JP2003003161A - Phosphor thin film, method for producing the same and el panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor thin film having a good color purity, suitable as RGB for especially a full-color EL without requiring a filter and capable of simplifying a production process of a full-color EL panel, increasing the yield and reducing the production cost with slight dispersion of the luminance, a method for producing the phosphor thin film and the EL panel. SOLUTION: This phosphor thin film is composed of a matrix material comprising an oxysulfide of at least one compound selected from a rare earth thioaluminate, a rare earth thiogallate and a rare earth thioindate in which oxygen is contained and further containing an element to be the luminescent center. The method for producing the phosphor thin film and the EL panel are provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sulfide light emitting layer having a light emitting function, and more particularly to a phosphor thin film used for a light emitting layer of an inorganic EL element or the like and an EL panel using the same.

[0002]

2. Description of the Related Art In recent years, thin-film EL devices have been actively researched as small-sized or large-sized lightweight flat panel displays. A monochrome thin film EL display using a phosphor thin film made of yellow-orange light emitting manganese-doped zinc sulfide has already been put into practical use with a double insulating structure using thin film insulating layers 2 and 4 as shown in FIG. In FIG. 2, the substrate 1
A lower electrode 5 having a predetermined pattern is formed on the upper surface, and the first insulating layer 2 is formed on the lower electrode 5. Further, the light emitting layer 3 and the second insulating layer 4 are sequentially formed on the first insulating layer 2, and the lower electrode 5 and the matrix circuit are formed on the second insulating layer 4. The upper electrode 6 is formed in a predetermined pattern.

Further, for a personal computer as a display,
Colorization is indispensable to support TV and other displays. Thin-film EL displays using sulfide phosphor thin films have excellent reliability and environmental resistance, but at present, the characteristics of EL phosphors that emit light in the three primary colors of red, green, and blue are not sufficient. , Is not suitable for color. The blue light emitting phosphor is Sr as a base material.
S, SrS: Ce or Zn using Ce as an emission center
S: Tm, ZnS: Sm, Ca as the red light emitting phosphor
S: Eu, ZnS: Tb, Ca as a green light emitting phosphor
S: Ce is a candidate and research is continuing.

These phosphor thin films which emit light in the three primary colors of red, green and blue have problems in emission brightness, efficiency and color purity, and at present, a color EL panel has not been put into practical use. In particular, blue has a relatively high luminance obtained by using SrS: Ce, but as blue for a full-color display, the luminance is insufficient and the chromaticity is shifted to the green side. Development of a good blue light emitting layer is desired.

To solve these problems, Japanese Unexamined Patent Publication No. 7-
122364, JP-A-8-134440,
SrGa ₂ S ₄ : Ce, CaG, as described in Technical Bulletin EID 98-113, pages 19-24, and Jpn.J.Appl.Phys.Vol.38, (1999) pp. L1291-1292.
Blue phosphors based on thiogallate or thioaluminate such as a ₂ S ₄ : Ce and BaAl ₂ S ₄ : Eu have been developed. These thiogallate-based phosphors have no problem in terms of color purity, but have low brightness and particularly have a multi-component composition, and thus it is difficult to obtain a thin film having a uniform composition. It is considered that a high quality thin film cannot be obtained due to poor crystallinity due to poor composition controllability, generation of defects due to sulfur escape, and mixing of impurities, and therefore brightness cannot be increased. In particular, thioaluminate is extremely difficult to control the composition.

Preparation of a thioaluminate-based thin film
As described in Japanese Patent Publication No. 8-134440, an example
If you want to get BaAl₂S_Four : Same composition as Eu thin film
Create a target and obtain the emission layer by sputtering
How to do. Jpn.J.Appl.Phys.Vol.38, (1999) pp. L1291-1
As described in 292, BaS: Eu and Al₂S ₃ 
Two pellets are prepared and two-source pulsed electron beam evaporation method is used.
By BaAl₂S_Four: There is a way to get Eu.

Further, Japanese Patent Application Laid-Open No. 7-122364 discloses a method for obtaining a SrIn ₂ S ₄ : Eu light emitting layer by using M
According to the BE method, Sr metal, In metal and EuCl ₃ are evaporated as a source in a vacuum chamber in which H ₂ S gas is introduced,
A method for forming a SrIn ₂ S ₄ : Eu light emitting layer on a substrate is described. However, according to this method, the metal of the host material (SrIn ₂ S ₄ ) and the emission center substance (Eu) are used.
It is extremely difficult to accurately control the amount of emission centers by controlling each of the sources. For example, by controlling the molar ratio of Sr and In to 1: 1 and causing a sulfurization reaction by H ₂ S,
In addition, it is almost impossible in the current evaporation process to set Eu in a molar ratio of 99.5: 0.1 to the base material and make the variation of 0.1 in Ce less than 5%. By the way, with the Al electrode used as the electrode of the LSI, even if the deposition source is relatively stable, Al in the deposition process
The variation in the film thickness of the thin film is about 5%. This also shows that it is extremely difficult to control the Eu concentration to an accuracy of 5% or less.

On the other hand, for red and green EL thin films other than blue, the red light emitting phosphors ZnS: Sm, CaS: Eu, the green light emitting phosphors ZnS: Tb, CaS: Ce, etc. are made into targets or pellets of respective compositions. However, a phosphor thin film that emits light with relatively high brightness can be obtained by the sputtering method or the EB vapor deposition method.

