JPS62157694A - Manufacture of thin film el device - 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] This is an improvement of a method for manufacturing a thin film EL device, and is a method for manufacturing a thin film EL device with excellent luminous efficiency and brightness characteristics using a vacuum evaporation method.

A method for manufacturing a thin film EL device, characterized in that an EL film is formed using a vacuum evaporation method in an atmosphere containing hydrogen or a hydrogen compound such as ammonia, methane, ethane, propane, butane, ethylene, acetylene, etc. .

[Industrial application field]

The present invention relates to a method for manufacturing a thin film EL device. In particular, the present invention relates to a method of manufacturing a thin film EL element with excellent luminous efficiency and brightness characteristics using a vacuum evaporation method.

[Conventional technology]

Thin-film EL devices use fluorescent materials such as zinc sulfide and zinc selenide containing manganese, which functions as a luminescent center, or compounds of rare earth elements such as terbinium, samarium, thulium, praseodium, etc., and halogen elements such as fluorine, chlorine, etc. It is a light-emitting element that applies an electric field to a polycrystalline thin film of the body (light-emitting base material) and emits light based on the electroluminescence phenomenon. Conventionally, there are two types: DC drive type as shown in Figure 3 and AC drive type as shown in Figure 4. The type is known.

Refer to Figure 3. In the case of a DC drive type thin film EL element, a glass substrate etc. 1
A transparent electrode 2 made of ITO or the like and having a thickness of about 1.50 l is formed on top of the transparent electrode 2, on which manganese or a compound of a rare earth element such as terbinium and a halogen element such as fluorine is formed. An EL film 4 made of zinc sulfide or the like is formed, and a counter electrode 6 made of aluminum or the like is further formed thereon.

Refer to FIG. 4 In the AC drive type @ film EL element, in addition to the layer structure shown in FIG. A first insulating film 3 and a second insulating film 5 having a thickness of about 3,000 are formed.

By the way, among the materials that function as a luminescent center, manganese emits yellow-orange, terbinium emits green, samarium emits red, thulium emits blue, and praseodium emits white, but their luminous efficiency φ luminance is Even with the most excellent manganese, the brightness is not necessarily satisfactory (the brightness corresponding to a voltage that exceeds the threshold voltage of one light emission by 30 V when driven with an 80 Hz pulsed AC signal with a pulse width of 100 bucc seconds).
is approximately 30 degrees Lambert, and it is desired to develop four methods for manufacturing thin film EL elements with excellent luminous efficiency and brightness characteristics.

Incidentally, it is known that the luminous efficiency and brightness characteristics of thin film EL elements depend on the crystallinity of the EL film, and efforts are being made to develop techniques for manufacturing EL films with excellent crystallinity.

In order to produce EL151 with excellent crystallinity.

Conventionally, methods such as (a) using a single crystal formation technique such as molecular beam epitaxial growth, and (b) a method of forming an EL film on a suitable base layer such as zinc selenide have been known, and their effects have been is recognized.

[Problem that the invention seeks to solve]

However, (a) methods using single crystal formation techniques, such as molecular beam epitaxial growth, not only require an expensive amount of molecular beam epitaxial growth.

Due to the nature of the loading, it is not easy to increase the flat area of the product, which has unacceptable drawbacks from an industrial practical point of view, and (b) the use of a base layer to improve crystallinity. This method has the disadvantage that it is not easy to select the material for the underlayer, and furthermore, it results in restrictions being added to the selection of the materials constituting the thin@EL element.

An object of the present invention is to provide a method for manufacturing a thin film EL device with excellent luminous efficiency and brightness characteristics without such drawbacks, and in particular, by using an economically advantageous vacuum evaporation method. It is an object of the present invention to provide a method for manufacturing a thin film EL element that can be used.

[Means for solving problems]

The means taken by the present invention to achieve the above object are as follows:
The reason is that it is formed using a vacuum evaporation method in an atmosphere containing hydrogen or a hydrogen compound.

In particular, the effect is extremely significant when using a vacuum evaporator equipped with means for ionizing the atmosphere within the vacuum evaporator, such as a vacuum evaporator having an electron beam evaporation source.

