JPS59169214A - Production of thin film piezoelectric oscillator - Google Patents
Production of thin film piezoelectric oscillatorInfo
- Publication number
- JPS59169214A JPS59169214A JP4348383A JP4348383A JPS59169214A JP S59169214 A JPS59169214 A JP S59169214A JP 4348383 A JP4348383 A JP 4348383A JP 4348383 A JP4348383 A JP 4348383A JP S59169214 A JPS59169214 A JP S59169214A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- silicon
- single crystal
- substrate
- crystal thin
- 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 93
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 65
- 239000010703 silicon Substances 0.000 claims abstract description 64
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 63
- 239000013078 crystal Substances 0.000 claims abstract description 37
- 239000000758 substrate Substances 0.000 claims abstract description 37
- 238000005530 etching Methods 0.000 claims abstract description 27
- 230000003647 oxidation Effects 0.000 claims abstract description 4
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 4
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 9
- 239000000395 magnesium oxide Substances 0.000 claims description 7
- 229910052596 spinel Inorganic materials 0.000 claims description 4
- 239000011029 spinel Substances 0.000 claims description 4
- 239000010980 sapphire Substances 0.000 claims description 3
- 229910052594 sapphire Inorganic materials 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims 1
- 239000010408 film Substances 0.000 abstract description 14
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052681 coesite Inorganic materials 0.000 abstract description 3
- 229910052906 cristobalite Inorganic materials 0.000 abstract description 3
- 229910052682 stishovite Inorganic materials 0.000 abstract description 3
- 229910052905 tridymite Inorganic materials 0.000 abstract description 3
- 239000000377 silicon dioxide Substances 0.000 abstract 2
- 235000012239 silicon dioxide Nutrition 0.000 abstract 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 4
- 229910052796 boron Inorganic materials 0.000 description 4
- YCIMNLLNPGFGHC-UHFFFAOYSA-N catechol Chemical compound OC1=CC=CC=C1O YCIMNLLNPGFGHC-UHFFFAOYSA-N 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- BYFGZMCJNACEKR-UHFFFAOYSA-N Al2O Inorganic materials [Al]O[Al] BYFGZMCJNACEKR-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Classifications
-
- 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
- H03H3/02—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 piezoelectric or electrostrictive resonators or networks
Abstract
Description
【発明の詳細な説明】
本発明は圧電薄膜を用いたＶＨＦ、 ＵＨＦ 用高周波
圧電振動子に関し、特にシリコン薄膜と圧電薄膜とから
なる複合構造の振動部位を有する薄膜圧電振動子に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency piezoelectric vibrator for VHF and UHF using a piezoelectric thin film, and more particularly to a thin film piezoelectric vibrator having a vibrating part of a composite structure consisting of a silicon thin film and a piezoelectric thin film.
一般に数十ＭＨ７以上の周波数で使用される圧電振動子
は振動モードとして板面が厚さに比べて十分広い圧電性
薄板の厚み振動を使用するが、厚み振動の共振周波数は
圧電性薄板の厚さに反比例し５０ＭＨｚ以上では厚さが
４０ミクロン以下となるため加工が極めて困難となり、
バルク圧電結晶或いは圧電セラミックを用いて５０ＭＨ
２以上の厚み振動圧電振動子を量産することは困難であ
る。Generally, piezoelectric vibrators used at frequencies of several tens of MH7 or more use thickness vibration of a piezoelectric thin plate whose plate surface is sufficiently wide compared to the thickness as a vibration mode, but the resonant frequency of thickness vibration is the thickness of the piezoelectric thin plate. At frequencies above 50MHz, the thickness becomes less than 40 microns, which makes processing extremely difficult.
50MH using bulk piezoelectric crystal or piezoelectric ceramic
It is difficult to mass produce vibrating piezoelectric vibrators with a thickness of two or more.
