JPH0749998B2 - Pyroelectric infrared array element - Google Patents
Pyroelectric infrared array elementInfo
- Publication number
- JPH0749998B2 JPH0749998B2 JP61272491A JP27249186A JPH0749998B2 JP H0749998 B2 JPH0749998 B2 JP H0749998B2 JP 61272491 A JP61272491 A JP 61272491A JP 27249186 A JP27249186 A JP 27249186A JP H0749998 B2 JPH0749998 B2 JP H0749998B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- pyroelectric
- array element
- infrared array
- substrate
- 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.)
- Expired - Fee Related
Links
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Radiation Pyrometers (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は焦電薄膜を用いた焦電型赤外線アレイ素子に関
するものである。TECHNICAL FIELD The present invention relates to a pyroelectric infrared array device using a pyroelectric thin film.
従来の技術 焦電型赤外線検出器は熱型の赤外線検出器で、常温動作
が可能で、感度の波長依存性が小さく、熱型検出器のな
かでは高感度である。2. Description of the Related Art Pyroelectric infrared detectors are thermal infrared detectors that are capable of operating at room temperature, have a small wavelength dependence of sensitivity, and have high sensitivity among thermal detectors.
焦電型検出器に使用されている材料にはTGS系・LiTaO3
系等の単結晶、PbTiO3系・Pbx Zr1-x TiO3系のセラミッ
ク、PVF2系等の有機膜等がある。The material used for the pyroelectric detector is TGS-based LiTaO 3
There is a single crystal such as a system, a PbTiO 3 system / Pb x Zr 1-x TiO 3 system ceramic, a PVF 2 system organic film, and the like.
PbTiO3は焦電材料の性能指数であるFv（＝γ／εCv）及
び が高い。ここでγは焦電係数、εは誘電率、Cvは体積比
熱、ｄは厚さである。また、PbTiO3は焦電係数の温度変
化が小さく、キュリー点が十分高い等の特長をもってい
る。焦電型検出器にはPbTiO3磁器が用いられる場合が多
い。磁器は多結晶であり、結晶軸の配列に方向性は無
く、したがって自発分極Psもランダムに配列している。
焦電材料は自発分極Psの変化を出力として取り出すた
め、Psが一方向に揃っているとき、最大出力が得られ
る。そこで、磁器には高電界を印加してPsの向きを揃え
る分極処理が必要である。PbTiO 3 is the figure of merit of pyroelectric materials Fv (= γ / εCv) and Is high. Here, γ is the pyroelectric coefficient, ε is the dielectric constant, Cv is the volume specific heat, and d is the thickness. In addition, PbTiO 3 has the characteristics that the change in pyroelectric coefficient with temperature is small and the Curie point is sufficiently high. PbTiO 3 porcelain is often used for the pyroelectric detector. The porcelain is a polycrystal, and the crystal axes are not directional, so that the spontaneous polarization Ps is also randomly arranged.
Since the pyroelectric material takes out the change in the spontaneous polarization Ps as an output, the maximum output is obtained when Ps is aligned in one direction. Therefore, it is necessary to apply a high electric field to the porcelain so that the Ps direction is aligned.
また、Ｃ軸配向したPbTiO3薄膜の配向軸方向に発生する
焦電気を利用した場合、Ｃ軸方向の誘電率が低下し、焦
電係数が増大するので、PbTiO3磁器の約３倍のFvを示す
高感度焦電材料を実現できることが、第30回応用物理学
関係連合講演予稿集7P−ｚ−２に報告されている。Also, when using a pyroelectric generated in the orientation direction of the PbTiO 3 films oriented C axis, the dielectric constant is reduced in the C-axis direction, the pyroelectric coefficient increases, about three times the Fv of PbTiO 3 ceramic It has been reported in the 30th Joint Lecture on Applied Physics Proceedings, 7P-z-2, that a highly sensitive pyroelectric material that exhibits
発明が解決しようとする問題点 焦電材料の厚さが薄くなるほど、雑音が小さくなり、検
出能:D＊は増大する。PbTiO3磁器でアレイを構成する場
合、磁器の薄膜化には限界があり、厚さを薄くしてＤ＊
を向上することは限界がある。また、各エレメント間の
クロストークが大きくなり空間分解能が低下する。その
ため各エレメントを分離することが必要となる。面積を
小さくすると電気容量が小さくなるため、外部からの静
電容量、浮遊容量の点から小形化も困難となる。Problems to be Solved by the Invention As the thickness of the pyroelectric material becomes thinner, the noise becomes smaller and the detectability: D * increases. When making an array with PbTiO 3 porcelain, there is a limit to how thin the porcelain can be made.
