistance meter for non-polarized lithium tantalate single crystal ingots or substrates reduced by using hydrogen as a reducing gas above a Curie temperature.
  • the reduction period to have a volume specific resistance of about - cm (which is a level for removing specific electricity) for the lithium tantalate substrate was shorter than the reduction period ofthe Comparative Example.
  • the lithium tantalate ingot or substrate according to an embodiment ofthe present invention is processed to produce a substrate for a surface acoustic wave device by using a general process which is easily known for one skilled in the art.
  • the surface acoustic wave device has an excellent specific resistance characteristic and is not affected from static electricity by the poling treatment process so that the life-shortening phenomenon ofthe surface acoustic wave device is reduced.
  • a working hour is reduced compared to a conventional process because a reduction time is decreased.
  • the lithium tantalate single crystal has an excellent electric conductivity or a volume specific resistance.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

A method of producing a lithium tantalate single crystal substrate for a surface acoustic wave device is provided which includes the steps of: reducing a lithium tantalate single crystal ingot or substrate by heating above a Curie temperature (Tc) of the lithium tantalate single crystal ingot or substrate under a reduction atmosphere; poling treatment of the lithium tantalate single crystal ingot or substrate under a reduction atmosphere or an inert atmosphere; and producing the surface acoustic wave device substrate by processing the lithium tantalate single crystal ingot or substrate. A working hour of the present method is decreased compared to a conventional process because a reduction time is decreased. Further, the lithium tantalate single crystal has an excellent electric conductivity or volume specific resistance. Advantageously, the static electricity generated by super-conductance of the lithium tantalate is rapidly removed and working instability caused by the static electricity during a manufacturing process for a surface acoustic device can be reduced.

