JPH0369158B2 - - Google Patents
Info
- Publication number
- JPH0369158B2 JPH0369158B2 JP59201269A JP20126984A JPH0369158B2 JP H0369158 B2 JPH0369158 B2 JP H0369158B2 JP 59201269 A JP59201269 A JP 59201269A JP 20126984 A JP20126984 A JP 20126984A JP H0369158 B2 JPH0369158 B2 JP H0369158B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- dielectric layer
- light absorption
- thin film
- absorption layer
- 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
Links
- 230000031700 light absorption Effects 0.000 claims description 44
- 239000010409 thin film Substances 0.000 claims description 29
- 238000005530 etching Methods 0.000 claims description 22
- 239000000463 material Substances 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 12
- 239000010408 film Substances 0.000 claims description 5
- 229910052732 germanium Inorganic materials 0.000 claims description 3
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 3
- 239000000243 solution Substances 0.000 description 13
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 12
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- 238000000151 deposition Methods 0.000 description 8
- 230000008021 deposition Effects 0.000 description 8
- 239000011521 glass Substances 0.000 description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 229910017604 nitric acid Inorganic materials 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 230000008033 biological extinction Effects 0.000 description 3
- 230000000740 bleeding effect Effects 0.000 description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 238000007738 vacuum evaporation Methods 0.000 description 3
- 229910004613 CdTe Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 238000001771 vacuum deposition Methods 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 230000005283 ground state Effects 0.000 description 1
- 229910000449 hafnium oxide Inorganic materials 0.000 description 1
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 1
- CJNBYAVZURUTKZ-UHFFFAOYSA-N hafnium(IV) oxide Inorganic materials O=[Hf]=O CJNBYAVZURUTKZ-UHFFFAOYSA-N 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 1
- 239000005361 soda-lime glass Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、平面薄型デイスプレイ・デバイスと
して、文字、記号及び図形等を含むコンピユータ
の出力表示端末機器その他種々の表示装置に文
字、記号及び図形等の静止画像、動画像の表示手
段として利用される薄膜EL素子に関し、より詳
しくはコントラストを向上させた薄膜EL素子に
関するものである。Detailed Description of the Invention [Field of Application of the Invention] The present invention is a flat thin display device that displays characters, symbols, graphics, etc. on computer output display terminal equipment and various other display devices. The present invention relates to thin film EL devices used as means for displaying still images and moving images, and more specifically relates to thin film EL devices with improved contrast.
〔従来技術とその問題点〕
従来、この種の薄膜EL素子としては、第１図
ａ及びｂに示すものがあつた。すなわち、１はガ
ラス基板等の透光性基板、２はIn2 O3，Sn O2等
からなる透明電極、３はY2 O3，Ta2 O5等から
なる第１誘電体層、４は発光中心として0.1〜2.0
重量％のMn（又はTb，Tm，Yb，Er，Sm，Cu，
Al，Br等）をドープしたZnS（又はZnSe等）から
なるEL発光層、５はY2 O3，Ta2 O5等からなる
第２誘電体層、６はCdTeからなる光吸収層、及
び７はAl等からなる背面電極である。ここで、
透明電極２は透光性基板１上に複数帯状に平行配
列され、背面電極７は透明電極２と直交する方向
に複数帯状に平行配列されており、透明電極２と
背面電極７とが平面図的に見て交叉した位置がパ
ネルの１絵素に相当する。そして、電極２，７間
にAC電圧を印加することにより、発光層４内に
発生した電界によつて伝導帯に励起され、かつ加
速されて充分なエネルギーを得た電子が、直接
Mn発光中心を励起し、この励起されたMn発光
中心が基底状態に戻る際に黄色の発光を呈する。[Prior art and its problems] Conventionally, this type of thin film EL device has been shown in FIGS. 1a and 1b. That is, 1 is a transparent substrate such as a glass substrate, 2 is a transparent electrode made of In 2 O 3 , Sn O 2, etc., 3 is a first dielectric layer made of Y 2 O 3 , Ta 2 O 5 , etc., 4 is 0.1 to 2.0 as the emission center
Weight% Mn (or Tb, Tm, Yb, Er, Sm, Cu,
5 is a second dielectric layer made of Y 2 O 3 , Ta 2 O 5 , etc., 6 is a light absorption layer made of CdTe, and 7 is a back electrode made of Al or the like. here,
The transparent electrodes 2 are arranged in parallel in a plurality of strips on the transparent substrate 1, and the back electrodes 7 are arranged in parallel in a plurality of strips in a direction perpendicular to the transparent electrodes 2. Visually, the position where they intersect corresponds to one pixel on the panel. By applying an AC voltage between the electrodes 2 and 7, the electric field generated in the light-emitting layer 4 excites electrons into the conduction band, accelerates them, and obtains sufficient energy.