振動部分の厚さを薄くして５０ＭＨ２以上の厚み振動圧
電振動子を得る方法としては第１図、第２図の構造の薄
膜圧電振動子が公知である。この薄膜圧電振動子は基板
１１の上に薄膜部材１３を形成した後、エツチングによ
って基板１１に空孔１２を形成し、さらに薄膜部材１３
の上に順に下地電極１４、圧電薄膜１５、上部電極１６
を形成することによって製造するもので、一般に非圧電
性の薄膜部材１３と圧電薄膜１５とからなる複合ダイア
フラムが周縁部を主板１１によって支持された構造とな
っている。As a method for obtaining a vibrating piezoelectric vibrator having a thickness of 50 MH2 or more by reducing the thickness of the vibrating portion, a thin film piezoelectric vibrator having the structure shown in FIGS. 1 and 2 is known. This thin film piezoelectric vibrator is manufactured by forming a thin film member 13 on a substrate 11, forming holes 12 in the substrate 11 by etching, and then forming the thin film member 13 on the substrate 11 by etching.
A base electrode 14, a piezoelectric thin film 15, and an upper electrode 16 are arranged on top in this order.
Generally, a composite diaphragm consisting of a non-piezoelectric thin film member 13 and a piezoelectric thin film 15 is supported at its peripheral portion by a main plate 11.
第１図、第２図の構造の薄膜圧電振動子において基板１
１としては一般に表面が（１００）面であるようなシリ
コンが用いられ、エチレンジアミン、ピロカテコール、
水からなるエツチング液（以下ＥＤＰ液という）或いは
水酸化カリウム（ＫＯＨ）水溶液による異方性エツチン
グを利用して精密に空孔１２を作成することができる。In the thin film piezoelectric vibrator having the structure shown in FIGS. 1 and 2, the substrate 1
Silicon having a (100) surface is generally used as 1, and silicones such as ethylenediamine, pyrocatechol,
The holes 12 can be precisely created using anisotropic etching using an etching solution made of water (hereinafter referred to as EDP solution) or an aqueous potassium hydroxide (KOH) solution.
薄膜部材１３としては上記のＥＤＰ液或いはＫＯＨ水溶
液に対してできるだけエツチング速度の小さい材料が必
要であり、従来このような材料として種々の酸化物、窒
化物なども提案されているが、機械的強度、音響的クォ
リティ・ファクタが大きいことが要求されるところから
シリコン薄膜が最も理想的な材料として使用されてきた
。シリコンのＥＤＰ液或いはＫＯＨ水溶液に対するエツ
チング速度は不純物であるホウ素の濃度に依存し、７
Ｘ １０”ｃＩｒＬ−３以上の濃度にドープしたシリコ
ンのＥＤＰ液或いはＫＯＨ水溶液に対するエツチング速
度は極めて小さいことが知られており、したがって従来
は所望の厚さのダイアフラムを作成するためにシリコン
基板上にエピタキシャル成長、拡散、イオン注入などに
よって形成したホウ素を高濃度にドープしたシリコン薄
膜が薄膜部材として使用されてきた。The thin film member 13 needs to be made of a material that has an etching rate as low as possible with respect to the above-mentioned EDP liquid or KOH aqueous solution, and various oxides and nitrides have been proposed as such materials, but the mechanical strength , silicon thin film has been used as the most ideal material since it requires a large acoustic quality factor. The etching rate of silicon with EDP solution or KOH aqueous solution depends on the concentration of boron, which is an impurity.
It is known that the etching rate of silicon doped to a concentration of X 10" cIrL-3 or higher with EDP liquid or KOH aqueous solution is extremely low. Therefore, in the past, in order to create a diaphragm with a desired thickness, etching was performed on a silicon substrate. Silicon thin films doped with a high concentration of boron formed by epitaxial growth, diffusion, ion implantation, etc. have been used as thin film members.
しかし、従来の薄膜圧電振動子では上記のようにホウ素
を高濃度にドープしたシリコン薄膜を使用しているため
以下に述べるような重大な欠点を有していた。However, since the conventional thin film piezoelectric vibrator uses a silicon thin film doped with boron at a high concentration as described above, it has serious drawbacks as described below.