Description

METHOD OF PRODUCING LITHIUM TANTALATE SUBSTRATE FOR SURFACE ACOUSTIC WAVE ELEMENT
TECHNICAL FIELD The present invention relates to a method of producing a lithium tantalate single crystal substrate, and more particularly, to a method of producing a lithium tantalate single crystal substrate for a surface acoustic wave element, which is removed static electricity of the substrate surface by increasing an electric conductivity of the single crystal substrate from reduction of the lithium tantalate single crystal substrate above a
Curie temperature ofthe single crystal substrate.
BACKGROUND ART
A lithium tantalate single crystal is widely used in a variety of a surface acoustic wave signal processing device, an infrared sensor, an optical switching device, an optical memory, and etc because the lithium tantalate single crystal has excellent piezoelectric
and electrical-optical characteristics.
However, in case of a poling treatment process for using the lithium tantalate single crystal as a substrate of a surface acoustic wave device, the process for producing the surface acoustic wave device has some problems including a spark generation by discharging static charge which is charged at both lateral surfaces of the lithium tantalate substrate. This phenomenon is caused by a superconductivity of the lithium tantalate. Generally, in case of the lithium tantalate which is an electrical insulating material, it needs a lot of time to be an electrical neutral state by moving of the static charge on the surface ofthe lithium tantalate. In contrast, in a condition of rapid temperature variation e.g., a process of producing a surface acoustic wave device, a spark may be easily generated by discharging the static charge. The static electricity by the static charge of the lithium tantalate substrate may cause mal-operation of a manufacturing apparatus for a surface acoustic wave device and the substrate is strongly attached to the manufacturing apparatus so that the substrate may be damaged because of a mechanical stress, thereby lowering a working stability.
Further, in case that a temperature of the substrate is rapidly varied during forming a device on the lithium tantalate substrate, a spark generated by discharging of the static charge attached on the substrate may damage the substrate or the device formed on the substrate or at the substrate, furthermore, may cause failure of an apparatus for manufacturing the device by an electric shock.
In addition, as a frequency range for the device is increased to a high frequency, a signal line width of the device is decreased from several tens micro-meters to several micro-meters. Thus, the signal line having a fine width is disconnected by small amount of discharge generated by a local static charge difference of the substrate surface, thereby shortening a device life-span.
To solve the above described problems, a method for manufacturing a device on a substrate is used after forming a conducting metal film on an opposite side of a device manufacturing side ofthe substrate and removing a static electricity by grounding or after discharging for long time by electrical connecting of the both sides of the substrate. However, the method needs additional steps for forming the conducting metal film and removing the conducting metal film after manufacturing the device or increases a manufacturing cost due to increase ofthe processing time. Further, even if the method is used, the shortening of the device life-span caused by small amount of discharge generated by a local static charge difference on the substrate surface cannot be effectively solved.
To solve those problems, a process for improving a static electricity characteristic of the substrate is disclosed, which includes a step of rapidly moving static charge on a substrate by increasing an electric conductivity of a lithium tantalate single crystal substrate which is polarized. A representative example is disclosed in US Patent No. 6,319,430 Bl. Referring to US Patent No. 6,319,430 Bl, a lithium niobate or lithium tantalate substrate is heated up to under a Curie temperature for maintaining a poling state and reduced, so that an electric conductivity of the single crystal substrate is increased. When the lithium niobate or lithium tantalate substrate is reduced under a reduction atmosphere, an electric conductivity is increased because an electronic density is increased due to variation of an oxidation state.
However, as a reduction rate of the lithium tantalate is rapidly increased as increasing of the processing temperature, in case of the lithium tantalate which has a lower Curie temperature (about 605 °C), a reaction rate is too slow to manufacture to a commercial product. Referring to US Patent No. 6,319,430 Bl, it requires very long time which is difficult to apply for manufacturing a commercial product, or it requires a very expensive equipment to obtain a satisfactory static electric characteristic for the lithium tantalate single crystal substrate.
DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to improve a static electricity characteristic of a lithium tantalate single crystal substrate for a surface acoustic wave element by a poling treatment of the lithium tantalate single crystal substrate under a reduction atmosphere or an inert atmosphere after reduction above a Curie temperature of lithium tantalate.
These and other objects, advantages and features ofthe present invention are provided by a method of producing a lithium tantalate single crystal substrate for a surface acoustic wave device, which includes the steps of: reducing a lithium tantalate single crystal ingot or substrate by heating above a
Curie temperature (Tc) ofthe lithium tantalate single crystal ingot or substrate under a reduction atmosphere; poling treatment of the lithium tantalate single crystal ingot or substrate under a reduction atmosphere or an inert atmosphere; and producing the surface acoustic wave device substrate by processing the lithium tantalate single crystal ingot or substrate.
A volume specific resistance ofthe reduced lithium tantalate single crystal ingot or substrate is preferably about 10 -10 Ω • cm.
BEST MODE FOR CARRYING OUT THE INVENTION
A reduction rate of a lithium tantalate is rapidly increased with increasing of a reaction temperature. However, as described above, a conventional reduction temperature is maintained below a Curie temperature for maintaining a poling state of a lithium tantalate single crystal. A poling treatment process involves exposing a material to high temperature while imposing a high electric filed intensity in a desired direction to align all poles formed at a single crystal in the desired direction. The poling treatment process includes the steps of: coating with electrodes at both sides of the single crystal according to a poling direction; de-poling by heating and maintaining at a given period above a Curie temperature; and cooling below the Curie temperature after forming electric field by applying a direct current (DC) voltage to the electrodes. According to an embodiment of the present invention, so called voluntary poles are formed by cooling below the Curie temperature, and the voluntary poles are aligned in one direction by the DC electric field applied to the single crystal.
However, as the poling state is not maintained above the Curie temperature which is a changing point of a single crystal structure, a conventional reduction temperature is controlled below the Curie temperature. That is, the reduction is performed under assuming that the poling treatment is performed. Therefore, while a lithium niobate single crystal (Tc= about 1140 °C), which has a higher reduction rate at a poling state because of relatively a higher Curie temperature, is widely commercially used. However, for the lithium tantalate single crystal having a lower reduction rate because of relatively a lower
