JPH0982474A - Thin-film type electroluminescent element and its manufacture - Google Patents
Thin-film type electroluminescent element and its manufactureInfo
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- JPH0982474A JPH0982474A JP8173138A JP17313896A JPH0982474A JP H0982474 A JPH0982474 A JP H0982474A JP 8173138 A JP8173138 A JP 8173138A JP 17313896 A JP17313896 A JP 17313896A JP H0982474 A JPH0982474 A JP H0982474A
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- light emitting
- emitting layer
- thin film
- layer
- electroluminescent element
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は薄膜エレクトロルミ
ネッセンス素子およびその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film electroluminescent device and a method for manufacturing the same.
【０００２】[0002]
【従来の技術】フラットディスプレイ素子の１つとして
の薄膜エレクトロルミネッセンス（以下、ＥＬと記す）
ディスプレイ素子は、鮮明でコントラストが高く、視野
角依存性も小さいためコンピュータ端末の表示素子、車
両への搭載用表示素子等として研究開発が進められてい
る。2. Description of the Related Art Thin film electroluminescence (hereinafter referred to as EL) as one of flat display elements
Since the display device is clear and has a high contrast and has a small viewing angle dependency, research and development have been advanced as a display device for a computer terminal, a display device for mounting on a vehicle, and the like.
【０００３】図６は代表的な薄膜ＥＬ装置の断面図であ
る。ガラス基板１の上に第１の電極層２、第１の絶縁層
３、発光層４、第２の絶縁層５、第２の電極層６が順次
積層され薄膜ＥＬ素子が作製される。薄膜ＥＬ素子には
封止板７および側壁８が被せられシリコーンオイル９が
内部に注入された後、気密封止される。両電極層に駆動
電源Ｖを接続し、両極性のパルス電圧を印加してＥＬ発
光させる。FIG. 6 is a sectional view of a typical thin film EL device. The first electrode layer 2, the first insulating layer 3, the light emitting layer 4, the second insulating layer 5, and the second electrode layer 6 are sequentially laminated on the glass substrate 1 to manufacture a thin film EL element. The thin film EL element is covered with the sealing plate 7 and the side wall 8 and silicone oil 9 is injected thereinto, and then hermetically sealed. A driving power supply V is connected to both electrode layers, and a pulse voltage of both polarities is applied to emit EL light.
【０００４】第１の電極層２は酸化インジウム酸化スズ
（以下、ＩＴＯと記す）等の透明導電層であり、第１の
絶縁層３および第２の絶縁層５は窒化ケイ素（以下、Si
3N4と記す）膜および酸化ケイ素（以下、SiO2と記す）
膜の積層であってSi3N4 膜が発光層４に隣接し、第２の
電極層６は金属膜であることが多い。発光層４として黄
橙色発光のZnS:Mnからなる蛍光体を用いたモノクローム
薄膜エレクトロルミネッセンスディスプレイは既に実用
化されているが、ディスプレイ内容の多様化に伴いカラ
ー化が不可欠となっている。The first electrode layer 2 is a transparent conductive layer such as indium tin oxide (hereinafter referred to as ITO), and the first insulating layer 3 and the second insulating layer 5 are made of silicon nitride (hereinafter referred to as Si).
3 N 4 ) film and silicon oxide (hereinafter referred to as SiO 2 )
In most cases, the Si 3 N 4 film is a film stack adjacent to the light emitting layer 4, and the second electrode layer 6 is a metal film. Although a monochrome thin-film electroluminescent display using a phosphor composed of yellow-orange-emitting ZnS: Mn as the light-emitting layer 4 has already been put into practical use, colorization is indispensable as the display contents are diversified.
【０００５】カラー薄膜ＥＬディスプレイに用いられる
発光層４の蛍光体としては、赤色用にはCaS:Eu、ZnS:S
m、SrS:Euなど、緑色用としてはZnS:Tb、CaS:Ceなど、
青色用にはSrS:Ceなどが用いられているが、次に述べる
ような問題点があり、いずれも実用的なカラーＥＬディ
スプレイは実現されていない。As the phosphor of the light emitting layer 4 used in the color thin film EL display, CaS: Eu, ZnS: S for red color are used.
m, SrS: Eu, etc., for green, ZnS: Tb, CaS: Ce, etc.
SrS: Ce and the like are used for blue, but there are problems as described below, and neither practical color EL display has been realized.
【０００６】[0006]
【発明が解決しようとする課題】これらの発光層薄膜は
いずれも、発光輝度が低い、寿命が短い、という問
題点があった。特に、の短寿命は実用化にとって大き
な問題であった。今回、我々は、寿命が短い原因が、発
光層の内部または表面に含まれる二酸化炭素、酸素また
は水分などの不純物に起因しており、これを除くことに
より長寿命が達成できることを発見した。All of these light emitting layer thin films have the problems of low emission brightness and short life. In particular, the short life of was a big problem for practical use. Here, we have found that the cause of the short life is due to impurities such as carbon dioxide, oxygen, or water contained in the inside or the surface of the light emitting layer, and the long life can be achieved by removing the impurities.
