JPS62237693A - Thin film el device - Google Patents
Thin film el deviceInfo
- Publication number
- JPS62237693A JPS62237693A JP61081328A JP8132886A JPS62237693A JP S62237693 A JPS62237693 A JP S62237693A JP 61081328 A JP61081328 A JP 61081328A JP 8132886 A JP8132886 A JP 8132886A JP S62237693 A JPS62237693 A JP S62237693A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- dielectric
- nitride
- dielectric layer
- 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.)
- Pending
Links
- 239000010409 thin film Substances 0.000 title claims description 106
- 150000004767 nitrides Chemical class 0.000 claims description 24
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 13
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 12
- BJXXCWDIBHXWOH-UHFFFAOYSA-N barium(2+);oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Ba+2].[Ba+2].[Ba+2].[Ba+2].[Ba+2].[Ta+5].[Ta+5].[Ta+5].[Ta+5] BJXXCWDIBHXWOH-UHFFFAOYSA-N 0.000 claims description 5
- VEALVRVVWBQVSL-UHFFFAOYSA-N strontium titanate Chemical compound [Sr+2].[O-][Ti]([O-])=O VEALVRVVWBQVSL-UHFFFAOYSA-N 0.000 claims description 4
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 3
- 229910052582 BN Inorganic materials 0.000 claims description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 2
- 238000010030 laminating Methods 0.000 claims 1
- 239000000758 substrate Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000004020 luminiscence type Methods 0.000 description 4
- 238000004544 sputter deposition Methods 0.000 description 4
- 229910052984 zinc sulfide Inorganic materials 0.000 description 4
- 239000005083 Zinc sulfide Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000010549 co-Evaporation Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 229910001882 dioxygen 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
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- -1 oxygen ions Chemical class 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
- 238000012856 packing Methods 0.000 description 1
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- RGZQGGVFIISIHZ-UHFFFAOYSA-N strontium titanium Chemical compound [Ti].[Sr] RGZQGGVFIISIHZ-UHFFFAOYSA-N 0.000 description 1
- 229910001936 tantalum oxide Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Landscapes
- Electroluminescent Light Sources (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
産業上の利用分野
この発明は、薄膜ＥＬ素子に関し、とりわけ、発光特性
の長期にわたる安定性に優れた薄膜ＥＬ素子に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film EL device, and more particularly to a thin film EL device with excellent long-term stability of light emitting characteristics.
従来の技術
］ンピュータ端末などに用いるフラットディスプレイと
して、薄膜ＥＬ素子が盛んに研究されている。従来この
ような薄膜ＥＬ素子は、ガラス基板上に順次、ＩＴＯ薄
膜からなるストライブ状透明電極、酸化イツトリウム、
酸化チタニウム、チタン酸ストロンチウム、窒化珪素、
あるいは酸化タンタルなどからなる第１誘電体層、マン
ガン添加硫化亜鉛やテルビウム添加硫化亜鉛からなるＥ
Ｌ発光体層、酸化イツ） ＩＪウム、酸化アルミユウム
、窒化珪素、あるいはタンタル酸バリウムなどからなる
第２誘電体層、およびアルミユウム薄膜からなる、透明
電極とは直交する方向のストライプ状背面電極を積層し
た構造を有する。上記の透明電極と背面電極間に、交流
パルス電圧を印加することにより、透明電極と背面電極
にはさまれた部分のＥＬ発光体層を発光させ、情報を表
示する。2. Description of the Related Art Thin film EL devices are being actively researched as flat displays used in computer terminals and the like. Conventionally, such a thin film EL element has a strip-shaped transparent electrode made of an ITO thin film, yttrium oxide, yttrium oxide, etc.
Titanium oxide, strontium titanate, silicon nitride,
Alternatively, the first dielectric layer is made of tantalum oxide, etc., and the E layer is made of manganese-doped zinc sulfide or terbium-doped zinc sulfide.
A second dielectric layer made of aluminum, aluminum oxide, silicon nitride, barium tantalate, etc., and a striped back electrode made of a thin aluminum film in a direction perpendicular to the transparent electrode are laminated. It has a structure that By applying an AC pulse voltage between the transparent electrode and the back electrode, the EL light emitting layer sandwiched between the transparent electrode and the back electrode emits light, thereby displaying information.