The Mn luminescent center is excited, and when the excited Mn luminescent center returns to the ground state, it emits yellow light.
しかしながら、第１図ａに示す薄膜EL素子、
すなわち、第２誘電体層５と背面電極７との間に
光吸収層６が介在している薄膜EL素子は、Alか
らなる背面電極７をリン酸と酢酸と硝酸との混合
液からなるエツチング液によつてエツチングして
形成すると、CdTeからなる光吸収層６も浸食さ
れてしまい光吸収効果を減少せしめる欠点があつ
た。さらに、絶縁性の光吸収層の存在によつて、
高電界を加えた場合に絶縁破壊を起こしやすいと
いう欠点もあつた。次に、第１図ｂに示す薄膜
EL素子、すなわち、発光層４と第２絶縁層５と
の間に光吸収層６が介在している薄膜EL素子は、
第２図の曲線Ｂに示すように、第２図の曲線Ａ
（第１図ａに示す薄膜EL素子の印加電圧−発行輝
度特性）と比較して、発光閾値電圧は小さくなる
ものの、印加電圧に対する発光輝度の立ち上りが
ゆるやかであり、発光輝度を高くするために、印
加電圧を相当高くしなければならず、また前述し
たと同様の理由により高電圧を加えた場合に絶縁
破壊を起こしやすい欠点があつた。 However, the thin film EL element shown in FIG.
That is, in a thin film EL element in which a light absorption layer 6 is interposed between a second dielectric layer 5 and a back electrode 7, a back electrode 7 made of Al is etched with a mixed solution of phosphoric acid, acetic acid, and nitric acid. When formed by etching with a liquid, the light absorption layer 6 made of CdTe is also eroded, reducing the light absorption effect. Furthermore, due to the presence of an insulating light absorption layer,
Another drawback was that dielectric breakdown was likely to occur when a high electric field was applied. Next, the thin film shown in FIG.
An EL element, that is, a thin film EL element in which a light absorption layer 6 is interposed between a light emitting layer 4 and a second insulating layer 5,
As shown in curve B of FIG. 2, curve A of FIG.
(Compared to the applied voltage-emission luminance characteristics of the thin film EL element shown in Figure 1a), although the emission threshold voltage is smaller, the rise of the emission luminance with respect to the applied voltage is gradual, and it is necessary to increase the emission luminance. However, the applied voltage had to be considerably high, and for the same reason as mentioned above, there was a drawback that dielectric breakdown was likely to occur when a high voltage was applied.
本発明は、前記の事情に鑑みてなされたもの
で、その目的は、コントラストを向上させるため
の光吸収層を設けた薄膜EL素子において、背面
電極を形成するためのエツチング手段に対して、
光吸収層が浸食されないようにすることであり、
また、印加電圧−発光輝度特性を良好に維持する
ことであり、更にまた、EL発光層と、このEL発
光層と当接している背面電極側の誘電体層との界
面による反射を減少させることである。
The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide etching means for forming a back electrode in a thin film EL element provided with a light absorption layer for improving contrast.
The purpose is to prevent the light absorption layer from being eroded.
Another purpose is to maintain good applied voltage-emission brightness characteristics, and furthermore, to reduce reflection at the interface between the EL light-emitting layer and the dielectric layer on the back electrode side that is in contact with this EL light-emitting layer. It is.
この目的を達成するために、透光性基板上に、
透明電極を設け、前記透明電極上に第１誘電体
層，EL発光層，第２誘電体層，光吸収層，第３
誘電体層を順次積層し、前記第３誘電体層上に背
面電極を設け、かつ前記光吸収層がゲルマニウム
の低級酸化物からなり、さらに前記第３誘電体層
が、前記背面電極を形成するときに使用されるエ
ツチング手段に対して耐エツチング性を有する材
質からなることを特徴とする薄膜EL素子を提供
し、さらに、印加電圧−発光輝度特性を良好に維
持するために、第２誘電体層の厚さを100Å以上
とし、また更に、第２誘電体層をEL発光層との
界面で光の反射が軽減される材質を選定する。以
下、本発明の実施例を図に基づき詳細に説明す
る。 To achieve this purpose, on a transparent substrate,
A transparent electrode is provided, and a first dielectric layer, an EL light emitting layer, a second dielectric layer, a light absorption layer, and a third dielectric layer are provided on the transparent electrode.