第１に、薄膜圧電振動子ではワイヤ・ホンディングなど
による配線を行なうために第１図、第２図に示すごとく
上部電極の引き出し″醒極１７が必要であるが、ホウ素
を高濃度にドープしたシリコン薄膜は導電率が非常に犬
きく、シたがって引き出し電極とシリコン薄膜との間の
容量がイ辰動子に並列に加わる結果、振動子の容量比が
見かけ上太きくなってしまい、このため従来の薄膜圧電
振動子ではこれを用いた発振器の制御範囲或いはフィル
タの比帯域幅を十分に広（取ることが不可能であった０
第２に、薄膜圧電振動子はシリコン基板上に形成できる
から、同一シリコン基板上に増幅器などの半導体素子を
形成して装置の小形化を図ることが望まれているが、従
来のごとくホウ素を高濃度にドープしたシリコン薄膜上
では増幅器などの半導体素子を形成することは困難であ
った。First, thin-film piezoelectric vibrators require a lead-out electrode 17 for the upper electrode, as shown in Figures 1 and 2, in order to perform wiring by wire bonding, etc. The conductivity of the silicon thin film is extremely low, and as a result, the capacitance between the extraction electrode and the silicon thin film is added in parallel to the oscillator, resulting in an apparent increase in the capacitance ratio of the oscillator. For this reason, with conventional thin film piezoelectric vibrators, it was impossible to sufficiently widen the control range of the oscillator or the fractional bandwidth of the filter using them.Secondly, thin film piezoelectric vibrators are Therefore, it is desired to miniaturize devices by forming semiconductor elements such as amplifiers on the same silicon substrate. Forming the device was difficult.
本発明の目的は、上記のような欠点を除いた薄膜圧電振
動子の製造方法を提供することであり、一本発明はシリ
コン基板上に酸化物単結晶薄膜をエピタキシャル成長さ
せた後、熱酸化によって酸化物単結晶薄膜とシリコンと
の界面にＳｉｎ、層を形成し、さらに酸化物単結晶薄膜
の上にシリコン単結晶薄膜をエピタキシャル成長させた
後、シリコン基板の裏側からエツチングを行ない、５Ｌ
０２層をエツチング停止層として使用することによりシ
リコン基板の一部を除去し、シリコン単結晶薄膜のダイ
アフラムを形成し、このシリコン・ダイアフラムの上に
下地電極、圧電薄膜、上部電極を順に形成する製造方法
である。An object of the present invention is to provide a method for manufacturing a thin film piezoelectric vibrator that eliminates the above-mentioned drawbacks.One purpose of the present invention is to epitaxially grow an oxide single-crystal thin film on a silicon substrate, and then grow it by thermal oxidation. After forming a Si layer at the interface between the oxide single crystal thin film and silicon, and epitaxially growing a silicon single crystal thin film on the oxide single crystal thin film, etching is performed from the back side of the silicon substrate to form a 5L layer.
A manufacturing process in which a part of the silicon substrate is removed by using the 02 layer as an etching stop layer, a diaphragm of a silicon single crystal thin film is formed, and a base electrode, a piezoelectric thin film, and an upper electrode are sequentially formed on this silicon diaphragm. It's a method.
本発明の製造方法によれば酸化物単結晶薄膜の上にエピ
タキシャル成長させるシリコン単結晶薄膜の不純物濃度
は任意に選択することができ、したがって従来の薄膜圧
電振動子の欠点を除いた薄膜圧電振動子を製造すること
ができる。According to the manufacturing method of the present invention, the impurity concentration of the silicon single-crystal thin film epitaxially grown on the oxide single-crystal thin film can be arbitrarily selected, and therefore a thin-film piezoelectric vibrator that eliminates the drawbacks of conventional thin-film piezoelectric vibrators can be manufactured.
次に本発明の詳細な説明する。Next, the present invention will be explained in detail.
第３図〜第６図に本発明による薄膜圧電振動子の製造工
程を示し、本発明の製造方法を説明する。3 to 6 show the manufacturing process of the thin film piezoelectric vibrator according to the present invention, and the manufacturing method of the present invention will be explained.
まず表面が（１００）面であるようなシリコン基板の上
に酸化物単結晶薄膜をエピタキシャル成長させた後、熱
酸化によって酸化物単結晶薄膜とシリコン基板との界面
にＳｉＯ！層を形成する。シリコン基板表面に存在する
薄膜は酸化物であるからシリコンの表面領域は容易に熱
酸化が可能であり、酸化物単結晶薄膜との界面にＳｉｎ
２層が形成できる。次に酸化物単結晶薄膜の上にシリコ
ン単結晶薄膜をエピタキシャル成長させて第３図のよう
な構造が得られる。第３図において３１はシリコン基板
、３２は酸化物単結晶薄膜、３３はＳｉｎ、層、３４は
シリコン単結晶薄膜である。First, a single crystal oxide thin film is epitaxially grown on a silicon substrate whose surface is a (100) plane, and then SiO! form a layer. Since the thin film existing on the surface of the silicon substrate is an oxide, the silicon surface region can be easily thermally oxidized, and the silicon layer is formed at the interface with the oxide single crystal thin film.