第１誘電体層や第２誘電体層に用いる材料としては、誘
電率が大きく、絶縁破壊電界強度が大きい材料が適して
いる。とくに低電圧駆動のためには誘電率の大きいこと
が要求される。前者は、主に透明電極および背面電極に
より印加される電圧の、より多くの割合をＥＬ発光体層
に印加し、駆動電圧を低下させるためであり、後者は主
に絶縁破壊を起こさない安定な動作のために重要である
。As the material used for the first dielectric layer and the second dielectric layer, a material having a large dielectric constant and a large dielectric breakdown field strength is suitable. In particular, a large dielectric constant is required for low voltage drive. The former is mainly to apply a larger proportion of the voltage applied by the transparent electrode and the back electrode to the EL light emitting layer to reduce the driving voltage, and the latter is mainly to reduce the driving voltage by applying a larger proportion of the voltage applied by the transparent electrode and the back electrode. Important for operation.
このような低電圧で駆動ができ、安定性の優れた薄膜Ｅ
Ｌ素子を構成するための誘電体層としては、誘電率の大
きな酸化物誘電体薄膜（特開昭６６−４６５９５号公報
参照）の方が、誘電率の小さな酸化珪素や窒化珪素（特
公昭５３−４２３９８号公報参照）より適しており、酸
化物誘電体薄膜を用いた薄膜ＥＬ素子が広く研究されて
いる。Thin film E that can be driven at such low voltage and has excellent stability
For the dielectric layer constituting the L element, an oxide dielectric thin film with a high dielectric constant (see Japanese Unexamined Patent Publication No. 66-46595) is preferable to silicon oxide or silicon nitride with a low dielectric constant (Japanese Patent Publication No. 66-46595). 42398), and thin film EL elements using oxide dielectric thin films have been widely studied.
発明が解決しようとする問題点
マトリックス状電極を有する薄膜ＥＬ素子を、−斉反転
方式によシ線項次駆動（特公昭６５−２７３５４号公報
参照）し、１走査期間で２回の発光を行わせる場合、透
明電極を背面電極にはさまれた各絵素のうち大部分の絵
素においては、正極性のパルスが印加されてから逆極性
のパルスが印加されるまでの時間と、逆極性のパルスが
印加されてから正極性のパルスが印加されるまでの時間
が異なる。このような正、逆パルスの位相が異なる駆動
法により従来技術による構成の薄膜ＥＬ素子を長時間駆
動した場合、表示情報に応じて発光させた絵素では、発
光させなかった絵素と比較して、発光開始電圧が数ボル
ト変動するという問題点があった。Problems to be Solved by the Invention A thin film EL element having matrix electrodes is driven linearly by a simultaneous inversion method (see Japanese Patent Publication No. 65-27354) to emit light twice in one scanning period. In this case, for most of the pixels in which the transparent electrode is sandwiched between the back electrodes, the time from when a pulse of positive polarity is applied to when a pulse of opposite polarity is applied is The time from when a pulse of polarity is applied to when a pulse of positive polarity is applied is different. When a thin-film EL element configured according to the conventional technology is driven for a long time using such a driving method in which the phases of positive and reverse pulses are different, the pixel that emitted light in accordance with display information has a lower rate of light than the pixel that did not emit light. However, there was a problem in that the light emission starting voltage fluctuated by several volts.
本発明の目的は、前記問題点を解決し、位相が異なる交
流パルスや正、逆方向の振幅が異なる交流パルスで駆動
しても、長時間に渡り安定した動作が可能な薄膜ＥＬ素
子を提供することにある。An object of the present invention is to solve the above-mentioned problems and provide a thin film EL element that can operate stably for a long time even when driven by AC pulses with different phases or AC pulses with different amplitudes in the forward and reverse directions. It's about doing.