Dielectric layers are sequentially laminated, a back electrode is provided on the third dielectric layer, the light absorption layer is made of a lower oxide of germanium, and the third dielectric layer forms the back electrode. In order to provide a thin film EL element characterized by being made of a material that has etching resistance against etching means that is sometimes used, and to maintain good applied voltage-emission brightness characteristics, a second dielectric material is provided. The thickness of the layer is 100 Å or more, and the second dielectric layer is made of a material that reduces light reflection at the interface with the EL light emitting layer. Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
〔実施例 １〕 第３図に基づき詳述する。[Example 1] This will be explained in detail based on FIG.
先ず、アルミノシリケートガラスNA40（(株)保
谷硝子製）からなるガラス基板１上に、スズ酸化
物を混入した酸化インジウムからなる層（膜厚：
2000Å）を成膜し、エツチング液によつて帯状の
パターンを形成して透明電極２を設け、次に、酸
化ハフニウム（Hf O2）からなる第１誘電体層３
（膜厚：3000Å）を前記透明電極２上に積層する。
次に、前記第１誘電体層３上に、活性物質として
0.5重量％のMnを添加したZnS：Mn焼結ペレツ
トを蒸着源として真空蒸着法により、ZnS：Mn
からなるEL発光層４（膜厚：6000Å，屈折率：
2.35）を成膜する。次に、Hf O2からなる第２誘
電体層８（膜厚：300Å，折率：1.9）を真空蒸着
法により成膜し、次に、基板温度350℃，酸素圧
力１×10-4Torr及び蒸着速度２Å／secの条件
で、Geを電子ビーム加熱し、反応性真空蒸着法
によつて、前記第２誘電体層８上に光吸収層であ
るゲルマニウムの低級酸化物層９（膜厚：1000
Å，屈折率：3.8，消衰係数：0.8，シート抵抗：
約1010Ω／□，光吸収係数：波長580nmにおいて
1.7×105cm-1）を積層する。次に、前記Geの低級
酸化物層９に、Hf O2からなる第３誘電体層１０
（膜厚：3000Å）を成膜し、さらに、Al層を真空
蒸着法によつて、前記第３誘電体層１０上に積層
して、リン酸と酢酸と硝酸との混合液のエツチン
グ液によつて、前記Al層を帯状のパターンにエ
ツチングし、Alからなる背面電極７を設けて本
実施例の薄膜EL素子を形成する。なお、透明電
極２と背面電極７は、第１図に示したものと同様
に互いに直交するように複数帯状に配列させてい
る。 First, a layer (film thickness:
2000 Å), a band-shaped pattern is formed using an etching solution to provide a transparent electrode 2, and then a first dielectric layer 3 made of hafnium oxide (Hf O 2 ) is formed.
(film thickness: 3000 Å) is laminated on the transparent electrode 2.
Next, on the first dielectric layer 3, as an active material,
ZnS:Mn was deposited by vacuum evaporation using ZnS:Mn sintered pellets containing 0.5% by weight of Mn as a deposition source.
EL light emitting layer 4 (thickness: 6000 Å, refractive index:
2.35) is deposited. Next, a second dielectric layer 8 (thickness: 300 Å, refractive index: 1.9) made of Hf O 2 was formed by vacuum evaporation, and then the substrate temperature was 350°C and the oxygen pressure was 1×10 -4 Torr. Ge is heated with an electron beam at a deposition rate of 2 Å/sec, and a germanium lower oxide layer 9 (thickness: :1000
Å, refractive index: 3.8, extinction coefficient: 0.8, sheet resistance:
Approximately 10 10 Ω/□, light absorption coefficient: at wavelength 580 nm
1.7×10 5 cm -1 ). Next, a third dielectric layer 10 made of HfO 2 is added to the Ge lower oxide layer 9.
(thickness: 3000 Å), and further, an Al layer was laminated on the third dielectric layer 10 by vacuum evaporation method, and an etching solution of a mixed solution of phosphoric acid, acetic acid, and nitric acid was used. Therefore, the Al layer is etched into a band-like pattern and a back electrode 7 made of Al is provided to form the thin film EL device of this example. Note that the transparent electrode 2 and the back electrode 7 are arranged in a plurality of strips so as to be orthogonal to each other, similar to those shown in FIG.
