JPH04301329A - Manufacture of ferroelectric thin film - Google Patents
Manufacture of ferroelectric thin filmInfo
- Publication number
- JPH04301329A JPH04301329A JP3087324A JP8732491A JPH04301329A JP H04301329 A JPH04301329 A JP H04301329A JP 3087324 A JP3087324 A JP 3087324A JP 8732491 A JP8732491 A JP 8732491A JP H04301329 A JPH04301329 A JP H04301329A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- producing
- ferroelectric thin
- substrate
- lithium
- 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.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- 239000002994 raw material Substances 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 19
- 239000010955 niobium Substances 0.000 claims abstract description 18
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 16
- 239000000758 substrate Substances 0.000 claims abstract description 16
- 239000007789 gas Substances 0.000 claims abstract description 15
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 13
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 10
- 150000004703 alkoxides Chemical class 0.000 claims abstract description 9
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 9
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims abstract description 9
- -1 Li(ta Inorganic materials 0.000 claims abstract description 8
- 239000001301 oxygen Substances 0.000 claims abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 7
- 229910003327 LiNbO3 Inorganic materials 0.000 claims abstract description 6
- 239000007800 oxidant agent Substances 0.000 claims abstract description 6
- 229910052796 boron Inorganic materials 0.000 claims abstract description 5
- 239000012159 carrier gas Substances 0.000 claims abstract description 4
- 238000005229 chemical vapour deposition Methods 0.000 claims description 9
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 claims description 3
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 3
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 claims description 3
- 239000001272 nitrous oxide Substances 0.000 claims description 3
- 238000005268 plasma chemical vapour deposition Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 239000013078 crystal Substances 0.000 abstract description 14
- 239000000203 mixture Substances 0.000 abstract description 12
- 239000010408 film Substances 0.000 abstract description 11
- 239000012535 impurity Substances 0.000 abstract description 9
- 230000007547 defect Effects 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 8
- 238000006243 chemical reaction Methods 0.000 abstract description 7
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 abstract description 2
- 239000012808 vapor phase Substances 0.000 abstract 2
- 229910011131 Li2B4O7 Inorganic materials 0.000 abstract 1
- 229910012463 LiTaO3 Inorganic materials 0.000 abstract 1
- 239000000126 substance Substances 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 description 9
- 238000004544 sputter deposition Methods 0.000 description 7
- 239000012071 phase Substances 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000010897 surface acoustic wave method Methods 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- 238000002230 thermal chemical vapour deposition Methods 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 229910015446 B(OCH3)3 Inorganic materials 0.000 description 1
- 229910019651 Nb(OC2H5)5 Inorganic materials 0.000 description 1
- 229910019645 Nb(OCH3)5 Inorganic materials 0.000 description 1
- 229910004440 Ta(OCH3)5 Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000005616 pyroelectricity Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 239000013077 target material Substances 0.000 description 1
- AJSTXXYNEIHPMD-UHFFFAOYSA-N triethyl borate Chemical compound CCOB(OCC)OCC AJSTXXYNEIHPMD-UHFFFAOYSA-N 0.000 description 1
- WRECIMRULFAWHA-UHFFFAOYSA-N trimethyl borate Chemical compound COB(OC)OC WRECIMRULFAWHA-UHFFFAOYSA-N 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Insulating Bodies (AREA)
Abstract
Description
【産業上の利用分野】本発明は、化学気相成長法による
強誘電体薄膜の作製方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a ferroelectric thin film by chemical vapor deposition.
【０００２】0002
【従来の技術】ニオブ酸リチウム（ＬｉＮｂＯ３）やタ
ンタル酸リチウム（ＬｉＴａＯ３）に代表されるリチウ
ム系複合酸化物単結晶は、圧電性・焦電性に優れており
、表面弾性波デバイス・焦電型赤外線センサ−等に応用
されている。また、電気光学効果や非線形光学効果を利
用した光変調器、光導波路、光スイッチ、光結合器等の
光集積回路用基板材料として用いられている。[Prior Art] Lithium-based composite oxide single crystals, represented by lithium niobate (LiNbO3) and lithium tantalate (LiTaO3), have excellent piezoelectricity and pyroelectricity, and are used in surface acoustic wave devices and pyroelectric devices. It is applied to infrared sensors, etc. It is also used as a substrate material for optical integrated circuits such as optical modulators, optical waveguides, optical switches, and optical couplers that utilize electro-optic effects and nonlinear optical effects.
