JPS62113387A - 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] Improvement to improve luminous efficiency and brightness of a thin film EL element,
This is an improvement that improves the productivity of thin film EL devices.

In order to improve the luminous efficiency by improving the orientation and crystallinity of the EL film constituting the thin-film EL element, a zinc sulfide film is interposed between the light-transmitting substrate and the light-transmitting electrode. Crystalline EL film! The entire region of the island has a crystal structure unique to zinc sulfide, and the oriented φ crystallinity is improved. Furthermore, in this way, by taking advantage of the fact that the orientation and crystallinity of the EL film can be improved, productivity is high because the time required is originally shorter than that of the vapor deposition method, and the layers above and below the EL film are By forming the EL film using the sputtering method, which has the advantage of being able to perform the same process as the first and second insulating films, it shortens the manufacturing time of thin film EL elements and improves productivity. This improves reproducibility.

[Industrial application field]

The present invention relates to a thin film EL device and a method for manufacturing the same. In particular, the present invention relates to a thin-film EL device with improved luminous efficiency and brightness, and a method for manufacturing a thin-film EL device with improved productivity and reproducibility.

[Conventional technology]

Thin-film EL elements are based on the electroluminescence phenomenon by applying an electric field to a polycrystalline thin film of a phosphor such as zinc sulfide containing manganese or a rare earth element such as terbium trifluoride or terbium trichloride, which functions as a luminescent center. As a light emitting element that emits light, a structure as shown in FIG. 3 is conventionally known.

Refer to Figure 3. On a glass substrate etc. 1, it is made of ITO and has a thickness of about 2,000 mm.
9 Forming a transparent electrode 3 to 0 using sputtering method
Next, it is made of silicon oxynitride and has a thickness of approximately 2. A first insulating film 4 is formed on Goo using a sputtering method. Here, the vacuum is once broken and the EL film 5 made of zinc sulfide containing manganese or a rare earth element such as terbium trifluoride or terbium trichloride, which functions as a luminescent center, is deposited to a thickness of about 5,000 yen. Deposit on people. Heat treatment is performed at a temperature of about 500° C. for about 1 hour. Here, the vacuum is broken again and the material is charged into a sputtering device, and a second film made of silicon oxynitride and having a thickness of about 2,000 yen is made using a sputtering method. An insulating film 6 is formed. Thereafter, a counter electrode 7 made of aluminum is formed.

[Problem that the invention seeks to solve]

The luminous efficiency and brightness characteristics of thin-film EL elements are controlled by the orientation and crystallinity of the EL film, which is made of zinc sulfide containing manganese or rare earth elements such as terbium trifluoride and terbium trichloride, which function as luminescent centers. , since the crystallinity of zinc sulfide film is easily affected by the surface condition of the base,
The crystallinity of the EL film 5 of the thin film EL element according to the above-mentioned prior art is likely to become defective near the region in contact with the insulating film 4, resulting in a so-called dead layer, and its luminous efficiency and brightness characteristics are not necessarily satisfactory. . For example, if the luminescent center is terbium fluoride, 0.1 to 0.2
lumen/W, and if the luminescent center is manganese, 1~
It is 1.5 lumen/W.

Therefore, we decided to use thin film type E, which has better luminous efficiency and brightness characteristics.
L ; Ji: Child development was desired.

In addition, in the prior art, the first
After forming the insulating layer 23, the -J vacuum is broken, the EL film 5 is formed using resistance heating evaporation method or electron beam heating evaporation method, and after the vacuum is broken again, the second layer is formed using sputtering method. However, if the first insulating film 3, ELIPJ 5, and second insulating film 6 could be formed in one step using a sputtering method, the deposition rate would be faster than that of the vacuum evaporation method. In addition to the essential benefits of sputtering, which are fast, in particular the time required to restore the vacuum should be reduced, reducing the turnaround time and increasing productivity. However, E
When sputtering is used to form the L film, the zinc sulfide film has poor orientation and crystallinity, resulting in extremely poor luminous efficiency and brightness characteristics, making it unusable.

Therefore, it has been desired to develop a method for manufacturing thin-film EL elements that allows the use of sputtering to form EL films and has excellent productivity.

[Means for solving problems]

The means adopted by the present invention in order to achieve the above object of fJIJl are as follows:
The purpose is to interpose a film of zinc sulfide between the two. It is desirable that the zinc sulfide film be formed sufficiently thick so that the influence of the underlying transparent substrate can be eliminated.