Curie temperature, the conventional reduction method cannot be effectively used. Further, a reduction rate of the conventional method is low, as well as it is very difficult to obtain a lithium tantalate single crystal having a volume specific resistance below about
10nΩ - cm which is a removal level of a static electricity at a surface of the lithium tantalate substrate.
According to an embodiment ofthe present invention, if a reduction is performed under a reduction atmosphere having a high temperature sufficient to have a reduction rate and a poling treatment is performed under a reduction atmosphere or an inert atmosphere to be in the reduction state, the reduction rate of the lithium tantalate single crystal is rapidly increased and the poling state is also maintained.
Further, a conventional poling process is performed by increasing a reaction temperature above a Curie temperature under an air atmosphere and applying an electric field on both sides of the single crystal substrate. Instead, according to an embodiment of the present invention, the poling treatment is performed under a reduction atmosphere or at least an inert atmosphere to increase a reduction rate and to maintain the poling state because a reduction state is removed by a re-oxidation reaction when the poling treatment of the reduced lithium tantalate is performed by a heat treatment under an air atmosphere like the conventional process.
According to an embodiment of the present invention, the reduction temperature is preferably over about 605 °C which is a Curie temperature of lithium tantalate and under about 1650 °C which is a melting point of lithium tantalate. A reduction atmosphere for a reduction heat treatment or a poling treatment is controlled by at least one of a gas and a solid selected from a group consisting of a reduction gas, such as hydrogen, carbon monoxide, steam, and the like, or a reduction solid, such as a graphite, a carbon black, and the like.
Further, an inert atmosphere is controlled by an inert gas including nitrogen and argon, or vacuum.
A variation of an electric conductivity of the reduced lithium tantalate single crystal can be known by measuring a volume specific resistance by using a high resistance meter. The volume specific resistance of a non-reduced lithium tantalate single crystal is about 1014 to about 1015Ω • cm and the volume specific resistance is decreased as increasing of a degree of reduction. According to an embodiment of the present invention, the volume specific resistance is below about 10πΩ • cm to be free from static electricity at a surface of a lithium tantalate substrate. The volume specific resistance is preferably below about 1010Ω • cm. If the volume specific resistance is below about 108Ω • cm, a mechanical strength of the lithium tantalate single crystal is weakened, therefore a bottom limit of the volume specific resistance is preferably above about 10 Ω • cm.
Further, with increasing of a reduction degree of the lithium tantalate single crystal, a color ofthe single crystal is changed into dark gray or black, and the black color is much darker with increasing of a reduction degree.
Comparative Example I:
Table 1 shows volume specific resistances measured by a high resistance meter for lithium tantalate substrates reduced by using hydrogen as a reducing agent below a Curie temperature after performing a poling treatment like a conventional treatment. [Table 1 ]
Figure imgf000008_0001
As shown in Table 1, it is difficult to obtain a lithium tantalate substrate having a volume specific resistance under 10πΩ • cm which is a removal level of static electricity even if it is reduced by a heat treatment for over about 72 hours. Further, in case of reduction at a temperature below about 550 °C, a decrease of the volume specific resistance is small, thus it has some problems such as partially removing of the poling state as shown in case of No. 8 of Table 1 which shows a closer volume specific resistance of about 10πΩ • cm. Example I :
Table 2 shows volume specific resistances measured by a high resistance meter for non-polarized lithium tantalate single crystal ingots or substrates reduced by using hydrogen as a reducing gas above a Curie temperature. [Table 2]
Figure imgf000009_0001
As shown in Table 2, the reduction period to have a volume specific resistance of about - cm (which is a level for removing specific electricity) for the lithium tantalate substrate was shorter than the reduction period ofthe Comparative Example.
Further, as the reduction temperature was increased, the reduction period was shorter and the volume specific resistance was smaller. Comparative Example II and Example II:
When a poling treatment process ofthe reduced ingot or substrate is performed under air atmosphere like a conventional poling treatment process, a re-oxidation reaction is occurred during a short period and a volume specific resistance is rapidly increased. As shown in Table 3, even if a reduction is performed over a Curie temperature like a Comparative Example II, in case that a poling treatment process is performed under air atmosphere, a volume specific resistance is rapidly increased. In contrast, as described in Example II, in case that a poling treatment process is performed under a reduction atmosphere like hydrogen or an inert atmosphere like nitrogen, a volume specific resistance is substantially the same as the volume specific resistance before the poling treatment process. According to an embodiment ofthe present invention, the poling treatment process can be performed under vacuum. [Table 3]
Figure imgf000010_0001
The lithium tantalate ingot or substrate according to an embodiment ofthe present invention is processed to produce a substrate for a surface acoustic wave device by using a general process which is easily known for one skilled in the art. The surface acoustic wave device has an excellent specific resistance characteristic and is not affected from static electricity by the poling treatment process so that the life-shortening phenomenon ofthe surface acoustic wave device is reduced.
According to an embodiment ofthe present invention, the present method can be independently applied to an existing lithium tantalate single crystal or substrate.
Especially, the present method can be applied to a step of cooling to a normal temperature after growing the lithium tantalate single crystal among the step of producing the lithium tantalate single crystal. That is, after growing the lithium tantalate single crystal around a melting point ofthe lithium tantalate, if an inside of a crystal growing furnace is controlled to be a reduction atmosphere during cooling to a normal temperature and the furnace is maintained with the conditions such as a temperature and a reaction time as mentioned in the Example, a reduced lithium tantalate single crystal ingot can be obtained.
Although the present invention has been described herein, it is to be understood that the present invention is not limited to those precise embodiments, and various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit. It will be apparent to one of ordinary skill in the art that modifications of the described embodiment may be made without departing from the spirit and scope of the invention. All such changes and modifications are intended to be included within the scope ofthe invention as defined by the appended claims. INDUSTRIAL APPLICABILITY
According to an embodiment of the present invention for producing a lithium tantalate single crystal substrate for a surface acoustic wave device, a working hour is reduced compared to a conventional process because a reduction time is decreased. Further, the lithium tantalate single crystal has an excellent electric conductivity or a volume specific resistance.
Advantageously, the static electricity generated by super-conductance of the lithium tantalate is rapidly removed and working instability caused by the static electricity during a manufacturing process for a surface acoustic wave device can be reduced.

Claims

What is claimed is:
1. A method of producing a lithium tantalate single crystal substrate for a surface acoustic wave device, the method comprising the steps of: reducing a lithium tantalate single crystal ingot or substrate by heating above a Curie temperature (Tc) ofthe lithium tantalate single crystal ingot or substrate under a reduction atmosphere; poling treatment of the lithium tantalate single crystal ingot or substrate under a reduction atmosphere or an inert atmosphere; and producing the surface acoustic wave device substrate by processing the lithium tantalate single crystal ingot or substrate.
2. The method of claim 1, wherein the reduced lithium tantalate single crystal ingot or substrate has a volume specific resistance of about 108 Ω • cm to about
10πΩ • cm.
3. The method of claim 1, wherein the reduction atmosphere comprises at least one of a gas and a solid selected from the group consisting of: a reduction gas including hydrogen, carbon monoxide, and steam; a reduction solid including a graphite and a carbon black.
4. The method of claim 1, wherein the inert atmosphere is formed by: an inert gas including nitrogen and argon; or vacuum.
PCT/KR2003/001958 2002-09-25 2003-09-25 Method of producing lithium tantalate substrate for surface acoustic wave element WO2004030046A1 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6932957B2 (en) 2002-06-28 2005-08-23 Silicon Light Machines Corporation Method and apparatus for increasing bulk conductivity of a ferroelectric material
US7153487B2 (en) 2004-05-25 2006-12-26 Crystal Technology, Inc. Using condensed chemicals to precondition lithium niobate and lithium tantalate crystals
US7309392B2 (en) 2003-11-25 2007-12-18 Sumitomo Metal Mining Co., Ltd. Lithium niobate substrate and method of producing the same
US7728697B2 (en) 2006-09-26 2010-06-01 Mg Materials Corporation Systems and methods for electrically reducing ferroelectric materials to increase bulk conductivity
CN108624961A (en) * 2018-05-29 2018-10-09 中国电子科技集团公司第二十六研究所 A kind of recycling method of lithium tantalate black-film

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100651760B1 (en) * 2004-05-14 2006-12-01 일진디스플레이(주) Method of producing lithium tantalate substrate for surface acoustic wave element and the substrate the same
JP7099203B2 (en) * 2018-09-06 2022-07-12 住友金属鉱山株式会社 Manufacturing method of lithium tantalate substrate
JPWO2022176689A1 (en) * 2021-02-19 2022-08-25

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5359452A (en) * 1992-04-24 1994-10-25 Hitachi Metals, Ltd. Lithium tantalate monocrystal, monocrystal substrate, and photo element
JPH10270977A (en) * 1997-03-21 1998-10-09 Mitsubishi Materials Corp Surface acoustic wave element
JP2000315928A (en) * 1999-04-28 2000-11-14 Murata Mfg Co Ltd Manufacture of surface wave element and manufacture of surface wave unit
JP2002226299A (en) * 2000-12-01 2002-08-14 Toshiba Corp Apparatus and method for manufacturing single crystal

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60246299A (en) * 1985-04-22 1985-12-05 Toshiba Corp Production of lithium tantalate single crystal wafer
JPS63218596A (en) * 1987-03-05 1988-09-12 Hitachi Metals Ltd Lithium tantalate single crystal excellent in light transmittance and production thereof
JPH06250399A (en) * 1993-02-24 1994-09-09 Fuji Elelctrochem Co Ltd Method and apparatus for heat treatment of material having pyroelectric property
JP3724509B2 (en) * 1993-04-05 2005-12-07 信越化学工業株式会社 LiTaO3 single crystal for light and manufacturing method thereof
US6319430B1 (en) * 1997-07-25 2001-11-20 Crystal Technology, Inc. Preconditioned crystals of lithium niobate and lithium tantalate and method of preparing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5359452A (en) * 1992-04-24 1994-10-25 Hitachi Metals, Ltd. Lithium tantalate monocrystal, monocrystal substrate, and photo element
JPH10270977A (en) * 1997-03-21 1998-10-09 Mitsubishi Materials Corp Surface acoustic wave element
JP2000315928A (en) * 1999-04-28 2000-11-14 Murata Mfg Co Ltd Manufacture of surface wave element and manufacture of surface wave unit
JP2002226299A (en) * 2000-12-01 2002-08-14 Toshiba Corp Apparatus and method for manufacturing single crystal

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6932957B2 (en) 2002-06-28 2005-08-23 Silicon Light Machines Corporation Method and apparatus for increasing bulk conductivity of a ferroelectric material
US7309392B2 (en) 2003-11-25 2007-12-18 Sumitomo Metal Mining Co., Ltd. Lithium niobate substrate and method of producing the same
DE102004056741B4 (en) * 2003-11-25 2015-05-21 Sumitomo Metal Mining Co., Ltd. Process for producing a lithium niobate substrate
US7153487B2 (en) 2004-05-25 2006-12-26 Crystal Technology, Inc. Using condensed chemicals to precondition lithium niobate and lithium tantalate crystals
US7381397B2 (en) 2004-05-25 2008-06-03 Crystal Technology, Inc. Using condensed chemicals to precondition lithium niobate and lithium tantalate crystals
US7728697B2 (en) 2006-09-26 2010-06-01 Mg Materials Corporation Systems and methods for electrically reducing ferroelectric materials to increase bulk conductivity
CN108624961A (en) * 2018-05-29 2018-10-09 中国电子科技集团公司第二十六研究所 A kind of recycling method of lithium tantalate black-film
CN108624961B (en) * 2018-05-29 2020-06-30 中国电子科技集团公司第二十六研究所 Method for recycling lithium tantalate black chips

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