In realizing a full color EL panel,
It is necessary to have a phosphor material and a manufacturing process phosphor that can realize blue, green, and red phosphors in a stable and low-cost manner. Alternatively, since the physical properties differ depending on the individual materials, the manufacturing method differs depending on the type of phosphor thin film. If a film forming method for obtaining high brightness with one material is used, high brightness of phosphor thin films of other colors cannot be realized.
Considering the manufacturing process of a full-color EL panel, a plurality of types of film forming apparatuses are required. The manufacturing process is more complicated, and the panel manufacturing cost is higher.

Further, the EL spectra of the blue, green, and red EL phosphor thin films described above are all broad, and when used in a full-color EL panel, using the RGB filters necessary for the panel, EL EL of phosphor thin film
It has to be cut out from the spectrum. Not only is the manufacturing process complicated when a filter is used, but the most problematic factor is the reduction in brightness. When RGB is taken out using a filter, the brightness of the blue, green, and red EL phosphor thin films is
Since a loss of 10 to 50% occurs, the brightness is lowered and it is not practical.

In order to solve the above-mentioned problems, red, green, and blue phosphor thin film materials which have good color purity and emit light with high brightness without using a filter, and the same film forming method or film forming method. It is possible to obtain high brightness using the device,
There has been a demand for a phosphor host material and an emission center material having similar chemical or physical properties.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a phosphor thin film which does not require a filter, has good color purity, and is particularly suitable for RGB for full-color EL, a manufacturing method thereof, and an EL panel. Is.

Further, the manufacturing process of the full-color EL panel is simplified, the variation in brightness is small, and the yield is increased.
An object of the present invention is to provide a phosphor thin film capable of reducing the manufacturing cost, a manufacturing method thereof, and an EL panel.

[0014]

This and other objects are achieved by any of the following constitutions (1) to (8). (1) A phosphor thin film in which a base material is an oxysulfide containing oxygen in at least one compound selected from rare earth thioaluminate, rare earth thiogallate, and rare earth thioindate, and further containing an element serving as an emission center. (2) When the molar ratio of the oxygen element and the sulfur element in the oxysulfide is expressed as O / (S + O), O / (S + O) = 0.01 to 0.85, the fluorescence of the above (1). Body thin film. (3) The above (1) or (2) represented by the following composition formula
Fluorescent thin film. _{R x A y O z S w} : M [ where, M represents a metal element of the light emitting center, at least one element R selected from rare earth elements, A is Al, Ga
And at least one element selected from In,
x = 1-5, y = 1-15, z = 3-30, w = 3-3
It is 0. (4) The emission center is a rare earth element (1) to
The phosphor thin film according to any one of (3). (5) An EL panel having the phosphor thin film according to any one of (1) to (4) above. (6) A method for manufacturing a phosphor thin film according to any one of (1) to (4) above, which comprises performing annealing treatment in an oxidizing atmosphere after forming the sulfide thin film. (7) A manufacturing method for forming the phosphor thin film according to any one of (1) to (4) above by a vapor deposition method, comprising:
At least one evaporation source selected from aluminum sulfide, gallium sulfide, and indium sulfide, and a rare earth sulfide evaporation source to which an emission center is added are arranged to introduce oxygen gas, and sulfurization from each of these evaporation sources is performed. Evaporating at least one compound selected from aluminum, gallium sulfide, indium sulfide and rare earth sulfide raw material,
A method for producing a phosphor thin film, which obtains a thin film by combining each raw material and oxygen gas when depositing on a substrate. (8) A manufacturing method for forming the phosphor thin film according to (1) above by vapor deposition, comprising at least one evaporation source selected from aluminum sulfide, gallium sulfide and indium sulfide in a vacuum chamber, and a rare earth element. A metal or a rare earth sulfide evaporation source added with an emission center is arranged and hydrogen sulfide gas is introduced, and at least one compound selected from aluminum sulfide, gallium sulfide, and indium sulfide from each of these evaporation sources, and Rare earth sulfide raw material or rare earth metal raw material is evaporated, and when deposited on the substrate, the respective raw materials are combined with hydrogen sulfide gas to obtain a sulfide phosphor thin film, and then annealing treatment in an oxidizing atmosphere is performed. Body thin film manufacturing method.

[0015]

The present invention is an invention obtained as a result of synthesizing a compound material using a chemically or physically stable oxide by using the reactive vapor deposition method as the same film forming method,
The obtained phosphor thin film emits light of various colors ranging from red to blue.

First of all, the inventors of the present invention have selected rare earth thioaluminate, rare earth thiogallate and rare earth thioindate as EL.
It was made into a thin film as a thin film phosphor for use. An EL device was produced using the obtained thin film, but desired light emission could not be obtained. The emission luminance of the obtained thin film is at most 2 cd / m ²
With low brightness, it was necessary to increase the brightness in order to apply the EL device to a panel.

Based on these results, as a result of repeated research on the phosphor thin film of this system, the present invention was achieved. That is, it has been found that by adding oxygen to a rare earth thioaluminate, a rare earth thiogallate, or a rare earth thioindate base material to form an oxysulfide, the brightness is dramatically increased.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. In the phosphor thin film of the present invention, the base material is an oxysulfide containing oxygen in at least one compound selected from rare earth thioaluminate, rare earth thiogallate, and rare earth thioindate, and further a rare earth element is added as an emission center. Is.