【０００３】これらの単結晶の一般的な作製法は、チョ
クラルスキ−法といわれる引き上げ法であるが、前述の
酸化物の融点が高い（ＬｉＮｂＯ３：Ｔｍ＝１２５３℃
，ＬｉＴａＯ３：Ｔｍ＝１６５０℃）ため、単結晶作製
時にはそれらを溶融する必要から融点以上の温度に加熱
する必要がある。そのため、白金やロジウム、イリジウ
ムといった高価なルツボが必要である。また、不純物の
混入も起こり易く、大口径の良質な単結晶が得難い。そ
の結果として、これらの単結晶は高価にならざるをえな
い。A common method for producing these single crystals is a pulling method called the Czochralski method, but the above-mentioned oxide has a high melting point (LiNbO3:Tm=1253°C).
, LiTaO3:Tm=1650° C.), therefore, when producing a single crystal, it is necessary to melt them and therefore it is necessary to heat them to a temperature above their melting point. Therefore, expensive crucibles such as platinum, rhodium, and iridium are required. Furthermore, contamination with impurities is likely to occur, making it difficult to obtain a high-quality single crystal with a large diameter. As a result, these single crystals must be expensive.
【０００４】現在上記応用開発においては、このように
高価なバルク単結晶から特定の面方位を持たせて切り出
された数百ミクロン厚のウエハを用いている。しかしな
がら、前述の多くのデバイスにおいて実際に機能するの
は結晶表面の数ミクロンから数十ミクロンの領域である
。よって、各種デバイスに応用可能な良質の強誘電体薄
膜材料を低コストに作製する技術を確立することは、多
分野におけるデバイス開発の工業化に大きく貢献するこ
とは明白である。また、薄膜化による異種材料との積層
化、半導体とのモノリシック化により、各種デバイスの
小型化、高性能化、多機能化が期待される。[0004]Currently, in the above-mentioned application development, wafers several hundred microns thick are used, which are cut out from such expensive bulk single crystals with specific plane orientations. However, in many of the above-mentioned devices, what actually functions is a region of several microns to several tens of microns on the crystal surface. Therefore, it is clear that establishing a technology for producing high-quality ferroelectric thin film materials at low cost that can be applied to various devices will greatly contribute to the industrialization of device development in many fields. In addition, it is expected that various devices will become smaller, have higher performance, and become more multifunctional by layering them with different materials through thinner films and making them monolithic with semiconductors.
【０００５】現在、これらの薄膜を作製する方法として
液相エピタキシャル法、スパッタリング法、ゾル−ゲル
法等が報告されている。これらのうち、目的材料の焼結
体をタ−ゲットに用いた高周波マグネトロンスパッタリ
ング法が一般的に用いられている。Currently, liquid phase epitaxial method, sputtering method, sol-gel method, etc. have been reported as methods for producing these thin films. Among these, a high frequency magnetron sputtering method using a sintered body of the target material as a target is generally used.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、一般的
にスパッタリング法においては、スパッタ中に高エネル
ギ−の原子やイオンにより基板表面や生成膜中に欠陥や
損傷が生じたり、スパッタリングガスとして用いられる
アルゴン等が不純物として膜中に混入する恐れがある。
表面弾性波デバイスにおいては基板表面の損傷が、また
光関連デバイスにおいては薄膜中の欠陥や不純物が散乱
等の原因となり問題である。[Problems to be Solved by the Invention] However, in general, in the sputtering method, defects or damage occur on the substrate surface or the produced film due to high-energy atoms and ions during sputtering, and argon used as the sputtering gas etc. may be mixed into the film as impurities. In surface acoustic wave devices, damage to the substrate surface is a problem, and in optical-related devices, defects and impurities in thin films cause scattering, etc., which is a problem.