The means taken by the present invention to achieve the above second object is to form a film of zinc sulfide on a transparent substrate sufficiently thick to the extent that the influence of the underlying transparent substrate disappears. , on which a thin film type EL element is formed as in the prior art, but the EL film is formed using a sputtering method.

[Effect]

The crystallinity of the zinc sulfide film is easily affected by the surface condition of the underlying film, and if the underlying film is different from the crystal structure of zinc sulfide, such as glass, the crystallinity of the zinc sulfide film formed on this base will be As mentioned above, this is particularly the case near the contact area, and the luminous efficiency-luminance characteristics of the thin film EL element are deteriorated.

In particular, if the base is glass, there will be less unevenness on the surface.
The above drawbacks are significant.

Therefore, first, a film is placed on a light-transmitting substrate made of glass or the like to a thickness sufficiently thick, for example, about s, o, to the extent that the influence of the light-transmitting substrate disappears.
A zinc sulfide film is formed to a thickness of 100 oz.

The surface is left in a crystalline state unique to zinc sulfide.

When a thin film type EL element similar to the conventional technology is formed on top of this, the EL film made of zinc sulfide can be in the crystalline state unique to zinc sulfide from the beginning, so that so-called dead layer does not occur, and the luminous efficiency and brightness characteristics are improved. improves.

With the above structure, this is due to the effect of the zinc sulfide film provided between the light-transmitting substrate and the light-transmitting electrode.

Since the orientation and crystallinity of the zinc sulfide film forming the EL film formed between the first insulating film and the second insulating film are good, the zinc sulfide film forming the EL film is formed by vapor deposition. method (restrictions on EL film formation method have been lifted),
It can be formed using a sputtering method with higher productivity, and in particular, no vacuum recovery time is required, which greatly improves productivity.

〔Example〕

Hereinafter, with reference to the drawings, one example of each of the first means and second means of the present invention will be explained to clarify the structure and unique effects of the present invention.

1±1 Refer to FIG. 1 A zinc sulfide film 2 is formed to a thickness of approximately 5,000 mm on a glass substrate l using an electron beam evaporation method or a resistance heating evaporation method.

Next, using a sputtering method, a thickness of about 2,000 thick
A transparent electrode 3 made of a TO film is formed.

Using the sputtering method again, the first insulating film 4 made of a silicon oxynitride film with a thickness of approximately 2,000 wafers is formed.

The surface of the first insulating film 4 formed through the above steps reflects the microstructure of the surface of the zinc sulfide film 2, particularly the unevenness caused by crystal grains, and has a crystalline state unique to the zinc sulfide film. ing.

Again using electron beam evaporation or resistance heating evaporation, zinc sulfide [I51] containing manganese, which functions as a luminescent center, is formed to a thickness of about 5,000 mm, and heat-treated at a temperature of about 500° C. for about 1 hour. After that, ELM! 51
form.

Furthermore, a second insulating film 6 made of a silicon oxynitride film is formed to a thickness of approximately 2,000 mm using a sputtering method.

Finally, an aluminum electrode 7 is formed using sputtering to complete the thin film EL element.

The thin-film EL device manufactured through the above process has good orientation and crystallinity of the EL film, and almost no so-called dead layer exists. This is clear from the fact that the diffraction intensity is about three times that of the prior art.

Further, the luminous efficiency is 2 to 3 lumens/W, which is about twice as much as the conventional technology. Brightness has also been significantly improved.

What should be noted here is that the reproducibility of the characteristics is extremely good, and there is little need for precise control, so the practical benefits are extremely large.

1. Referring to FIG. 3, a zinc sulfide film 2 is formed to a thickness of about 5,000 mm on a glass substrate 1 using an electron beam evaporation method or a resistance heating evaporation method.

Next, using a sputtering method, a thickness of about 2,000 thick
A transparent electrode 3 made of a TO film is formed.

Using the sputtering method again, a first insulator@4 made of a silicon oxynitride film with a thickness of about 2,000^ is formed.

The surface of the first insulating film 4 formed through the above steps reflects the microstructure, particularly the unevenness caused by crystal grains, on the surface of the zinc sulfide film 2, and has a crystalline state unique to the zinc sulfide film. ing.

After the sputtering process for forming the insulating film 4 described above, without breaking the vacuum, a sputtering method is used to continue using zinc sulfide containing terbium fluoride as a luminescent center.
The EL film 52 is formed to have a thickness of about 5,000 mm and subjected to heat treatment at a temperature of about 500° C. for about 1 hour.