Hydrogen compounds contained in the atmosphere include ammonia,
Methane, ethane, propane, butane.

Ethylene or acetylene are suitable.

[Effect]

The effect of the present invention is not necessarily clear, but in an atmosphere containing hydrogen or hydrogen compounds, zinc sulfide, which is a luminescent base material,
When zinc selenide, etc. is vacuum-deposited, a base layer (a base layer on which a zinc sulfide layer and a zinc selenide layer are sequentially deposited)
Hydrogen is bonded to each of the bonds of zinc and sulfide, zinc and selenium, etc. that make up the single crystal layer of zinc sulfide and zinc selenide that forms the base layer. A monoatomic layer of hydrogen is formed on the surface. here,
Zinc and sulfide, zinc and selenium, etc., which are deposited and become luminescent base materials, have high energy and form the base layer.
When the surface of a single crystal layer of zinc selenide is irradiated, highly substitutable hydrogen selectively replaces zinc with sulfur, selenium, etc., and sulfur, selenium, etc. It is presumed that zinc selectively binds to sulfur, selenium, etc., forming good single crystals of zinc and sulfur, zinc and selenium, etc.

After growing a zinc sulfide film using a vacuum evaporation method using an electron beam evaporation source using zinc sulfide containing 10νt% manganese as a source while changing the partial pressure of hydrogen in the range of O to 1O-4 Torr. , X of the zinc sulfide crystals formed
As is clear from the graph in Figure 5, which shows the relationship between the crystallinity and hydrogen partial pressure obtained by measuring the line diffraction intensity and normalizing the results with the film thickness, when the hydrogen partial pressure is zero, When the crystallinity of is 1, the hydrogen partial pressure exceeds zero and is approximately 2
In the range of -5T orr, the crystallinity is up to 1.5
improve to a certain extent.

It has been confirmed that the thin 18 IEL device manufactured using this method has a 30-60% improvement in luminous efficiency and brightness characteristics compared to a thin film EL device with the same material and geometric structure. .

In other words, in the conventional technology, the brightness characteristic is about 530 degrees (80 microseconds with a pulse width of 100 microseconds).
It was confirmed that when driven with a Hz pulsed AC signal, the luminance corresponding to a voltage exceeding the emission threshold voltage by 30 V was 40 to 50 foot Lambert under the present invention under the same conditions. has been done.

〔Example〕

Hereinafter, thin film EL devices according to two embodiments of the present invention will be further described with reference to the drawings.

Example 2 Using a vacuum evaporation method using an electron beam evaporation source with zinc sulfide containing 0.4 wt% manganese as a source, 0.5 wt% manganese was used as the luminescent center and zinc sulfide was used as the luminescent host. An example of manufacturing an AC-driven thin film EL element having an EL film as a material will be described.

The reference figure in FIG. 6 shows the amount of vacuum evaporation used in this example. Hydrogen gas is supplied under pressure. A substrate holder 72 supports the substrate 73. 74 is an electron beam evaporation source, and in this example, the above-mentioned! J, o, 4
A zinc sulfide source containing wt% manganese is used.

Refer to FIG. 1. Using a reactive sputtering method in oxygen using indium tin as a source, a film with a thickness of approximately 2.00 mm was deposited on a glass substrate 1.
A transparent electrode 2 made of an ITO film is formed.

Next, a first insulating film 3 made of yttrium oxide and having a thickness of about 3,000 wafers is formed using a vacuum evaporation method.

After forming a zinc sulfide layer containing 0.5 wt% manganese and having a thickness of approximately 5,000 yen using a vacuum evaporation method in a hydrogen atmosphere according to the gist of the present invention, A heat treatment is performed at about 450''O for about 1 hour to form the EL film 4.

Again, using the vacuum evaporation method, a second insulating film 5 made of yttrium oxide and having a thickness of about 3,000 A is formed,
Furthermore, a counter electrode (back electrode) 6 made of aluminum is formed using a vacuum evaporation method.