【０００７】また、スパッタリング法ではタ−ゲットと
して用いる焼結体の構成原子のスパッタ率が元素により
異なるため、生成した薄膜の組成比はタ−ゲットのもの
とは必ずしも一致せず、上述のペロブスカイト構造を有
するような複合酸化物系の薄膜を化学量論的に作製する
ことは比較的難しい。さらに用いる原料タ−ゲットの組
成により得られる薄膜の組成がほぼ一元的に規定されて
しまうため、Ｌｉ（ＴａｘＮｂ１―ｘ）Ｏ３ （０
≦ｘ≦１）のような混晶系の薄膜を作製する場合、組成
ｘの異なる薄膜を作製するためにはその度ごとに原料タ
−ゲットの組成調整を厳密に行わなければならない。In addition, in the sputtering method, since the sputtering rate of the constituent atoms of the sintered body used as a target differs depending on the element, the composition ratio of the produced thin film does not necessarily match that of the target. It is relatively difficult to stoichiometrically produce a complex oxide-based thin film that has a structure. Furthermore, since the composition of the thin film obtained is almost uniformly defined by the composition of the raw material target used, Li(TaxNb1-x)O3 (0
When producing a mixed crystal thin film such as ≦x≦1), the composition of the raw material target must be precisely adjusted each time in order to produce thin films with different compositions x.
【０００８】本発明の目的は、上述のデバイスに適用可
能な欠陥や損傷、不純物の少ない緻密かつ均質な所望組
成の強誘電体薄膜を再現性良く作製する方法を確立する
ことである。An object of the present invention is to establish a method for producing a dense and homogeneous ferroelectric thin film of a desired composition with good reproducibility, with few defects, damages, and impurities, which can be applied to the above-mentioned devices.
【０００９】[0009]
【発明の構成】即ち本発明は、
（１）化学気相成長法で強誘電体薄膜を作製する方法に
おいて、リチウムのアルコキシド叉はβ−ジケトン系金
属錯体の内の一種以上と、タンタル、ニオブ、ボロンの
各アルコキシド叉は各β−ジケトン系金属錯体の内の一
種以上を気相原料とし、これらのガスを不活性キャリア
ガスで反応器内に導入するとともに、前記原料ガスを酸
素等の酸化剤により酸化して、基板上にＬｉＴａＯ３，
ＬｉＮｂＯ３，Ｌｉ（Ｔａ，Ｎｂ）Ｏ３， Ｌｉ２Ｂ
４Ｏ７のいずれかの薄膜を作製することを特徴とする強
誘電体薄膜の作製方法。
（２）気相原料として、リチウムとニオブまたはリチウ
ムとタンタルのダブルアルコキシドを用いることを特徴
とする上記（１）記載の強誘電体薄膜の作製法。
（３）化学気相成長法（ＣＶＤ法）として、熱ＣＶＤ法
、プラズマＣＶＤ法，光ＣＶＤ法の内の一種以上である
ことを特徴とする上記（１）及び（２）記載の強誘電体
薄膜の作製法。
（４）酸化剤として、酸素、水蒸気、亜酸化窒素、二酸
化窒素、原子状酸素、オゾンの内の一種以上であること
を特徴とする（１）項乃至（３）記載の強誘電体薄膜の
作製法。に関する。SUMMARY OF THE INVENTION That is, the present invention provides: (1) A method for producing a ferroelectric thin film by chemical vapor deposition, in which one or more of lithium alkoxide or β-diketone metal complexes and tantalum or niobium are used. , boron alkoxides, or β-diketone metal complexes as gas phase raw materials, these gases are introduced into the reactor with an inert carrier gas, and the raw material gases are oxidized with oxygen, etc. LiTaO3,
LiNbO3, Li(Ta,Nb)O3, Li2B
A method for producing a ferroelectric thin film, the method comprising producing a 4O7 thin film. (2) The method for producing a ferroelectric thin film as described in (1) above, characterized in that a double alkoxide of lithium and niobium or lithium and tantalum is used as the gas phase raw material. (3) The ferroelectric material according to (1) and (2) above, wherein the chemical vapor deposition method (CVD method) is one or more of thermal CVD method, plasma CVD method, and photoCVD method. Method for producing thin films. (4) The ferroelectric thin film according to items (1) to (3), wherein the oxidizing agent is one or more of oxygen, water vapor, nitrous oxide, nitrogen dioxide, atomic oxygen, and ozone. Fabrication method. Regarding.