Rare earths are stable as sulfides and selenides, and are formed during the process of producing the conventionally used alkaline earth thioaluminates, thiogallates, and thioindates such as Ba, Sr, and Ca. Since it is more stable than the compounds BaS, SrS, etc., and resistant to humidity and oxidation, it is possible to obtain a high quality phosphor thin film with less contamination in the phosphor thin film forming step.

The rare earth oxysulfide used for the phosphor thin film of the present invention has a composition formula R _x A _y O _{z Sw} : M [wherein Re represents an element serving as an emission center and R is at least selected from rare earth elements]. One element, A is Al, G
a represents at least one element selected from In. ]
It is preferable that it is represented by

In the above formula, x, y, z and w represent the molar ratio of the elements R, A, O and S.

X, y, z are preferably x = 1 to 5 y = 1 to 15 z = 3 to 30 w = 3 to 30 Is.

As the rare earth element which is the element R, Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Eu, G
Examples thereof include d, Tb, Dy, Ho, Er, Tm, Yb and Lu. Among them, Y, La, Ce, Eu, Gd,
Er and Yb are preferable, and Eu and Yb are particularly preferable.

The element A is any one of Al, Ga and In, and the combination of these elements and the above element R is arbitrary.

The ratio of the element represented by R to the element represented by A is preferably an atomic ratio of 2 to 7 when expressed as A / R, and further, 2.2 to 3. Stable light emission can be obtained by setting A / R within the above range, which is preferably 0.

R _x A _y O _{z Sw} : M, that is, R _x A _y (O,
S) _{z + w} : M is x {R (O, S)}-(y / 2) {A ₂
(O, S) ₃ }, that is, z + w = x + 3y / 2
Is almost stoichiometric composition. The composition of the phosphor thin film is preferably near the stoichiometric composition in order to obtain high-luminance light emission, and specifically, 0.9 ≦ (x + 3y / 2) / (z + w) ≦ 1.1. Is preferred.

Further, these compounds may be used alone or as a mixture of two or more kinds, or may be in an amorphous state having no definite crystal structure.

Oxygen contained in the rare earth oxysulfide matrix material is O in the atomic ratio of the matrix material to sulfur.
When expressed as / (S + O), it is preferably added within the range of 0.01 to 0.85, and particularly 0.05 to 0.5.
That is, in the above equation, the value of z / (z + w) is 0.01 to
It is 0.85, preferably 0.01 to 0.5, more preferably 0.05 to 0.5, and particularly preferably 0.1 to 0.4.

Oxygen has the effect of dramatically increasing the luminance of the phosphor thin film EL emission. The light emitting element has a life in which the luminance deteriorates with the lapse of the light emitting time. By adding oxygen, life characteristics can be improved and luminance deterioration can be prevented. When oxygen is added to thioaluminate, thiogallate, and thioindate to form oxysulfide, crystallization is promoted during film formation of this base material or during post-treatment such as annealing after film formation. It is considered that has an effective transition in the compound crystal field and that stable light emission with high brightness can be obtained. Also, the base material itself is more stable in air than pure sulfide. It is considered that this is because the stable oxide component protects the sulfide component in the film from the atmosphere. In addition, a panel using this phosphor has a long light emission life and can realize a highly reliable panel.

The composition of the phosphor thin film is determined by fluorescent X-ray analysis (XR
F), X-ray photoelectron analysis (XPS) or the like.

The element Re contained as the emission center is M
Examples include one or more elements selected from transition metal elements such as n and Cu, rare earth metal elements, Pb, and Bi. Rare earth is at least Sc, Y, L
a, Ce, Pr, Nd, Gd, Tb, Ho, Er, T
m, Lu, Sm, Eu, Dy, and Yb, and the blue phosphor is Eu or C.
e, green phosphors such as Eu, Ce, Tb and H
o, as the red phosphor, Pr, Sm, Yb and Nd
Is preferred. Of these, Eu, Tb, Ce and Sm are preferable in combination with the base material, and Eu and Sm are most preferable. The addition amount is preferably 0.1 to 10 atom% with respect to the rare earth atom.

The selenide is not particularly limited, but rare earth selenaluminate [R _x A
l _y Se _z : R = Sc, Y, La, Ce, Pr, Nd,
Gd, Tb, Ho, Er, represents one of Tm and Lu, x, y, z = may be are different from each integers], rare earth Serenagareto _{[R x Ga y Se z: R} =
Sc, Y, La, Ce, Pr, Nd, Gd, Tb, H
represents any one of o, Er, Tm, and Lu, x, y,
z = integer and may be different from each other], rare earth selenate rate [R _x In _y Se _z : R = Sc, Y, L
a, Ce, Pr, Nd, Gd, Tb, Ho, Er, Tm
And Lu, each of which represents an integer of x, y, z and may be different from each other], and a compound containing oxygen.

The rare earth element Re added as an emission center is at least Sc, Y, La, Ce, Pr, Nd, Gd, T.
b, Ho, Er, Tm, Lu, Sm, Eu, Dy, Yb
However, Ce, Eu, Tb and Tm are preferred. These elements have an effective transition in the compound crystal field, and high-luminance light emission can be obtained.

In order to obtain such a phosphor thin film, for example, the following reactive vapor deposition method is preferable. _{Here, EuAl 2 O z S w:} Ce phosphor thin film as an example will be described.

Europium aluminate pellets to which Ce is added may be produced, and the pellets may be EB vapor-deposited in a vacuum chamber into which H ₂ S gas is introduced. Here, H ₂ S gas is used to react sulfur.

In addition, a method used in the multi-source reactive vapor deposition method is also possible.

For example, binary reactive vapor deposition using Ce-added europium oxide pellets, alumina pellets, and H ₂ S gas. Alternatively, Ce-added europium sulfide pellets, alumina pellets, and two-source vacuum vapor deposition without gas. Europium oxide pellets to which Ce is added, aluminum sulfide pellets, and binary vacuum deposition without using gas.
Methods such as Ce-added europium sulfide pellets, aluminum sulfide pellets, and binary reactive vapor deposition using O ₂ gas are preferable.

In particular, at least an aluminum sulfide evaporation source and a europium sulfide evaporation source to which a luminescence center is added are placed in a vacuum chamber, oxygen gas (O ₂ ) is introduced, and sulfurization is performed from each of these evaporation sources. It is preferable to vaporize aluminum and europium sulfide raw materials and combine the respective raw materials with oxygen gas when depositing on the substrate to obtain a thin film.

Further, it may be combined with an annealing treatment. That is, a europium thioaluminate thin film can be formed by europium sulfide pellets, aluminum sulfide pellets, binary reactive vapor deposition using H ₂ S gas, europium sulfide pellets, aluminum sulfide pellets, binary reactive vapor deposition without gas, or the like. After obtaining, an annealing method is preferable in an oxidizing atmosphere such as oxygen or air. For example, Ce-added europium sulfide pellets, aluminum sulfide pellets, hydrogen sulfide (H ₂ S)
After obtaining a thin film by a method such as binary reactive vapor deposition using gas,
Anneal in air. As the annealing condition, it is preferable to perform the annealing in an oxidizing atmosphere having an oxygen concentration of the atmosphere or above at a temperature of preferably 500 ° C. to 1000 ° C., particularly 600 ° C. to 800 ° C.

In particular, at least an aluminum sulfide evaporation source and a europium sulfide evaporation source to which a luminescence center is added are placed in a vacuum chamber, hydrogen sulfide gas is introduced, and aluminum sulfide and sulfide are supplied from each of these evaporation sources. It is preferable to evaporate the europium raw material, combine the respective raw materials with hydrogen sulfide gas when depositing on the substrate to obtain a sulfide phosphor thin film, and then perform annealing in an oxidizing atmosphere to obtain the thin film.

The Ce to be added is added to the raw material in the form of metal, fluoride, oxide or sulfide. The addition amount differs depending on the raw material and the thin film to be formed, so the composition of the raw material is adjusted so that the addition amount is appropriate.

The substrate temperature during vapor deposition may be room temperature to 600 ° C., preferably 100 ° C. to 300 ° C. When the substrate temperature is too high, the surface of the thin film of the base material becomes rough, pinholes are generated in the thin film, and a current leakage problem occurs in the EL element. Also, the thin film may turn brown. Therefore, the above temperature range is preferable.

Oxysulfide fluorescent thin film formed
Is preferably a highly crystalline thin film. Evaluation of crystallinity
Valence can be determined, for example, by X-ray diffraction. crystalline
In order to raise the temperature, the substrate temperature should be as high as possible.
Also, in a vacuum after thin film formation, N ₂ Medium, Ar, S vapor
Medium, H₂Annealing in S, air, oxygen, etc. is also effective
Is.

The thickness of the light emitting layer is not particularly limited, but if it is too thick, the driving voltage increases, and if it is too thin, the light emitting efficiency decreases. Specifically, depending on the fluorescent material, it is preferably 100 to 2000 nm, particularly 150 to 70 nm.
It is about 0 nm.

The pressure during vapor deposition is preferably 1.33 × 10.
^{-4 to} 1.33 x 10 ^-1 Pa (1 x 10 ^-6 to 1 x 10 ^-3
Torr). Particularly, the introduction amounts of O ₂ gas for adding oxygen and H ₂ S gas for promoting sulfidation are both adjusted to be 6.65 × 10 ⁻³ to 6.65 × 10 ⁻² Pa (5 × 10
^{-5 to} 5 × 10 ^-4 Torr) is preferable. If the pressure is higher than this, the operation of the E gun becomes unstable, and composition control becomes extremely difficult. The amount of H ₂ S gas or oxygen gas introduced is 5 to 200 depending on the capacity of the vacuum system.
SCCM, especially 10-30 SCCM are preferred.

If necessary, the substrate may be moved or rotated during vapor deposition. By moving and rotating the substrate, the film composition becomes uniform and variations in the film thickness distribution are reduced.

When the substrate is rotated, the number of rotations of the substrate is preferably 10 times / min or more, more preferably 1
It is about 0 to 50 times / min, particularly about 10 to 30 times / min. If the number of rotations of the substrate is too high, problems such as sealing property tend to occur when the substrate is introduced into the vacuum chamber. Also,
If it is too late, compositional unevenness occurs in the film thickness direction in the tank, and the characteristics of the manufactured light emitting layer deteriorate. As a rotating means for rotating the substrate, a power transmission mechanism combining a power source such as a motor and a hydraulic rotation mechanism and a gear, a belt, a pulley, etc.
It can be configured by a known rotation mechanism using a speed reduction mechanism or the like.

Any heating means for heating the evaporation source or the substrate may be used as long as it has a predetermined heat capacity, reactivity and the like, and examples thereof include a tantalum wire heater, a sheath heater and a carbon heater. The heating temperature by the heating means is preferably 10
About 0 to 1400 ° C, the accuracy of temperature control is ± 1 ° C at 1000 ° C, preferably ± 0.5 ° C.

One example of the constitution of an apparatus for forming the light emitting layer of the present invention is shown in FIG. Here, using aluminum sulfide and europium sulfide as evaporation sources, while introducing oxygen,
The method for producing oxygenated europium thioaluminate: Ce is taken as an example. In the figure, a substrate 12 on which a light emitting layer is formed and EB evaporation sources 14 and 15 are arranged in a vacuum layer 11.

EB (electron beam) evaporation source 14, which serves as evaporation means for aluminum sulfide and europium sulfide,
15 is europium sulfide 14a to which an emission center is added
"Crucible" containing aluminum and aluminum sulfide 15a
40 and 50, and filaments 41a and 51 for emitting electrons
and electron guns 41 and 51 having a built-in a. Electron gun 4
A mechanism for controlling the beam is built in each of 1, 51. The electron gun 41, 51 has an AC power source 4
2, 52 and bias power supplies 43, 53 are connected.

The electron beams are controlled from the electron guns 41 and 51, and the crucible 4 is controlled with a preset power.
It is possible to evaporate the europium sulfide 14a and the aluminum sulfide 15a, which are irradiated with 0.50 and have the luminescence center added, at a predetermined ratio. Alternatively, a multi-source pulse deposition method in which multi-source simultaneous deposition is performed with one E gun may be used.

The vacuum chamber 11 has an exhaust port 11a,
By exhausting from the exhaust port, the inside of the vacuum chamber 11 can be made to have a predetermined vacuum degree. The vacuum chamber 11 also has a source gas introduction port 11b for introducing oxygen gas or hydrogen sulfide gas.

The substrate 12 is fixed to the substrate holder 12a, and the fixed shaft 12b of the substrate holder 12a is rotatably fixed from the outside while maintaining the degree of vacuum in the vacuum chamber 11 by a rotating shaft fixing means (not shown). There is. And
By a rotating means (not shown), it can be rotated at a predetermined rotation speed as needed. Also, the substrate holder 1
2a is a heating means 1 composed of a heater wire or the like.
3 is adhered and fixed, heats the substrate to a desired temperature,
It can be held.

Using such a device, the EB evaporation source 14,
Europium sulfide vapor and aluminum sulfide vapor evaporated from 15 are deposited on the substrate 12 and combined with the introduced oxygen to form an oxysulfide fluorescent layer. At that time, the composition and the film thickness distribution of the deposited light emitting layer can be made more uniform by rotating the substrate 12 if necessary. In the above example, the case where two EB evaporation sources are used has been described, but the evaporation source is not limited to the EB evaporation source, and other evaporation sources such as a resistance heating evaporation source may be used depending on the materials and conditions used. You may use.

Further, for example, a method of obtaining a thioaluminate thin film by the following multi-source reactive vapor deposition method and then performing an annealing treatment in an oxidizing atmosphere is also preferable.

That is, the rare earth metal and aluminum sulfide are evaporated and reacted on the substrate to obtain a thioaluminate thin film. Here, the explanation will focus on the rare earth thioaluminate, but when obtaining thiogalade or thioindate,
Group III sulfides such as gallium sulfide and indium sulfide may be used. In order to promote sulfurization, it is preferable to use hydrogen sulfide gas (H ₂ S) as the sulfur supply source.

Aluminum sulfide may be deviated by about 10% with respect to the stoichiometric composition, but the luminescence center is added to the sulfide to improve the accuracy of the addition amount of the luminescence center when producing an evaporation source. Therefore, it is preferable that the stoichiometric composition is as close as possible.

An emission center is added to aluminum sulfide. It is possible to add several mol% or less of luminescence centers to aluminum sulfide uniformly.
Evaporate powders, green compacts, lumps, etc. The emission center substance evaporates with aluminum sulfide and reaches the substrate,
A small amount of luminescent centers can be added with good controllability to the thioaluminate-based luminescent layer. That is, aluminum sulfide has a function as a carrier of an impurity substance (emission center), and the emission center of 1 mol% or less in thioaluminate can be accurately measured,
It can be added uniformly.

To the emission center, the above-mentioned rare earth element or the like is added. The rare earth to be added is added to the raw material in the form of metal, fluoride or sulfide. The addition amount differs depending on the raw material and the thin film to be formed, so the composition of the raw material is adjusted so that the addition amount is appropriate.

According to this method, not only the composition of thioaluminate can be controlled, but also the crystallinity of thioaluminate is improved. Thioaluminate thin film, eg EuAl ₂ S ₄
Eu, Al and S can be easily controlled to 1: 2: 1 respectively, so that the crystallinity becomes high and at the same time, S, Al, Eu, Al ₂ S ₃ , EuS on the substrate surface and these Due to the surface diffusion of the clusters, each element is located in a stable crystal site, so that a highly crystalline thin film can be obtained. In particular, the EL element is a light emitting phenomenon under a high electric field, and therefore, in order to obtain a phosphor thin film with high brightness, it is necessary to enhance the crystallinity of the base material. According to the present invention, an easily crystallizable product is obtained. If necessary, a gas such as S may be introduced.

The formed sulfide fluorescent thin film is preferably a highly crystalline thin film. The crystallinity is evaluated by, for example, X
It can be performed by line diffraction. In order to improve the crystallinity, the substrate temperature should be as high as possible. Further, annealing in vacuum, N ₂ , Ar, S vapor, H ₂ S or the like after forming the thin film is also effective. In particular, by the method described above,
An oxysulfide phosphor thin film is obtained by obtaining a thioaluminate thin film and then annealing it in an oxidizing atmosphere.

As described above, according to the fluorescent thin film material and the manufacturing method by vapor deposition of the present invention, it is possible to easily form a fluorescent thin film that emits light with high brightness.

In order to obtain an inorganic EL element using the light emitting layer 3 of the fluorescent thin film of the present invention, for example, the structure shown in FIG. 2 may be used.

FIG. 2 is a partial cross-sectional perspective view showing the structure of an inorganic EL device using the light emitting layer of the present invention. In FIG.
A lower electrode 5 having a predetermined pattern is formed on the substrate 1, and the lower electrode 5 is formed to form a thick film first electrode on the substrate 1.
An insulating layer (thick film dielectric layer) 2 is formed. Also,
A light emitting layer 3 and a second insulating layer (thin film dielectric layer) 4 are sequentially formed on the first insulating layer 2, and the lower electrode 5 and the matrix circuit are formed on the second insulating layer 4. The upper electrode 6 is formed in a predetermined pattern so as to be configured.

Between the substrate 1, the electrodes 5 and 6, the thick film insulating layer 2 and the thin film insulating layer 4, a layer for improving adhesion,
An intermediate layer such as a layer for relieving stress and a layer for preventing reaction may be provided. The thick film surface may be polished or a flattening layer may be used to improve the flatness.

The material used as the substrate is a thick film forming temperature,
And a substrate having a heat-resistant temperature or melting point of 600 ° C. or higher, preferably 700 ° C. or higher, particularly 800 ° C. or higher, which can withstand the formation temperature of the EL phosphor layer and the annealing temperature of the EL element, and a light-emitting layer or the like formed thereon. The EL element is not particularly limited as long as it can form an EL element with a functional thin film and can maintain a predetermined strength. Specifically, alumina (Al
₂ O ₃ ), forsterite (2MgO · SiO ₂ ),
Steatite (MgO ・ SiO ₂ ), Mullite (3Al
₂ O ₃ .2SiO ₂ ), beryllia (BeO), aluminum nitride (AlN), silicon nitride (SiN), silicon carbide (SiC + BeO) and other ceramic substrates, heat-resistant glass substrates and the like can be mentioned. Among these, alumina substrates and heat-resistant glass are particularly preferable, and beryllia, aluminum nitride, silicon carbide and the like are preferable when thermal conductivity is required.

In addition to this, it is also possible to use a metal substrate such as quartz, a thermally-oxidized silicon wafer, titanium, stainless steel, Inconel, or an iron-based material. When a conductive substrate made of metal or the like is used, a structure in which a thick film having electrodes inside is formed on the substrate is preferable.

As the dielectric thick film material (first insulating layer), a known dielectric thick film material can be used. Further, a material having a relatively large dielectric constant is preferable.

For example, a lead titanate-based material, a lead niobate-based material, a barium titanate-based material, or the like can be used.

The resistivity of the thick dielectric film is 10 ⁸ Ω.
cm or more, particularly about 10 ¹⁰ to 10 ¹⁸ Ω · cm. Further, it is preferable that the substance has a relatively high dielectric constant,
The dielectric constant ε is preferably ε = 100 to 100
It is about 00. The film thickness is preferably 5 to 50 μm, particularly preferably 10 to 30 μm.

The method for forming the thick film of the insulating layer is not particularly limited, and it is preferable that the film having a thickness of 10 to 50 μm can be obtained relatively easily, but the sol-gel method, the printing firing method, etc. are preferable.

In the case of the printing and firing method, the particle size of the material is appropriately adjusted and mixed with a binder to obtain a paste having an appropriate viscosity. This paste is formed on a substrate by a screen printing method and dried. The green sheet is fired at an appropriate temperature to obtain a thick film.

As the constituent material of the thin film insulating layer (second insulating layer), for example, silicon oxide (SiO ₂ ), silicon nitride (SiN), tantalum oxide (Ta ₂ O ₅ ), strontium titanate (SrTiO ₃ ), Yttrium oxide (Y ₂ O ₃ ), barium titanate (BaTiO ₃ ), lead titanate (PbTiO ₃ ), PZT, zirconia (Zr
O ₂ ), silicon oxynitride (SiON), alumina (Al ₂ O ₃ ), lead niobate, PMN-PT-based materials and the like, and multilayers or mixed thin films of these can be mentioned. As a method of forming,
An existing method such as a vapor deposition method, a sputtering method, a CVD method, a sol-gel method, a printing and baking method may be used. In this case, the thickness of the insulating layer is preferably 50 to 1000 nm, particularly 10
It is about 0 to 500 nm.

