JPS636778A - Thin film el device and manufacture of the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Summary] The first invention included in the present application is an improvement of a thin film EL device, in which an EL film made of a composition of zinc sulfide, a rare earth element, a chlorine element, or manganese. The EL film constituting the g-film EL element, which has improved luminous efficiency and brightness characteristics by bringing the composition ratio of rare earth elements and halogen elements close to 1, is coated with the underlying film (lower insulating film or translucent electrode). ) This is an improvement that prevents peeling from the surface.

The second invention included in this application is an improvement of the method for manufacturing a thin film EL element, and the composition ratio of rare earth elements and halogen elements contained in EL 11, which is composed of a composition of zinc sulfide, rare earth elements, and halogen elements. f! of the EL film 2 made of a composition of zinc sulfide and manganese. Yellow becomes too small and EL
In order to prevent the quality of the film from deteriorating, the ELM manufacturing method uses a sputtering method using a gas containing hydrogen sulfide as a sputtering gas to form an EL film. This is a method for producing an EL film that improves the drawback of easy peeling from the underlying film (lower insulating film or transparent electrode).

The gist of invention ii and the second invention is that a bonding film made of a compound of sulfur or selenium and a group II, group m, or group V element is interposed on the lower surface of the EL film.

[Industrial application field]

The present invention relates to improvements in thin film EL devices and methods for manufacturing the same. In particular, in order to improve luminous efficiency and brightness characteristics, we created an EL film in which the composition ratio of earth elements and halogen elements, which are the luminescent centers contained in the base material zinc sulfide, is close to 1, and the underlying layer ( A thin film EL element with a structure that improves adhesion to the lower insulating film or translucent electrode) and 1 Rare earth elements and halogen elements, which are light emitting centers, contained in zinc sulfide, the base material, to improve luminous efficiency and brightness characteristics. In order to bring the composition ratio of zinc sulfide closer to 1 or to improve the quality of the EL film I8 made of zinc sulfide containing manganese as a luminescent center, a sputtering method using hydrogen sulfide as a sputtering gas is used to improve the quality of the EL film.
The present invention relates to an improvement in improving the adhesion between an EL film and an underlying layer (a lower insulating film or a transparent electrode) with good reproducibility in a method for manufacturing a thin film EL device.

[Conventional technology]

II Pe2 E L elements are composed of rare earth elements such as terbium, samarium, thulium, praseodium, etc., which function as luminescent centers, and halogen elements such as fluorine,
Polycrystalline tI of phosphor such as zinc sulfide containing chlorine etc.
It is a light-emitting element that emits light based on an electroluminescence phenomenon by applying an electric field to an I film, and conventionally, a DC drive type as shown in FIG. 2 and an AC drive type as shown in FIG. 3 are known.

Referring to FIG. 2, a DC-driven thin EL element is made of ITO or the like on a glass substrate or the like, and n is about 2. A transparent electrode 2 containing Boo is formed thereon, and an EL1 electrode 4 made of a combination of a rare earth element, such as terbium, and a halogen element, such as fluorine, or zinc sulfide containing manganese, which functions as a luminescent center, is further formed. A counter electrode 6 made of aluminum or the like is formed thereon.

Refer to Figure 3. In addition to the layer structure shown in Figure 2 above, the AC drive type thin film EL element is made of silicon oxynitride, aluminum oxide, yttrium chloride, etc. with the EL film in between. A first insulation I8!3 and a second insulation v5 of approximately 2,000 people are formed.

By the way, among the rare earth elements that function as luminescent centers,
Terbium emits green, samarium red, thulium blue, praseodium white, and manganese orange, but the luminous efficiency and brightness of all of them are not satisfactory, except for terbium. .

Even with the most excellent terbium, the luminous efficiency is 0.1 to 0.2 lumen/W, and the brightness is 3
0 foot lambert, which cannot be said to be fully satisfactory, and furthermore, the reproducibility is not necessarily good.