【０００７】本発明の目的は、長時間の発光後も、輝度
の低下の少ない薄膜ＥＬ素子およびその製造方法を提供
することにある。It is an object of the present invention to provide a thin film EL element and a method for manufacturing the same, in which the luminance is less likely to decrease even after long-term light emission.
【０００８】[0008]
【課題を解決するための手段】上記の目的を達成するた
め、ガラス基板上に、第１の電極層、第１の絶縁層、少
なくともアルカリ土類硫化物に希土類元素を添加した材
料よりなる発光層、第２の絶縁層、第２の電極層が順次
積層された薄膜エレクトロルミネッセンス素子におい
て、前記発光層の内部または表面に含まれる二酸化炭
素、酸素または水分が除去されていることとする。In order to achieve the above-mentioned object, light emission comprising a glass substrate, a first electrode layer, a first insulating layer, and a material in which a rare earth element is added to at least an alkaline earth sulfide. In the thin film electroluminescent element in which the layer, the second insulating layer, and the second electrode layer are sequentially stacked, carbon dioxide, oxygen, or moisture contained in the inside or the surface of the light emitting layer is removed.
【０００９】前記酸素の残留量は１×１０16分子／cm2
以下であると良い。前記二酸化炭素の残留量は１×１０
17分子／cm2 以下であると良い。前記水分の残留量は３
×１０16分子／cm2 以下であると良い。ガラス基板上
に、第１の電極層、第１の絶縁層、少なくともアルカリ
土類硫化物に希土類元素を添加した材料よりなる発光
層、第２の絶縁層、第２の電極層を順次積層する薄膜エ
レクトロルミネッセンス素子の製造方法において、前記
第２の絶縁層の成膜前に、前記発光層の不純物分子を除
去させる除去工程を行うこととする。The residual amount of oxygen is 1 × 10 16 molecule / cm 2
The following is good. The residual amount of carbon dioxide is 1 × 10
It is preferably 17 molecules / cm 2 or less. The residual amount of water is 3
It is preferably × 10 16 molecules / cm 2 or less. A first electrode layer, a first insulating layer, a light emitting layer made of at least a material obtained by adding a rare earth element to an alkaline earth sulfide, a second insulating layer, and a second electrode layer are sequentially stacked on a glass substrate. In the method for manufacturing a thin film electroluminescent element, a removing step for removing impurity molecules in the light emitting layer is performed before forming the second insulating layer.
【００１０】前記除去工程は発光層の表面のスパッタで
あると良い。前記スパッタに用いられるガスには水素ガ
スが含まれていると良い。前記除去工程は発光層の真空
熱処理であると良い。前記熱処理は圧力１×１０-1Pa以
下の真空中で、発光層の温度を２５０〜６００℃とする
と良い。The removing step may be sputtering of the surface of the light emitting layer. The gas used for the sputtering may include hydrogen gas. The removing step is preferably a vacuum heat treatment of the light emitting layer. In the heat treatment, the temperature of the light emitting layer is preferably 250 to 600 ° C. in a vacuum with a pressure of 1 × 10 -1 Pa or less.
【００１１】ガラス基板上に、第１の電極層、第１の絶
縁層、少なくともアルカリ土類硫化物に希土類元素を添
加した材料よりなる発光層、第２の絶縁層、第２の電極
層とを順次積層した薄膜エレクトロルミネッセンス素子
の製造方法において、前記発光層の成膜後ひき続き真空
中に保持し第２の絶縁層を成膜すると良い。本発明によ
れば、発光層中の二酸化炭素または酸素、あるいは発光
層表面の吸着水分を除去したため、駆動中に残留してい
る二酸化炭素、酸素分子または水分子が発光層に拡散
し、これらの酸素または酸素分子が発光中心に作用して
輝度を低下させたとしてもその影響は小さいと推定され
る。On a glass substrate, a first electrode layer, a first insulating layer, a light emitting layer made of at least a material obtained by adding a rare earth element to an alkaline earth sulfide, a second insulating layer, and a second electrode layer. In the method for manufacturing a thin film electroluminescent element in which the above are sequentially stacked, it is preferable that after the light emitting layer is formed, the second insulating layer is formed by keeping it in vacuum. According to the present invention, since carbon dioxide or oxygen in the light emitting layer or adsorbed water on the surface of the light emitting layer is removed, carbon dioxide, oxygen molecules or water molecules remaining during driving are diffused into the light emitting layer. It is presumed that even if oxygen or oxygen molecules act on the emission center to reduce the brightness, the effect is small.