There is a limit to improving. In addition, the crosstalk between each element increases and the spatial resolution decreases. Therefore, it is necessary to separate each element. If the area is made smaller, the electric capacity becomes smaller, so it is difficult to make it smaller in terms of external electrostatic capacity and stray capacity.
さらに、焦電材料に分極処理を施すとき次のような問題
点が生じる。Further, the following problems occur when the pyroelectric material is polarized.
（１）分極処理により絶縁破壊が生じる場合がある。(1) Dielectric breakdown may occur due to polarization treatment.
（２）高密度に配列している高分解能アレイ素子では、
それらを均一に分極することが困難である。(2) In the high resolution array elements arranged in high density,
It is difficult to polarize them uniformly.
（３）半導体デバイス上に焦電薄膜を形成した集積化デ
バイスでは、分極処理そのものが不可能な場合がある。(3) In an integrated device in which a pyroelectric thin film is formed on a semiconductor device, polarization treatment itself may not be possible.
問題点を解決するための手段 化学式がPb1-x Lax Ti1-0.75x O3で組成範囲が０＜ｘ＜
0.15であり分極軸の75％以上が一方向に配向している焦
電薄膜と、焦電薄膜上に形成され膜方向の熱伝導が焦電
薄膜による熱伝導より小さくなるように薄膜化された受
光電極と、焦電薄膜と基板との間に設けられた各エレメ
ント毎に分離された電極薄膜とを用いる。Means for Solving Problems The chemical formula is Pb 1-x La x Ti 1-0.75x O 3 and the composition range is 0 <x <
Pyroelectric thin film with 0.15 and more than 75% of the polarization axis is oriented in one direction, and thin film was formed on the pyroelectric thin film so that the heat conduction in the film direction was smaller than that of the pyroelectric thin film. A light-receiving electrode and an electrode thin film separated between each element provided between the pyroelectric thin film and the substrate are used.
作用 上記のような焦電薄膜を用いた赤外線アレイ素子におい
ては、各エレメントを分離しなくてもクロストークが小
さいため工程数を低減できる。またPsが既に揃った自然
分極を有する焦電薄膜を用いることにより、分極処理を
おこなう必要が無く、歩留まり良く、高性能の焦電型赤
外線アレイ素子が実現できる。Action In the infrared array element using the pyroelectric thin film as described above, the number of steps can be reduced because the crosstalk is small even if the elements are not separated. Further, by using a pyroelectric thin film having natural polarization with Ps already aligned, it is not necessary to perform polarization treatment, and a high-performance pyroelectric infrared array element with good yield can be realized.
実施例 第１図は本発明の焦電型赤外線アレイ素子の構造を示す
図である。EXAMPLE FIG. 1 is a diagram showing the structure of a pyroelectric infrared array element of the present invention.
（100）でへき開し鏡面研摩したMgO単結晶基板１上に、
電極薄膜２として膜厚0.2μｍのPt薄膜をスパッタリン
グにより形成した。前記Pt電極薄膜２はアレイのピッチ
に合わせて格子状に分離、配列されており、（100）に
配向されている。その上に絶縁薄膜３としてArとO2の雰
囲気ガスでスパッタリングにより酸化チタン薄膜を形成
した。On the MgO single crystal substrate 1 cleaved with (100) and mirror-polished,
As the electrode thin film 2, a Pt thin film having a thickness of 0.2 μm was formed by sputtering. The Pt electrode thin films 2 are separated and arranged in a lattice pattern according to the pitch of the array, and are oriented in (100). A titanium oxide thin film was formed thereon as an insulating thin film 3 by sputtering in an atmosphere gas of Ar and O 2 .