The electrode (lower electrode) is formed at least on the substrate side or in the first dielectric body. The electrode layer, which is exposed to a high temperature of heat treatment together with the light emitting layer during the thick film formation, contains palladium, rhodium, iridium, rhenium, ruthenium, platinum, tantalum, nickel, chromium as main components,
One or more commonly used metal electrodes such as titanium may be used.

Further, the other electrode layer serving as the upper electrode is
Since the emission is usually taken from the side opposite the substrate,
A transparent electrode having a light-transmitting property in the wavelength range is preferable. Transparent power
The poles take out the emitted light from the substrate side if the substrate is transparent.
Since it can be used, it may be used for the lower electrode. This place
In particular, it is particularly preferable to use a transparent electrode such as ZnO or ITO.
preferable. ITO is usually In₂O₃ And SnO chemistry
Although it is contained in a stoichiometric composition, the O content is slightly deviated from this.
May be. In₂O₃ Against SnO₂ The mixing ratio of is 1
It is preferably -20% by mass, more preferably 5-12% by mass. Well
Also, In at IZO ₂O₃ The mixing ratio of ZnO to
Usually, it is about 12 to 32% by mass.

Further, the electrodes may have silicon. This silicon electrode layer is made of polycrystalline silicon (p-S
It may be i) or amorphous (a-Si), and may be single crystal silicon if necessary.

The electrodes are doped with impurities in order to secure conductivity in addition to silicon as the main component. The dopant used as an impurity may be any dopant that can ensure a predetermined conductivity, and a normal dopant used in silicon semiconductors can be used. Specifically, B,
P, As, Sb, Al and the like are mentioned, and among these, B, P, As, Sb and Al are particularly preferable. The dopant concentration is preferably about 0.001 to 5 at%.

As a method for forming an electrode layer using these materials, existing methods such as a vapor deposition method, a sputtering method, a CVD method, a sol-gel method and a printing and firing method may be used. In particular, an electrode is internally formed on a substrate. The same method as for the dielectric thick film is preferable when manufacturing a structure in which the thick film is formed.

The preferable resistivity of the electrode layer is 1 Ω · cm or less, and particularly 0.003 to 0.1 Ω · cm in order to efficiently apply an electric field to the light emitting layer. The thickness of the electrode layer depends on the material to be formed, but is preferably 50 to 200.
It is 0 nm, especially about 100 to 1000 nm.

The case where the light emitting layer of the present invention is applied to an inorganic EL element has been described above. However, as long as it is an element in which the phosphor thin film of the present invention can be used, another type of element, red,
By using an element that emits blue and green, it can be applied to a full-color panel for a display.

[0081]

EXAMPLES The present invention will be described in more detail below by showing specific examples of the present invention. Example 1 FIG. 1 shows an example of a vapor deposition apparatus that can be used in the manufacturing method of the present invention. Here, one E gun and one resistance heating evaporation source (cell source) were used instead of two E guns.

An EB source 15 containing EuS powder containing 5 mol% of Ce ₂ S ₃ and a cell source 14 containing Al ₂ S ₃ powder are provided in the vacuum chamber 11 and vaporized simultaneously from the respective sources. EuAl ₂ on the substrate which was heated to ℃ and rotated.
S ₄ : The Ce layer was formed. The evaporation rate of each evaporation source is
The deposition rate of EuAl ₂ S ₄ was adjusted to 1 nm / sec, and the molar ratio of Eu: Al ₂ S ₃ was adjusted to 1: 1. At this time, ₂₀ SCCM of H ₂ S gas was introduced. After forming the insulating thin film thereon, and annealed for 10 minutes in 750 ° C. in air, oxysulfide phosphor thin film, EuAl ₂ O _z S _w: to obtain a Ce.

The composition of the obtained EuAl ₂ O _z S _w : Ce thin film was analyzed by fluorescent X-ray analysis. As a result, Eu: A in atomic ratio was obtained.
l: O: S: Eu = 13.14: 29.29: 17.4
It was 4: 30.14: 0.21.

Further, an EL device using this light emitting layer was prepared. By applying an electric field having a pulse width of 50 kHz of 1 kHz between the electrodes sandwiching the light emitting layer through the insulating layer, 100
A green emission brightness of cd / m ² was obtained with good reproducibility. The emission spectrum is shown in FIG.

Example 2 In Example 1, when the rare earth metal was Yb instead of Eu, Nd instead of Ce and Ga ₂ S ₃ instead of Al ₂ S ₃ , the same results were obtained. Was obtained. In this case, red light emission was obtained.

<Example 3> In Example 1, as the rare earth metal, Eu was replaced by Y, and Ce was replaced by Eu and A.
When In ₂ S ₃ was used instead of l ₂ S ₃ , almost the same result was obtained. In this case as well, red light emission was obtained.

<Example 4> In Example 1, Yb was used instead of Eu as the rare earth metal, and Eu was used instead of Ce. YbAl ₂ O were obtained in the same manner as in Example 1 _z S _w: Eu
Analysis of the thin film revealed that the atomic ratio was Yb: Al: O: S:
Eu = 7.18: 15.93: 381: 27.20:
It was 0.32. Further, an EL device was produced using this light emitting layer and driven in the same manner as in Example 1 to confirm blue light emission.

FIG. 4 shows the spectrum of this EL emission. As is clear from the figure, a spectrum having a peak wavelength at 452 nm and purple was obtained. The brightness was 10 cd / m ² .

As described above, the phosphor thin film of the present invention has a red, green, and blue phosphor thin film material that has good color purity and emits light with high brightness without using a filter, and the same film forming method and the same film forming method. It is possible to obtain high brightness using the film device.

Further, by using a phosphor matrix material or a luminescent center material having similar chemical or physical properties, the manufacturing process of the full-color EL panel is simplified, the variation in luminance is small, the yield is increased, and the manufacturing cost is reduced. Can be reduced.

It can be seen that in the production method of the present invention, the composition control is performed with good reproducibility, the sulfur deficiency of the sulfide, which is the base material of the phosphor thin film, and the incorporation of impurities are solved, and a light emitting layer with high brightness can be obtained.

Further, the EL element using such a thin film has excellent light emitting characteristics, and in particular, when forming a multicolor EL element or a full color EL element, the light emitting layer can be manufactured with good reproducibility, which is of practical value. Is big.

[0093]

As described above, according to the present invention, there is no need for a filter and the color purity is good, especially the full-color EL.
Thin film suitable for RGB and its manufacturing method and E
An L panel can be provided.

Further, it is possible to provide a phosphor thin film capable of simplifying the manufacturing process of a full-color EL panel, reducing variations in brightness, increasing the yield, and reducing the manufacturing cost, a manufacturing method thereof, and an EL panel.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration example of an apparatus to which the method of the present invention is applicable, or a manufacturing apparatus of the present invention.

FIG. 2 Inorganic EL that can be manufactured by the method and apparatus of the present invention
It is a partial cross section figure which shows the structural example of an element.

FIG. 3 is a graph showing an emission spectrum of the EL device of Example 1.

FIG. 4 is a graph showing an emission spectrum of the EL device of Example 4.

[Explanation of symbols]

1 substrate 2 First insulating layer (dielectric layer) 3 Phosphor thin film (light emitting layer) 4 Second insulating layer (dielectric layer) 5 Lower electrode 6 Upper electrode (transparent electrode) 11 vacuum chamber 12 substrates 13 Heating means 14 EB evaporation source 15 EB evaporation source

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/14 H05B 33/14 ZF term (reference) 3K007 AB03 AB04 AB18 BA06 DA02 DA05 DC04 EA02 FA01 4H001 CA04 CF02 XA00 XA08 XA13 XA16 XA31 XA49 YA00

Claims (8)

[Claims] 1. A phosphor thin film in which a base material is an oxysulfide in which at least one compound selected from rare earth thioaluminate, rare earth thiogallate and rare earth thioindate contains oxygen, and which further contains an element serving as an emission center. . 2. The O / (S + O) = 0.01 to 0.85 when the molar ratio of the oxygen element and the sulfur element in the oxysulfide is expressed as O / (S + O). Phosphor thin film. 3. The composition according to claim 1, which is represented by the following composition formula:
Fluorescent thin film. _{R x A y O z S w} : M [ where, M represents a metal element of the light emitting center, at least one element R selected from rare earth elements, A is Al, Ga
And at least one element selected from In,
x = 1-5, y = 1-15, z = 3-30, w = 3-3
It is 0. ] 4. The phosphor thin film according to claim 1, wherein the emission center is a rare earth element. 5. An EL panel having the phosphor thin film according to claim 1. 6. A method of manufacturing a phosphor thin film according to claim 1, wherein the phosphor thin film is annealed in an oxidizing atmosphere after forming the sulfide thin film. 7. A manufacturing method for forming the phosphor thin film according to claim 1 by vapor deposition, comprising at least one selected from aluminum sulfide, gallium sulfide and indium sulfide in a vacuum chamber. An evaporation source and a rare earth sulfide evaporation source to which an emission center is added are arranged and oxygen gas is introduced, and at least one compound selected from aluminum sulfide, gallium sulfide, and indium sulfide from each of these evaporation sources and A method for producing a phosphor thin film, which comprises vaporizing a rare earth sulfide raw material and combining the respective raw materials with oxygen gas to deposit a thin film on the substrate. 8. A manufacturing method for forming the phosphor thin film according to claim 1 by a vapor deposition method, wherein at least one evaporation source selected from at least aluminum sulfide, gallium sulfide and indium sulfide is provided in a vacuum chamber. Arranging a rare earth metal or a rare earth sulfide evaporation source added with an emission center and introducing hydrogen sulfide gas, and at least one compound selected from aluminum sulfide, gallium sulfide, and indium sulfide from each of these evaporation sources. And the rare earth sulfide raw material or the rare earth metal raw material is evaporated, and when deposited on the substrate, the respective raw materials are combined with hydrogen sulfide gas to obtain a sulfide phosphor thin film, and then an annealing treatment is performed in an oxidizing atmosphere. Method for manufacturing phosphor thin film.