【００１２】プラズマを用いて発光層表面をスパッタす
ることにより、発光層表面の水分を取り除くこともでき
る。とくに、スパッタガスに水素が含まれいると、発光
層内部の二酸化炭素および酸素分子を除去することがで
きる。また、発光層を真空中で加熱することにより、発
光層表面に吸着した水分や酸素などの吸着ガスを除去さ
せることができる。水分の除去は２５０℃以上が必要で
あるが、温度を高くしすぎると発光層中の硫黄が蒸発し
かえって発光輝度の低下を招くので、加熱温度としては
２５０〜６００℃、好ましくは３５０〜５００℃が適当
である。It is also possible to remove water on the surface of the light emitting layer by sputtering the surface of the light emitting layer using plasma. In particular, if the sputtering gas contains hydrogen, carbon dioxide and oxygen molecules inside the light emitting layer can be removed. Further, by heating the light emitting layer in a vacuum, it is possible to remove adsorbed gas such as water and oxygen adsorbed on the surface of the light emitting layer. It is necessary to remove water at 250 ° C. or higher, but if the temperature is too high, sulfur in the light emitting layer evaporates and the emission brightness is lowered. Therefore, the heating temperature is 250 to 600 ° C., preferably 350 to 500 ° C. ℃ is suitable.
【００１３】また、発光層の成膜後に、発光層成膜後、
真空中に保持して第２絶縁層を成膜すれば、発光層には
水分などは吸着されない。Further, after forming the light emitting layer, after forming the light emitting layer,
If the second insulating layer is formed while being held in vacuum, moisture or the like will not be adsorbed on the light emitting layer.
【００１４】[0014]
【発明の実施の形態】本発明に係る薄膜ＥＬ素子は図６
を用いて既に説明した構造である。第１の電極層２はＩ
ＴＯなどの透明電極とし、第１の絶縁層３および第２の
絶縁層５は窒化ケイ素（Si3N4)膜および酸化ケイ素（Si
O2）膜の積層とし窒化ケイ素膜が発光層４に隣接し、第
２の電極層６はアルミニウムとニッケルなど金属層の積
層とした。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thin film EL device according to the present invention is shown in FIG.
This is the structure already described using. The first electrode layer 2 is I
As a transparent electrode such as TO, the first insulating layer 3 and the second insulating layer 5 are made of a silicon nitride (Si 3 N 4 ) film and a silicon oxide (Si
O 2) laminated and then a silicon nitride layer of the membrane adjacent to the luminescent layer 4, the second electrode layer 6 was laminated metal layer such as aluminum and nickel.
【００１５】発光層４として赤色用にはCaS:EuまたはSr
S:Euのいずれか両者、これらとZnS:Smの積層、緑色用と
してはCaS:CeとこれとZnS:Tbの積層、青色用にはSrS:Ce
などを用いることができる。以下の実施例では、絶縁層
の形成にはスパッタ法、発光層の形成には蒸着法を用い
たが、各々他の成膜法を用いても同様な効果が得られ
る。 実施例１ 図５は本発明の実施例に用いた薄膜ＥＬ素子の絶縁層用
のスパッタ装置の模式断面図である。CaS: Eu or Sr for the red light emitting layer 4
S: Eu or both, a stack of these and ZnS: Sm, a stack of CaS: Ce and this and ZnS: Tb for green, and a stack of SrS: Ce for blue
Etc. can be used. In the following examples, the sputtering method was used for forming the insulating layer and the vapor deposition method was used for forming the light emitting layer. However, similar effects can be obtained by using other film forming methods. Example 1 FIG. 5 is a schematic sectional view of a sputtering apparatus for an insulating layer of a thin film EL element used in an example of the present invention.
【００１６】このスパッタ装置においては、カソード１
２に接続されそこに設置されているターゲット１３をス
パッタするＲＦ電源１６ａの他にガラス基板１が置かれ
るアノード１４にはこちら側をスパッタできるように別
のＲＦ電源１６ｂ（１３．５６ＭＨｚ）が接続されてい
る。このＲＦ電源１６ｂを用いてガラス基板１をエッチ
ングすることができる。このときアノード１４は接地さ
れる。In this sputtering apparatus, the cathode 1
In addition to the RF power source 16a that is connected to No. 2 and sputters the target 13 installed there, another RF power source 16b (13.56 MHz) is connected to the anode 14 on which the glass substrate 1 is placed so that this side can be sputtered. Has been done. The glass substrate 1 can be etched using this RF power supply 16b. At this time, the anode 14 is grounded.
【００１７】本実施例の薄膜ＥＬ素子は以下の手順で製
作した。 ガラス基板１の表面に透明電極層２としてＩＴＯをス
パッタにより成膜し、湿式プロセスによりストライプ状
にパターニングした。 第１の絶縁層３として反応性スパッタにより、SiO ２
とSi3N4 とを順次積層し、膜厚を２００ｎｍとした。The thin film EL device of this example was manufactured by the following procedure. ITO was deposited as a transparent electrode layer 2 on the surface of the glass substrate 1 by sputtering, and was patterned into a stripe shape by a wet process. The first insulating layer 3 is formed of SiO 2 by reactive sputtering.
And Si 3 N 4 were sequentially laminated to a film thickness of 200 nm.