次に、高周波マグネトロンスパッタ法で焦電薄膜４とし
てPb1-x Lax Ti1-0.75x O3（PLT）を４μｍ成長させ
た。雰囲気ガスにはArとO2の混合ガスを用い、スパッタ
リングターゲットは ｛（１−Ｙ）Pb1-x Lax Ti
1-0.75x O3＋Y PbO｝ の粉末である。表１にスパッタ
リング条件を示す。Next, Pb 1-x La x Ti 1-0.75x O 3 (PLT) was grown to 4 μm as the pyroelectric thin film 4 by the high frequency magnetron sputtering method. A mixed gas of Ar and O 2 was used as the atmosphere gas, and the sputtering target was {(1-Y) Pb 1-x La x Ti
It is a powder of 1-0.75x O 3 + Y PbO}. Table 1 shows the sputtering conditions.
この焦電薄膜４上にNiCrからなる複数の受光電極薄膜４
を蒸着により作製した。さらに、焦電薄膜４の下部にお
けるMgO基板１を熱農燐酸によりエッチングし開口部６
を設けた。A plurality of light receiving electrode thin films 4 made of NiCr are formed on the pyroelectric thin film 4.
Was produced by vapor deposition. Further, the MgO substrate 1 under the pyroelectric thin film 4 was etched with hot agricultural phosphoric acid to form the opening 6
Was set up.
第２図に本焦電型赤外線アレイ素子のクロストークを、
電極薄膜２が連続のときの試料と比較して示す。本焦電
型赤外線アレイ素子のクロストークの値は約1/3に低減
した。 Figure 2 shows the crosstalk of the pyroelectric infrared array element.
It shows in comparison with the sample when the electrode thin film 2 is continuous. The crosstalk value of this pyroelectric infrared array element was reduced to about 1/3.
PLT焦電薄膜が分極軸の75％以上が一方向に配向してい
るとき、焦電係数：γは５×10-8C／cm2Kとなり、この
値は200℃で100kV/cm印加して分極処理を行ったPbTiO3
セラミクス（γ＝1.8x10-8C／cm2K）とくらべかなり大
きい。配向率90％の場合焦電係数は6.8x10-8C／cm2Kで
ある。また、分極処理後の値と比べ殆ど変わらないばか
りでなく、配向率が小さい場合の分極後の値より大き
い。誘電率は、配向率90％の場合、セラミクスとほぼ同
等の値で約200である。When 75% or more of the polarization axis of the PLT pyroelectric thin film is oriented in one direction, the pyroelectric coefficient: γ is 5 × 10 -8 C / cm 2 K, and this value is 100 kV / cm at 200 ° C. Polarized PbTiO 3
It is considerably larger than the ceramics (γ = 1.8x10 -8 C / cm 2 K). When the orientation rate is 90%, the pyroelectric coefficient is 6.8 × 10 -8 C / cm 2 K. In addition, it is almost the same as the value after the polarization treatment, and is larger than the value after the polarization when the orientation ratio is small. When the orientation rate is 90%, the dielectric constant is about 200, which is almost the same value as that of ceramics.
このように本実施例に用いたPLT膜厚では、薄膜作製時
に十分にｃ軸に配向しておれば分極処理を行わなくても
自発分極が揃っており、特に配向率75％以上の薄膜でそ
の効果が大きいことが明らかになった。また、焦電材料
としての性能指数であるFv（＝γ／εCv）の値も大きく
なる。200℃で10分間100kV/cm印加して分極処理を行っ
たPbTiO3セラミクスの値と比較して、PLT薄膜は３倍強
の値を示した。As described above, in the PLT film thickness used in this example, if the film is sufficiently oriented in the c-axis at the time of thin film production, spontaneous polarization is uniform even if polarization treatment is not performed. It was revealed that the effect was great. Further, the value of Fv (= γ / εCv), which is a figure of merit as a pyroelectric material, also becomes large. Compared with the value of PbTiO 3 ceramics which was subjected to polarization treatment by applying 100 kV / cm for 10 minutes at 200 ° C., the PLT thin film showed a value more than 3 times.
絶縁薄膜３を設けることにより、開口部６を作製するさ
いの破壊が著しく減少し、膜強度が向上した。By providing the insulating thin film 3, the breakage when forming the opening 6 was significantly reduced and the film strength was improved.