問題点を解決するだめの手段
本発明の薄膜ＥＬ素子は、透光性基板上に、透明電極、
第１誘電体層、ＥＬ発光体層、第２誘電体層、および背
面電極を順次積層した構造を有し、前記第１誘電体層の
前記ＥＬ発光体層側の部分は、厚さ１００Å以上、ｅｏ
ｏÅ以下の窒化物誘電体薄膜で構成し、前記第１誘電体
層の前記透明電極側の部分は酸化物誘電体薄膜で構成し
たことを特徴とするものである。Means for Solving the Problems The thin film EL device of the present invention has transparent electrodes,
It has a structure in which a first dielectric layer, an EL light emitting layer, a second dielectric layer, and a back electrode are sequentially laminated, and a portion of the first dielectric layer on the EL light emitting layer side has a thickness of 100 Å or more. ,eo
The device is characterized in that it is composed of a nitride dielectric thin film with a thickness of less than 0 Å, and a portion of the first dielectric layer on the transparent electrode side is composed of an oxide dielectric thin film.
作 用
発光開始電圧の変動は、ＥＬ発光体層と誘電体層との界
面に種々の深さのトラップ準位が形成されることや、Ｅ
Ｌ発光体層と誘電体層との反応により生ずるものと考え
られる。ＥＬ発光体層と誘電体層との間に１ｏｏλ以上
、６００Å以下の薄い窒化物誘電体薄膜を介在させるこ
とにより、トラップ準位の形成が抑制され、長期間に渡
シ安定した動作が可能になったものと考えられる。Fluctuations in the operational light emission starting voltage are caused by the formation of trap levels of various depths at the interface between the EL emitter layer and the dielectric layer, and by the fact that the E
This is thought to be caused by a reaction between the L emitter layer and the dielectric layer. By interposing a thin nitride dielectric thin film of 1ooλ or more and 600Å or less between the EL emitter layer and the dielectric layer, the formation of trap levels is suppressed and stable operation over a long period of time is possible. It is thought that it has become.
実施例 第１図は本発明の薄膜ＥＬ素子の断面構造を示す。Example FIG. 1 shows a cross-sectional structure of a thin film EL device of the present invention.
１はガラス基板であり、コーニング７０５９ガラスを用
いた。ガラス基板１上に、スパッタリング法により厚さ
２，０００への錫添加酸化インジウム薄膜を形成し、ホ
トリソグラフィ技術によりストライブ状に加工し透明電
極２とした。その上にチタンジルコン酸ストロンチウム
〔Ｓτ（Ｔｉ工Ｚｔ１−ｘ）０３〕を基板温度４００℃
でスパッタリングすることにより厚さ６，０００人の酸
化物誘電体薄膜３を形成した。さらにその上に、窒化珪
素焼結体を、２０％の窒素を含むアルゴン雰囲気中、基
板温度４００℃でスパッタリングすることにより厚さ３
５０人の窒化珪素薄膜からなる窒化物誘電体薄膜４を形
成した。酸化物誘電体薄膜３と窒化物誘電体薄膜４によ
り、第１誘電体層８が形成される。窒化物誘電体薄膜４
の上には、共蒸着法により、基板温度２ｏｏ℃で、厚さ
４，０００人のマンガン添加硫化亜鉛薄膜からなるＥＬ
発光体層５を形成した。1 is a glass substrate, and Corning 7059 glass was used. A tin-doped indium oxide thin film with a thickness of 2,000 mm was formed on a glass substrate 1 by a sputtering method, and was processed into a stripe shape by a photolithography technique to form a transparent electrode 2. On top of that, strontium titanium zirconate [Sτ (Ti process Zt1-x) 03] was added at a substrate temperature of 400°C.
An oxide dielectric thin film 3 having a thickness of 6,000 wafers was formed by sputtering. Furthermore, a silicon nitride sintered body is sputtered on top of the silicon nitride sintered body in an argon atmosphere containing 20% nitrogen at a substrate temperature of 400°C.
A nitride dielectric thin film 4 made of 50 silicon nitride thin films was formed. A first dielectric layer 8 is formed by the oxide dielectric thin film 3 and the nitride dielectric thin film 4. Nitride dielectric thin film 4
On top of the film, an EL layer consisting of a 4,000 yen thick manganese-doped zinc sulfide thin film was deposited using a co-evaporation method at a substrate temperature of 200°C.