【００１８】発光層４として、電子線蒸着によりＣｅ
を発光中心とする硫化ストロンチウム（ＳｒＳ：Ｃｅ）
膜を成膜した。成膜時の基板温度は５００℃とし、発光
層４の厚さは約１μｍとした。 発光層４までを積層したガラス基板１を常温常湿中に
取り出してから第１の絶縁層３を成膜したスパッタ装置
内に移し、絶縁層３を成膜する本スパッタ装置内で、発
光層表面をArとH2との混合ガスでガス圧力０．１Pa、投
入電力５００Wの条件で、４min 間スパッタを行ない、
不純物除去を行った。The light emitting layer 4 is made of Ce by electron beam evaporation.
Strontium sulfide (SrS: Ce)
A film was formed. The substrate temperature during film formation was 500 ° C., and the thickness of the light emitting layer 4 was about 1 μm. The glass substrate 1 on which the light emitting layer 4 has been laminated is taken out at room temperature and normal humidity, and then transferred into the sputtering apparatus in which the first insulating layer 3 is formed, and in the present sputtering apparatus for forming the insulating layer 3, the light emitting layer is formed. The surface is sputtered with a mixed gas of Ar and H 2 under a gas pressure of 0.1 Pa and an input power of 500 W for 4 minutes.
Impurities were removed.
【００１９】発光層４の不純物除去後、同じスパッタ
装置内で引き続き第１の絶縁層３と同じ条件で、第２の
絶縁層５としてSi3N4 膜とSiO2膜とを順次積層した。発
光層４はSi3N4 に挟まれている。 第２の電極層６としてＡｌとＮｉの積層膜を電子線蒸
着により積層し、透明電極層２のストライプと直角方向
のストライプを湿式プロセスによりパターニングした。After removing the impurities from the light emitting layer 4, a Si 3 N 4 film and a SiO 2 film were successively laminated as a second insulating layer 5 under the same conditions as the first insulating layer 3 in the same sputtering apparatus. The light emitting layer 4 is sandwiched between Si 3 N 4 . A laminated film of Al and Ni was laminated as the second electrode layer 6 by electron beam evaporation, and the stripe of the transparent electrode layer 2 and the stripe in a direction perpendicular to the stripe were patterned by a wet process.
【００２０】発光層からの脱ガス成分を調べるために発
光層の昇温脱離ガス分析（以下、ＴＤＳと記す）を行っ
た。図２は不純物除去を行っていない発光層の O2 分子
（質量数３２）の昇温脱離ガス分析のグラフである。縦
軸は検出分子数に比例する任意単位であり、目盛りは以
降のＴＤＳのグラフ（図３、図４）と共通とする。図２
から、 O2 分子は４００℃付近から脱離を開始し、６５
０℃付近で大部分が脱離し尽くしていることが判る。脱
離した O2 分子の総量は約３×１０16分子/cm2であっ
た。また、図３は不純物除去を行っていない発光層のCO
2 分子（質量数４４）の昇温脱離ガス分析のグラフであ
る。縦軸は検出分子数に比例する任意単位である。図３
から、CO2 分子も４００℃付近から脱離を開始し、８０
０℃付近まで脱離していることが判る。脱離したCO2 分
子の総量は約３×１０17分子/cm2であった。In order to investigate outgassing components from the light emitting layer, thermal desorption gas analysis (hereinafter referred to as TDS) of the light emitting layer was performed. FIG. 2 is a graph of thermal desorption gas analysis of O 2 molecules (mass number 32) in the light emitting layer in which impurities are not removed. The vertical axis is an arbitrary unit proportional to the number of detected molecules, and the scale is common to the subsequent TDS graphs (FIGS. 3 and 4). FIG.
Therefore, the O 2 molecule starts desorption at around 400 ° C,
It can be seen that most of them are completely desorbed near 0 ° C. The total amount of released O 2 molecules was about 3 × 10 16 molecules / cm 2 . In addition, FIG. 3 shows the CO of the light emitting layer where impurities are not removed.
It is a graph of thermal desorption gas analysis of 2 molecules (mass number 44). The vertical axis is an arbitrary unit proportional to the number of detected molecules. FIG.
Therefore, CO 2 molecules also start desorption from around 400 ℃,
It can be seen that desorption is performed up to around 0 ° C. The total amount of desorbed CO 2 molecules was about 3 × 10 17 molecules / cm 2 .
【００２１】本発明にかかる不純物除去工程終了後に、
基板上の発光層を真空に保持したままＴＤＳ装置中に取
り込みＴＤＳを行うと、 O2 分子の脱離総量は約１×１
０16分子/cm2以下、CO2 分子の脱離総量は約１×１０17
分子/cm2以下であった。不純物除去工程により O2 分
子、CO2 分子ともに約１／３に減少していることが判
る。スパッタガスに水素ガスが含まれていないと、 O2
とCO2 の減少は少なく、水素ガスが重要であることが判
る。 実施例２ 本実施例の薄膜ＥＬ素子は、不純物の除去工程を変え
た以外は実施例１と同じとした。スパッタ条件を、ガス
をArのみ、基板温度を室温、スパッタ時間を2minとし
た。After the completion of the impurity removing step according to the present invention,
When the light emitting layer on the substrate is held in a vacuum and taken into a TDS device for TDS, the total amount of desorbed O 2 molecules is about 1 × 1.
0 16 molecule / cm 2 or less, total desorption of CO 2 molecule is about 1 × 10 17
The molecule / cm 2 or less. It can be seen that both the O 2 molecule and the CO 2 molecule are reduced to about 1/3 by the impurity removal process. If the sputtering gas does not contain hydrogen gas, O 2
And CO 2 reduction is small, and hydrogen gas is important. Example 2 The thin-film EL device of this example was the same as Example 1 except that the impurity removing step was changed. The sputtering conditions were that the gas was Ar only, the substrate temperature was room temperature, and the sputtering time was 2 min.
【００２２】実施例１と同様にＴＤＳを水に対して行っ
た。図４は不純物除去を行っていない発光層の水分子
（質量数１８）の昇温脱離ガス分析のグラフである。縦
軸は検出分子数に比例する任意単位であ。図４から、水
分子は１５０℃付近から脱離を開始し、５５０℃付近で
大部分が脱離し尽くしたことが判る。脱離した水分子の
総量は約１×１０17分子/cm2であった。TDS was performed on water in the same manner as in Example 1. FIG. 4 is a graph of thermal desorption gas analysis of water molecules (mass number 18) in the light emitting layer where impurities are not removed. The vertical axis is an arbitrary unit proportional to the number of detected molecules. It can be seen from FIG. 4 that water molecules started desorption at around 150 ° C. and most of them were desorbed at around 550 ° C. The total amount of desorbed water molecules was about 1 × 10 17 molecules / cm 2 .
【００２３】実施例１と同様に、本発明にかかる不純物
除去工程終了後に、発光層を真空に保持したままＴＤＳ
装置中に取り込みＴＤＳを行うと、水分子の脱離総量は
約３×１０16分子/cm2以下であり、不純物除去工程を経
ないときの約１／３以下となっていた。上記のようにし
て得られた実施例１、２の薄膜ＥＬ素子の発光層側をガ
ラスの封止板７と側壁８でなる箱で覆い、シリコーンオ
イル９を注入して封止し、薄膜ＥＬ装置（図６）を作製
した。この薄膜ＥＬ装置の両電極層間に駆動電源Ｖを接
続し、両極性のパルス電圧を印加して発光輝度の経時変
化を評価した。図１は本発明に係る薄膜ＥＬ素子の発光
輝度の経時変化のグラフである。図１には、不純物除去
を行わない発光層のＥＬ素子を用いた薄膜ＥＬ装置の経
時変化（カーブｃ）も付記した。カーブａは実施例１で
作製した素子、カーブｂは実施例２で作製した素子を用
いた薄膜ＥＬ装置に対応する。６０Ｈｚ換算で５万時間
駆動した後の薄膜ＥＬ素子の発光輝度は、実施例１のＥ
Ｌ素子では初期輝度の約６０％であり（カーブａ）、実
施例２のＥＬ素子では初期輝度の約４５％であった（カ
ーブｂ）。一方、不純物除去を行わない発光層のＥＬ素
子（カーブｃ）では１万時間で５０％にも低下してお
り、不純物除去の発光輝度の経時変化に対する効果は明
らかである。Similar to the first embodiment, after the impurity removing step according to the present invention is completed, the TDS is performed while keeping the light emitting layer in vacuum.
When TDS was taken into the device, the total amount of desorbed water molecules was about 3 × 10 16 molecules / cm 2 or less, which was about 1/3 or less of that when the impurity removal step was not performed. The light emitting layer side of the thin film EL elements of Examples 1 and 2 obtained as described above is covered with a box composed of the glass sealing plate 7 and the side wall 8, and silicone oil 9 is injected to seal the thin film EL element. A device (FIG. 6) was made. A driving power supply V was connected between both electrode layers of this thin film EL device, and a pulse voltage of both polarities was applied to evaluate the change over time in the emission luminance. FIG. 1 is a graph showing changes with time of the emission luminance of the thin film EL device according to the present invention. FIG. 1 also shows the change with time (curve c) of the thin film EL device using the EL element of the light emitting layer in which impurities are not removed. The curve a corresponds to the element manufactured in Example 1, and the curve b corresponds to the thin film EL device using the element manufactured in Example 2. The light emission luminance of the thin film EL element after being driven for 50,000 hours at 60 Hz was E of Example 1.
The L element had an initial luminance of about 60% (curve a), and the EL element of Example 2 had an initial luminance of about 45% (curve b). On the other hand, in the case of the EL element (curve c) of the light emitting layer in which the impurities are not removed, it is as low as 50% in 10,000 hours, and the effect of the removal of impurities on the change over time of the emission luminance is clear.
【００２４】以上の解析から、発光輝度の経時劣化には
発光層内部または表面に存在していた二酸化炭素、酸素
または水分が薄膜ＥＬ素子の寿命に大きく影響を及ぼし
ており、これらの不純物を除去された発光層を有する薄
膜ＥＬ素子は長寿命であることが判った。 実施例３ 本実施例の薄膜ＥＬ素子の製造方法は、不純物の除去工
程が異なるのみで他は実施例１と同じとした。From the above analysis, it is found that carbon dioxide, oxygen or water present inside or on the surface of the light emitting layer has a great influence on the life of the thin film EL element for the deterioration of the emission luminance with time, and these impurities are removed. It was found that the thin film EL device having the above-mentioned light emitting layer has a long life. Example 3 The manufacturing method of the thin film EL element of this example was the same as that of Example 1 except that the impurity removing step was different.
【００２５】発光層４までを積層したガラス基板１を
常温常湿中に取り出してから、第１の絶縁層３を成膜し
たスパッタ装置内に移し、１．５×１０-3Paの真空中
で、基板温度を４００℃に加熱し、発光層の吸着ガスの
脱ガスを１ｈ行った。発光層４までを積層したガラス
基板を、ＴＤＳ装置中でと同じ温度プロフィルの脱ガ
スを行った後、ＴＤＳを行うと、水分子の総量は約３×
１０16分子/cm2以下であり、実施例２と同様に、水分の
除去が確かめられた。The glass substrate 1 on which the light-emitting layer 4 has been laminated is taken out at room temperature and normal humidity, and then transferred into the sputtering apparatus in which the first insulating layer 3 is formed, and in a vacuum of 1.5 × 10 −3 Pa. Then, the substrate temperature was heated to 400 ° C., and the adsorbed gas in the light emitting layer was degassed for 1 hour. When the glass substrate on which the light emitting layer 4 is laminated is degassed with the same temperature profile as in the TDS apparatus and then TDS is performed, the total amount of water molecules is about 3 ×.
It was 10 16 molecules / cm 2 or less, and removal of water was confirmed as in Example 2.
【００２６】なお、基板温度は、ＴＤＳから判るように
水の脱離が始まる２５０℃以上、発光層から硫黄の脱離
が始まる６００℃以下とする必要がある。また、この素
子を用いた薄膜ＥＬ装置の発光輝度の経時変化は実施例
２の場合と略同じであった。 実施例４ 本実施例では、発光層４の成膜後から第２の絶縁層５の
成膜までの間、基板を真空中に保持して、発光層４への
ガス吸着を防止した例である。The substrate temperature must be 250 ° C. or higher where desorption of water begins, as can be seen from TDS, and 600 ° C. or lower where desorption of sulfur from the light emitting layer begins. In addition, the change with time of the emission luminance of the thin film EL device using this element was substantially the same as in the case of Example 2. Example 4 In this example, the substrate is kept in vacuum between the formation of the light emitting layer 4 and the formation of the second insulating layer 5 to prevent gas adsorption to the light emitting layer 4. is there.
【００２７】薄膜ＥＬ素子は以下の手順で製作した。 〜 実施例１と同様である。 発光層４としてSrS:Ce膜を電子線蒸着により成膜し
た。基板温度は５００℃、発光層４の厚さは約１μｍと
した。 同じ真空装置内で真空を保持したまま、別の成膜室に
基板を移動した後、第２の絶縁層を第１の絶縁層と同じ
条件でSi3N4 とSiO2との第２の絶縁層を順次積層した。The thin film EL device was manufactured by the following procedure. ~ The same as Example 1. A SrS: Ce film was formed as the light emitting layer 4 by electron beam evaporation. The substrate temperature was 500 ° C., and the thickness of the light emitting layer 4 was about 1 μm. After moving the substrate to another film formation chamber while maintaining the vacuum in the same vacuum device, the second insulating layer was formed into a second insulating layer containing Si 3 N 4 and SiO 2 under the same conditions as the first insulating layer. Insulating layers were sequentially stacked.
【００２８】以下、実施例１と同様にして、薄膜ＥＬ
素子を作製した。 また、この素子を用いた薄膜ＥＬ装置の発光輝度の経時
変化は実施例２の場合と同じであった。発光層が水蒸気
に曝されることなく、すなわち、水分子を吸着すること
なく発光層は次工程以下の耐湿構造により被覆されたか
らである。Thereafter, in the same manner as in Example 1, the thin film EL
An element was manufactured. In addition, the change with time of the emission luminance of the thin film EL device using this element was the same as in the case of Example 2. This is because the light emitting layer was covered with the moisture resistant structure of the next step and thereafter without being exposed to water vapor, that is, without adsorbing water molecules.
【００２９】[0029]
【発明の効果】本発明によれば、ガラス基板上に、第１
の電極層、第１の絶縁層、少なくともアルカリ土類硫化
物に希土類元素を添加した材料よりなる発光層、第２の
絶縁層、第２の電極層とを順次積層した薄膜ＥＬ素子に
おいて、前記発光層の内部または表面に含まれる二酸化
炭素、酸素または水分を除去したため、本発明の薄膜Ｅ
Ｌ素子は駆動中に不純物に起因する酸素の発光中心への
影響は少なくなり、輝度低下は小さく長寿命であり、こ
れを用いて信頼性の高い薄膜ＥＬ装置を得ることができ
る。According to the present invention, the first substrate is formed on the glass substrate.
And a first insulating layer, a light emitting layer made of a material in which a rare earth element is added to at least an alkaline earth sulfide, a second insulating layer, and a second electrode layer are sequentially stacked. Since the carbon dioxide, oxygen or water contained in or inside the light emitting layer has been removed, the thin film E of the present invention is obtained.
The L element has less influence of oxygen due to impurities on the emission center during driving, has a small decrease in luminance and has a long life, and by using this, a highly reliable thin film EL device can be obtained.
【００３０】また、そのような発光層を得る製造方法
は、発光層表面のスパッタによるエッチング、発光層の
真空中での加熱あるいは発光層成膜から第２の絶縁層成
膜までの間の真空保持等であるため、成膜装置に特別の
改良は必要でなく、製造方法は煩雑化しない。従ってコ
ストアップは殆どない。Further, the manufacturing method for obtaining such a light emitting layer is carried out by etching the surface of the light emitting layer by sputtering, heating the light emitting layer in a vacuum, or vacuuming from the formation of the light emitting layer to the formation of the second insulating layer. Since it is holding and the like, no special improvement is required for the film forming apparatus, and the manufacturing method does not become complicated. Therefore, there is almost no cost increase.
【図１】本発明に係る薄膜ＥＬ素子の発光輝度の経時変
化のグラフFIG. 1 is a graph showing changes with time in emission luminance of a thin film EL device according to the present invention.
【図２】不純物除去を行っていない発光層の酸素（質量
数３２）の昇温脱離ガス分析のグラフFIG. 2 is a graph of thermal desorption gas analysis of oxygen (mass number 32) in the light emitting layer where impurities are not removed.
【図３】不純物除去を行っていない発光層の二酸化炭素
（質量数４４）の昇温脱離ガス分析のグラフFIG. 3 is a graph of thermal desorption gas analysis of carbon dioxide (mass number 44) in the light emitting layer where impurities are not removed.
【図４】不純物除去を行っていない発光層の水分子（質
量数１８）の昇温脱離ガス分析のグラフFIG. 4 is a graph of thermal desorption gas analysis of water molecules (mass number 18) in the light emitting layer where impurities are not removed.
【図５】本発明の実施例で用いた薄膜ＥＬ素子の絶縁層
用のスパッタ装置の模式断面図FIG. 5 is a schematic cross-sectional view of a sputtering apparatus for an insulating layer of a thin film EL element used in an example of the present invention.
【図６】代表的な薄膜ＥＬ装置の断面図FIG. 6 is a cross-sectional view of a typical thin film EL device.
【符号の説明】 １ ガラス基板 ２ 第２の電極層 ３ 第１の絶縁層 ４ 発光層 ５ 第１の絶縁層 ６ 第２の電極層 ７ 封止板 ８ 側壁 ９ シリコーンオイル Ｖ 駆動電源 １０ 真空容器 １１ ガス導入口 １２ カソード １３ ターゲット １４ アノード １５ シャッタ １６ａ ＲＦ電源 １６ｂ ＲＦ電源 １７ａ マッチングボックス １７ｂ マッチングボックス[Description of Reference Signs] 1 glass substrate 2 second electrode layer 3 first insulating layer 4 light emitting layer 5 first insulating layer 6 second electrode layer 7 sealing plate 8 side wall 9 silicone oil V drive power supply 10 vacuum container 11 Gas Inlet 12 Cathode 13 Target 14 Anode 15 Shutter 16a RF Power Supply 16b RF Power Supply 17a Matching Box 17b Matching Box
───────────────────────────────────────────────────── フロントページの続き (72)発明者 寺尾 豊 神奈川県川崎市川崎区田辺新田１番１号 富士電機株式会社内 (72)発明者 仲俣 伸一 神奈川県川崎市川崎区田辺新田１番１号 富士電機株式会社内 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yutaka Terao 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. No. 1 inside Fuji Electric Co., Ltd.
Claims (10)
縁層、少なくともアルカリ土類硫化物に希土類元素を添
加した材料よりなる発光層、第２の絶縁層、第２の電極
層が順次積層された薄膜エレクトロルミネッセンス素子
において、前記発光層の内部または表面に含まれる二酸
化炭素、酸素または水分が除去されていることを特徴と
する薄膜エレクトロルミネッセンス素子。1. A first electrode layer, a first insulating layer, a light emitting layer made of a material in which a rare earth element is added to at least an alkaline earth sulfide, a second insulating layer, and a second electrode on a glass substrate. A thin-film electroluminescent element, in which carbon dioxide, oxygen, or moisture contained in or on the surface of the light-emitting layer is removed in the thin-film electroluminescent element in which layers are sequentially laminated.