Two layers can be formed. Next, a silicon single crystal thin film is epitaxially grown on the oxide single crystal thin film to obtain a structure as shown in FIG. In FIG. 3, 31 is a silicon substrate, 32 is an oxide single crystal thin film, 33 is a Sin layer, and 34 is a silicon single crystal thin film.
次に第４図のように基板の両面に窒化シリコン（Ｓｉｌ
Ｎ４） などのエツチング保護膜３５を形成し、ダイヤ
フラムを形成する部分の裏面のエツチング保護膜を除去
してＥＤＰ液中でシリコン基板のエツチングを行なう。Next, as shown in Figure 4, silicon nitride (Sil) is applied to both sides of the substrate.
An etching protection film 35 such as N4) is formed, the etching protection film on the back surface of the portion where the diaphragm is to be formed is removed, and the silicon substrate is etched in an EDP solution.
ＥＤＰ液による８ｉ０．のエツチング速度は極めて小さ
く、例えば１１８℃のＥＤＰ液中でのエツチング速度は
シリコンの（１００）面が５０μｍ／ｈであるのに対し
、８ｉ０．は０．０１５ ｔｔｍ／ｈにすぎない。した
がって第４図の構造の基板をＢＤＰ 液中でエツチング
すれば、エツチングは基板の裏側から進行して８ｉ０．
層に到達した時点で自動的に停止する。8i0. with EDP liquid. For example, the etching rate in an EDP solution at 118°C is 50 μm/h for the (100) plane of silicon, whereas the etching rate for 8i0. is only 0.015 ttm/h. Therefore, if the substrate having the structure shown in FIG. 4 is etched in a BDP solution, the etching will proceed from the back side of the substrate, and the etching will proceed from the back side of the substrate.
It will automatically stop when it reaches the layer.
本製造方法においては、上記の説明から明らかなように
Ｓｉｎ２層３３がエツチング停止層となるから、酸化物
単結晶薄膜３２はシリコン上にエピタキシャル成長が可
能な種々の酸化物材料を用いることができる。代表的な
材料はスピネル、サファイヤ或いはマグネシアである。In this manufacturing method, since the Sin2 layer 33 serves as an etching stop layer as is clear from the above description, various oxide materials that can be epitaxially grown on silicon can be used for the oxide single crystal thin film 32. Typical materials are spinel, sapphire or magnesia.
ここでスピネルとしてはＭｇ０−Ａｌ２Ｏ，、Ｍｇ０−
Ｇａ、０８．ＭｇＯ・（ＡＩ 、Ｇａ）、０． 。Here, the spinel is Mg0-Al2O, Mg0-
Ga, 08. MgO.(AI, Ga), 0. .
Ｚｎ Ｏｅ Ａ１２０Ｂなどがある。There are Zn Oe A120B, etc.
上記の工程の後、保護膜３５ 、Ｓ １０２ ）＠ ３
３及び酸化物単結晶薄膜３２を適当なエツチング液で除
することによって、第５図に示すような周縁部をシリコ
ン基板に支持されたシリコン・ダイヤフラムカ九得られ
る。なお、これらの！３５ 、３３及び３２は必ずしも
すべて除去する必要はなく、必要に応じて除去すれば良
い。さらに、順に下地電極３６、圧電薄膜３７、上部電
極３８を形成して第６図に示すような薄膜圧電振動子が
得られる。After the above steps, the protective film 35, S102)@3
By removing the oxide single crystal thin film 3 and the oxide single crystal thin film 32 with a suitable etching solution, a silicon diaphragm 9 supported on a silicon substrate with a peripheral portion as shown in FIG. 5 is obtained. In addition, these! 35, 33, and 32 do not necessarily all need to be removed, and may be removed as necessary. Furthermore, a base electrode 36, a piezoelectric thin film 37, and an upper electrode 38 are formed in this order to obtain a thin film piezoelectric vibrator as shown in FIG.