A light emitter layer 5 was formed.
その後真空中、４５０℃で１時間熱処理の後、その上に
タンタル酸バリウム（ＢａＴａ２０６）焼結体を、基板
温度１００℃でスパッタリングすることにより厚さ２，
０００人の酸化物誘電体薄膜６を形成した。この酸化物
誘電体薄膜６が第２誘電体層となる。最後にその上に厚
さ１，５ｏ○人のＡＩを真空蒸着し、ホトリングラフィ
技術により、透明電極とは直交する方向のストライプ状
の背面電極子を形成し、薄膜ＥＬ素子を完成した。Thereafter, after heat treatment in vacuum at 450°C for 1 hour, a barium tantalate (BaTa206) sintered body was sputtered on top of it at a substrate temperature of 100°C to a thickness of 2.
000 oxide dielectric thin film 6 was formed. This oxide dielectric thin film 6 becomes the second dielectric layer. Finally, AI was vacuum-deposited to a thickness of 1.50 mm on top of it, and a striped back electrode element was formed in a direction perpendicular to the transparent electrode using photolithography technology, completing a thin film EL device.
本発明の薄膜ＥＬ素子と本発明の薄膜ＥＬ素子から窒化
物誘電体薄膜４を除いた従来の薄膜ＥＬ素子に、第３図
に示すような位相の異なる交流パルス電圧を印加し、発
光開始電圧の経時変化を測定したところ、第２図に示す
ように、従来の素子では１００時間で約６チ発光開始電
圧が低下したのに対しく第２図ｂ）、本発明の素子では
１％以内であった（第２図ａ）。AC pulse voltages with different phases as shown in FIG. 3 are applied to the thin film EL device of the present invention and a conventional thin film EL device obtained by removing the nitride dielectric thin film 4 from the thin film EL device of the present invention, and the emission starting voltage is As shown in Fig. 2, the luminescence starting voltage decreased by about 6% in 100 hours in the conventional device (Fig. 2b), but within 1% in the device of the present invention. (Figure 2a).
本実施例では窒化物誘電体薄膜４をＥＬ発光体層の基板
側の面上にのみ形成したが、第４図に示すように、ＥＬ
発光体層６の両方の面に形成しても再現性良く本発明の
効果を発揮させることができた。またスパッタリング法
以外に、蒸着法。In this example, the nitride dielectric thin film 4 was formed only on the substrate side surface of the EL light emitter layer, but as shown in FIG.
Even when it was formed on both surfaces of the light emitting layer 6, the effects of the present invention could be exhibited with good reproducibility. In addition to the sputtering method, there is also a vapor deposition method.
ＣＶＤ法あるいはＥＣＲプラズマＣＶＤ法によシ形成し
ても同様の効果が得られた。A similar effect was obtained even when the film was formed by the CVD method or the ECR plasma CVD method.
窒化物誘電体薄膜の厚さは、１００人より薄い場合は、
発光開始電圧の経時変化を抑える効果が少なく、６００
人より厚くした場合は、第５図に示すように薄膜ＥＬ素
子の発光効率が低下したり、発光が不均一になった。ま
た、窒化物誘電体の誘電率は一般に小さく、厚くするほ
ど薄膜ＥＬ素子を駆動するのに必要な電圧が高くなり、
駆動用のＩＣが高価なものになり、厚い窒化物誘電体薄
膜を用いるのは好ましくない。これらの点を考慮した場
合、窒化物誘電体薄膜の厚さとしては１５０Å以上、４
５０八以下がより好ましい。If the thickness of the nitride dielectric thin film is less than 100,
It is less effective in suppressing changes in luminescence starting voltage over time;
When the thickness was made thicker than that of a human, the luminous efficiency of the thin film EL element decreased and the luminescence became non-uniform, as shown in FIG. In addition, the dielectric constant of nitride dielectrics is generally small, and the thicker the material, the higher the voltage required to drive the thin film EL element.
The driving IC becomes expensive, and it is not desirable to use a thick nitride dielectric thin film. Considering these points, the thickness of the nitride dielectric thin film should be 150 Å or more, 4
More preferably, it is 508 or less.
