JP6757544B2 - Piezoelectric device, its manufacturing method and optical deflector - Google Patents
Piezoelectric device, its manufacturing method and optical deflector Download PDFInfo
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- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 2
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Description
本発明は圧電体装置、その製造方法及び光偏向器に関する。 The present invention relates to a piezoelectric device, a method for manufacturing the same, and an optical deflector.
最近、光スキャナに用いられる圧電アクチュエータ、圧電センサ等の圧電体装置は半導体製造技術及びマイクロマシン技術によって製造されたマイクロエレクトロメカニカルシステム（ＭＥＭＳ）装置によって構成されている。 Recently, piezoelectric devices such as piezoelectric actuators and piezoelectric sensors used in optical scanners are composed of microelectromechanical system (MEMS) devices manufactured by semiconductor manufacturing technology and micromachine technology.
図８は第１の従来の圧電体装置を示す全体断面図である（参照：特許文献１）。 FIG. 8 is an overall cross-sectional view showing the first conventional piezoelectric device (see: Patent Document 1).
図８において、第１の従来の圧電体装置は、単結晶シリコン基板１、酸化シリコンよりなる絶縁層２、Ｔｉ／Ｐｔ／ＳＲＯ下部電極層３、ジルコン酸チタン酸鉛（ＰｂＺｒｘＴｉ１−ｘＯ３）（ＰＺＴ）よりなる柱状構造のＰＺＴ層４、及びＰｔよりなる上部電極層５によって構成されている。また、下部電極層３は、絶縁層２の酸化シリコン及びＰｔとの密着性がよいＴｉ又はＴｉＯ２よりなる密着層３−１、密着層３−１上のＰｔよりなる金属層３−２、及び金属層３−２の配向面方位（１１１）がＰＺＴ層４の配向面方向（１００）又は（１１０）に影響しないようにするシード層として作用する金属酸化物たとえばルテニウム酸ストロンチウム（ＳｒＲｕＯ３）（ＳＲＯ）よりなるＳＲＯ層３−３によって構成されている。この場合、ＳＲＯ層３−３とＰＺＴ層４とは同一の結晶構造つまりペロブスカイト相を有する。 In FIG. 8, the first conventional piezoelectric device includes a single crystal silicon substrate 1, an insulating layer 2 made of silicon oxide, a Ti / Pt / SRO lower electrode layer 3, and lead zirconate titanate (PbZr x Ti 1-x). It is composed of a columnar PZT layer 4 made of O 3 ) and (PZT) and an upper electrode layer 5 made of Pt. Further, the lower electrode layer 3 has an adhesion layer 3-1 made of Ti or TiO 2 having good adhesion to silicon oxide and Pt of the insulating layer 2, and a metal layer 3-2 made of Pt on the adhesion layer 3-1. And a metal oxide acting as a seed layer that prevents the orientation plane orientation (111) of the metal layer 3-2 from affecting the orientation plane orientation (100) or (110) of the PZT layer 4, such as strontium ruthenate (SrRuO 3 ). It is composed of an SRO layer 3-3 composed of (SRO). In this case, the SRO layer 3-3 and the PZT layer 4 have the same crystal structure, that is, a perovskite phase.
ＳＲＯ層３−３が存在しない場合には、ＰＺＴ層４の成膜時の基板加熱時のＴｉ成分のＴｉ密着層３−１からＰｔ金属層３−２への拡散、表面露出、Ｐｔ金属層３−２の表面の空孔形成があるが、これらはＳＲＯ層３−３によって抑制される。 When the SRO layer 3-3 does not exist, the Ti component diffuses from the Ti adhesion layer 3-1 to the Pt metal layer 3-2 when the substrate is heated during film formation of the PZT layer 4, surface exposure, and the Pt metal layer. There are vacancies on the surface of 3-2, which are suppressed by the SRO layer 3-3.
また、ＳＲＯ層３−３が存在しない場合には、ＰＺＴ層４の成膜時の基板加熱時にＰｂ成分のＰＺＴ層４からＰｔ金属層３−２へ拡散してＰＺＴ層４の成膜初期に圧電相であるペロブスカイト相に常誘電体相であるパイロクロア相が混在してＰＺＴ層４の圧電特性の劣化及び駆動耐久性の低下を招き、また、連続駆動時にＰｂ欠損によるリーク電流が発生して絶縁耐性が劣化するが、これらはＳＲＯ層３−３によって抑制される。 When the SRO layer 3-3 does not exist, it diffuses from the PZT layer 4 of the Pb component to the Pt metal layer 3-2 when the substrate is heated during the formation of the PZT layer 4, and at the initial stage of the formation of the PZT layer 4. The perovskite phase, which is a piezoelectric phase, and the pyrochlor phase, which is a normal dielectric phase, are mixed to cause deterioration of the piezoelectric characteristics of the PZT layer 4 and deterioration of drive durability, and leakage current due to Pb deficiency occurs during continuous drive. The insulation resistance deteriorates, but these are suppressed by the SRO layer 3-3.
さらに、応力が大きいＰｔ金属層３−２では半円球上突起物（ヒロック）が発生し易いが、ＳＲＯ層３−３の形成前に急加熱（ＲＴＡ）処理によってＰｔ金属層３−２の残留応力を解放してヒロックの発生を抑制する。尚、Ｐｔ金属層３−２にヒロックが発生すると、ＳＲＯ層３−３が存在しない場合、その上のＰＺＴ層４の膜構造が乱れ、ＰＺＴ層４の膜中にボイド、結晶境界の開きが発生して圧電特性、絶縁耐性が劣化する。 Further, although hemispherical protrusions (hillocks) are likely to occur in the Pt metal layer 3-2 having a large stress, the Pt metal layer 3-2 is subjected to rapid heating (RTA) treatment before the formation of the SRO layer 3-3. Relieves residual stress and suppresses the generation of hillock. When hillock is generated in the Pt metal layer 3-2, if the SRO layer 3-3 does not exist, the film structure of the PZT layer 4 above it is disturbed, and voids and crystal boundaries are opened in the film of the PZT layer 4. It occurs and the piezoelectric characteristics and dielectric strength deteriorate.