上述のような本発明の製造方法で製造する薄膜圧電振動
子は、第６図の３４に示すシリコン薄膜の不純物濃度が
任意に選択できるから、従来の薄膜圧電振動子の欠点を
除くことができる。すなわち、容量比の十分小さい振動
子を得ることが可能である。また同一シリコン基板上に
増幅器などの半導体素子を形成することが可能である。In the thin film piezoelectric vibrator manufactured by the manufacturing method of the present invention as described above, the impurity concentration of the silicon thin film shown at 34 in FIG. 6 can be arbitrarily selected, so that the drawbacks of the conventional thin film piezoelectric vibrator can be eliminated. . That is, it is possible to obtain a vibrator with a sufficiently small capacitance ratio. Furthermore, it is possible to form semiconductor elements such as amplifiers on the same silicon substrate.
この４付、Ｓｉ単結晶膜が絶縁体層上に形成されている
ため半導体素子を絶縁体分離したいわゆる、５ＯＩ（Ｓ
ｉｌｉｃｏｎ ｏｎ Ｉｎ５ｕｌａｔｏｒ）構造にする
ことができ、素子の高集積化、高速化が可能である。と
（番こ熱酸化８ｉ０．層は優れた電気絶縁体であり、誘
電率も小さく素子動作の高速化には優れた素材である。Since the Si single crystal film is formed on the insulator layer, the so-called 5OI (S
It is possible to have a structure such as ilicon on inverter), and it is possible to increase the integration and speed of the device. The thermal oxide 8i0. layer is an excellent electrical insulator and has a low dielectric constant, making it an excellent material for increasing the speed of device operation.
この点に関しても本発明の意義は大きＧ１０（実施例１
）
表面が（１００）面であるようなシリコン基板の表面に
厚さ０．２μｍのマグネシア（ＭｇＯ）を気相成長法で
エピタキシャル成長させた後、熱酸化法を用いてＭｇＯ
とシリコンの界面に０．５μｍのＳｉｎ。The significance of the present invention in this respect is also large in G10 (Example 1)
) Magnesia (MgO) with a thickness of 0.2 μm was epitaxially grown on the surface of a silicon substrate with a (100) plane using a vapor phase growth method, and then MgO was grown using a thermal oxidation method.
0.5 μm of Sin at the interface between silicon and silicon.
層を形成した。次にＭｇＯの上に厚さ３μｍのシリコン
単結晶薄膜をエピタキシャル成長させた。続いてＣＶＤ
法を用いてシリコン基板の両面に０．２μｍの８ｉ、Ｎ
、薄膜を形成し、裏面のＳｉ、Ｎ、膜番こウィンドウを
形成した後、エチレンジアミン、ピロカテコール及び水
からなるエツチング液（ＥＤＰ液）中でエツチングを行
なった。エツチング終了後、リン酸でＳｉ、Ｎ４膜を除
去し、さらにフッ酸でダイヤフラムの裏側の８ｉ０．と
ＭｇＯを除去した。得られたシリコン・ダイヤフラムの
厚さを測定したところ３μｍであり、エピタキシャル成
長させたシリコン単結晶薄膜からなるダイヤフラムが形
成されていることが確認された。formed a layer. Next, a silicon single crystal thin film with a thickness of 3 μm was epitaxially grown on the MgO. followed by CVD
0.2 μm of 8i, N was deposited on both sides of the silicon substrate using the method
After forming a thin film and forming a Si, N, and film window on the back side, etching was performed in an etching solution (EDP solution) consisting of ethylenediamine, pyrocatechol, and water. After etching, remove the Si and N4 films with phosphoric acid, and then remove the 8i0 film from the back side of the diaphragm with hydrofluoric acid. and MgO were removed. The thickness of the obtained silicon diaphragm was measured to be 3 μm, and it was confirmed that a diaphragm made of an epitaxially grown silicon single crystal thin film was formed.