本実施例による薄膜EL素子は、第３誘電体層
としてHf O2を使用しているので、Alの背面電
極を形成するときに使用されるエツチング液（リ
ン酸と酢酸と硝酸との混合液）に対して耐エツチ
ング性を示し、光吸収層を浸食することはない。
また、第２誘電体層の厚さが300Åであるので、
透明電極２と背面電極７間に交流電圧（周波数
1000Hz正弦波）を印加したとき、第５図の曲線Ｃ
に示すように、従来の第１図ｂの薄膜EL素子の
ように、印加電圧に対する発光輝度の立ち上りが
ゆるやかになることもなく、良好な印加電圧−発
光輝度特性を示す。また、本実施例の薄膜EL素
子のガラス基板１側での分光反射率特性は、第６
図の曲線Ｅに示すように低く、波長450〜700nm
における平均反射率は、約13％であり、低い反射
率の薄膜EL素子が得られた。この理由は、EL発
光層としてのZnS：Mnの屈折率が2.35に対して、
Hf O2からなる第２誘電体層の屈折率が1.9であ
り、かつ光吸収層としてのGeの低級酸化物の屈
折率が3.8，消衰係数が0.8であるので、それぞれ
の界面での反射率を低減することができたためで
ある。ここで、光吸収層としてGeの低級酸化物
を用いたのは、基板温度，蒸着速度，酸素圧力等
の蒸着条件を変化させることにより、光学定数の
屈折率と消衰係数とを制御することが可能とな
り、第２誘電体層と光吸収層との界面による反射
を防止することができ、コントラストを向上させ
ることもできる。さらに、本実施例では、光吸収
層のシート抵抗が約1010Ω／□であるので、クロ
ストーク及び絵素のにじみという現象も発生しな
かつた。 Since the thin film EL device according to this example uses HfO 2 as the third dielectric layer, the etching solution used when forming the Al back electrode (a mixture of phosphoric acid, acetic acid, and nitric acid) ) and does not corrode the light absorption layer.
Also, since the thickness of the second dielectric layer is 300 Å,
AC voltage (frequency
When a 1000Hz sine wave) is applied, curve C in Figure 5
As shown in FIG. 1, unlike the conventional thin film EL device shown in FIG. 1b, the rise of luminance with respect to applied voltage does not become gradual, and the device exhibits good applied voltage-emission luminance characteristics. In addition, the spectral reflectance characteristics on the glass substrate 1 side of the thin film EL element of this example are as follows:
As shown in curve E in the figure, the wavelength is 450 to 700 nm.
The average reflectance was about 13%, and a thin film EL element with low reflectance was obtained. The reason for this is that the refractive index of ZnS:Mn as an EL emitting layer is 2.35, whereas
The refractive index of the second dielectric layer made of Hf O 2 is 1.9, and the refractive index of the lower Ge oxide serving as the light absorption layer is 3.8, and the extinction coefficient is 0.8, so the reflection at each interface is This is because we were able to reduce the rate. Here, the reason why a lower oxide of Ge was used as the light absorption layer is that the optical constants refractive index and extinction coefficient can be controlled by changing the deposition conditions such as substrate temperature, deposition rate, and oxygen pressure. This makes it possible to prevent reflection at the interface between the second dielectric layer and the light absorption layer, and also to improve contrast. Furthermore, in this example, since the sheet resistance of the light absorption layer was approximately 10 10 Ω/□, phenomena such as crosstalk and pixel bleeding did not occur.
〔実施例 ２〕 第４図に基づき詳述する。[Example 2] This will be explained in detail based on FIG.