しかしながら、上述の図８の第１の従来の圧電体装置においては、ＳＲＯ層３−３はその上のＰＺＴ層４と共に（１００）又は（１１０）面に優先配向して柱状構造を形成する。従って、ＳＲＯ層３−３を厚くすると、その表面ラフネスＲａが２０ｎｍ以上となり、その上のＰＺＴ層４の表面ラフネスＲａもさらに大きくなる。この結果、電場がＰＺＴ層４の粗い表面に集中してＰＺＴ層４に亀裂が発生する。このため、ＳＲＯ層３−３は２０〜４０ｎｍと極めて薄くしなければならない。ＳＲＯ層３−３が薄くなると、大量のＰｂ蒸気が存在するアーク放電イオンプレーティング（ＡＤＲＩＰ）法等のプラズマ成膜処理においてＰｂ成分の下部電極層３への拡散防止が不充分となり、ＰＺＴ層４中のＰｂ濃度が低下する。この結果、図９に示すように、ＰＺＴ層４のＸ線回析（ＸＲＤ）パターンにおいて、ペロブスカイト相（１１０）に由来する３１°ピークに加えてパイロクロア相に由来する２９.９°ピークが観察される。尚、図９のＸ線回析（ＸＲＤ）パターンはナロースキャンと呼ばれる狭い角度範囲を常にゆっくりと行うことにより通常のＸＲＤ評価測定で見逃される微量な異相も検出できる。しかも、対数表示なので、さらに微量の異相も検出できる。このように、ＰＺＴ層４の成膜初期にバイロクロア相が混在してＰＺＴ層４と下部電極層３との界面に形成されて圧電特性は低下する。 However, in the first conventional piezoelectric device of FIG. 8 described above, the SRO layer 3-3 is preferentially oriented toward the (100) or (110) plane together with the PZT layer 4 on the SRO layer 3-3 to form a columnar structure. Therefore, when the SRO layer 3-3 is made thicker, its surface roughness Ra becomes 20 nm or more, and the surface roughness Ra of the PZT layer 4 above it also becomes larger. As a result, the electric field is concentrated on the rough surface of the PZT layer 4, and cracks are generated in the PZT layer 4. Therefore, the SRO layer 3-3 must be extremely thin, 20 to 40 nm. When the SRO layer 3-3 becomes thin, the prevention of diffusion of the Pb component into the lower electrode layer 3 becomes insufficient in the plasma film formation process such as the arc discharge ion plating (ADRIP) method in which a large amount of Pb vapor is present, and the PZT layer The Pb concentration in 4 decreases. As a result, as shown in FIG. 9, in the X-ray diffraction (XRD) pattern of the PZT layer 4, a 29.9 ° peak derived from the pyrochlore phase was observed in addition to the 31 ° peak derived from the perovskite phase (110). Will be done. The X-ray diffraction (XRD) pattern of FIG. 9 can detect a minute amount of heterogeneous phase that is overlooked by a normal XRD evaluation measurement by always slowly performing a narrow angle range called a narrow scan. Moreover, since it is a logarithmic display, even a small amount of different phases can be detected. As described above, the bilochrome phase is mixed at the initial stage of film formation of the PZT layer 4 and is formed at the interface between the PZT layer 4 and the lower electrode layer 3, and the piezoelectric characteristics are deteriorated.
図１０は図８の圧電体装置の組織を示す走査型電子顕微鏡（ＳＥＭ）写真であり、（Ａ）はＰＺＴ層４の上面、（Ｂ）はＰＺＴ層４近傍の断面、（Ｃ）は下部電極層３近傍の断面を示す。ＳＲＯ層３−３が薄いと、図１０（Ｃ）に示す黒い染み状が下部電極層３に拡散浸透したＰｂであることが図１１に示す２次イオン質量スぺクトロメトリ（ＳＩＭＳ）結果で確認された。つまり、Ｐｂ成分の下部電極層３への拡散は薄いＳＲＯ層３−３では抑制されなかった。 10 is a scanning electron microscope (SEM) photograph showing the structure of the piezoelectric device of FIG. 8, where (A) is an upper surface of the PZT layer 4, (B) is a cross section near the PZT layer 4, and (C) is a lower portion. The cross section in the vicinity of the electrode layer 3 is shown. When the SRO layer 3-3 is thin, it is confirmed by the secondary ion mass spectrometry (SIMS) results shown in FIG. 11 that the black stain shown in FIG. 10 (C) is Pb diffused and permeated into the lower electrode layer 3. Was done. That is, the diffusion of the Pb component into the lower electrode layer 3 was not suppressed by the thin SRO layer 3-3.
Ｐｂの下部電極層３への拡散、浸透が激しいと、ＰＺＴ層４内のＰｂ欠損により図１０の（Ｃ）に示すごとく、下部電極層３の表面ラフネスＲａが大きくなり、図１０の（Ｂ）に示すごとく、ＰＺＴ層４内に縦筋状の欠損巣が生じ、上部電極層５の表面ラフネスＲａも大きくなる。従って、図１０の（Ａ）に示すごとく、ＰＺＴ層４の表面平坦性も劣化する。このようにして、絶縁耐性が劣化し、連続駆動時に縦筋状の欠陥巣をきっかけにリーク電流による絶縁破壊、機械的なクラックの発生による破壊を招く。 When the diffusion and penetration of Pb into the lower electrode layer 3 is intense, the surface roughness Ra of the lower electrode layer 3 increases due to the Pb deficiency in the PZT layer 4, as shown in FIG. 10 (C), and (B) in FIG. ), Longitudinal streaks are formed in the PZT layer 4, and the surface roughness Ra of the upper electrode layer 5 is also increased. Therefore, as shown in FIG. 10A, the surface flatness of the PZT layer 4 also deteriorates. In this way, the dielectric strength deteriorates, and during continuous driving, dielectric breakdown due to leakage current and breakdown due to the occurrence of mechanical cracks are caused by the vertical streak-shaped defect nests.
さらに、圧電特性及び絶縁特性がロット毎にばらつき、ＰＺＴ層４の特性の再現性が十分にとれない。 Further, the piezoelectric characteristics and the insulating characteristics vary from lot to lot, and the characteristics of the PZT layer 4 cannot be sufficiently reproducible.
図１２は第２の従来の圧電体装置を示す全体断面図である（参照：非特許文献１）。 FIG. 12 is an overall cross-sectional view showing a second conventional piezoelectric device (see: Non-Patent Document 1).