窒化物誘電体薄膜として、本実施例では窒化珪素を用い
たが、窒化珪素以外に、窒化はう素、あるいは窒化アル
ミユウムを用いても、発光開始電圧の変化を抑制するこ
とができた。しかし絶縁破壊電界強度の大きさや製造し
易さなどを考慮した場合、窒化珪素が最も好ましかった
。Although silicon nitride was used as the nitride dielectric thin film in this example, changes in the light emission starting voltage could also be suppressed by using boron nitride or aluminum nitride in addition to silicon nitride. However, when considering the dielectric breakdown field strength and ease of manufacture, silicon nitride was the most preferred.
第１誘電体層に用いる酸化物誘電体薄膜の厚さは、第２
誘電体層より厚くした方が、絶縁破壊に対する安定性が
高い。厚い第１誘電体層を用いるには、第１誘電体層に
用いる酸化物誘電体層の比誘電率が大きいほど好ましく
、実験結果からは１５以上が好ましかった。１５より小
さい場合、１００〜１８ｏｖの電圧で安定に駆動できる
薄膜ＥＩ、素子を形成するのは困難であった。このよう
な酸化物誘電体薄膜としては、ペロブスカイト形の結晶
構造を含む薄膜が、絶縁破壊電圧の面からも適していた
。その中でも５ｒＴｉｏ３．ＳｒｘＭｇ、 −、ＴｉＯ
２゜Ｓ ｒ Ｔ ｉ ｘ Ｚ ｒ １−ｘ Ｔ ｉ Ｏ
ｓ ！あるいはＳ ｒｘ Ｍｇ １−ｘ Ｔ ｉ ｙ
Ｚ １−ｙ Ｔ ｌ○３などの比誘電率および絶縁破壊
電界強度のとくに優れたチタン酸ストロンチウム系の薄
膜を、第１誘電体層の酸化物誘電体薄膜に用いることに
よシ極めて安定な薄膜ＥＬ素子を構成することができた
。第２誘電体層としては酸化物誘電体薄膜で構成しても
、長時間の駆動にも耐え、発光開始電圧の変動の少ない
薄膜ＥＬ素子を形成できた。この第２誘電体層の酸化物
誘電体薄膜の１つとして比誘電率が２２のタンタル酸バ
リウム系薄膜を用いることにより、伝播性絶縁破壊を抑
制することができ、信頼性の高い素子を形成することが
できた。The thickness of the oxide dielectric thin film used for the first dielectric layer is the same as that for the second dielectric layer.
The thicker it is than the dielectric layer, the higher the stability against dielectric breakdown. In order to use a thick first dielectric layer, it is preferable that the dielectric constant of the oxide dielectric layer used for the first dielectric layer is as large as possible, and from experimental results, a dielectric constant of 15 or more is preferable. If it is smaller than 15, it is difficult to form a thin film EI or element that can be stably driven at a voltage of 100 to 18 ov. As such an oxide dielectric thin film, a thin film containing a perovskite crystal structure is suitable from the viewpoint of dielectric breakdown voltage. Among them, 5rTio3. SrxMg, -, TiO
2゜S r T i x Z r 1-x T i O
S! Or S rx Mg 1-x T i y
By using a strontium titanate thin film, which has particularly excellent dielectric constant and dielectric breakdown field strength such as Z 1-y T l○3, as the oxide dielectric thin film of the first dielectric layer, an extremely stable structure can be obtained. A thin film EL device could be constructed. Even if the second dielectric layer was composed of an oxide dielectric thin film, it was possible to form a thin film EL element that withstood long-time driving and had little fluctuation in emission start voltage. By using a barium tantalate thin film with a relative dielectric constant of 22 as one of the oxide dielectric thin films of this second dielectric layer, propagating dielectric breakdown can be suppressed and a highly reliable device can be formed. We were able to.