As a means to solve this problem, the inventor of the present invention
There is a correlation between the composition ratio of rare earth elements and halogen elements contained in the film and the luminous efficiency and brightness characteristics, and when the number of atoms of the rare earth element and the number of atoms of the halogen element are the same, M also exhibits excellent light emission. It is possible to achieve high efficiency, efficiency, and brightness.
It was discovered that it is effective to increase the composition ratio of rare earth elements and halogen elements contained during EL film removal, at least compared to the stoichiometric composition ratio.・Completed the invention of a thin film EL element with excellent brightness characteristics.

In addition, the thin 115! has an EL film made of zinc sulfide containing manganese as two luminescent centers! In EL elements, the chemical properties of manganese and zinc are similar, so when manganese, which is the luminescent center, is added to the base material, the number of cations becomes greater than the number of anions, and the number of cations contained in the EL film increases. There is a drawback that the amount of sulfur released is too small, resulting in poor film quality of the EL film and poor luminous efficiency and brightness characteristics.

The purpose is to bring the composition ratio of rare earth elements and halogen elements, which are the luminescent centers, close to 1, and to prevent the film quality of the EL film from becoming poor due to the addition of manganese, which is the luminescent center, and the luminance efficiency Φ brightness characteristics worsening. In order to achieve this, the present inventor has proposed a sputtering method in which a gas containing hydrogen sulfide as a component is used as a sputtering gas and zinc sulfide and a rare earth halide element as targets, or a sputtering method in which a gas containing hydrogen sulfide as a component is used as a target. We have completed a method for manufacturing a tiI film El element in which an EL film is manufactured using a sputtering method using gas as a sputtering gas and zinc sulfide and manganese as targets.

[Problem that the invention seeks to solve]

The above-mentioned method for manufacturing a thin flQEL element (method for manufacturing a thin film EL element in which an EL film is manufactured using a sputtering method in a sputtering gas containing sulfide-hydrogen as a component)
The thin 119 EL element manufactured by carrying out this method had excellent luminous efficiency and brightness characteristics at the beginning of manufacture, but the ELlfJ and the lower Jl! ! (The lower insulating film (first insulator 119) for the AC drive type, and the translucent Ml made of ITO, etc. for the DC drive type) are poor, and the slicing process, mounting process, etc. ELII during the handling period! 2 has the disadvantage that it easily peels off from the base.

The first object of the present invention is to improve the adhesion between the EL film and its base in a thin film EL element whose EL film is made of lead-free sulfide in which the composition ratio of the rare earth element serving as the luminescent center and the halogen element is close to 1. Another object of the present invention is to provide a thin 119 EL element in which the EL film does not peel off from its base.

The second object of the present invention is to improve luminous efficiency and brightness characteristics by bringing the composition ratio of rare earth elements, which are luminescent centers, to halogen elements close to 1, or to improve luminous efficiency and brightness characteristics by improving the film quality of zinc sulfide. In a method for manufacturing a thin film EL element, EX, [9 is manufactured by sputtering in a sputtering gas containing hydrogen sulfide as a component in order to improve brightness characteristics.

A thin film EL element that can improve the adhesion between the EL film and its base! The purpose of the present invention is to provide a V manufacturing method.

[Means for solving problems]

The means taken by the present invention to achieve the above first object are as follows: (a) A transparent electrode 2 is formed on a transparent substrate l, and an EL layer is formed on this transparent electrode 2. A thin film 11 is formed on which a counter electrode 6 is formed on the ELllQA.
QEL element.

Alternatively, a transparent electrode 2 is formed on a transparent substrate l, a first insulating film 3 is formed on this transparent electrode 2, and an EL A film is formed, a second insulation [5 is formed on this EL change number, and this second insulation I! ! In the thin film EL element in which a counter electrode 6 is formed on the EL element 5, (b) between the transparent electrode 2 and the EL g 4,
Or, the first insulation I8!3 and the E L l
The reason is that a bonding film 7 made of a compound of sulfur or selenium and an element of group Ⅰ, group m, or group V is interposed between 1J and 4.

Suitable examples of the bonding film include gadolinium oxysulfide, ifthurium Sa oxide, gadolinium oxyselenide, yttrium oxyselenide, and the like.

The means taken by the present invention to achieve the above-mentioned second object are as follows: (a) A transparent electrode 2 is formed on a transparent substrate l, and hydrogen sulfide is formed on the transparent electrode 2. Using a sputtering method using a gas containing as a sputtering gas, ELIλ4 made of zinc sulfide alone or a zinc sulfide composition containing a nine-earth element and an alkali element or manganese is formed, and a A method for manufacturing a thin film EL element forming an electrode 6,
Alternatively, a transparent electrode 2 is formed on a transparent substrate 1, a first insulating film 3 is formed on this transparent substrate 1, and a layer containing hydrogen sulfide is formed on this first insulating film 3. Using a sputtering method in which gas is used as a sputtering gas, f! Zinc chloride alone.

Alternatively, an EL film formed from a zinc sulfide composition containing a rare earth element and an alkali element or manganese is formed, and this E
In a method of manufacturing a thin film EL element, a second insulating PIIJ 5 is formed on the L-number, and a counter electrode 6 is formed on the second insulating film 5.

(b) Prior to the formation of the ELM 4, a bonding film 7 made of a compound of sulfur or selenium and a group Ⅰ, group m, or group V element is formed.

As the above-mentioned bonding film, dolinium oxysulfide, yttrium oxysulfide, gadolinium oxyselenide, yttrium oxyselenide, etc. are suitable.

[Effect]

It is clear that the cause of the poor adhesion described above is due to the small chemical bonding force between the ELl19 material and the underlying material.

In the case of the above, the first insulating film or ITO that forms the base
When hydrogen sulfide comes into contact with the surface of a transparent electrode made of
A layer of sulfur adheres to its surface. However, this am
is simply adsorbed to the underlying first insulating film or the transparent electrode made of ITO or the like due to van der Waals forces. In other words, the value and the silicon forming the first insulating film It is not chemically bonded to atoms, oxygen atoms, indium atoms, tin atoms, oxygen atoms, etc. that make up ITO.
The film peels off from its base.

In order to eliminate this cause, it is possible to interpose a bonding film between the EL film and the underlying material, which is made of a material that can chemically bond strongly with both the EL film material and the underlying material. is clear.

By the way, in thin film EL elements, the materials used as the base of the EL film are insulators such as silicon oxide, silicon oxynitride, yttrium oxide, ITO, etc. H
The material is zinc sulfide.

All of these materials are easily bonded chemically, i.e.
Materials containing sulfur or selenium.

For example, a bonding film made of gadolinium oxysulfide, yttrium oxysulfide, gadolinium oxyselenide (1m yttrium selenide, etc.) is placed between the light-transmitting electrode and the EL film, or between the first insulating film and the EL film. If you do this, the vapor pressure of sulfur is very high, so
The bond between sulfur and sulfur is not formed, and the sulfur base component and the zinc of zinc sulfide that forms the EL film are directly and firmly bonded, and the EL film made of zinc sulfide will not peel off from the base. .

〔Example〕

The following claims 2 and 5 with reference to the drawings.
An example of an AC-driven thin film EL element according to the embodiment of Claims 1 and an example of a DC-driven sieve 115iEL element according to an embodiment of Claims 1 and 4 will be further described.

Kame 11 The case of manufacturing an AC driven thin film EL element will be described.

Using the sputtering method, see FIG. 1a, a thickness of approximately 2. G
A transparent electrode 2 made of ITO II 51 of OOA and a thickness of about 2.0 mm made of silicon oxide or silicon oxynitride. Goo
A first insulating film 3 is then formed.

Next, use argon as the sputtering gas.

Targeting yttrium oxysulfide, the thickness is about 2.0
A bonding film 7 made of a yttrium oxysulfide film of 0.00% is formed.

Next, using argon containing hydrogen sulfide (5%) as a sputtering gas, and using zinc sulfide and terbium fluoride as targets, the typical sputtering conditions are to form an ELv4 of approximately 200 s thick and 300 yen thick.

The gas pressure is IXIQ torr, the power is 300 W for a zinc sulfide target, IKW for a zinc sulfide target, and 300 W for a fluoride target, and the substrate temperature is about 230<0>C. After the film is formed, it is heat treated at 600° C. for 2 hours to improve crystallinity and at the same time to position the 7-2 element and terbium at optimal lattice positions.

Next, a second insulating film 5 made of silicon oxide or silicon oxynitride and having a thickness of about 2,000 A is formed using a sputtering method, and then a second insulating film 5 having a thickness of about 2,000 A is formed using a vapor deposition method or a sputtering method. A counter electrode (back electrode) 6 made of 3,000 aluminum films is formed.

The ELM4 of the thin film EL element manufactured through the above process is strongly chemically bonded to its base, and will not peel off during the handling period such as the slicing process or mounting process. The number of atoms of terbium and the number of atoms of fluorine contained are approximately the same. Its brightness (emission threshold voltage when driven at 1 Hz is 30
FIG. 4 shows a comparison of the brightness vs. voltage relationship A of the AC-driven thin film EL element manufactured by carrying out this example with the brightness vs. voltage relationship B of the prior art. As shown in the graph (graph), there is a significant improvement compared to the conventional technology. In FIG. 1, A indicates the value of this embodiment, and B indicates i(1) of the prior art.

As is clear from the figure, the luminous efficiency and luminance (luminance for a voltage exceeding the luminescent threshold voltage by 30 V when driven at IKHz) have been improved to 1.1 lumen/W and 200 foot lambert, respectively.

Example L The case of manufacturing a DC-driven thin film EL device will be described.

Refer to FIG. ib As in the case of the first example, a light-transmitting electrode 2 made of ITOM with a thickness of about 2,000 wafers is formed on a glass substrate 1 using a sputtering method.

Next, use argon as the sputtering gas.

Targeting ugly yttrium sulfide, approximately 500 mm thick
The φ bonding film 7 is formed of a lithium oxysulfide film having a thickness of less than Å.

Next, using argon containing hydrogen sulfide (5%) as a sputtering gas and using zinc sulfide and terbium fluoride as targets, the typical sputtering conditions are as follows: Gas pressure is I x 10 torr
r and the power is I K for the zinc sulfide target
l+1. 300 against terbium fluoride target
W, and the 2&i plate temperature is about 230°C. After film formation, heat treatment was performed at 800°C for 2 hours to improve crystallinity.
At the same time, fluorine and terbium are positioned at optimal lattice positions.

Next, as in the case of the first example, a counter electrode (back electrode) 6 made of an aluminum film with a thickness of approximately 3,000 wafers is formed using a vapor deposition method or a sputtering method.

ELl19 of the thin film EL device manufactured using the above steps
4 is strongly chemically bonded to its base and will not peel off during handling such as slicing and mounting processes. Also, the number of terbium atoms and fluorine contained in this EL number The number of atoms is almost the same. The brightness (brightness with respect to a voltage exceeding the emission threshold voltage by IOV) is shown in FIG. As shown in the graph (graph B) showing a comparison with the conventional technology, there is a significant improvement. In the figure, A indicates the value of this example, and B indicates the value of the conventional technology.As is clear from the figure, the luminous efficiency and luminance (luminance for a voltage exceeding the luminescence threshold voltage by IOV) are respectively 0. This has improved to .5 lumens/W and 400 foot runs/<-t.

In addition, similar attempts were made using gadolinium oxysulfide, gadolinium oxyselenide, yttrium oxyselenide, etc. instead of yttrium oxysulfide as materials for the bonding film, but exactly the same results were obtained. .