図１２においては、図８の圧電体装置の下部電極層３とＰＺＴ層４との間に金属酸化膜たとえばＰｂＯ１−ｘ（ｘは正の一定値）よりなる若干Ｐｂリッチな単一組成ＰｂＯ１−ｘバッファ層６を挿入してある。すなわち、ＰＺＴ層４の成長初期におけるパイロクロア相の発生抑制のために、ＰｂＯ１−ｘは若干Ｐｂリッチとなっている。これにより、ＰＺＴ層４の成膜時のＰｂの下部電極層３への拡散及び下部電極層３の歪みのＰＺＴ層４への直接伝播を緩和し、ＰＺＴ層４の膜質を向上させる。特に、バッファ層６はＰｂＯ１−ｘ、ＴｉＯｘ、ＰｂＴｉＯ３で構成することができるが、ＰｂＯ１−ｘはＰＺＴ層４の（１００）又は（１１０）優先配向を促進し、ドメインスイッチングを行うＰＺＴ層４にとって有益である。 In FIG. 12, a slightly Pb-rich single composition PbO composed of a metal oxide film, for example, PbO 1-x (x is a positive constant value) between the lower electrode layer 3 and the PZT layer 4 of the piezoelectric device of FIG. The 1-x buffer layer 6 is inserted. That is, PbO 1-x is slightly Pb-rich in order to suppress the generation of the pyrochlore phase in the early stage of growth of the PZT layer 4. As a result, the diffusion of Pb into the lower electrode layer 3 and the direct propagation of the strain of the lower electrode layer 3 to the PZT layer 4 at the time of film formation of the PZT layer 4 are alleviated, and the film quality of the PZT layer 4 is improved. In particular, the buffer layer 6 can be composed of PbO 1-x , TiO x , and PbTiO 3 , but PbO 1-x promotes (100) or (110) preferential orientation of the PZT layer 4 and performs domain switching. It is beneficial for PZT layer 4.
尚、単一組成ＰｂリッチＰｂＯ１−ｘバッファ層６の代わりに化学量論（ストキオメトリ）組成ＰｂＯの単一組成ＰｂＯバッファ層と用いる場合には、圧電特性を示すペロブスカイト相（１００）又は（１１０）の核成長に重要な役割を果たすＰｂＴｉＯ３の生成は起きにくく、ペロブスカイト相よりも生成の自由エネルギーの小さい常誘電性パイロクロア相が混入し易くなり、圧電特性を劣化させる。 When used in place of the single composition Pb-rich PbO 1-x buffer layer 6 with a single composition PbO buffer layer having a stoichiometric composition PbO, the perovskite phase (100) or (110) exhibiting piezoelectric characteristics. nucleation hardly occurs an important role PbTiO 3 to grow), a small paraelectric pyrochlore phase of free energy generated than a perovskite phase is easily mixed deteriorates the piezoelectric characteristics.
そこで、図１２のＰｂリッチな単一組成ＰｂＯ１−ｘバッファ層６においては、たとえば２０〜３０ｍｏｌ％ＰｂリッチなＰｂＯ１−ｘとしたので、ＰｂＯ１−ｘの蒸発とＰｂＴｉＯ３の核形成とが同時に進行し、ペロブスカイト相のＰＺＴ層４の成長が促進される。この場合、リッチなＰｂはＰｂＯ１−ｘとして蒸発するだけでなく、下部電極層３及びＰＺＴ層４の界面に拡散して、下部電極層３のモフォロジー（表面形態性）を低下させてＰＺＴ層４表面が粗くなったり、ＰＺＴ層４の結晶粒界にＰｂが偏析してリークパスを形成したり、ＰＺＴ層４の耐電圧を低下させたりする。従って、Ｐｂリッチ量としては、最適値が存在し、たとえば１０〜４０ｍｏｌ％Ｐｂがパイロクロア相抑制に効果的であり、さらに、２０〜３０ｍｏｌ％Ｐｂがリークパス等の欠陥抑制に効果的である。 Therefore, in the Pb-rich single-composition PbO 1-x buffer layer 6 of FIG. 12, for example, 20 to 30 mol% Pb-rich PbO 1-x was used, so that PbO 1-x was evaporated and PbTiO 3 was formed. At the same time, the growth of the PZT layer 4 of the perovskite phase is promoted. In this case, the rich Pb not only evaporates as PbO 1-x , but also diffuses to the interface between the lower electrode layer 3 and the PZT layer 4 to reduce the morphology (surface morphology) of the lower electrode layer 3 and reduce the PZT layer. 4 The surface becomes rough, Pb segregates at the crystal grain boundary of the PZT layer 4 to form a leak path, and the withstand voltage of the PZT layer 4 is lowered. Therefore, there is an optimum value for the amount of Pb rich, for example, 10 to 40 mol% Pb is effective for suppressing the pyrochlore phase, and 20 to 30 mol% Pb is effective for suppressing defects such as leak paths.
Ｐｂリッチな単一組成ＰｂＯ１−ｘバッファ層６によりＰｂ成分の下部電極層３への拡散が抑制され、ＰＺＴ層４中のＰｂ濃度が保持される。この結果、図１３のＸＲＤパターンに示すように、パイロクロア相に由来する２９．９°ピークは観察されない。 The Pb-rich single-composition PbO 1-x buffer layer 6 suppresses the diffusion of the Pb component into the lower electrode layer 3 and maintains the Pb concentration in the PZT layer 4. As a result, as shown in the XRD pattern of FIG. 13, the 29.9 ° peak derived from the pyrochlore phase is not observed.
図１４は図１２の圧電体装置の組織を示すＳＥＭ写真であり、（Ａ）はＰＺＴ層４の上面、（Ｂ）はＰＺＴ層４近傍の断面、（Ｃ）は下部電極層３近傍の断面を示す。図１４の（Ｃ）に示すごとく、下部電極層３にはほとんどＰｂの浸透が観察されず、下部電極層３の表面ラフネスＲａも小さくなり、図１４の（Ｂ）に示すごとく、縦筋状の欠陥巣もほとんどなくなり、上部電極層５の表面ラフネスＲａも小さくなる。従って、図１４の（Ａ）に示すごとく、ＰＺＴ層４の表面平坦性も良好となる。 14A and 14B are SEM photographs showing the structure of the piezoelectric device of FIG. 12, where FIG. 14A is a cross section of the upper surface of the PZT layer 4, FIG. 14B is a cross section near the PZT layer 4, and FIG. 14C is a cross section near the lower electrode layer 3. Is shown. As shown in FIG. 14 (C), almost no Pb permeation was observed in the lower electrode layer 3, and the surface roughness Ra of the lower electrode layer 3 was also reduced, and as shown in FIG. 14 (B), vertical stripes were formed. The defect foci of the upper electrode layer 5 are almost eliminated, and the surface roughness Ra of the upper electrode layer 5 is also reduced. Therefore, as shown in FIG. 14A, the surface flatness of the PZT layer 4 is also good.