ＥＬ発光体層形成後の熱処理は、本実施例では４５Ｃ）
Ｃで行ったが、３００℃以上、６８０℃以下の温度範囲
が適切であった。熱処理温度が３００℃より低い場合は
薄膜ＥＬ素子の発光効率が低く、６８０℃より高い場合
は発光開始電圧の経時変化を抑える効果が若干弱くなる
ことがあった。この原因としては窒化物誘電体薄膜が、
酸化物誘電体薄膜や、ＥＬ発光体層と相互拡散し、ＥＬ
発光体層と誘電体層との界面が、駆動中にトラップが形
成されやすい状態に変質したものと考えられる。In this example, the heat treatment after forming the EL light emitting layer was 45C)
The temperature range was 300°C or higher and 680°C or lower. When the heat treatment temperature was lower than 300°C, the luminous efficiency of the thin film EL element was low, and when it was higher than 680°C, the effect of suppressing the change in luminescence start voltage over time was sometimes slightly weakened. The reason for this is that the nitride dielectric thin film
Interdiffuses with the oxide dielectric thin film and the EL luminescent layer, and the EL
It is thought that the interface between the light emitter layer and the dielectric layer has changed into a state where traps are likely to be formed during driving.
窒化物誘電体薄膜を用いたＥＬ素子に関する従来技術は
特公昭５３−４２３９８号公報に記載されているが、こ
の技術は、薄膜発光層の上に、酸素ガスを含む雰囲気中
でスパッタリング法により酸化物薄膜を形成した場合、
［基板が高密度の酸素プラズマ中に保持されるため、薄
膜生成過程の初期に薄膜発光層の表面が負の酸素イオン
衝撃をうけて酸化され、この結果発光を伴わない再結合
中心が増加して素子の発光効率および寿命特性の劣化の
原因となる」ため、薄膜発光層の上に形成する絶縁層（
第３誘電体層）を窒化物で構成するものであり、本発明
の目的や構成とは異なり、そのため発揮される効果も異
なったものである。A conventional technique for an EL element using a nitride dielectric thin film is described in Japanese Patent Publication No. 53-42398, but this technique involves oxidizing a thin film light-emitting layer by sputtering in an atmosphere containing oxygen gas. When a thin film is formed,
[Since the substrate is held in a high-density oxygen plasma, the surface of the thin film emissive layer is bombarded with negative oxygen ions and oxidized at the beginning of the thin film formation process, resulting in an increase in the number of recombination centers that do not emit light.] The insulating layer formed on the thin-film light-emitting layer (
The third dielectric layer) is made of nitride, which is different from the purpose and structure of the present invention, and therefore the effects achieved are also different.
また特公昭５８−６２４３８号公報に記載の技術は、Ｓ
ｌｏ、５ｌａ２．ＧｅＱ２．Ｙ２Ｏ２，Ｓｉ３Ｎ４゜Ａ
４゜０３膜などは、「一般に生成条件によって誘電特性
が大きく変化し、多くの場合組成ずれ、充填密度の低下
及びピンホール、マイクロクラック等の欠陥が生じ、そ
の結果絶縁耐圧及び耐湿特性の劣化など、物理的化学的
に多くの不安定要素を含む。従ってこのような誘電体薄
膜を、ＺｎＳ 発光層をはさむ上下の誘電体層として用
いた場合、薄膜発光素子の寿命特性に与える影響が大き
く、特に背面電極側の第２の誘電体層６に於ては、層中
に存在するピンホール、マイクロクラック等の欠陥を通
して発光層中に湿気が侵入し、薄膜素子動作時の輝度の
低下や偶発的故障の原因になり易い。」ため、誘電体層
のうち少なくとも背面電極側のものを、第１３Ｎ４から
成る第１の薄膜と該第１の薄膜より誘電率の高い第２の
薄膜の少なくとも２層以上の複合誘電体薄膜で構成した
ものであり、本発明の目的や手段とは異なり、そのため
構成も異っている。つまり本願発明の効果を発揮するた
めには、透明電極側の第１誘電体層を、厚さ１００Å以
上、６００Å以下の窒化物誘電体薄膜と、比誘電率が１
５以上の酸化物誘電体薄膜とで構成し、かつＥＬ発光体
層と前記窒化物誘電体薄膜が接するようにＥＬ素子を構
成することが必要である。Furthermore, the technology described in Japanese Patent Publication No. 58-62438 is S
lo, 5la2. GeQ2. Y2O2, Si3N4゜A