以下であることを特徴とする請求項１に記載の薄膜エレ
クトロルミネッセンス素子。2. The residual amount of oxygen is 1 × 10 16 molecule / cm 2
It is the following, The thin film electroluminescent element of Claim 1 characterized by the following.
／cm2 以下であることを特徴とする請求項１に記載の薄
膜エレクトロルミネッセンス素子。3. The thin film electroluminescent device according to claim 1, wherein the residual amount of carbon dioxide is 1 × 10 17 molecules / cm 2 or less.
以下であることを特徴とする請求項１に記載の薄膜エレ
クトロルミネッセンス素子。4. The residual amount of water is 3 × 10 16 molecules / cm 2
It is the following, The thin film electroluminescent element of Claim 1 characterized by the following.
縁層、少なくともアルカリ土類硫化物に希土類元素を添
加した材料よりなる発光層、第２の絶縁層、第２の電極
層を順次積層する薄膜エレクトロルミネッセンス素子の
製造方法において、前記第２の絶縁層の成膜前に、前記
発光層の不純物分子を除去させる除去工程を行うことを
特徴とする請求項１ないし３に記載の薄膜エレクトロル
ミネッセンス素子の製造方法。5. A first electrode layer, a first insulating layer, a light emitting layer made of a material in which a rare earth element is added to at least an alkaline earth sulfide, a second insulating layer, and a second electrode on a glass substrate. In the method for manufacturing a thin film electroluminescent element in which layers are sequentially laminated, a removing step for removing impurity molecules in the light emitting layer is performed before the film formation of the second insulating layer. A method for producing the thin-film electroluminescent element according to claim 1.
あることを特徴とする請求項５に記載の薄膜エレクトロ
ルミネッセンス素子の製造方法。6. The method for manufacturing a thin film electroluminescent element according to claim 5, wherein the removing step is sputtering of the surface of the light emitting layer.
スが含まれていることを特徴とする請求項６に記載の薄
膜エレクトロルミネッセンス素子の製造方法。7. The method for manufacturing a thin film electroluminescent element according to claim 6, wherein the gas used for the sputtering includes hydrogen gas.
ことを特徴とする請求項５に記載の薄膜エレクトロルミ
ネッセンス素子の製造方法。8. The method of manufacturing a thin film electroluminescent element according to claim 5, wherein the removing step is a vacuum heat treatment of the light emitting layer.
中で、発光層の温度を２５０〜６００℃とすることを特
徴とする請求項８に記載の薄膜エレクトロルミネッセン
ス素子の製造方法。9. The method for manufacturing a thin film electroluminescent element according to claim 8, wherein the heat treatment is performed at a temperature of the light emitting layer of 250 to 600 ° C. in a vacuum with a pressure of 1 × 10 -1 Pa or less. .
絶縁層、少なくともアルカリ土類硫化物に希土類元素を
添加した材料よりなる発光層、第２の絶縁層、第２の電
極層とを順次積層した薄膜エレクトロルミネッセンス素
子の製造方法において、前記発光層の成膜後ひき続き真
空中に保持し第２の絶縁層を成膜することを特徴とする
薄膜エレクトロルミネッセンス素子の製造方法。10. A first electrode layer, a first insulating layer, a light emitting layer made of a material in which a rare earth element is added to at least an alkaline earth sulfide, a second insulating layer, and a second electrode on a glass substrate. A method for manufacturing a thin film electroluminescent element, which comprises sequentially laminating layers to form a second insulating layer after the light emitting layer has been formed and subsequently kept in a vacuum. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17313896A JP3750199B2 (en) | 1995-07-07 | 1996-07-03 | Method for manufacturing thin-film electroluminescence device |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17174995 | 1995-07-07 | ||
| JP7-171749 | 1995-07-07 | ||
| JP17313896A JP3750199B2 (en) | 1995-07-07 | 1996-07-03 | Method for manufacturing thin-film electroluminescence device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0982474A true JPH0982474A (en) | 1997-03-28 |
| JP3750199B2 JP3750199B2 (en) | 2006-03-01 |
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ID=26494362
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| JP17313896A Expired - Fee Related JP3750199B2 (en) | 1995-07-07 | 1996-07-03 | Method for manufacturing thin-film electroluminescence device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006070713A1 (en) * | 2004-12-28 | 2006-07-06 | Idemitsu Kosan Co., Ltd. | Organic electroluminescent device |
-
1996
- 1996-07-03 JP JP17313896A patent/JP3750199B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006070713A1 (en) * | 2004-12-28 | 2006-07-06 | Idemitsu Kosan Co., Ltd. | Organic electroluminescent device |
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| Publication number | Publication date |
|---|---|
| JP3750199B2 (en) | 2006-03-01 |
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