しかしながら、図１２に示す第２の従来の圧電体装置においては、ＰＺＴ層４の成膜初期のパイロクロア相発生の抑制のために、化学量論組成（ストキオメトリ）ＰｂＯより若干Ｐｂ組成リッチな組成ＰｂＯ１−ｘ（ｘは正の一定値）で構成されているので、単一組成ＰｂＯ１−ｘバッファ層６の成長初期に過剰なＰｂが下部電極層３に僅かに拡散し、この結果、下部電極層３の属構造が乱れ、同時に単一組成ＰｂＯ１−ｘバッファ層６上に成長するＰＺＴ層４の成長も乱れ、ＰＺＴ層４中に僅かながらボイドや、結晶粒界の開きが発生するという課題がある。特に、高温での連続駆動耐久性が要求される車載用途においてこの課題は無視できない。 However, in the second conventional piezoelectric device shown in FIG. 12, the composition PbO is slightly richer in Pb composition than the chemical quantitative composition (stochiometri) PbO in order to suppress the generation of the pyrochlorophase in the initial stage of film formation of the PZT layer 4. Since it is composed of 1-x (x is a positive constant value), excess Pb diffuses slightly into the lower electrode layer 3 in the early stage of growth of the single composition PbO 1-x buffer layer 6, and as a result, the lower part is formed. The genus structure of the electrode layer 3 is disturbed, and at the same time, the growth of the PZT layer 4 growing on the single composition PbO 1-x buffer layer 6 is also disturbed, and voids and crystal grain boundaries are slightly opened in the PZT layer 4. There is a problem. In particular, this problem cannot be ignored in in-vehicle applications where continuous drive durability at high temperatures is required.
上述の課題を解決するために、本発明に係る圧電体装置は、基板と、基板上に設けられた絶縁層と、絶縁層に設けられた下部電極層と、下部電極層上に設けられた傾斜組成ＰｂＯ１−ｘバッファ層と、傾斜組成ＰｂＯ１−ｘバッファ層上に設けられたＰｂを含む圧電体層と、圧電体層上に設けられた上部電極層とを具備し、下部電極層側の傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘは圧電体層側の傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘより大きく、傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘは下部電極層側から圧電体層側へ傾斜的に減少したものである。 In order to solve the above-mentioned problems, the piezoelectric device according to the present invention is provided on the substrate, the insulating layer provided on the substrate, the lower electrode layer provided on the insulating layer, and the lower electrode layer. a graded composition PbO 1-x buffer layer, comprising a piezoelectric layer containing Pb provided on the graded composition PbO 1-x buffer layer, and an upper electrode layer provided on the piezoelectric layer, the lower electrode layer oxygen composition 1-x graded composition PbO 1-x buffer layer side is greater than the oxygen composition 1-x of the piezoelectric layer side gradient composition PbO 1-x buffer layers, oxygen composition of the graded composition PbO 1-x buffer layer 1-x is a gradient decrease from the lower electrode layer side to the piezoelectric layer side.
また、本発明に係る圧電体装置の製造方法は、基板上に絶縁層を形成する絶縁層形成工程と、絶縁層上に下部電極層を形成する下部電極層形成工程と、アーク放電反応性イオンプレーティング装置を用いて酸素ガス量を一定としＰｂ蒸気量を徐々に増加させることにより、下部電極層上に傾斜組成ＰｂＯ１−ｘバッファ層を形成する傾斜組成ＰｂＯ１−ｘバッファ層形成工程と、アーク放電反応性イオンプレーティング装置を用いて傾斜組成ＰｂＯ１−ｘバッファ層上にＰｂを含む圧電体層を形成する圧電体層形成工程と、圧電体層上に上部電極層を形成する工程とを具備するものである。 Further, the method for manufacturing the piezoelectric device according to the present invention includes an insulating layer forming step of forming an insulating layer on a substrate, a lower electrode layer forming step of forming a lower electrode layer on the insulating layer, and an arc discharge reactive ion. by gradually increasing the Pb amount of steam to a constant amount of oxygen gas by using the plating apparatus, the graded composition PbO 1-x buffer layer forming step of forming a graded composition PbO 1-x buffer layer on the lower electrode layer , A step of forming a piezoelectric layer containing Pb on a gradient composition PbO 1-x buffer layer using an arc discharge reactive ion plating apparatus, and a step of forming an upper electrode layer on the piezoelectric layer. And.
さらに、本発明に係る光偏向器は、上述の圧電体装置により構成されたカンチレバーを具備するものである。 Further, the optical deflector according to the present invention includes a cantilever configured by the above-mentioned piezoelectric device.
Ｐｂの下部電極層への拡散防止及び圧電体層におけるパイクロア相の生成防止の両立を図ると共に、１００℃を超える連続駆動耐久性を図ることができる。 It is possible to prevent diffusion of Pb into the lower electrode layer and prevent the formation of a pyrochlore phase in the piezoelectric layer, and to achieve continuous drive durability exceeding 100 ° C.
図１は本発明に係る圧電体装置の実施の形態を示し、（Ａ）は全体断面図、（Ｂ）は（Ａ）の部分拡大断面図である。 FIG. 1 shows an embodiment of a piezoelectric device according to the present invention, (A) is an overall sectional view, and (B) is a partially enlarged sectional view of (A).