先ず、前記実施例１と同一のガラス基板１上
に、前記実施例１と同一の透明電極２を形成す
る。次に、五酸化タンタル（Ta2 O5）からなる
第１誘電体層３（膜厚：3000Å）と、活性物質と
して0.5重量％のMnを添加したZnS：Mn焼結ペ
レツトを蒸着源としたZnS：MnからなるEL発光
層４（膜厚：6000Å，屈折率：2.35）と、Hf O2
からなる第２誘電体層８（膜厚：300Å，屈折
率：1.9）とをそれぞれ高周波イオンプレテイン
グ法により成膜する。次に、Geをターゲツトと
して電子ビームにより加熱して、温度350℃，酸
素分圧１×10-4Torr，蒸着速度１Å／secで反応
性真空蒸着法により、Geの低級酸化物から成る
第１光吸収層９１（膜厚：500Å）を前記第２誘
電体層８上に成膜し、続いて、温度350℃，酸素
分圧５×10-5Torr，蒸着速度２Å／secで反応性
真空蒸着法により、Geの低級酸化物から成る第
２光吸収層９２（膜厚：800Å）を成膜し、前記
第１光吸収層９１と前記第２光吸収層９２からな
る光吸収層９を設けた。第１光吸収層９１及び第
２光吸収層９２の光吸収係数αは、波長580nmに
おいてそれぞれ0.7×105cm-1及び2.3×105cm-1で
あり、２層からなる光吸収層シート抵抗は約
109Ω／□である。次に、前記第２光吸収層９２
上に、高周波スパツタリング法により酸化アルミ
ニウム（Al2 O3）からなる第３誘電体層１０
（膜厚：2300Å）を成膜し、さらに、真空蒸着法
によりAl層（膜厚：5000Å）を積層し、アルカ
リ性である炭酸カルシウムの溶液をエツチング液
として、前記Al層を帯状のパターンにエツチン
グしてAlからなる背面電極７を設けて本実施例
の薄膜EL素子を形成する。なお、透明電極２と
背面電極７は、前記実施例１と同様の配列となつ
ている。 First, on the same glass substrate 1 as in Example 1, the same transparent electrode 2 as in Example 1 is formed. Next, a first dielectric layer 3 (thickness: 3000 Å) made of tantalum pentoxide (Ta 2 O 5 ) and ZnS:Mn sintered pellets to which 0.5% by weight of Mn was added as an active substance were used as a deposition source. EL light emitting layer 4 made of ZnS:Mn (film thickness: 6000 Å, refractive index: 2.35) and Hf O 2
A second dielectric layer 8 (thickness: 300 Å, refractive index: 1.9) is formed by high frequency ion plating. Next, Ge was heated with an electron beam as a target, and a first layer consisting of a lower Ge oxide was deposited by reactive vacuum evaporation at a temperature of 350°C, an oxygen partial pressure of 1×10 -4 Torr, and a deposition rate of 1 Å/sec. A light absorption layer 91 (thickness: 500 Å) is formed on the second dielectric layer 8, and then subjected to reactive vacuum at a temperature of 350°C, an oxygen partial pressure of 5×10 -5 Torr, and a deposition rate of 2 Å/sec. A second light absorption layer 92 (thickness: 800 Å) made of a lower Ge oxide is formed by vapor deposition, and a light absorption layer 9 made of the first light absorption layer 91 and the second light absorption layer 92 is formed. Established. The light absorption coefficient α of the first light absorption layer 91 and the second light absorption layer 92 is 0.7×10 5 cm −1 and 2.3×10 5 cm −1 at a wavelength of 580 nm, respectively, and the light absorption layer sheet consists of two layers. The resistance is approx.
10 9 Ω/□. Next, the second light absorption layer 92
A third dielectric layer 10 made of aluminum oxide (Al 2 O 3 ) is formed on top by a high-frequency sputtering method.
(thickness: 2300 Å), and further layered an Al layer (thickness: 5000 Å) by vacuum evaporation method, and etched the Al layer into a band-shaped pattern using an alkaline calcium carbonate solution as an etching solution. Then, a back electrode 7 made of Al is provided to form the thin film EL element of this example. Note that the transparent electrode 2 and the back electrode 7 are arranged in the same manner as in the first embodiment.
本実施例による薄膜EL素子は、第３誘電体層
としてAl2 O3を使用しているので、Alの背面電
極を形成するときに使用されるエツチング液（炭
酸カルシウム溶液）に対して耐エツチング性を示
す。また、第２誘電体層の厚さが300Åであるの
で、前記実施例と同様に、第５図の曲線Ｄで示す
とおり、良好な印加電圧−発光輝度特性を示す。
また、本実施例の薄膜EL素子のガラス基板１側
での分光反射率特性は、第６図の曲線Ｆに示すよ
うに低く、前記実施例１と同様の波長範囲、450
〜700nmにおける平均反射率は、約８％であつ
た。この理由は、前記実施例１と同様の理由に加
え、さらに前記実施例１と比較して反射率が低い
のは、第１光吸収層９１と第２光吸収層９２との
間の反射波の相互干渉を起こして光学的バツフア
層の作用をしているためである。さらに、Geの
低級酸化物のシート抵抗が109Ω／□と高いため
クロストーク及び絵素のにじみに対しても、前記
実施例１と同様に効果がある。 Since the thin film EL device according to this example uses Al 2 O 3 as the third dielectric layer, it is etching resistant to the etching solution (calcium carbonate solution) used when forming the Al back electrode. Show your gender. Further, since the thickness of the second dielectric layer is 300 Å, it exhibits good applied voltage-emission brightness characteristics, as shown by curve D in FIG. 5, similarly to the previous example.
Furthermore, the spectral reflectance characteristics of the thin film EL element of this example on the glass substrate 1 side are low as shown by curve F in FIG.
The average reflectance at ~700 nm was about 8%. The reason for this is that in addition to the same reason as in Example 1, the reason why the reflectance is lower than that in Example 1 is due to the reflected waves between the first light absorption layer 91 and the second light absorption layer 92. This is because they cause mutual interference and function as an optical buffer layer. Furthermore, since the sheet resistance of the lower Ge oxide is as high as 10 9 Ω/□, it is effective against crosstalk and picture element bleeding, similar to Example 1.
また、本実施例においては、光吸収層９を第１
光吸収層９１と第２光吸収層９２との２層にして
光吸収係数を段階的に増大させたが、Geの低級
酸化物の蒸着速度を、例えば、ＯÅ／secから連
続的に蒸着速度を高めて４Å／secにし、連続的
に光吸収係数を増大させ、１層の光吸収層として
もよい。 Further, in this example, the light absorption layer 9 is
The light absorption coefficient was increased stepwise by using two layers, the light absorption layer 91 and the second light absorption layer 92, but the deposition rate of the lower Ge oxide was changed continuously from, for example, OÅ/sec. The light absorption coefficient may be increased to 4 Å/sec, and the light absorption coefficient may be continuously increased to form a single light absorption layer.
以上、前記実施例１及び２において、Alの背
面電極をエツチングするエツチング液と耐エツチ
ング性を有する第３誘電体層の材質は、それぞれ
リン酸と酢酸と硝酸との混合液に対してHf O2，
炭酸カルシウムに対してAl2 O3であるが、これ
らに限らず、希塩酸，希硫酸等の酸性溶液をエツ
チング液として用いるときは、第３誘電体層の材
質としてTa2 O5，Si3 N4，Al2 O3，Zr O2（ただ
し、Zr O2は硫酸のときは不適。）も使用するこ
とができ、水酸化ナトリウム等のアルカリ性溶液
を用いるときは、第３誘電体層の材質としてY2
O3，Hf O2，Si3 N4，Zr O2も使用することがで
きる。また、背面電極としてAlを用いたときは、
前述のようなエツチング液を用いたが、他の材質
（例えば、Fe，Ni等の金属）からなる背面電極の
ときは、それをエツチングすることができるエツ
チング液を適宜選択すればよい。すなわち、本発
明においては、背面電極の材質に適するエツチン
グ液を選択し、かつ選択されたエツチング液に対
して耐エツチング性を有する材質からなる第３誘
電体層を設ければよい。 As described above, in Examples 1 and 2, the etching solution for etching the Al back electrode and the material of the third dielectric layer having etching resistance were HfO to a mixed solution of phosphoric acid, acetic acid, and nitric acid, respectively. 2 ,
Al 2 O 3 is used for calcium carbonate, but when an acidic solution such as dilute hydrochloric acid or dilute sulfuric acid is used as an etching solution, Ta 2 O 5 or Si 3 N can be used as the material for the third dielectric layer. 4 , Al 2 O 3 , Zr O 2 (however, Zr O 2 is not suitable when using sulfuric acid) can also be used, and when using an alkaline solution such as sodium hydroxide, the material of the third dielectric layer as Y 2
O3 , HfO2 , Si3N4 , ZrO2 can also be used . Also, when Al is used as the back electrode,
Although the above-mentioned etching solution was used, when the back electrode is made of other materials (for example, metals such as Fe, Ni, etc.), an etching solution capable of etching the back electrode may be appropriately selected. That is, in the present invention, it is sufficient to select an etching solution suitable for the material of the back electrode, and to provide the third dielectric layer made of a material that is resistant to etching with respect to the selected etching solution.
次に、本発明において、クロストーク及び絵素
のにじみを防止するためには、前記実施例１，２
では、それぞれ約1010Ω／□，約109Ω／□とした
が、低電圧で薄膜EL素子を駆動させるときは、
シート低抗は109Ω／□より低くてもよい。 Next, in the present invention, in order to prevent crosstalk and picture element bleeding, it is necessary to
In this case, we set the values to be approximately 10 10 Ω/□ and approximately 10 9 Ω/□, respectively, but when driving a thin film EL element with low voltage,
The sheet resistance may be lower than 10 9 Ω/□.