【００１０】0010
【発明の具体的説明】本発明の理解を容易にするため具
体的かつ詳細に説明する。上記本発明で気相原料として
は、リチウム、タンタル、ニオブ、ボロンの各アルコキ
シド叉は各β−ジケトン系金属錯体及びリチウムとニオ
ブまたはリチウムとタンタルのダブルアルコキシドであ
る。アルコキシド原料とは、例えば Ｌｉ（ｔ−ＯＣ４
Ｈ９），Ｔａ（ＯＣＨ３）５，Ｔａ（ＯＣ２Ｈ５）５，
Ｔａ（ｎ−ＯＣ３Ｈ７）５，Ｔａ（ｉ−ＯＣ３Ｈ７）５
，Ｔａ（ｎ−ＯＣ４Ｈ９）５，Ｔａ（ｔ−ＯＣ４Ｈ９）
５， Ｎｂ（ＯＣＨ３）５，Ｎｂ（ＯＣ２Ｈ５）５，Ｎ
ｂ（ｎ−ＯＣ３Ｈ７）５，Ｎｂ（ｉ−ＯＣ３Ｈ７）５，
Ｎｂ（ｎ−ＯＣ４Ｈ９）５，Ｎｂ（ｔ−ＯＣ４Ｈ９）５
， Ｂ（ＯＣＨ３）３，Ｂ（ＯＣ２Ｈ５）３ である。
β−ジケトン系金属錯体原料とは、例えば Ｌｉ（ＤＰ
Ｍ），Ｌｉ（ＨＦＡ），Ｔａ（ＤＰＭ）５，Ｔａ（ＨＦ
Ａ）５，Ｎｂ（ＤＰＭ）５，Ｎｂ（ＨＦＡ）５，Ｂ（Ｄ
ＰＭ）３，Ｂ（ＨＦＡ）３である。ダブルアルコキシド
原料とは、ＬｉＴａ（ＯＣ３Ｈ７）６，ＬｉＴａ（ＯＣ
４Ｈ９）６，ＬｉＮｂ（ＯＣ３Ｈ７）６，ＬｉＮｂ（Ｏ
Ｃ４Ｈ９）６等である。DETAILED DESCRIPTION OF THE INVENTION In order to facilitate understanding of the present invention, the present invention will be explained specifically and in detail. In the present invention, the gas phase raw materials include alkoxides of lithium, tantalum, niobium, and boron, or β-diketone metal complexes, and double alkoxides of lithium and niobium or lithium and tantalum. The alkoxide raw material is, for example, Li(t-OC4
H9), Ta(OCH3)5, Ta(OC2H5)5,
Ta(n-OC3H7)5, Ta(i-OC3H7)5
,Ta(n-OC4H9)5,Ta(t-OC4H9)
5, Nb(OCH3)5,Nb(OC2H5)5,N
b(n-OC3H7)5, Nb(i-OC3H7)5,
Nb(n-OC4H9)5, Nb(t-OC4H9)5
, B(OCH3)3, B(OC2H5)3. The β-diketone metal complex raw material is, for example, Li(DP
M), Li (HFA), Ta (DPM)5, Ta (HF
A) 5, Nb (DPM) 5, Nb (HFA) 5, B (D
PM)3, B(HFA)3. Double alkoxide raw materials include LiTa(OC3H7)6, LiTa(OC
4H9)6, LiNb(OC3H7)6, LiNb(O
C4H9)6 etc.
【００１１】前記の原料は、ＣＶＤに好適な蒸気圧とな
る温度範囲が室温から２００℃までの間にあるため好ま
しい。それは、 ２００℃より高い加熱が必要な原料の
場合、供給量の制御性が悪くなるばかりか、バルブ等の
装置を構成する部品類の使用できる範囲が狭くなり装置
構成上の自由度が大きく減少してしまうためである。[0011] The above-mentioned raw material is preferable because the temperature range in which it has a vapor pressure suitable for CVD is between room temperature and 200°C. In the case of raw materials that require heating above 200°C, not only is it difficult to control the supply amount, but the usable range of parts that make up the equipment, such as valves, is narrowed and the degree of freedom in equipment configuration is greatly reduced. This is because you end up doing it.