The EL film 4 of the AC-driven thin-film EL device manufactured through the above steps is formed using a vacuum evaporation method in which the crystallinity mirrors the partial pressure of hydrogen, as described in the [Function] section. This is a maximum improvement of 1.5 times compared to conventional EL films, and the luminous efficiency and brightness characteristics of the manufactured thin film EL elements are improved by up to 50% compared to conventional technology. It cannot be denied that there is some variation in C.

1 or 3 Using a vacuum evaporation method using an electron beam evaporation source with zinc sulfide containing 0.4wt% manganese as a source, 0.51i1t% manganese is used as the luminescent center and zinc sulfide is the luminescent matrix. DC-driven thin film EL having an EL film with
An example of manufacturing the device will be described.

Refer to Fig. 2. Using reactive sputtering method in oxygen using indium tin as a source, a film with a thickness of about 2,000 mm was deposited on a glass substrate 1.
A transparent electrode 2 made of an ITO film is formed.

Next, using a vacuum evaporation equipment having an electron beam evaporation source as described with reference to FIG.
After forming a zinc sulfide layer containing swt% manganese and having a thickness of about 5,000 yen, heat treatment is performed at about 450''C for about 1 hour to form the EL film 4.

Thereafter, a counter electrode (back electrode) 6 made of aluminum is formed using a vacuum evaporation method.

As described in the [Function] section, the EL film 4 of the DC-driven thin film EL device manufactured through the above steps is formed using a vacuum evaporation method in which the crystallinity is achieved by setting the partial pressure of hydrogen to zero. The luminous efficiency and brightness characteristics of the manufactured thin film EL element are improved by up to 50% compared to the conventional technology.

〔Effect of the invention〕

As explained above, in the method for manufacturing a thin film EL element according to the present invention, the EL film is formed using a vacuum evaporation method in an atmosphere containing hydrogen or a hydrogen compound. φAlthough the economically extremely advantageous vacuum evaporation method is used, the crystallinity of the formed EL film is extremely good, and the luminous efficiency and brightness characteristics of the manufactured thin film EL device are lower than those of conventional methods. Up to 50% improvement compared to technology.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of an AC-driven thin film EL device according to an embodiment of the present invention. FIG. 2 is a structural diagram of a DC-driven thin film EL device according to an embodiment of the present invention. FIG. 3 is a structural diagram of a DC-driven thin 1Ii EL device according to the prior art. FIG. 4 is a structural diagram of an AC driven thin film EL device according to the prior art. FIG. 5 is a graph (graph showing the relationship between crystallinity and hydrogen partial pressure) showing the effects of the method for manufacturing a thin film EL device according to the present invention. FIG. 6 is used in the method for manufacturing a thin 111 EL device according to the present invention. FIG. 2 is a block diagram of a vacuum evaporation system having an electron beam evaporation source. 1... Transparent substrate (glass substrate), 2... Transparent electrode CITO electrode), 3... First insulating film (yttrium oxide, silicon oxynitride, aluminum oxide), 4...・EL film (composition of zinc sulfide and manganese or rare earth elements and halogen elements),
5...Second insulating film (yttrium oxide, a# silicon nitride, aluminum oxide), 6φ ・ ・
Counter electrode, 7... Vacuum container, 71... Air supply hole, 72, Competitive substrate holder, 73... Substrate, 74
・Electron beam evaporation source. Fig. 3 4g1 Present invention Fig. 1

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 an EL film (4) is formed on the transparent electrode (2). Thin film EL forming a counter electrode (6) on the EL film (4)
A method for manufacturing a thin film EL device, characterized in that the EL film (4) is formed using a vacuum evaporation method in an atmosphere containing hydrogen or a hydrogen compound. [2] Manufacturing the thin film EL device according to claim 1, which comprises the step of forming a first insulating film (3) and a second insulating film (5) with the EL film (4) interposed therebetween. Method. [3] The thin film EL according to claim 1 or 2, wherein the vacuum evaporation method is performed using a vacuum evaporation equipment equipped with means for ionizing substances contained in the atmosphere. Method of manufacturing elements. [4] The hydrogen compound contained in the atmosphere is ammonia, methane, ethane, propane, butane, ethylene or acetylene, according to claim 1, 2 or 3. A method for manufacturing a thin film EL element.