次に、シリコン単結晶薄膜上に蒸着法でＡｕ／Ｔｉ電極
を形成し、続いてスパッタリング法で厚さ４μｍの酸化
亜鉛（ＺｎＯ）圧電薄膜を形成した。最後にＺｎＯ薄膜
上に蒸着法でＡｌ電極を形成して第６図の構造の薄膜圧
電振動子を製造した。Next, an Au/Ti electrode was formed on the silicon single crystal thin film by vapor deposition, and then a 4 μm thick zinc oxide (ZnO) piezoelectric thin film was formed by sputtering. Finally, an Al electrode was formed on the ZnO thin film by vapor deposition to produce a thin film piezoelectric vibrator having the structure shown in FIG.
同時に、従来の方法を用いて、ダイヤフラムを形成する
シリコン薄膜がホウ素をＩＱ” ／ｃｒｎ”の濃度にド
ープしたシリコン薄膜であるような薄膜圧電振動子を製
造した。At the same time, using a conventional method, a thin film piezoelectric vibrator was manufactured in which the silicon thin film forming the diaphragm was a silicon thin film doped with boron to a concentration of IQ''/crn''.
２種類の振動子の特性を測定した結果、従来方法による
振動子の容量比は８０、本発明の方法によって製造した
振動子の容量比は２５であり、本発明を適用することに
よって容量比が従来方法に比べて約％に改善できること
が実証された。As a result of measuring the characteristics of two types of vibrators, the capacitance ratio of the vibrator manufactured by the conventional method was 80, and the capacity ratio of the vibrator manufactured by the method of the present invention was 25. By applying the present invention, the capacitance ratio was It has been demonstrated that this can be improved by approximately % compared to the conventional method.
（実施例２）
酸化物薄膜としてマグネシア・スピネル（ＭｇＯ−Ａ
Ｉ、０． ）単結晶薄膜をシリコン基板上にエピタキシ
ャル成長させ、実施例１とまった（同様に薄膜圧電振動
子を製造した。この振動子についても容量比は２５であ
った。(Example 2) Magnesia spinel (MgO-A
I, 0. ) A single crystal thin film was epitaxially grown on a silicon substrate, and Example 1 was completed (A thin film piezoelectric vibrator was similarly manufactured. The capacitance ratio of this vibrator was also 25.
（実施例３）
酸化物薄膜としてサファイヤ（Ａｌ、Ｏｓ）単結晶薄膜
をシリコン基板上にエピタキシャル成長させ、実施例１
とまったく同様に薄膜圧電振動子を製造した。この振動
子についても容量比は２５であった。(Example 3) A sapphire (Al, Os) single crystal thin film was epitaxially grown on a silicon substrate as an oxide thin film, and Example 1
A thin film piezoelectric vibrator was manufactured in exactly the same manner. The capacitance ratio of this vibrator was also 25.
以上の実施例から明らかなように、本発明を適用するこ
とによって従来方法の欠点を除いて容量比の十分小さい
薄膜圧電振動子を製造することが可能となり、この薄膜
圧電振動子を用いれば制御範囲の広い発振器及び比帯域
の広いフィルタが実現できる。As is clear from the above embodiments, by applying the present invention, it is possible to eliminate the drawbacks of the conventional method and to manufacture a thin film piezoelectric vibrator with a sufficiently small capacitance ratio. An oscillator with a wide range and a filter with a wide fractional band can be realized.
さらに本発明の製造方法においてはダイヤフラムを構成
するシリコン単結晶薄膜の不純物濃度について何らの制
約もなく、シたがって薄膜圧電振動子を形成すると同一
のシリコン基板上に増幅器などの半導体素子を容易に形
成できることが明らかであり、この場合素子をＳＯＩ構
造にして高速化、高集積化を計るときに本発明になる５
ｉｏ２層は有利に働く。Furthermore, in the manufacturing method of the present invention, there are no restrictions on the impurity concentration of the silicon single crystal thin film constituting the diaphragm, and therefore, once a thin film piezoelectric vibrator is formed, semiconductor devices such as amplifiers can be easily fabricated on the same silicon substrate. It is clear that it can be formed, and in this case, the present invention becomes possible when the device is made into an SOI structure to achieve high speed and high integration.
The io2 layer works to your advantage.