【００１２】本発明では、これらの原料をそれぞれ所望
温度に設定された恒温槽内に設置し、それらの原料蒸気
を不活性ガスでキャリアし反応器内に導入する。複合酸
化物薄膜の組成比は、各恒温槽の温度及び各キャリアガ
ス流量により精密に制御される。さらに、リチウムとニ
オブまたはリチウムとタンタルのダブルアルコキシド原
料を用いてＬｉＮｂＯ３やＬｉＴａＯ３を作製する場合
には、ＬｉとＮｂまたはＬｉとＴａが １：１、即ち所
望の化学量論組成のまま蒸気化しキャリアされるので、
各元素の供給量を正確に制御する手間を省くことが可能
となる。各原料を酸化する酸化材には、酸素、水蒸気、
亜酸化窒素、二酸化窒素、原子状酸素、オゾンの内の一
種以上が用いられ、酸化反応を促進させるため過剰であ
ることが望ましい。反応器内圧は、０．０１〜５０Ｔｏ
ｒｒであることが好ましい。これは、０．０１Ｔｏｒｒ
より低いと成膜速度が遅くなり、５０Ｔｏｒｒより高い
と気相中での均一核生成等により表面が平滑で緻密な薄
膜の作製が難しくなるからである。In the present invention, each of these raw materials is placed in a constant temperature bath set at a desired temperature, and the raw material vapor is carried with an inert gas and introduced into the reactor. The composition ratio of the composite oxide thin film is precisely controlled by the temperature of each constant temperature bath and the flow rate of each carrier gas. Furthermore, when producing LiNbO3 or LiTaO3 using a double alkoxide raw material of lithium and niobium or lithium and tantalum, Li and Nb or Li and Ta are vaporized in a 1:1 ratio, that is, the desired stoichiometric composition, and the carrier is Because it is done,
It becomes possible to save the effort of accurately controlling the supply amount of each element. Oxidizing agents that oxidize each raw material include oxygen, water vapor,
One or more of nitrous oxide, nitrogen dioxide, atomic oxygen, and ozone is used, and it is desirable to use an excess amount in order to promote the oxidation reaction. The reactor internal pressure is 0.01 to 50To
Preferably it is rr. This is 0.01Torr
This is because if it is lower than 50 Torr, the film formation rate becomes slow, and if it is higher than 50 Torr, it becomes difficult to produce a dense thin film with a smooth surface due to uniform nucleation in the gas phase.
【００１３】化学反応を誘発するエネルギ−源としては
、熱、プラズマ、光等があるが、それらは目的によって
最適なものを選択できる。例えば基板温度の低下にはプ
ラズマＣＶＤ法、光ＣＶＤ法が有利であり、基板表面・
生成膜内の欠陥・損傷の低減には熱ＣＶＤ法、光ＣＶＤ
法が有利である。基板には、所望基板温度での酸化雰囲
気に耐えるものであれば何でも用いることは可能だが、
サファイア等の単結晶を用いるのがより好ましい。
基板温度は、３５０〜７００℃とする。これは、 ３５
０℃より低い温度ではペロブスカイト構造の酸化物がで
きないためであり、 ７００℃より高い温度では電極等
のデバイス構造が拡散や化学反応等により破壊されるか
らである。このように、比較的低温での化学反応という
穏やかな条件下で薄膜を作製するため、生成する薄膜の
結晶欠陥や基板表面の損傷を少なくすることが可能とな
る。Energy sources for inducing chemical reactions include heat, plasma, light, etc., and the most suitable one can be selected depending on the purpose. For example, plasma CVD and photo-CVD are advantageous for lowering the substrate temperature.
Thermal CVD method and photo CVD method are used to reduce defects and damage in the produced film.
The law is favorable. Any substrate can be used as long as it can withstand the oxidizing atmosphere at the desired substrate temperature.
It is more preferable to use a single crystal such as sapphire. The substrate temperature is 350 to 700°C. This is 35
This is because a perovskite-structured oxide cannot be formed at a temperature lower than 0°C, and a device structure such as an electrode is destroyed by diffusion or chemical reaction at a temperature higher than 700°C. In this way, since the thin film is produced under mild conditions such as a chemical reaction at a relatively low temperature, it is possible to reduce crystal defects in the produced thin film and damage to the substrate surface.
【００１４】即ち本発明を用いることにより、表面弾性
波デバイスや光関連デバイスに適用可能な欠陥や損傷、
不純物の少ない緻密かつ均質な所望組成の強誘電体薄膜
を再現性良く作製することが可能になるわけである。That is, by using the present invention, defects and damage that can be applied to surface acoustic wave devices and optical related devices,
This makes it possible to fabricate a dense and homogeneous ferroelectric thin film with a desired composition with a good reproducibility and less impurities.
【００１５】以下、本発明の実施例について説明する。Examples of the present invention will be described below.
【実施例】ベロ−ズバルブ付きステンレススチール製の
原料容器にそれぞれＬｉ（Ｃ１１Ｈ１９Ｏ２）〔Ｌｉ（
ＤＰＭ）〕及びＴａ（ＯＣ２Ｈ５）５を封入し、それぞ
れ１４０℃及び１１０℃に設定された恒温槽内に設置し
た。原料蒸気は、それぞれ流量６０ｍｌ／ｍｉｎ及び４
０ｍｌ／ｍｉｎのアルゴンガスを用いて反応器内に導入
した。さらに酸化材として酸素を １００ｍｌ／ｍｉｎ
混合し、 ５００℃に加熱した２５ｍｍ角のサファイア
Ｃ面上にＬｉＴａＯ３薄膜を作製した。なお、反応器内
の圧力は １Ｔｏｒｒとした。この反応条件下において
、実験時間 ２００分で約２μｍの薄膜を得た。[Example] Li(C11H19O2) [Li(
DPM)] and Ta(OC2H5)5 were sealed and placed in constant temperature baths set at 140°C and 110°C, respectively. The raw material steam has a flow rate of 60 ml/min and 4 ml/min, respectively.
Argon gas was introduced into the reactor at a rate of 0 ml/min. Furthermore, oxygen is added as an oxidizing agent at 100ml/min.
A LiTaO3 thin film was produced on a 25 mm square sapphire C surface which was mixed and heated to 500°C. Note that the pressure inside the reactor was 1 Torr. Under these reaction conditions, a thin film of about 2 μm was obtained in an experimental time of 200 minutes.
【００１６】生成した薄膜の表面及び破断面を走査形電
子顕微鏡で観察した結果、膜は緻密かつ均質でありその
表面は平滑であった。膜厚は均一であった。２次イオン
質量分析計により組成分析を行った結果、膜中ほぼすべ
てにわたりＬｉとＴａの原子比が１：１であった。また
、その他の不純物元素は検出されなかった。Ｘ線回折に
よる結晶構造解析より、生成膜はｃ軸に配向しており、
その格子定数はｃ＝１３．７８Ａとバルク単結晶とほぼ
同じ値であることがわかった。Observation of the surface and fracture surface of the produced thin film using a scanning electron microscope revealed that the film was dense and homogeneous, and its surface was smooth. The film thickness was uniform. Composition analysis using a secondary ion mass spectrometer revealed that the atomic ratio of Li to Ta was 1:1 throughout almost the entire film. Further, no other impurity elements were detected. Crystal structure analysis by X-ray diffraction shows that the produced film is oriented along the c-axis.
It was found that its lattice constant c=13.78A, which is almost the same value as that of the bulk single crystal.
【００１７】[0017]
【発明の効果】以上のように本発明においては、気相原
料としてリチウム、タンタル、ニオブ、ボロンの各アル
コキシドまたはβ−ジケトン系金属錯体を用いるため、
不純物の混入が無く、組成の均一な薄膜を作製できると
ともに、その制御が容易に行える。また、比較的低温で
の化学反応を用いるため、スパッタリング法におけるス
パッタダメ−ジが無く、膜中に結晶欠陥が少なく、基板
との界面状態の良い薄膜を得ることが可能である。これ
らの特徴は表面弾性波デバイスや光関連デバイス作製用
の基板材料として好適であり、本発明によりこれらの薄
膜基板材料を安価かつ大量に供給することが可能となる
。As described above, in the present invention, since lithium, tantalum, niobium, and boron alkoxides or β-diketone metal complexes are used as gas phase raw materials,
A thin film with a uniform composition can be produced without contamination with impurities, and it can be easily controlled. Further, since a chemical reaction is used at a relatively low temperature, there is no sputter damage caused by sputtering, and it is possible to obtain a thin film with few crystal defects in the film and a good interface state with the substrate. These characteristics make it suitable as a substrate material for producing surface acoustic wave devices and optical-related devices, and the present invention makes it possible to supply these thin film substrate materials at low cost and in large quantities.
Claims (4)
方法において、リチウムのアルコキシド叉はβ−ジケト
ン系金属錯体の内の一種以上と、タンタル、ニオブ、ボ
ロンの各アルコキシド叉は各β−ジケトン系金属錯体の
内の一種以上を気相原料とし、これらのガスを不活性キ
ャリアガスで反応器内に導入するとともに、前記原料ガ
スを酸素等の酸化剤により酸化し、基板上にＬｉＴａＯ
３，ＬｉＮｂＯ３，Ｌｉ（Ｔａ，Ｎｂ）Ｏ３，Ｌｉ２Ｂ
４Ｏ７のいずれかの薄膜を作製することを特徴とする強
誘電体薄膜の作製方法。Claim 1: A method for producing a ferroelectric thin film by chemical vapor deposition, in which one or more of lithium alkoxides or β-diketone metal complexes, and tantalum, niobium, and boron alkoxides or each One or more types of β-diketone metal complexes are used as gas phase raw materials, and these gases are introduced into the reactor using an inert carrier gas, and the raw material gases are oxidized with an oxidizing agent such as oxygen, and then deposited on the substrate. LiTaO
3, LiNbO3, Li(Ta,Nb)O3, Li2B
A method for producing a ferroelectric thin film, the method comprising producing a 4O7 thin film.
リチウムとタンタルのダブルアルコキシドを用いること
を特徴とする特許請求の範囲第１項記載の強誘電体薄膜
の作製法。2. The method for producing a ferroelectric thin film according to claim 1, wherein a double alkoxide of lithium and niobium or lithium and tantalum is used as the gas phase raw material.
ＶＤ法、プラズマＣＶＤ法，光ＣＶＤ法の内の一種以上
であることを特徴とする特許請求の範囲第１項及び第２
項記載の強誘電体薄膜の作製法。Claim 3: As a chemical vapor deposition method (CVD method), heat C
Claims 1 and 2 are characterized in that the method is one or more of VD method, plasma CVD method, and photo-CVD method.
A method for producing a ferroelectric thin film as described in Section 1.
、二酸化窒素、原子状酸素、オゾンの内の一種以上であ
ることを特徴とする特許請求の範囲第１項乃至第３項記
載の強誘電体薄膜の作製法。 【０００１】4. The method according to claim 1, wherein the oxidizing agent is one or more of oxygen, water vapor, nitrous oxide, nitrogen dioxide, atomic oxygen, and ozone. Method for producing ferroelectric thin films. 0001
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3087324A JPH04301329A (en) | 1991-03-28 | 1991-03-28 | Manufacture of ferroelectric thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3087324A JPH04301329A (en) | 1991-03-28 | 1991-03-28 | Manufacture of ferroelectric thin film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04301329A true JPH04301329A (en) | 1992-10-23 |
Family
ID=13911683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3087324A Pending JPH04301329A (en) | 1991-03-28 | 1991-03-28 | Manufacture of ferroelectric thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04301329A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6208453B1 (en) * | 1995-06-19 | 2001-03-27 | Northwestern University | Oriented niobate ferroelectric thin films for electrical and optical devices |
| JP2008532238A (en) * | 2005-03-03 | 2008-08-14 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Method for producing electrochemical energy source, electrochemical energy source obtained by the method, and electronic device |
-
1991
- 1991-03-28 JP JP3087324A patent/JPH04301329A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6208453B1 (en) * | 1995-06-19 | 2001-03-27 | Northwestern University | Oriented niobate ferroelectric thin films for electrical and optical devices |
| JP2008532238A (en) * | 2005-03-03 | 2008-08-14 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Method for producing electrochemical energy source, electrochemical energy source obtained by the method, and electronic device |
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