4゜03 films etc. generally have dielectric properties that change significantly depending on the formation conditions, and in many cases, compositional deviations, decreases in packing density, and defects such as pinholes and microcracks occur, resulting in deterioration of dielectric strength and moisture resistance properties. Therefore, when such a dielectric thin film is used as the upper and lower dielectric layers sandwiching the ZnS light emitting layer, it has a large effect on the lifetime characteristics of the thin film light emitting device. In particular, in the second dielectric layer 6 on the back electrode side, moisture enters the light-emitting layer through defects such as pinholes and microcracks existing in the layer, resulting in a decrease in brightness during operation of the thin film device. Therefore, at least the back electrode side of the dielectric layer is made of at least a first thin film made of 13N4 and a second thin film having a higher dielectric constant than the first thin film. It is composed of two or more layers of composite dielectric thin films, which is different from the object and means of the present invention, and therefore the structure is also different. In other words, in order to exhibit the effects of the present invention, the first dielectric layer on the transparent electrode side must be a nitride dielectric thin film with a thickness of 100 Å or more and 600 Å or less, and a dielectric constant of 1.
It is necessary to configure the EL element with five or more oxide dielectric thin films, and to configure the EL element so that the EL light emitter layer and the nitride dielectric thin film are in contact with each other.
以上のように本願発明の構成は、薄膜ＥＬ素子に用いる
各種誘電体薄膜の組み合わせや厚さを詳細に研究するこ
とにより新しく見い出されたものである。As described above, the structure of the present invention was newly discovered through detailed research on the combinations and thicknesses of various dielectric thin films used in thin film EL devices.
発明の効果
本発明によれば、低電圧駆動が可能であり、長時間の駆
動を行っても発光開始電圧の変動が極めて小さい薄膜Ｅ
Ｌ素子を再現性よく形成でき、コンピュータ端末などの
薄形、高品位ディスプレイなどに広く実用できる。Effects of the Invention According to the present invention, a thin film E that can be driven at a low voltage and exhibits extremely small fluctuations in the emission starting voltage even after long-term driving.
L elements can be formed with good reproducibility and can be widely used in thin, high-quality displays such as computer terminals.
第１図は本発明の一実施例における薄膜ＥＬ素子の断面
図、第２図は発光開始電圧の経時変化を示すグラフ、第
３図は薄膜ＥＬ素子の駆動電圧波形を示す波形図、第４
図は本発明の他の実施例における薄膜ＥＬ素子の断面図
、第５図は本発明の薄膜ＥＬ素子における窒化物誘電体
薄膜の厚さと発光効率との関係を示すグラフである。
１・・・・・・ガラス基板、２・・・・・・透明電極、
３・・・・・・酸化物誘電体薄膜、４・・・・・・窒化
物誘電体薄膜、５・・・・・・ＥＬ発光体層、６・・・
・・・酸化物誘電体薄膜、７・・・・・・背面電極、８
・・・・・・第１誘電体層、９・・・・・・第２誘電体
層。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第１
図
背面電極
第２図
時間
第３図
第４図FIG. 1 is a cross-sectional view of a thin film EL device according to an embodiment of the present invention, FIG. 2 is a graph showing changes over time in the light emission starting voltage, FIG. 3 is a waveform diagram showing the drive voltage waveform of the thin film EL device, and FIG.
The figure is a cross-sectional view of a thin film EL device according to another embodiment of the present invention, and FIG. 5 is a graph showing the relationship between the thickness of the nitride dielectric thin film and luminous efficiency in the thin film EL device of the present invention. 1...Glass substrate, 2...Transparent electrode,
3... Oxide dielectric thin film, 4... Nitride dielectric thin film, 5... EL light emitter layer, 6...