以上のように本発明の製造方法は、従来方法の欠点を除
いて特性の良好な薄膜圧電振動子の製造を可能にし、ま
た発振器などの装置の小形化を可能にするものである。As described above, the manufacturing method of the present invention makes it possible to manufacture a thin film piezoelectric vibrator with good characteristics without the drawbacks of the conventional method, and also makes it possible to downsize devices such as oscillators.
第１図、第２図は薄膜圧電振動子の構造を示す図であり
、第１図は平面図、第２図は断面図である。図において
１１はシリコン基板、１２は空孔、１３はシリコン薄膜
、１４は下地電極、１５は圧電薄膜、１６は上部電極、
１７は引き出し電極である。
第３図〜第６図は本発明による薄膜圧電振動子の製造工
程を示す図。３１はシリコン基板、３２は酸化物単結晶
薄膜、３３は８ｉ０２層、３４はシリコン単結晶薄膜、
３５はエツチング保護膜、３６は下地電極、第１図
５
第 ２ 図
第 ３ 図
第５図
第６図FIGS. 1 and 2 are diagrams showing the structure of a thin film piezoelectric vibrator, with FIG. 1 being a plan view and FIG. 2 being a sectional view. In the figure, 11 is a silicon substrate, 12 is a hole, 13 is a silicon thin film, 14 is a base electrode, 15 is a piezoelectric thin film, 16 is an upper electrode,
17 is an extraction electrode. FIGS. 3 to 6 are diagrams showing the manufacturing process of a thin film piezoelectric vibrator according to the present invention. 31 is a silicon substrate, 32 is an oxide single crystal thin film, 33 is an 8i02 layer, 34 is a silicon single crystal thin film,
35 is an etching protective film, 36 is a base electrode, FIG. 1, 5, 2, 3, 5, and 6.
Claims (2)
シャル成長させる工程と、熱酸化によって該酸化物単結
晶薄膜とシリコン基板との界面にＳ ｉＯ。 層を形成する工程と、該酸化物単結晶薄膜の上にシリコ
ン単結晶薄膜をエピタキシャル成長させる工程と、シリ
コン基板の一部をエツチングによって除去する工程と、
該シリコン基板が除去された部分に対応する前記シリコ
ン単結晶薄膜上に下地電極、圧電薄膜、上部電極を順に
形成する工程とを有することを特徴とする薄膜圧電振動
子の製造方法。(1) A step of epitaxially growing an oxide single crystal thin film on a silicon substrate, and depositing SiO at the interface between the oxide single crystal thin film and the silicon substrate by thermal oxidation. a step of epitaxially growing a silicon single crystal thin film on the oxide single crystal thin film; and a step of removing a portion of the silicon substrate by etching.
A method for manufacturing a thin film piezoelectric vibrator, comprising the step of sequentially forming a base electrode, a piezoelectric thin film, and an upper electrode on the silicon single crystal thin film corresponding to the portion where the silicon substrate has been removed.
化物単結晶薄膜はスピネル、サファイヤ、或いはマグネ
シアのうちの１以上からなる単結晶薄膜である特許請求
の範囲第１項記載の薄膜圧電振動子の製造方法。(2) The method for manufacturing a thin film piezoelectric vibrator according to claim 1, wherein the oxide single crystal thin film epitaxially grown on the silicon substrate is a single crystal thin film made of one or more of spinel, sapphire, or magnesia. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4348383A JPS59169214A (en) | 1983-03-16 | 1983-03-16 | Production of thin film piezoelectric oscillator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4348383A JPS59169214A (en) | 1983-03-16 | 1983-03-16 | Production of thin film piezoelectric oscillator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59169214A true JPS59169214A (en) | 1984-09-25 |
Family
ID=12664966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4348383A Pending JPS59169214A (en) | 1983-03-16 | 1983-03-16 | Production of thin film piezoelectric oscillator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59169214A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5552347A (en) * | 1992-01-16 | 1996-09-03 | Oki Electric Industry Co., Ltd. | Fabrication process for a semiconductor pressure sensor for sensing pressure applied thereto |
-
1983
- 1983-03-16 JP JP4348383A patent/JPS59169214A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5552347A (en) * | 1992-01-16 | 1996-09-03 | Oki Electric Industry Co., Ltd. | Fabrication process for a semiconductor pressure sensor for sensing pressure applied thereto |
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