図１においては、図１２の単一組成ＰｂＯ１−ｘバッファ層６の代りに、傾斜組成ＰｂＯ１−ｘバッファ層７を設けてある。傾斜組成ＰｂＯ１−ｘバッファ層７においては、Ｐｂに対する酸素の組成比１−ｘは膜厚方向に傾斜的に又は徐々に変化させる。たとえば、下部電極層３との界面側の値ｘはｘ＝０（ストキオメトリＰｂＯ）としてリッチなＰｂを抑制し、ＰＺＴ層４との界面側値ｘはｘ＝０．２５（ＰｂＯ０．７５）としてリッチなＰｂによりＰＺＴ層４の成膜初期の核形成時におけるパイクロア相の発生を抑制する。この場合、値ｘは急峻ではなく徐々にｘ＝０からｘ＝０．２５まで変化させて傾斜組成ＰｂＯ１−ｘバッファ層７の膜質低下及び応力の増加を抑制する。値ｘの最大値は０．１〜０．４が好ましく、さらに、０．２〜０．３が好ましい。これにより、Ｐｂの下部電極層３への拡散防止及びＰＺＴ層４におけるパイクロア相の生成防止の両立を図ると共に、１００℃を超える連続駆動耐久性を図ることができる。 In FIG. 1, the inclined composition PbO 1-x buffer layer 7 is provided instead of the single composition PbO 1-x buffer layer 6 of FIG. In the inclined composition PbO 1-x buffer layer 7, the composition ratio 1-x of oxygen with respect to Pb is changed obliquely or gradually in the film thickness direction. For example, the value x on the interface side with the lower electrode layer 3 is x = 0 (stochiometri PbO) to suppress rich Pb, and the value x on the interface side with the PZT layer 4 is x = 0.25 (PbO 0.75 ). The rich Pb suppresses the generation of the pycroa phase during nucleation of the PZT layer 4 at the initial stage of film formation. In this case, the value x is not steep but gradually changed from x = 0 to x = 0.25 to suppress the deterioration of the film quality and the increase of stress of the inclined composition PbO 1-x buffer layer 7. The maximum value of the value x is preferably 0.1 to 0.4, and more preferably 0.2 to 0.3. As a result, it is possible to prevent the diffusion of Pb into the lower electrode layer 3 and prevent the formation of the pyrochlore phase in the PZT layer 4, and to achieve continuous drive durability exceeding 100 ° C.
詳細には、傾斜組成ＰｂＯ１−ｘバッファ層７によりＰｂ成分の下部電極層３への拡散が完全に抑制され、ＰＺＴ層４中のＰｂ濃度が保持される。この結果、図２に示すごとく、ＸＲＤパターンにおいてパイクロア相に由来する３０°ピークは全く観察されない。 Specifically, the gradient composition PbO 1-x buffer layer 7 completely suppresses the diffusion of the Pb component into the lower electrode layer 3, and the Pb concentration in the PZT layer 4 is maintained. As a result, as shown in FIG. 2, no 30 ° peak derived from the pyrochlore phase is observed in the XRD pattern.
図３は図１の圧電体装置の組織を示すＳＥＭ写真であり、（Ａ）はＰＺＴ層４の上面、（Ｂ）はＰＺＴ層４近傍の断面、（Ｃ）は下部電極層３近傍の断面を示す。図３の（Ｃ）に示すごとく、下部電極層３にはＰｂの浸透が全く観察されず、下部電極層３の表面ラフネスＲａも小さくなり、図３の（Ｂ）に示すごとく、縦筋状の欠陥巣も全くなくなり、上部電極層５の表面ラフネスＲａも小さくなる。従って、図３の（Ａ）に示すごとく、ＰＺＴ層４の表面平坦性は顕著に良好となる。 3A and 3B are SEM photographs showing the structure of the piezoelectric device of FIG. 1, where FIG. 3A is a cross section of the upper surface of the PZT layer 4, FIG. 3B is a cross section near the PZT layer 4, and FIG. 3C is a cross section near the lower electrode layer 3. Is shown. As shown in FIG. 3 (C), no penetration of Pb was observed in the lower electrode layer 3, the surface roughness Ra of the lower electrode layer 3 was also reduced, and as shown in FIG. 3 (B), vertical stripes were formed. The defect nests of the upper electrode layer 5 are completely eliminated, and the surface roughness Ra of the upper electrode layer 5 is also reduced. Therefore, as shown in FIG. 3A, the surface flatness of the PZT layer 4 is remarkably good.
尚、化学量論（ストキオメトリ）ＰｂＯ層とＰｂリッチなＰｂＯ１−ｘ（ｘは正の一定値）層とを積層させた場合にも、ＰＺＴ層の成長促進及びＰｂリッチなＰｂＯ１−ｘの拡散防止を両立させることができると考えられるが、この場合、積層界面でＰｂの拡散が生じてＰｂリッチなＰｂＯ１−ｘの組成が変化してしまい、やはり、パイクロア相の抑制が不充分となり、ＰＺＴ層４の圧電特性が劣化する。 In addition, even when the chemical quantity theory (stochiometry) PbO layer and the Pb-rich PbO 1-x (x is a positive constant value) layer are laminated, the growth of the PZT layer is promoted and the Pb-rich PbO 1-x It is considered that diffusion prevention can be achieved at the same time, but in this case, Pb diffusion occurs at the laminated interface and the composition of Pb-rich PbO 1-x changes, and the suppression of the pyroa phase becomes insufficient. , The piezoelectric characteristics of the PZT layer 4 deteriorate.
図４は図１の圧電体装置の製造に用いられるアーク放電反応性イオンプレーティング装置を示す。 FIG. 4 shows an arc discharge reactive ion plating apparatus used for manufacturing the piezoelectric apparatus of FIG.
図４において、真空チャンバ４０１内の下方側に、Ｐｂ、Ｚｒ、Ｔｉを独立に蒸発させるためのＰｂ蒸発源４０２−１、Ｚｒ蒸発源４０２−２、Ｔｉ蒸発源４０２−３が設けられる。Ｐｂ蒸発源４０２−１、Ｚｒ蒸発源４０２−２、Ｔｉ蒸発源４０２−３上には、蒸気量センサ４０２−１Ｓ、４０２−２Ｓ、４０２−３Ｓが設けられている。真空チャンバ４０１内の上方側に、ウェハ４０３ａを載置するためのヒータ付ウェハ回転ホルダ４０３が設けられる。 In FIG. 4, Pb evaporation sources 402-1, Zr evaporation sources 402-2, and Ti evaporation sources 402-3 for independently evaporating Pb, Zr, and Ti are provided on the lower side in the vacuum chamber 401. Steam amount sensors 402-1S, 402-2S, and 402-3S are provided on the Pb evaporation source 402-1, the Zr evaporation source 402-2, and the Ti evaporation source 402-3. A wafer rotation holder 403 with a heater for mounting the wafer 403a is provided on the upper side in the vacuum chamber 401.