Without breaking the vacuum, a second insulating film 6 made of a silicon oxynitride film having a thickness of about 2,000 wafers is formed using a sputtering method.

Finally, using the sputtering method, the aluminum electrode 7 is
is formed to complete a thin film type EL element.

The thin film EL film produced through the above process has good orientation and crystallinity, and almost no so-called dead layers. This is clear from the fact that the linear diffraction intensity is about three times that of the prior art.

In addition, the luminous efficiency is 0.8 to 1.5 lumen/W,
This is an improvement of about 8 times compared to the conventional technology. Brightness has also been significantly improved.

What should be noted here is that EL is produced using the sputtering method.
As a result of being able to form the film, in addition to improving the deposition rate of the EL film (the deposition rate of the sputtering method is more than twice that of the vapor deposition method), the first insulating film, the EL15B, and the second This makes it possible to form an insulating film in one step without breaking the vacuum.As a result, the time required for vacuum recovery (approximately 2 hours for each opening) is no longer required, and the manufacturing time is significantly shortened. This means that productivity has improved. Further, as in the case of the first example, the reproducibility of the characteristics is extremely good, there is little need for precise control, and the practical benefits are extremely large.

〔Effect of the invention〕

As explained above, in the thin film EL element according to the first means of the present invention, since the zinc sulfide film is provided between the light-transmitting substrate and the light-transmitting electrode, the first insulating film is The crystalline state of the EL film formed on this film is good in its entire region, reflecting the surface state of the intervening zinc sulfide film, there is no so-called dead layer, and the X-ray diffraction intensity is high. , has high luminous efficiency and excellent brightness characteristics.

Moreover, the reproducibility is also excellent.

Furthermore, the method for manufacturing a thin film EL device according to the second means of the present invention includes forming a film of zinc sulfide on a transparent substrate, and then forming a thin film EL device having a structure similar to that of the prior art. However, due to the effect of the zinc sulfide film provided between the light-transmitting substrate and the light-transmitting electrode, the E L and film formed between the first insulating film and the second insulating film are Since the orientation and crystallinity of the zinc sulfide film that forms the EL film are improved, it is no longer necessary to use vapor deposition to form the zinc sulfide film that forms the EL film (restrictions on the EL film formation method are lifted); Since the ELM is supposed to be formed using a highly productive sputtering method, in addition to the effect of the first means described above, in addition to the inherent advantage of the sputtering method, which is a short turnaround time, No recovery time is required, reducing manufacturing time and increasing productivity.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thin film type EL element according to a first means of the present invention. FIG. 2 is a sectional view of a thin film type EL element according to a second means of the present invention. FIG. 3 is a cross-sectional view of a thin film type EL element according to the prior art. ■... Transparent substrate (glass substrate), 2... Zinc sulfide film according to the gist of the present invention, 3. - Transparent electrode (ITO electrode), 4. First insulating film ( silicon oxynitride film), 5. -EL film, 51-- E LI8J according to the first embodiment of the present invention. 52... EL according to the first embodiment of the present invention [, 6 dispute/second insulation 119 (silicon oxynitride film), 7...
Counter electrode (aluminum electrode). 1st means fig. 2 2nd means fig. 16 Jujutsu fig. 3

Claims (1)

[Claims] [1] A transparent electrode (3) is formed on a transparent substrate (1), and a first insulating film (4) and a first insulating film (4) are formed on the transparent electrode (3). An EL film (5) made of a composition of zinc sulfide and a rare earth element or manganese is formed between the second insulating film (6), and a counter electrode (7) is formed on the second insulating film (6). ), characterized in that a zinc sulfide film (2) is interposed between the light-transmitting substrate (1) and the light-transmitting electrode (3). Thin film type EL element. [2] Forming a transparent electrode (3) on a transparent substrate (1), forming a first insulating film (4) on the transparent electrode (3), and forming a first insulating film (4) on the transparent electrode (3). An EL film (5) made of a composition of zinc sulfide and a rare earth element or manganese is formed on the film (4), a second insulating film (6) is formed on the EL film (5), and the second insulating film (6) is formed on the EL film (5). In the method for manufacturing a thin film EL element in which a counter electrode (7) is formed on a second insulating film (6), a sulfurized A method for manufacturing a thin-film EL device, characterized in that a zinc film (2) is formed, and the EL film (5) is formed using a sputtering method.