... Oxide dielectric thin film, 7 ... Back electrode, 8
. . . 1st dielectric layer, 9 . . . 2nd dielectric layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Back electrode Figure 2 Time Figure 3 Figure 4
Claims (8)
Ｌ発光体層，第２誘電体層，および背面電極を順次積層
してなる薄膜ＥＬ素子において、前記第１誘電体層の前
記ＥＬ発光体層側の部分を、厚さ１００Å以上，６００
Å以下の窒化物誘電体薄膜で構成し、前記第，誘電体層
の前記透明電極側の部分を比誘電率が１５以上の酸化物
誘電体薄膜で構成したことを特徴とする薄膜ＥＬ素子。(1) Transparent electrode, first dielectric layer, E
In a thin film EL device formed by sequentially laminating an L emitter layer, a second dielectric layer, and a back electrode, a portion of the first dielectric layer on the EL emitter layer side has a thickness of 100 Å or more, and a thickness of 600 Å or more.
1. A thin film EL device comprising a nitride dielectric thin film having a thickness of Å or less, and a portion of the first dielectric layer on the transparent electrode side comprising an oxide dielectric thin film having a dielectric constant of 15 or more.
１００Å以上，６００Å以下の窒化物誘電体薄膜で構成
し、前記第２誘電体層の背面電極側の部分を酸化物誘電
体薄膜で構成したことを特徴とする特許請求の範囲第１
項に記載の薄膜ＥＬ素子。(2) The part of the second dielectric layer on the EL emitter layer side is made of a nitride dielectric thin film with a thickness of 100 Å or more and 600 Å or less, and the part of the second dielectric layer on the back electrode side is made of oxide. Claim 1, characterized in that the structure is made of a dielectric thin film.
The thin film EL device described in .
および窒化アルミユウムのうち、少なくとも１種以上か
らなることを特徴とする特許請求の範囲第１項あるいは
第２項に記載の薄膜ＥＬ素子。(3) The nitride dielectric thin film is made of silicon nitride, boron nitride,
The thin film EL device according to claim 1 or 2, characterized in that the thin film EL device is made of at least one of aluminum nitride and aluminum nitride.
カイト形構造の結晶部分を有することを特徴とする特許
請求の範囲第１項あるいは第２項に記載の薄膜ＥＬ素子
。(4) The thin film EL device according to claim 1 or 2, wherein the oxide dielectric thin film of the first dielectric layer has a crystalline portion having a perovskite structure.
トロンチウム系薄膜で構成したことを特徴とする特許請
求の範囲第１項あるいは第２項に記載の薄膜ＥＬ素子。(5) The thin film EL device according to claim 1 or 2, wherein the oxide dielectric thin film of the first dielectric layer is composed of a strontium titanate thin film.
特徴とする特許請求の範囲第４項あるいは第５項に記載
の薄膜ＥＬ素子。(6) The thin film EL device according to claim 4 or 5, wherein the nitride dielectric thin film is made of silicon nitride.
トロンチウム系薄膜で構成し、窒化物誘電体薄膜を窒化
珪素で構成し、第２誘電体層を酸化物誘電体薄膜で構成
したことを特徴とする特許請求の範囲第１項に記載の薄
膜ＥＬ素子。(7) The oxide dielectric thin film of the first dielectric layer was composed of a strontium titanate thin film, the nitride dielectric thin film was composed of silicon nitride, and the second dielectric layer was composed of an oxide dielectric thin film. The thin film EL device according to claim 1, characterized in that:
バリウム系薄膜を含むことを特徴とする特許請求の範囲
第１項，第２項，第４項，第５項，第６項，あるいは第
７項に記載の薄膜ＥＬ素子。(8) Claims 1, 2, 4, 5, and 6, characterized in that the oxide dielectric thin film of the second dielectric layer includes a barium tantalate thin film. , or the thin film EL device according to item 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61081328A JPS62237693A (en) | 1986-04-09 | 1986-04-09 | Thin film el device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61081328A JPS62237693A (en) | 1986-04-09 | 1986-04-09 | Thin film el device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62237693A true JPS62237693A (en) | 1987-10-17 |
Family
ID=13743318
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61081328A Pending JPS62237693A (en) | 1986-04-09 | 1986-04-09 | Thin film el device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62237693A (en) |
-
1986
- 1986-04-09 JP JP61081328A patent/JPS62237693A/en active Pending
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