また、真空チャンバ４０１の上流側には、アーク放電を維持するために不活性ガスたとえば１０ｓｃｃｍのＡｒガスおよび１００ｓｃｃｍのＨｅガスを導入する圧力勾配型プラズマガン４０４、傾斜組成ＰｂＯ１−ｘバッファ層７及びＰＺＴ層４の酸素原料となる酸素（Ｏ２）ガスを導入するＯ２ガス導入口４０５とが設けられる。他方、真空チャンバ４０１の下流側には、真空ポンプ（図示せず）に接続された排気口４０６が設けられる。 Further, on the upstream side of the vacuum chamber 401, a pressure gradient type plasma gun 404 in which an inert gas such as 10 sccm Ar gas and 100 sccm He gas is introduced to maintain arc discharge, and a gradient composition PbO 1-x buffer layer 7 And an O 2 gas introduction port 405 for introducing an oxygen (O 2 ) gas which is an oxygen raw material of the PZT layer 4 is provided. On the other hand, on the downstream side of the vacuum chamber 401, an exhaust port 406 connected to a vacuum pump (not shown) is provided.
図４のＡＤＲＩＰ装置において、圧力勾配型プラズマガン４０４によって導入されたＡｒガスおよびＨｅガスによって高密度・低電子温度の放電電圧８０Ｖ、放電電流約８０Ａのウェハ３０３ａ直下５×１０１１個／ｃｍ３の高密度のアーク放電プラズマ４０７を発生させ、そしてＯ２ガス導入口から約２００ｓｃｃｍのＯ２ガスを導入し真空チャンバ４０１内に発生している高密度・低電子温度のアーク放電プラズマ４０７でＯ２ガスを励起させることによって、真空チャンバ４０１内に多量の酸素ラジカルを主とする活性原子、分子が生成される。酸素ラジカルはプラズマ発光分析による７７７ｎｍ発光ピークで確認できる。他方、Ｐｂ蒸発源４０２−１、Ｚｒ蒸発源４０２−２及びＴｉ蒸発源４０２−３より発生したＰｂ蒸気、Ｚｒ蒸気及びＴｉ蒸気が上述の活性原子、分子と反応し、所定温度たとえば約５００℃に加熱されたウェハ４０３ａ上に付着し、この結果、ＰｂＯ１−ｘ及びＰｂＺｒｘＴｉ１−ｘＯ３が形成されることになる。尚、Ｐｂ蒸気、Ｚｒ蒸気、Ｔｉ蒸気は蒸気量センサ（一般的には、水晶振動子式膜厚モニタと呼ばれることが多い）４０２−１Ｓ、４０２−２Ｓ、４０２−３Ｓによって検出される。 In the ADRIP apparatus of FIG. 4, the Ar gas and He gas introduced by the pressure gradient type plasma gun 404 have a discharge voltage of 80 V at a high density and a low electron temperature, and a discharge current of about 80 A. Directly below the wafer 303a 5 × 10 11 pieces / cm 3 O in a to generate a high density of the arc discharge plasma 407, and O 2 gas inlet of about 200sccm of O 2 gas was introduced to the high density and low electron temperature is generated within the vacuum chamber 401 arc discharge plasma 407 By exciting two gases, active atoms and molecules mainly composed of a large amount of oxygen radicals are generated in the vacuum chamber 401. Oxygen radicals can be confirmed by 777 nm emission peak by plasma emission analysis. On the other hand, the Pb vapor, Zr vapor and Ti vapor generated from the Pb evaporation source 402-1, the Zr evaporation source 402-2 and the Ti evaporation source 402-3 react with the above-mentioned active atoms and molecules, and the predetermined temperature is, for example, about 500 ° C. It adheres to the heated wafer 403a, and as a result, PbO 1-x and PbZr x Ti 1-x O 3 are formed. The Pb steam, Zr steam, and Ti steam are detected by steam amount sensors (generally often referred to as crystal oscillator type film thickness monitors) 402-1S, 402-2S, and 402-3S.
次に、図１の圧電体装置の製造方法を図５を参照して説明する。 Next, a method of manufacturing the piezoelectric device of FIG. 1 will be described with reference to FIG.
始めに、熱酸化工程５０１にて、単結晶シリコン基板１を熱酸化して厚さ１μｍの酸化シリコンよりなる絶縁層２を形成する。この場合、単結晶シリコン基板１の代りに、厚さ４０μｍの単結晶シリコン活性層、厚さ１μｍの埋込み酸化シリコン層及び厚さ３５０μｍの支持層よりなるシリコンオンインシュレータ（ＳＯＩ）ウェハを用いてもよい。 First, in the thermal oxidation step 501, the single crystal silicon substrate 1 is thermally oxidized to form an insulating layer 2 made of silicon oxide having a thickness of 1 μm. In this case, instead of the single crystal silicon substrate 1, a silicon on insulator (SOI) wafer composed of a single crystal silicon active layer having a thickness of 40 μm, an embedded silicon oxide layer having a thickness of 1 μm, and a support layer having a thickness of 350 μm may be used. Good.
次に、スパッタリング工程４０２にて、マグネトロンスパッタ装置を用いて、厚さ１０ｎｍのＴｉ密着層３−１、厚さ１５０ｎｍのＰｔ金属層３−２及び厚さ４０ｎｍのＳＲＯ層３−３を連続的に成長させ、下部電極層３を形成する。この場合、ＳＲＯ層３−３の成膜温度は７００℃であり、電極として十分に使える抵抗値であった。 Next, in the sputtering step 402, a Ti adhesion layer 3-1 having a thickness of 10 nm, a Pt metal layer 3-2 having a thickness of 150 nm, and an SRO layer 3-3 having a thickness of 40 nm are continuously formed by using a magnetron sputtering apparatus. To form the lower electrode layer 3. In this case, the film formation temperature of the SRO layer 3-3 was 700 ° C., which was a resistance value that could be sufficiently used as an electrode.
次に、ＡＤＲＩＰ工程５０３にて、図４のＡＤＲＩＰ装置を用いて傾斜組成ＰｂＯ１−ｘバッファ層７を形成する。すなわち、図６に示すように、時刻ｔ０＝０分にて図４のアーク放電プラズマ４０７で２００ｓｃｃｍのＯ２ガスを励起させた酸素ラジカルの発生状態でＰｂ蒸発源４０２−１をＰｂ蒸発量を膜厚速度換算値０．３ｎｍ／ｓとし、基板温度を６００℃とする。この結果、蒸発したＰｂが酸素ラジカルと反応する。Ｐｂ蒸発量が安定した時刻ｔ１＝１分にて基板シャッタ（図示せず）を開とし、ＳＲＯ層３−３上にＰｂＯ１−ｘの成膜を開始する。この時刻ｔ１では、組成はストキオメトリＰｂＯである。次いで、Ｐｂ蒸発量を膜厚速度換算値０．３ｎｍ／ｓから１秒当たり１／６００ｎｍ／ｓと徐々に大きくし、Ｐｂ蒸発量を膜厚速度換算値０．５ｎｍ／ｓとなった時刻ｔ２＝３分にて基板シャッタ（図示せず）を閉とし、ＰｂＯｘの成膜を停止する。この時点では組成はＰｂリッチなＰｂＯ０．８（ｘ＝０．２）である。その後、時刻ｔ３＝４分までＰｂ蒸発量を膜厚速度換算値０．５ｎｍ／ｓに保持してオフとする。このようにして、ストキオメトリＰｂＯからＰｂリッチなＰｂＯ０．８へ徐々に変化して厚さ１００ｎｍの傾斜組成ＰｂＯ１−ｘバッファ層７が形成される。この場合、傾斜組成ＰｂＯ１−ｘバッファ層７の膜質の低下及び応力の発生は徐々の組成変化によって抑制できる。 Next, in the ADRIP step 503, the inclined composition PbO 1-x buffer layer 7 is formed using the ADRIP apparatus of FIG. That is, as shown in FIG. 6, the amount of Pb evaporation of the Pb evaporation source 402-1 in the state of generating oxygen radicals in which 200 sccm of O 2 gas was excited by the arc discharge plasma 407 of FIG. 4 at time t0 = 0 minutes. The film thickness rate conversion value is 0.3 nm / s, and the substrate temperature is 600 ° C. As a result, the evaporated Pb reacts with oxygen radicals. The substrate shutter (not shown) is opened at a time t1 = 1 minute when the amount of Pb evaporation is stable, and the film formation of PbO 1-x is started on the SRO layer 3-3. At this time t1, the composition is stochiometry PbO. Next, the amount of Pb evaporation was gradually increased from the film thickness rate conversion value of 0.3 nm / s to 1/600 nm / s per second, and the Pb evaporation amount became the film thickness rate conversion value of 0.5 nm / s at time t2. = substrate shutter (not shown) is closed at 3 minutes, it stops the formation of PbO x. At this point, the composition is Pb-rich PbO 0.8 (x = 0.2). After that, the amount of Pb evaporation is kept at the film thickness rate conversion value of 0.5 nm / s until time t3 = 4 minutes to turn it off. In this way, the gradient composition PbO 1-x buffer layer 7 having a thickness of 100 nm is formed by gradually changing from stochiometry PbO to Pb-rich PbO 0.8 . In this case, the deterioration of the film quality of the inclined composition PbO 1-x buffer layer 7 and the generation of stress can be suppressed by the gradual change in composition.
次に、ＡＤＲＩＰ工程５０４にて、図４のＡＤＲＩＰ装置を用いてＰＺＴ層４を形成する。すなわち、図４のアーク放電プラズマ４０７で２００ｓｃｃｍのＯ２ガスを励起させた酸素ラジカルの発生状態でＰｂ蒸発源４０２−１、Ｚｒ蒸発源４０２−２及びＴｉ蒸発源４０２−３を同時に蒸発させ、酸素ラジカルと反応させる。このとき、基板温度６００℃とする。次に、各Ｐｂ、Ｚｒ、Ｔｉ蒸発量が安定した時点で基板シャッタ（図示せず）を開としてペロブスカイト相のＰＺＴの成膜を開始し、所定時間後に、基板シャッタを閉とし、その後、各蒸発量をオフとする。このようにして、厚さ５μｍのＰＺＴ層４が形成される。 Next, in the ADRIP step 504, the PZT layer 4 is formed using the ADRIP apparatus of FIG. That is, the Pb evaporation source 402-1, the Zr evaporation source 402-2, and the Ti evaporation source 402-3 are simultaneously evaporated in a state where oxygen radicals excited by 200 sccm of O 2 gas are generated by the arc discharge plasma 407 of FIG. React with oxygen radicals. At this time, the substrate temperature is set to 600 ° C. Next, when the evaporation amounts of each Pb, Zr, and Ti became stable, the substrate shutter (not shown) was opened to start film formation of PZT of the perovskite phase, and after a predetermined time, the substrate shutter was closed, and then each Turn off the amount of evaporation. In this way, the PZT layer 4 having a thickness of 5 μm is formed.
最後に、スパッタリング工程５０５にて、マグネトロンスパッタ装置を用いて厚さ１５０ｎｍのＰｔ上部電極層５を形成し、図１の圧電体装置が完成する。 Finally, in the sputtering step 505, a Pt upper electrode layer 5 having a thickness of 150 nm is formed using a magnetron sputtering apparatus, and the piezoelectric apparatus of FIG. 1 is completed.
図１の圧電体装置をＭＥＭＳ技術によって長さ２ｍｍ、幅３００μｍのカンチレバー素子とし、これをリッド封止したセラミックパッケージに実装して初期の圧電定数（ｄ３１）を測定した。この結果、圧電定数（ｄ３１）は１０Ｖ／μｍの電圧印加の基で２２０ｐｍ／Ｖと良好な圧電特性を示した。また、１０５℃の環境局面の基で振幅５０Ｖの６０Ｈｚの単極性三角波電圧を印加して連続駆動試験を行った。その結果を図７に示す。図７に示すように、ＰｂＯ１−ｘバッファ層を有しない第１の従来の圧電体装置を含む光偏向器は２７０時間で絶縁破壊し、単一組成ＰｂＯ１−ｘバッファ層６を有する第２の従来の圧電体装置を含む光偏向器は６８０時間で絶縁破壊したのに対し、本発明に係る傾斜組成ＰｂＯ１−ｘバッファ層７を有する圧電体装置を含む光偏向器は１０００時間以上まで絶縁破壊せず耐久性が向上した。 The piezoelectric device of FIG. 1 was made into a cantilever element having a length of 2 mm and a width of 300 μm by MEMS technology, and this was mounted on a lid-sealed ceramic package to measure the initial piezoelectric constant (d 31 ). As a result, the piezoelectric constant (d 31 ) showed good piezoelectric characteristics of 220 pm / V under a voltage application of 10 V / μm. Further, a continuous drive test was conducted by applying a unipolar triangular wave voltage of 60 Hz having an amplitude of 50 V under an environmental aspect of 105 ° C. The result is shown in FIG. As shown in FIG. 7, the optical deflector comprising a first conventional piezoelectric device having no PbO 1-x buffer layer dielectric breakdown at 270 hours, the having a single composition PbO 1-x buffer layer 6 The optical deflector including the conventional piezoelectric device of No. 2 had dielectric breakdown in 680 hours, whereas the optical deflector including the piezoelectric device having the inclined composition PbO 1-x buffer layer 7 according to the present invention had 1000 hours or more. Durability has been improved without breaking the insulation.
上述の実施の形態においては、圧電体層としてＰＺＴ層を用いたが、本発明はＰｂを含む圧電体層に適用できる。 In the above-described embodiment, the PZT layer is used as the piezoelectric layer, but the present invention can be applied to the piezoelectric layer containing Pb.
また、本発明は上述の実施の形態の自明の範囲内のいかなる変更も適用し得る。 The present invention may also apply any modification within the obvious scope of the embodiments described above.
本発明は、超小型レーザプロジェクタ、車載用ヘッドアップディスプレイ、車載インパネ用リアプロジェクションディスプレイ、車載Ａピラー用プロジェクションディスプレイ、アダプティブ・ドライビング・ビーム（ＡＤＢ）灯体、車載レーザレーダ（ＬＩＤＡＲ）等に利用できる。 The present invention can be used for an ultra-small laser projector, an in-vehicle head-up display, an in-vehicle instrument panel rear projection display, an in-vehicle A-pillar projection display, an adaptive driving beam (ADB) lamp, an in-vehicle laser radar (LIDAR), and the like. ..
１：単結晶シリコン基板
２：酸化シリコン層
３：下部電極層
３−１：Ｔｉ密着層
３−２：Ｐｔ金属層
３−３：ＳＲＯ層
４：ＰＺＴ層
５：Ｐｔ上部電極層
６：単一組成ＰｂＯ１−ｘバッファ層
７：傾斜組成ＰｂＯ１−ｘバッファ層
1: Single crystal silicon substrate 2: Silicon oxide layer 3: Lower electrode layer 31: Ti adhesion layer 3-2: Pt metal layer 3-3: SRO layer 4: PZT layer 5: Pt upper electrode layer 6: Single Composition PbO 1-x buffer layer 7: Inclined composition PbO 1-x buffer layer
Claims (10)
前記基板上に設けられた絶縁層と、
前記絶縁層に設けられた下部電極層と、
前記下部電極層上に設けられた傾斜組成ＰｂＯ１−ｘバッファ層と、
前記傾斜組成ＰｂＯ１−ｘバッファ層上に設けられたＰｂを含む圧電体層と、
前記圧電体層上に設けられた上部電極層と
を具備し、
前記下部電極層側の前記傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘは前記圧電体層側の前記傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘより大きく、前記傾斜組成ＰｂＯ１−ｘバッファ層の酸素組成１−ｘは前記下部電極層側から前記圧電体層側へ傾斜的に減少した圧電体装置。 With the board
The insulating layer provided on the substrate and
The lower electrode layer provided on the insulating layer and
An inclined composition PbO 1-x buffer layer provided on the lower electrode layer, and
A piezoelectric layer containing Pb provided on the inclined composition PbO 1-x buffer layer and
It is provided with an upper electrode layer provided on the piezoelectric layer.
The oxygen composition 1-x of the inclined composition PbO 1-x buffer layer on the lower electrode layer side is larger than the oxygen composition 1-x of the inclined composition PbO 1-x buffer layer on the piezoelectric layer side, and the inclined composition PbO. The oxygen composition 1-x of the 1-x buffer layer is a piezoelectric device in which the oxygen composition 1-x is obliquely decreased from the lower electrode layer side to the piezoelectric layer side.
前記絶縁層は酸化シリコンよりなり、
前記上部電極層はＰｔよりなる請求項１に記載の圧電体装置。 The substrate is made of single crystal silicon
The insulating layer is made of silicon oxide.
The piezoelectric device according to claim 1, wherein the upper electrode layer is made of Pt.
前記絶縁層上に設けられた密着層と、
前記密着層上に設けられた金属層と、
前記金属層上に設けられた金属酸化物層と
を具備する請求項１に記載の圧電体装置。 The lower electrode layer includes an adhesion layer provided on the insulating layer and
The metal layer provided on the adhesion layer and
The piezoelectric device according to claim 1, further comprising a metal oxide layer provided on the metal layer.
前記金属層はＰｔよりなり、
前記金属酸化物層はＳｒＲｕＯ３よりなる請求項５に記載の圧電体装置。 The adhesion layer is made of Ti or TIO 2 .
The metal layer is made of Pt
The metal oxide layer piezoelectric device according to claim 5 consisting of SrRuO 3.
前記絶縁層上に下部電極層を形成する下部電極層形成工程と、
アーク放電反応性イオンプレーティング装置を用いて酸素ガス量を一定としＰｂ蒸気量を徐々に増加させることにより、前記下部電極層上に傾斜組成ＰｂＯ１−ｘバッファ層を形成する傾斜組成ＰｂＯ１−ｘバッファ層形成工程と、
前記アーク放電反応性イオンプレーティング装置を用いて前記傾斜組成ＰｂＯ１−ｘバッファ層上にＰｂを含む圧電体層を形成する圧電体層形成工程と、
前記圧電体層上に上部電極層を形成する工程と
を具備する圧電体装置の製造方法。 An insulating layer forming process for forming an insulating layer on a substrate,
A lower electrode layer forming step of forming a lower electrode layer on the insulating layer,
By gradually increasing the Pb amount of steam to the oxygen gas amount is constant with arc discharge reactive ion plating apparatus, gradient composition PbO forming a gradient composition PbO 1-x buffer layer on the lower electrode layer 1 x- buffer layer forming process and
A piezoelectric layer forming step of forming a piezoelectric layer containing Pb on the inclined composition PbO 1-x buffer layer using the arc discharge reactive ion plating apparatus.
A method for manufacturing a piezoelectric device including a step of forming an upper electrode layer on the piezoelectric layer.
An optical deflector including a cantilever configured by the piezoelectric device according to any one of claims 1 to 6.
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