〔Effect of the invention〕

As explained above, the EL of the thin film EL element according to the present invention is as follows.
Between the film and the transparent electrode, or between the EL film and the first insulating film, sulfur or selenium and group II, group
Since a bonding film made of a compound with a group element is interposed, the EL film is strongly chemically bonded to its base.
It does not peel off during handling during the slicing process or mounting process, and since the number of terbium atoms and the number of fluorine atoms contained in this ELM are approximately the same, its brightness is significantly reduced. has improved.

[Brief explanation of drawings]

FIG. 1a is a sectional view of an AC-driven thin film EL device according to an embodiment of claims 2 and 5 of the present invention. FIG. 1b is a sectional view of a DC-driven thin film EL device according to an embodiment of Claims 1 and 814 of the present invention. FIG. 2 is a cross-sectional view of a DC-driven → membrane EL element according to the prior art. FIG. 3 is a sectional view of an AC driven thin film EL element according to the prior art. FIG. 4 shows the luminance (1 KHz
3 is a graph showing a comparison between the brightness vs. voltage relationship A and the brightness vs. voltage relationship B of the prior art for a voltage that exceeds the emission threshold voltage by 30 V when driven with a luminance threshold voltage of 30 V. FIG. 5 shows the luminance (luminance for a voltage exceeding the emission threshold voltage by IOV) versus voltage relationship A of the DC-driven thin film EL element according to the embodiment of claims 1 and 4 of the present invention. 3 is a graph comparing and showing the brightness vs. voltage relationship B of the prior art. l...Transparent substrate. 2＠Φ・Transparent electrode. 3...rfSl insulating film 4---ELl19°5-sha/second insulating film 6...counter electrode, 7...bonding film. Mi, ≦j-'' Present invention No. 1ag1 Present invention Fig. 1b Fig. 2 Fig. 3 Port

Claims (1)

[Claims] [1] A transparent electrode (2) is formed on a transparent substrate (1), an EL film (4) is formed on the transparent electrode (2), and the EL film (4) is formed on the transparent electrode (2). In a thin film EL element in which a counter electrode (6) is formed on a film (4), between the transparent electrode (2) and the EL film (4),
A thin film EL device comprising a bonding film (7) made of a compound of sulfur or selenium and a group II, group III, or group V element. [2] A first insulating film is provided between the light-transmitting electrode (2) and the bonding film (7) and between the EL film (4) and the counter electrode (6), respectively. (3) and the second insulating film (5
2. The thin film EL device according to claim 1, characterized in that the thin film EL device comprises: [3] The compound of sulfur or selenium and a group II, group III, or group V element is characterized in that it is gadolinium oxysulfide, yttrium oxysulfide, gadolinium oxyselenide, or yttrium oxyselenide. A thin film EL device according to claim 1 or 2. [4] A transparent electrode (2) is formed on a transparent substrate (1), and zinc sulfide alone or a rare earth element and a halogen are sputtered using a sputtering method in which a gas containing hydrogen sulfide is used as a sputtering gas. A thin film EL in which an EL film (4) made of a zinc sulfide composition containing the element or manganese is formed, and a counter electrode (6) is formed on the EL film (4).
In the device manufacturing method, prior to forming the EL film (4), sulfur or selenium is added.
A method for manufacturing a thin film EL device, comprising forming a bonding film (7) made of a compound with a group II, group III, or group V element. [5] A first insulating film ( 3) and second insulating film (5)
5. The method of manufacturing a thin film EL device according to claim 4, further comprising: forming a thin film EL device. [6] The compound of sulfur or selenium and a group II, group III, or group V element is characterized in that it is gadolinium oxysulfide, yttrium oxysulfide, gadolinium oxyselenide, or yttrium oxyselenide. A method for manufacturing a thin film EL device according to claim 4 or 5.