以上述べたように、本発明による焦電薄膜を用いた焦電
型赤外線アレイ素子は、焦電薄膜を各エレメント毎に分
離することなく優れた特性を実現することができる。As described above, the pyroelectric infrared array element using the pyroelectric thin film according to the present invention can realize excellent characteristics without separating the pyroelectric thin film for each element.
発明の効果 本発明による焦電型赤外線アレイ素子は、焦電薄膜を各
エレメント毎に分離しない構成であるので、工程数が減
り、位置合わせの問題が解消し、高密度アレイが可能と
なる。また分極処理が不要であり高性能指数である焦電
薄膜を用いるので、特性も優れていて、歩留まりも大幅
に減少するので実用的にきわめて有効である。EFFECTS OF THE INVENTION Since the pyroelectric infrared array element according to the present invention has a configuration in which the pyroelectric thin film is not separated for each element, the number of steps is reduced, the problem of alignment is solved, and a high-density array is possible. Further, since a pyroelectric thin film which does not require polarization treatment and has a high performance index is used, the characteristics are excellent and the yield is greatly reduced, which is extremely effective in practice.
第１図は本発明の一実施例における焦電型赤外線アレイ
素子の構造を示す断面図、第２図は本発明の一実施例に
於けるクロストークを示すグラフである。 １……MgO基板、２……電極薄膜、３……絶縁薄膜、４
……PLT焦電薄膜、５……受光電極薄膜、６……開口
部。FIG. 1 is a sectional view showing the structure of a pyroelectric infrared array element in one embodiment of the present invention, and FIG. 2 is a graph showing crosstalk in one embodiment of the present invention. 1 ... MgO substrate, 2 ... electrode thin film, 3 ... insulating thin film, 4
...... PLT pyroelectric thin film, 5 …… light receiving electrode thin film, 6 …… opening.
Claims (4)
離した第１の電極薄膜と、前記第１の電極薄膜上に作製
された化学式がPb1-x Lax Ti1-0.75x O3で組成範囲が
０＜Ｘ＜0.15であり〈001〉方向に配向している焦電薄
膜と、前記焦電薄膜上に形成された受光電極薄膜とを有
することを特徴とする焦電型赤外線アレイ素子。1. A substrate, a plurality of separated first electrode thin films formed on the substrate, and a chemical formula prepared on the first electrode thin film is Pb 1-x La x Ti 1-0.75x. Pyroelectric type having a pyroelectric thin film having a composition range of 0 <X <0.15 of O 3 and oriented in a <001> direction, and a light receiving electrode thin film formed on the pyroelectric thin film. Infrared array element.
基板の一部を取り除いたことを特徴とする特許請求の範
囲第１項記載の焦電型赤外線アレイ素子。2. The pyroelectric infrared array element according to claim 1, wherein a part of the substrate which is in contact with the first electrode thin film or the pyroelectric thin film is removed.
ことを特徴とする特許請求の範囲第１項記載の焦電型赤
外線アレイ素子。3. A pyroelectric infrared array element according to claim 1, wherein an insulating thin film is provided between the substrate and the pyroelectric thin film.
に（100）配向した白金を用いたことを特徴とする特許
請求の範囲第２項記載の焦電型赤外線アレイ素子。4. The pyroelectric infrared array element according to claim 2, wherein the substrate is MgO single crystal, and (100) -oriented platinum is used for the first electrode thin film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61272491A JPH0749998B2 (en) | 1986-11-14 | 1986-11-14 | Pyroelectric infrared array element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61272491A JPH0749998B2 (en) | 1986-11-14 | 1986-11-14 | Pyroelectric infrared array element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63124924A JPS63124924A (en) | 1988-05-28 |
| JPH0749998B2 true JPH0749998B2 (en) | 1995-05-31 |
Family
ID=17514656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61272491A Expired - Fee Related JPH0749998B2 (en) | 1986-11-14 | 1986-11-14 | Pyroelectric infrared array element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0749998B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR950001303A (en) * | 1993-06-22 | 1995-01-03 | 이헌조 | Thin film infrared sensor structure and manufacturing method |
| US5558905A (en) * | 1994-03-08 | 1996-09-24 | The United States Of America As Represented By The Secretary Of The Army | Method of making a pyroelectric film sensing device |
-
1986
- 1986-11-14 JP JP61272491A patent/JPH0749998B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63124924A (en) | 1988-05-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |