JPH02301991A - El display - Google Patents
El displayInfo
- Publication number
- JPH02301991A JPH02301991A JP1122593A JP12259389A JPH02301991A JP H02301991 A JPH02301991 A JP H02301991A JP 1122593 A JP1122593 A JP 1122593A JP 12259389 A JP12259389 A JP 12259389A JP H02301991 A JPH02301991 A JP H02301991A
- Authority
- JP
- Japan
- Prior art keywords
- transparent electrode
- insulating layer
- display
- transparent conductive
- conductive film
- 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.)
- Granted
Links
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000011787 zinc oxide Substances 0.000 claims abstract description 15
- 230000015556 catabolic process Effects 0.000 abstract description 18
- 239000012535 impurity Substances 0.000 abstract description 7
- 239000011521 glass Substances 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 4
- 238000010438 heat treatment Methods 0.000 description 13
- 239000005083 Zinc sulfide Substances 0.000 description 7
- 229910052984 zinc sulfide Inorganic materials 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 238000004544 sputter deposition Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 4
- LKNRQYTYDPPUOX-UHFFFAOYSA-K trifluoroterbium Chemical compound F[Tb](F)F LKNRQYTYDPPUOX-UHFFFAOYSA-K 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 229910004299 TbF3 Inorganic materials 0.000 description 3
- 239000003086 colorant Substances 0.000 description 3
- -1 rare earth metal ions Chemical class 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- 229910001887 tin oxide Inorganic materials 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- QZQVBEXLDFYHSR-UHFFFAOYSA-N gallium(III) oxide Inorganic materials O=[Ga]O[Ga]=O QZQVBEXLDFYHSR-UHFFFAOYSA-N 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910003437 indium oxide Inorganic materials 0.000 description 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- HTXDPTMKBJXEOW-UHFFFAOYSA-N iridium(IV) oxide Inorganic materials O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 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
- 239000008188 pellet Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910001936 tantalum oxide Inorganic materials 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野コ
本発明は、例えば計器類のバックライト用の面光源等に
使用されるエレクトロルミネッセンス（ＥＬ）ディスプ
レイに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electroluminescent (EL) display used, for example, as a surface light source for backlighting instruments.
［従来の技術］
ＥＬディスプレイは、硫化亜鉛（ＺｎＳ）等の蛍光体に
電界をがけなときに発光する現象を利用したもので、自
発光型の平面ディスプレイとして注目されている。[Prior Art] EL displays utilize the phenomenon that a phosphor such as zinc sulfide (ZnS) emits light when no electric field is applied to it, and is attracting attention as a self-luminous flat display.
このような従来のＥＬディスプレイの一例を第３図に示
す。An example of such a conventional EL display is shown in FIG.
図において、ガラス基板１上には、ＩｒＯ２よりなる透
明電極６１、酸化タンタル（ＴａｚＯ５）等よりなる第
１絶縁層３１、発光層４１、第２絶縁層３２が順次積層
形成してあり、さらにその上にＩＴＯ膜よりなる透明電
極６２が配設しである。In the figure, a transparent electrode 61 made of IrO2, a first insulating layer 31 made of tantalum oxide (TazO5), a light emitting layer 41, and a second insulating layer 32 are sequentially laminated on a glass substrate 1. A transparent electrode 62 made of an ITO film is disposed thereon.
Ｉ Ｔｏ （Ｉｎｄｉｕｍ Ｔｉｎ ０ｘｉｄｅ）膜は
、酸化インジウム（ＩｎｚＯ３）にすず（Ｓｎ）をドー
プした透明の導電膜で、低抵抗率であることがら従来よ
り透明電極用として広く使用されている。An I To (Indium Tin Oxide) film is a transparent conductive film made of indium oxide (InzO3) doped with tin (Sn), and has been widely used for transparent electrodes because of its low resistivity.
発光層４１としては、例えば、ＺｎＳを母材層とし、発
光中心としてマンガン（Ｍｎ＞や三フッ化テルビウム（
ＴｂＦ３）を添加したものが使用される。ＥＬ発光によ
る発光色はＺｎＳ中の添加物の種類によって決まり、例
えば発光ｉ心とじてＭｎを添加した場合にはオレンジの
、ＴｂＦ３を添加した場合にはグリーンの発光が得られ
る。The light-emitting layer 41 may be made of, for example, ZnS as a base material layer and manganese (Mn> or terbium trifluoride (
TbF3) is used. The color of light emitted by EL light emission is determined by the type of additive in ZnS; for example, when Mn is added as the light emitting i core, orange light is obtained, and when TbF3 is added, green light is obtained.
［発明が解決しようとする課題］
しかしながら、上記構造のＥＬディスプレイを製作し、
連続発光試験に供したところ、わずか２００時間で絶縁
破壊が生じ、耐久性能面で大きな問題を有することが判
明した。これは駆動電圧が低い場合にはそれほど重要で
はないが、表示面積の拡大等で駆動電圧を高くする必要
が生じた場合には大きな問題となる。[Problem to be solved by the invention] However, when producing an EL display with the above structure,
When subjected to a continuous light emission test, dielectric breakdown occurred in just 200 hours, and it was found that there was a major problem in terms of durability performance. Although this is not so important when the driving voltage is low, it becomes a big problem when it becomes necessary to increase the driving voltage due to expansion of the display area or the like.
また、近年、異なる発光色を示す発光層を複数積層して
、ＥＬディスプレイを多色化することが提案されている
（例えば、特開昭６０−２６４０９６号公報、特開昭６
０−２１６４９６号公報等）。Furthermore, in recent years, it has been proposed to make EL displays multicolored by stacking a plurality of light-emitting layers that emit light of different colors (for example, Japanese Patent Laid-Open No. 60-264096,
0-216496, etc.).
ところが、上記した絶縁層の耐圧低下現象は、このよう
な積層型のＥ Ｌディスプレイにおいて特に顕著である
ことが判明し、実用化に際し大きな障害となっている。However, it has been found that the above-mentioned phenomenon of reduction in breakdown voltage of the insulating layer is particularly noticeable in such a stacked type EL display, and has become a major obstacle to practical application.
しかして、本発明の目的は、絶縁層の電気耐圧が高く、
高電圧駆動時においても絶縁破壊が生じることかない、
高い信顆性を有するＥＬディスプレイを提供することに
ある。Therefore, an object of the present invention is to provide an insulating layer with a high electric withstand voltage.
No dielectric breakdown occurs even when driven at high voltage.
An object of the present invention is to provide an EL display with high reliability.
［課題を解決するための手段］
上記目的を達成するために、本発明では、少なくとも一
方を透明導電膜で構成した一対の電極層に、絶縁層を介
して発光層を設けてなるＥＬディスプレイにおいて、上
記透明導電膜を、酸化亜鈴を主成分とし、３価以上の原
子価を有する少なくとも一種の元素を含有する材料で構
成しである。[Means for Solving the Problems] In order to achieve the above object, the present invention provides an EL display in which a light emitting layer is provided on a pair of electrode layers, at least one of which is composed of a transparent conductive film, with an insulating layer interposed therebetween. The transparent conductive film is made of a material containing tin oxide as a main component and at least one element having a valence of 3 or more.
また、本発明のＥＬディスプレイは、上記発光層を複数
設けてこれらを透明導電膜よりなる中間電極を挟んで積
層し、該中間電極と複数の発光層との間にそれぞれ絶縁
層を形成した積層型の構成としてもよい。Further, the EL display of the present invention includes a stacked structure in which a plurality of the above-mentioned light-emitting layers are provided, these are laminated with an intermediate electrode made of a transparent conductive film sandwiched therebetween, and an insulating layer is formed between each of the intermediate electrodes and the plurality of light-emitting layers. It may also be a type configuration.
［作用］
従来のＥＬディスプレイにおいて絶縁層の耐圧低下現象
が生じるのは、製造工程において、透明電極を構成する
ＩＴＯ膜が部分的に還元され、導電体であるＩｎが、熱
処理の過程で絶縁層中に拡散するためと考えられる。[Function] The reason why the breakdown voltage of the insulating layer decreases in conventional EL displays is that the ITO film constituting the transparent electrode is partially reduced during the manufacturing process, and the conductor In is removed from the insulating layer during the heat treatment process. This is thought to be because it diffuses into the atmosphere.
これに対し、本発明において使用するＺｎ○を主成分と
する透明導電膜は、安定で、ＩＴＯのような拡散現象を
生じないので、耐圧低下を抑制することができる。On the other hand, the transparent conductive film containing Zn◯ as a main component used in the present invention is stable and does not cause the diffusion phenomenon like ITO, and therefore can suppress a decrease in breakdown voltage.
［実施例］
第１図には本発明のＥＬディスプレイの一実施例を示す
。図において、ガラス基板上上には第１透明電極２１が
形成してあり、その上面には第１絶縁層３１、発光層４
１、第２絶縁層３２、第２透明電極２２が順次積層形成
しである。[Embodiment] FIG. 1 shows an embodiment of the EL display of the present invention. In the figure, a first transparent electrode 21 is formed on the glass substrate, and a first insulating layer 31 and a light emitting layer 4 are formed on the top surface of the first transparent electrode 21.
1. The second insulating layer 32 and the second transparent electrode 22 are sequentially laminated.
第１透明電極２１および第２透明電極２２は、酸化亜鈴
を主成分とし、不純物ドナーとして３価以上の原子価を
有する少なくとも一種の元素を含有する透明導電膜で構
成されている。The first transparent electrode 21 and the second transparent electrode 22 are composed of a transparent conductive film containing tin oxide as a main component and at least one element having a valence of 3 or more as an impurity donor.
以下、上記構造のＥＬディスプレイの製造方法の一例を
説明する。An example of a method for manufacturing an EL display having the above structure will be described below.
まず、ガラス基板１上に、第１透明電極２１を成膜した
。蒸着材料としては、ＺｎＯ粉末にＧａ２Ｏ３粉末を２
重量％加えて混合し、ペレット状に成形したものを用い
、成膜装置としてはイオンブレーティング装置を用いた
。装置内にＡｒガスを導入して装置内圧力を３Ｘ１０−
４Ｔｏｒｒに保持し、高周波型カフ０Ｗ、基板温度１０
０°Ｃで、蒸着レートが１．０〜２．０人／ ｓ ｅ
ｃの範囲になるように電子ビーム電力を調整した。First, the first transparent electrode 21 was formed on the glass substrate 1 . As a vapor deposition material, 2 Ga2O3 powders are added to ZnO powder.
% by weight and mixed and formed into pellets, and an ion blating device was used as a film forming device. Ar gas is introduced into the device to increase the pressure inside the device to 3X10-
Maintained at 4 Torr, high frequency cuff 0W, substrate temperature 10
At 0°C, the deposition rate is 1.0-2.0 people/s e
The electron beam power was adjusted to fall within the range of c.
このようにして得られた第１透明電極２１の抵抗値は約
２Ｘ１０−４Ω】であり、従来のＩＴＯとほぼ同等の抵
抗値が得られた。The resistance value of the first transparent electrode 21 thus obtained was approximately 2×10 −4 Ω, which was approximately the same as that of conventional ITO.
ＺｎＯに添加する不純物としては、Ｇａに限らず、３価
以上の原子価を有する元素であれば透明電極の抵抗値を
下げる効果を有する。具体的には、Ｇａ以外に、Ａ、Ｉ
ｌ 、Ｓｉ、Ｐ、Ｇｅ、Ｌａ、Ｂ、Ｔｉ、Ｈｆ、Ｚｒ、
Ｓｎ、Ｐｂ等が挙げられ、これらは通常、酸化物等の形
で添加される。The impurity added to ZnO is not limited to Ga, but any element having a valence of 3 or more has the effect of lowering the resistance value of the transparent electrode. Specifically, in addition to Ga, A, I
l, Si, P, Ge, La, B, Ti, Hf, Zr,
Examples include Sn, Pb, etc., and these are usually added in the form of oxides or the like.
ここで、ＺｎＯに添加する不純物の量は、０゜５〜５原
千％とすることが望ましい。これら不純物の役割は、余
剰電子を生成することにあり、抵抗値の低減に大きく寄
与する。添加量が０．５原子％未満ではこの効果が小さ
く、また５原子％を超えるとＺｎＯの結晶性が低下する
ので好ましくない。Here, the amount of impurities added to ZnO is preferably 0.5 to 5.000%. The role of these impurities is to generate surplus electrons, which greatly contributes to reducing the resistance value. If the amount added is less than 0.5 atom %, this effect will be small, and if it exceeds 5 atom %, the crystallinity of ZnO will decrease, which is not preferable.
第１透明電極２１の上面には、ＴａｚＯａよりなる第１
絶縁層３１をスパッタにより形成し、第１絶縁１３１上
にはＺｎＳを母材層とし、発光中心としてＭｎを添加し
た発光層４１を蒸着により形成した。その後、発光層４
１の結晶性を向上させ、発光輝度を上げるため、真空中
、３００〜５００℃で熱処理を行なった。A first transparent electrode made of TazOa is provided on the upper surface of the first transparent electrode 21.
An insulating layer 31 was formed by sputtering, and a light emitting layer 41 containing ZnS as a base material layer and Mn added as a luminescent center was formed on the first insulating layer 131 by vapor deposition. After that, the light emitting layer 4
In order to improve the crystallinity of No. 1 and increase the luminance, heat treatment was performed at 300 to 500° C. in vacuum.
さらにＴａ２０５よりなる第２絶縁層３２をスパッタに
より、第２透明電極２２を蒸着により順次積層して本発
明のＥＬディスプレイとした。各々の膜厚は、透明電極
２１．２２が３０００Ａ、絶縁層３１．３２が６０００
人、発光層４１が６０００人である。なお、熱処理は第
２透明電極２２の成膜後に行なってもよい。Further, a second insulating layer 32 made of Ta205 was sequentially laminated by sputtering, and a second transparent electrode 22 was laminated by vapor deposition to obtain an EL display of the present invention. The thickness of each film is 3000A for the transparent electrodes 21 and 22, and 6000A for the insulating layers 31 and 32.
The number of people in the light emitting layer 41 is 6000. Note that the heat treatment may be performed after the second transparent electrode 22 is formed.
このようにして得たＥＬディスプレイを、連続発光試験
に供したところ（印加電圧１３０〜１８０Ｖ）、５００
時間経過後も絶縁破壊は認められず、絶縁破壊に対し良
好な性能を有することがわかった。When the EL display thus obtained was subjected to a continuous light emission test (applied voltage 130 to 180 V), 500
No dielectric breakdown was observed even after the passage of time, indicating that it had good performance against dielectric breakdown.
第２図には本発明の他の実施例を示す。本実施例では上
記第１実施例の構造上にさらに第２の発光層を積層した
積層型のＥＬディスプレイとしである。FIG. 2 shows another embodiment of the invention. This embodiment is a stacked EL display in which a second light emitting layer is further stacked on the structure of the first embodiment.
図において、中間電極となる第２透明電極２２上にはＴ
ａ２０５よりなる第３絶縁層３３がスパッタにより形成
してあり、その上に第２発光層４２が形成しである。第
２発光層４２は、ＺｎＳを母材層とし、発光中心として
ＴｂＦ３を添加したものでグリーン発光する。In the figure, there is a T on the second transparent electrode 22 serving as the intermediate electrode.
A third insulating layer 33 made of a205 is formed by sputtering, and a second light emitting layer 42 is formed thereon. The second light-emitting layer 42 has a base material layer of ZnS to which TbF3 is added as a light-emitting center, and emits green light.
第２発光層４２上には、Ｔａ２０５よりなる第４絶縁層
３４を介してＡＭよりなる上部電極５が形成しである。An upper electrode 5 made of AM is formed on the second light emitting layer 42 with a fourth insulating layer 34 made of Ta205 interposed therebetween.
絶縁層３３．３４、第２発光層４２の膜厚はいずれも６
０００人であり、上部電極５は１０００人である。The film thicknesses of the insulating layers 33 and 34 and the second light emitting layer 42 are both 6
000 people, and the upper electrode 5 has 1000 people.
上記構造のＥＬディスプレイにおいて、第１の発光層４
１、または第２の発光層４２に電圧を印加することによ
り、それぞれオレンジ、グリーンの発光色が得られ、さ
らに発光層４１．４２を同時に発光させることによりこ
れらの混色であるイエローの発光色が得られるので、こ
れらを組合わせることによりマルチカラーディスプレイ
が可能となる。In the EL display having the above structure, the first light emitting layer 4
By applying a voltage to the first or second light emitting layer 42, orange and green light emitting colors can be obtained, respectively, and by making the light emitting layers 41 and 42 emit light at the same time, a yellow light emitting color, which is a mixture of these colors, can be obtained. Therefore, by combining these, a multicolor display is possible.
上記構造のＥしディスプレイでも絶縁破壊に対し良好な
性能が得られ、連続発光試験に供したところ、５００時
間経過後も絶縁破壊は認められなかった。The E-type display with the above structure also showed good performance against dielectric breakdown, and when subjected to a continuous light emission test, no dielectric breakdown was observed even after 500 hours had elapsed.
次に、比較のため、第３図、第４図に示す従来構造のＥ
Ｌディスプレイを作製した。これらは、それぞれ、上記
第１実施例（第１図）および第２実施例（第２図）の第
１透明電極２１および第２透明電極２２に代えて、ＩＴ
Ｏ膜よりなる透明電極６１および透明電極６２を有して
いる。他の構造は上記第１．２実施例と同じである。Next, for comparison, the E of the conventional structure shown in Figs. 3 and 4 is shown.
An L display was created. These are the IT
It has a transparent electrode 61 and a transparent electrode 62 made of an O film. The other structure is the same as the above-mentioned Embodiment 1.2.
これらを連続発光試験に供したところ、第３図の構造で
は２００時間で絶縁破壊が生じ、第４図の構造では４０
時間で絶縁破壊が生じた。When these were subjected to a continuous light emission test, dielectric breakdown occurred in the structure shown in Figure 3 after 200 hours, and in the structure shown in Figure 4, dielectric breakdown occurred after 200 hours.
Dielectric breakdown occurred over time.
このＩＴＯによる絶縁破壊を調べるため、第５図のよう
に、ガラス基板１上にＩＴＯ電極６を設け、その上にＴ
ａ２ｏ５絶縁膜３をスパッタ法で成膜した試料を作製し
てＡＥＳ分析（オージェ電子分光分析）を行なった。試
料は側端面を５°に斜め研磨し、深さ方向の元素の分布
がわかるようにした。結果を第６図に示す。In order to investigate the dielectric breakdown caused by this ITO, as shown in FIG. 5, an ITO electrode 6 is provided on the glass substrate 1, and a T
A sample in which the a2o5 insulating film 3 was formed by sputtering was prepared and subjected to AES analysis (Auger electron spectroscopy). The side end surfaces of the samples were polished at an angle of 5° so that the distribution of elements in the depth direction could be seen. The results are shown in Figure 6.
また、成膜後、３５０℃で熱処理したもの、５５０°Ｃ
で熱処理したものにつき、同様の分析を行ない、結果を
それぞれ第７図、第８図に示した。Also, after film formation, heat treated at 350°C, 550°C
A similar analysis was conducted on the heat-treated samples, and the results are shown in FIGS. 7 and 8, respectively.
各図に明らかなように、熱処理によりＴａとＩｎのオー
バーラツプが大きくなっており、Ｉｎが絶縁層３を構成
するＴａ２ｏ５中に浸入していく様子がよくわかる。ま
た、熱処理温度を高くすることでさらにその傾向が増加
している。As is clear from each figure, the overlap between Ta and In increases due to the heat treatment, and it can be clearly seen that In penetrates into the Ta2O5 constituting the insulating layer 3. Moreover, this tendency is further increased by increasing the heat treatment temperature.
Ｉｎは導電体であるため、絶縁層３中へＩｎが拡散する
と絶縁層の電気耐圧は低くなり、これが原因となって絶
縁破壊が生じると考えられる。このＩｎの絶縁層中への
拡散は、ＩＴＯ膜の上層の絶縁層の成膜時に、スパッタ
のようにプラズマを利用する方法を用いるため、Ｉｎ２
Ｏ３が還元されて部分的にＩｎ金属となって存在するか
らで、このＩｎ金属が熱処理の過程で拡散するためでは
ないかと考えられている。Since In is a conductor, when In diffuses into the insulating layer 3, the electric withstand voltage of the insulating layer decreases, which is considered to be the cause of dielectric breakdown. This diffusion of In into the insulating layer is possible because a method using plasma such as sputtering is used when forming the upper insulating layer of the ITO film.
It is thought that this is because O3 is reduced and partially exists as In metal, and this In metal diffuses during the heat treatment process.
なお、同様の試験をＺｎ○にＧａを添加じなＺｎＯ系透
明導電膜を用いて行なった結果を第９図に示しな。図に
明らかなように５５０℃熱処理後もＺｎの絶縁層中への
拡散は見られない。Incidentally, FIG. 9 shows the results of a similar test using a ZnO-based transparent conductive film in which no Ga was added to Zn○. As is clear from the figure, no diffusion of Zn into the insulating layer is observed even after heat treatment at 550°C.
さらに第５図の構成の試料につき、第１０図に示す装置
を使用して、絶縁層６のリーク電流を調べた。第１０図
において、７はＡｕメッキの針電極であり、これと試料
のＩＴ○電極６間に電圧を印加して、熱処理前、５５０
℃熱処理後においてリーク電流がどのように変化するか
を調べた。また、ＩＴＯ電極６に代えてＺｎＯ系透明導
電膜を用いた場合についても同様に熱処理前後のリーク
電流変化を調べ、結果を第１１図に示した。Furthermore, the leakage current of the insulating layer 6 was investigated using the apparatus shown in FIG. 10 for the sample having the configuration shown in FIG. In FIG. 10, 7 is an Au-plated needle electrode, and a voltage is applied between this and the IT○ electrode 6 of the sample, and 550
We investigated how the leakage current changes after heat treatment at ℃. Furthermore, when a ZnO-based transparent conductive film was used in place of the ITO electrode 6, changes in leakage current before and after heat treatment were similarly investigated, and the results are shown in FIG.
これらの結果を比較して明らかなように、ＺｎＯ系透明
導電膜では熱処理してもリーク電流はほとんど変化しな
いが、ＩＴＯ膜では熱処理によりリーク電流が大きく増
加しており、絶縁破壊しやすくなっていることがわかる
。このように、ＺｎＯ系透明導電膜を用いることにより
絶縁破壊を抑制でき、高電圧駆動のＥＬディスプレイに
おいて大きな効果を発揮する。As is clear from comparing these results, the leakage current of the ZnO-based transparent conductive film hardly changes even after heat treatment, but the leakage current of the ITO film increases significantly due to heat treatment, making it more susceptible to dielectric breakdown. I know that there is. In this way, dielectric breakdown can be suppressed by using a ZnO-based transparent conductive film, which is highly effective in high-voltage driven EL displays.
上記実施例では、絶縁層をＴａ２０５で構成したが、Ａ
、ｆｆ ２０３、Ｓｉ３Ｎ４、Ｙ２Ｏ３等の他の絶縁材
料で構成してもよい。In the above embodiment, the insulating layer was made of Ta205, but A
, ff 203, Si3N4, Y2O3, etc. may be used.
また、発光層として、ＺｎＳにＳｍ、Ｔｍ等の他の希土
類金属イオンを添加したもの、あるいはＣａＳ、ＳｒＳ
に希土類金属イオンを添加したものを用いてもよい。In addition, as a light-emitting layer, ZnS with other rare earth metal ions such as Sm and Tm added, or CaS, SrS
A material to which rare earth metal ions are added may also be used.
上記実施例では発光層を１層または２層有する構成のも
のを示したか、本発明のＥＬディスプレイは、発光層を
３層以上有する構成としてももちろんよく、例えば、赤
色系、緑色系、青色系の発光層を重ねることによりフル
カラー化が可能となる。In the above embodiments, the structure having one or two light-emitting layers is shown, but the EL display of the present invention may of course have a structure having three or more light-emitting layers. For example, the EL display may have a structure having three or more light-emitting layers. By stacking two light-emitting layers, full color is possible.
Ｕ発明の効果］
以上のように、本発明のＥＬディスプレイは、透明電極
を、酸化亜鉛を主成分とする透明導電膜で構成したので
、絶縁層の電気耐圧が飛躍的に向上し、絶縁破壊が生じ
ることを防止する。また、酸化亜鉛を主成分とする透明
導電膜は、抵抗率が低く、安価であり、高い信頼性と優
れた特性を有するＥＬディスプレイを実現する。[Effects of the Invention] As described above, in the EL display of the present invention, the transparent electrode is composed of a transparent conductive film containing zinc oxide as a main component, so the electric withstand voltage of the insulating layer is dramatically improved, and dielectric breakdown is prevented. prevent the occurrence of Furthermore, a transparent conductive film containing zinc oxide as a main component has low resistivity, is inexpensive, and realizes an EL display having high reliability and excellent characteristics.
第１図は本発明の一実施例を示すＥＬディスプレイの全
体断面図、第２図は本発明の他の実施例を示すＥｌ−デ
ィスプレイの全体断面図、第３図および第４図は従来の
ＥＬディスプレイの全体断面図、第５図は従来のＥＬデ
ィスプレイにおけるＩｎの拡散状態を調べるための試料
の部分断面図、第６図〜第８図は従来のＥＬディスプレ
イにおけるＩｎの拡散状態を示す図、第９図は本発明の
ＥＬディスプレイにおけるＺｎの拡散状態を示す図、第
１０図は熱処理前後のリーク電流変化を調べるための試
験方法を示す図、第１１図は熱処理前後のリーク電流変
化を示す図である。
１・・・・・・ガラス基板
２１．２２・・・・・・透明電極
３１．３２．３３．３４・・・・・・絶縁層４１．４２
・・・・・・発光層
５・・・・・・上部電極
第１図
第２図
第３図
第４図
第５図
顕 雛
距 離
第 １０ 図
第１１図
電圧 （Ｖ）FIG. 1 is an overall sectional view of an EL display showing one embodiment of the present invention, FIG. 2 is an overall sectional view of an EL display showing another embodiment of the invention, and FIGS. 3 and 4 are conventional EL displays. 5 is a partial sectional view of a sample for investigating the diffusion state of In in a conventional EL display, and FIGS. 6 to 8 are diagrams showing the diffusion state of In in a conventional EL display. , FIG. 9 is a diagram showing the diffusion state of Zn in the EL display of the present invention, FIG. 10 is a diagram showing a test method for investigating leakage current changes before and after heat treatment, and FIG. 11 is a diagram showing leakage current changes before and after heat treatment. FIG. 1...Glass substrate 21.22...Transparent electrode 31.32.33.34...Insulating layer 41.42
...Light-emitting layer 5...Top electrode Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Observation distance Fig. 10 Fig. 11 Voltage (V)
Claims (2)
極間に、絶縁層を介して発光層を設けてなるＥＬディス
プレイにおいて、上記透明導電膜が、酸化亜鉛を主成分
とし、３価以上の原子価を有する少なくとも一種の元素
を含有することを特徴とするＥＬディスプレイ。(1) In an EL display in which a light emitting layer is provided between a pair of electrodes, at least one of which is composed of a transparent conductive film, with an insulating layer interposed therebetween, the transparent conductive film contains zinc oxide as a main component and has a valence of 3 or more. An EL display characterized by containing at least one element having a valence.
なる中間電極を挟んで積層し、該中間電極と複数の発光
層との間にそれぞれ絶縁層を形成した請求項１記載のＥ
Ｌディスプレイ。(2) E according to claim 1, wherein a plurality of the light emitting layers are provided, and these are laminated with an intermediate electrode made of a transparent conductive film sandwiched therebetween, and an insulating layer is formed between each of the intermediate electrodes and the plurality of light emitting layers.
L display.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1122593A JPH0817115B2 (en) | 1989-05-16 | 1989-05-16 | EL display manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1122593A JPH0817115B2 (en) | 1989-05-16 | 1989-05-16 | EL display manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02301991A true JPH02301991A (en) | 1990-12-14 |
| JPH0817115B2 JPH0817115B2 (en) | 1996-02-21 |
Family
ID=14839772
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1122593A Expired - Fee Related JPH0817115B2 (en) | 1989-05-16 | 1989-05-16 | EL display manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0817115B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57180891A (en) * | 1981-04-30 | 1982-11-08 | Fujitsu Ltd | El display element |
| JPS63190294A (en) * | 1987-01-31 | 1988-08-05 | 株式会社リコー | Electroluminescence device |
-
1989
- 1989-05-16 JP JP1122593A patent/JPH0817115B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57180891A (en) * | 1981-04-30 | 1982-11-08 | Fujitsu Ltd | El display element |
| JPS63190294A (en) * | 1987-01-31 | 1988-08-05 | 株式会社リコー | Electroluminescence device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0817115B2 (en) | 1996-02-21 |
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