次に、本発明の第２誘電体層の膜厚は、100Å
以上が望ましい。すなわち、100Å未満であると、
印加電圧−発光輝度特性が、従来の第１図ｂの薄
膜EL素子の特性のようになる傾向があるので、
より印加電圧−発光輝度特性を良好に保つため
に、第２誘電体層の膜厚は100Å以上が望ましい。 Next, the film thickness of the second dielectric layer of the present invention is 100 Å.
The above is desirable. That is, if it is less than 100 Å,
Since the applied voltage-emission brightness characteristics tend to be similar to those of the conventional thin film EL element shown in Figure 1b,
In order to maintain better applied voltage-emission brightness characteristics, the thickness of the second dielectric layer is preferably 100 Å or more.
さらに、本発明は以上の実施例１，２に使用し
た各物質以外にガラス基板についてはソーダライ
ムガラス等の多成分系ガラス又は石英ガラス、透
明電極についてはIn2 O3若しくはこれにＷを添加
したもの又はSn O2にSb，Ｆ等を添加したもの、
第１誘電体層及び第２誘電体層については、
Al2 O3，Hf O2，Ta2 O5，Y2 O3，Zr O2等の
酸化物又はSi3 N4等の窒化物をそれぞれ使用し
てもよい。また、第２誘電体層の材質は、EL発
光層がZnSからなるとき、EL発光層と第２誘電
体層との界面の反射を極力防止するため、屈折率
が1.8以上の材質（例えば、Y2 O3，Ta2 O5，Hf
O2，Si3 N4，Zr O2）が望ましい。EL発光層に
ついてはZnS：Cu，ZnS：Al（何れも黄縁色発
光），Zn（Ｓ・Se）：Cu，Zn（Ｓ・Se）：Br（何れ
も縁色発光），ZnS：Sm（赤色発光），ZnS：Tb
（縁色発光），ZnS：Tm（青色発光）を使用しても
よい。 Furthermore, in addition to the materials used in Examples 1 and 2, the present invention also uses multi-component glass such as soda lime glass or quartz glass for the glass substrate, and In 2 O 3 or W added to it for the transparent electrode. or added Sb, F, etc. to Sn O 2 ,
For the first dielectric layer and the second dielectric layer, oxides such as Al 2 O 3 , Hf O 2 , Ta 2 O 5 , Y 2 O 3 , Zr O 2 or nitrides such as Si 3 N 4 are used. You may use each. In addition, when the EL emitting layer is made of ZnS, the material of the second dielectric layer is a material with a refractive index of 1.8 or more (for example, Y 2 O 3 , Ta 2 O 5 , Hf
O 2 , Si 3 N 4 , Zr O 2 ) are preferable. Regarding the EL emitting layer, ZnS:Cu, ZnS:Al (all emit yellow edge color), Zn(S/Se):Cu, Zn(S/Se):Br (all emit edge color), ZnS:Sm( red emission), ZnS:Tb
(marginal color emission), ZnS:Tm (blue emission) may also be used.
以上のとおり、本発明によれば、光吸収層が浸
食されないので、光吸収効果及びコンストラスト
を向上させることができ、印加電圧−発光輝度特
性も良好に維持することができるので、発光輝度
を高くするために印加電圧を高くすることもない
ので、絶縁破壊も起こりにくくなつた。
As described above, according to the present invention, since the light absorption layer is not eroded, the light absorption effect and contrast can be improved, and the applied voltage-emission brightness characteristic can also be maintained favorably, so the light emission brightness can be improved. Since there is no need to increase the applied voltage to increase the voltage, dielectric breakdown is less likely to occur.
第１図は従来の薄膜EL素子を示す断面図、第
２図は従来の薄膜EL素子における印加電圧−発
光輝度特性図、第３図は本発明の一実施例の薄膜
EL素子を示す断面図、第４図は本発明の他の実
施例の薄膜EL素子を示す断面図、第５図は、前
記第３図及び第４図で示す薄膜EL素子の印加電
圧−発光輝度特性図、第６図は前記第３図及び第
４図で示す薄膜EL素子における分光反射率特性
図である。
１……ガラス基板、２……透明電極、３……第
１誘電体層、４……EL発光層、７……背面電極、
８……第２誘電体層、９……光吸収層、１０……
第３誘電体層、９１……第１光吸収層、９２……
第２光吸収層。
FIG. 1 is a cross-sectional view of a conventional thin film EL device, FIG. 2 is an applied voltage-emission luminance characteristic diagram of a conventional thin film EL device, and FIG. 3 is a thin film of an embodiment of the present invention.
4 is a sectional view showing a thin film EL device according to another embodiment of the present invention, and FIG. 5 is a graph showing applied voltage vs. light emission of the thin film EL device shown in FIGS. 3 and 4. The luminance characteristic diagram, FIG. 6, is a spectral reflectance characteristic diagram of the thin film EL element shown in FIGS. 3 and 4. DESCRIPTION OF SYMBOLS 1... Glass substrate, 2... Transparent electrode, 3... First dielectric layer, 4... EL light emitting layer, 7... Back electrode,
8... Second dielectric layer, 9... Light absorption layer, 10...
Third dielectric layer, 91... First light absorption layer, 92...
Second light absorption layer.
Claims (1)
電極上に、第１誘電体層，EL発光層，第２誘電
体層，光吸収層，第３誘電体層を順次積層し、前
記第３誘電体層上に、背面電極を設け、かつ前記
光吸収層がゲルマニウムの低級酸化物からなり、
さらに前記第３誘電体層が、前記背面電極を形成
するときに使用されるエツチング手段に対して耐
エツチング性を有する材質からなることを特徴と
する薄膜EL素子。 ２ 前記光吸収層の光吸収係数が前記EL発光層
側から前記背面電極の膜厚方向に沿つて連続的又
は段階的に増大していることを特徴とする特許請
求の範囲第１項記載の薄膜EL素子。 ３ 前記第２誘電体層の厚さが100Å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２
項記載の薄膜EL素子。[Claims] 1. A transparent electrode is provided on a light-transmitting substrate, and a first dielectric layer, an EL light emitting layer, a second dielectric layer, a light absorption layer, and a third dielectric layer are provided on the transparent electrode. are sequentially laminated, a back electrode is provided on the third dielectric layer, and the light absorption layer is made of a lower oxide of germanium,
Furthermore, the thin film EL device is characterized in that the third dielectric layer is made of a material that is resistant to etching with respect to the etching means used when forming the back electrode. 2. The light absorption coefficient of the light absorption layer increases continuously or stepwise from the EL light emitting layer side along the film thickness direction of the back electrode. Thin film EL element. 3. Claims 1 to 2, characterized in that the thickness of the second dielectric layer is 100 Å or more.
The thin film EL device described in Section 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59201269A JPS6177883A (en) | 1984-09-26 | 1984-09-26 | Thin film el element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59201269A JPS6177883A (en) | 1984-09-26 | 1984-09-26 | Thin film el element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6177883A JPS6177883A (en) | 1986-04-21 |
| JPH0369158B2 true JPH0369158B2 (en) | 1991-10-31 |
Family
ID=16438151
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59201269A Granted JPS6177883A (en) | 1984-09-26 | 1984-09-26 | Thin film el element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6177883A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100472502B1 (en) * | 2001-12-26 | 2005-03-08 | 삼성에스디아이 주식회사 | Organic electro luminescence display device |
-
1984
- 1984-09-26 JP JP59201269A patent/JPS6177883A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6177883A (en) | 1986-04-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5003221A (en) | Electroluminescence element | |
| US4870322A (en) | Electroluminescent panel having a layer of germanium nitride between an electroluminescent layer and a back electrode | |
| JPH07211458A (en) | Thin film electroluminescent element | |
| US4634639A (en) | Electroluminescent panel having a light absorption layer of germanium oxide | |
| JPH0369158B2 (en) | ||
| JPH0460317B2 (en) | ||
| JPS5829880A (en) | Electric field luminescent element | |
| JPS5824915B2 (en) | Thin film EL element | |
| JPS6315718B2 (en) | ||
| JPH0325916B2 (en) | ||
| JPH0160917B2 (en) | ||
| JPH0152878B2 (en) | ||
| JP2686170B2 (en) | Thin film EL element | |
| JP2502560B2 (en) | Method for forming dielectric film | |
| JPH0460318B2 (en) | ||
| JPH0326919B2 (en) | ||
| JPH0243190B2 (en) | ||
| JPH0124358B2 (en) | ||
| JPH01213991A (en) | Transparent electrode substrate and electroluminescence element utilizing same | |
| JP3308308B2 (en) | Thin film EL display element and method of manufacturing the same | |
| JPH08106983A (en) | Thin film electroluminescent element | |
| JPH0322394A (en) | Thin film el device | |
| JPH0214711B2 (en) | ||
| JPS6314833B2 (en) | ||
| JPS62115691A (en) | Manufacture of electroluminescence panel |