JP2001192813A - Method and device for producing sulfide light emitting layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an SrS series light emitting layer small in impurities and capable of conrolling the amount of the center of light emitting to be added at a practical level and to provide a producing device therefor. SOLUTION: In this method and device for producing a sulfide light emitting layer, the sulfide light emitting layer formed by an evaporating method at least has a strontium evaporation source and a zinc sulfide evaporation source to which the center of light emitting has been added, strontium and zinc sulfide raw materials are evaporated from these evaporation sources, and the respective raw material substances are bonded when being deposited on a substrate to obtain the sulfide light emitting layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sulfide light-emitting layer used for an inorganic EL device or the like, and more particularly to a sulfide having a small impurity in the light-emitting layer, excellent controllability of sulfur composition, and high emission luminance. The present invention relates to a method for manufacturing a light emitting layer and a manufacturing apparatus.

[0002]

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

[0003] Furthermore, as a display for personal computers,
Colorization is indispensable for TVs and other displays. The thin-film EL display using the sulfide phosphor thin film is excellent in reliability and environmental resistance. However, at present, the characteristics of the EL phosphor emitting in the three primary colors of red, green and blue are not sufficient. Are unsuitable for color applications. The blue light emitting phosphor is Sr as a base material.
S, SrS using Ce as an emission center: Ce or Zn
S: Tm, ZnS: Sm, Ca
S: Eu, green light emitting phosphors: ZnS: Tb, Ca
S: Ce is a candidate and research is ongoing.

[0004] These phosphor thin films which emit light in the three primary colors of red, green and blue have problems in light emission luminance, efficiency and color purity, and color EL panels have not been put to practical use at present. In particular, for blue, relatively high luminance is obtained using SrS: Ce, but for blue for full-color display, luminance is insufficient and chromaticity is shifted to the green side. Development of a good blue light emitting layer is desired.
The lack of luminance and the shift of the chromaticity toward the edge are caused by Sr
S: It is attributed to poor crystallinity of the Ce light emitting layer, generation of defects due to sulfur removal, and contamination of impurities.

[0005] In order to solve these problems, high purity,
As a method of manufacturing a high-quality sulfide phosphor thin film, there is a method of forming a sulfide phosphor having a composition to be formed at a high temperature of 600 ° C. or more and a method of annealing at a high temperature of 600 ° C. or more. . In addition, page 593 of the IDW 97 Proceedings and IEICE EID 97-57 (1)
997-10) As shown on page 13, by introducing H ₂ S gas or S gas at the time of vapor deposition,
Methods for supplementing sulfur deficiencies, and J. Appl. Phys. 78, 1995,
A method of annealing in a sulfur atmosphere after forming a thin film as shown on page 428, and furthermore, SID95 DIG
In the method shown on page EST 720, SrS and ZnS are co-evaporated at a high substrate temperature, and SrS is obtained by re-evaporation of ZnS. The method aims at the addition of Zn and the compensation of S from ZnS. For example, a method for eliminating a sulfur composition deviation has been attempted.

However, any of these methods uses SrS: C
e pellets are prepared and provided for vapor deposition. SrS: C
Regarding the production of e-pellet, as indicated on IDW 97 Proceedings page 593, it has been pointed out that impurities such as oxygen are mixed in the commercially available SrS raw material. The SrS-based light-emitting layer is sensitive to impurities such as oxygen, and it is necessary to reduce impurities in the light-emitting layer as much as possible to obtain a high-luminance light-emitting body. However, with current technology, S
It is inevitable that impurities are mixed during the synthesis of rS and the production of pellets.

On the other hand, an evaporation method using no pellet, such as SrS: Ce, is disclosed in Japanese Patent No. 2549319 and Japanese Patent Publication No. 6-68999. This method is a so-called co-evaporation method in which a sulfur elemental gas is introduced into a vacuum chamber, and a metal element and a luminescent center constituting a base material are supplied from respective metal sources to obtain a luminescent layer. This method is called S
When applied to the production of the rS: Ce light-emitting layer, the starting material is a metal, and a high-purity raw material can be used as a single metal, so that the above-described contamination of impurities during the production of the SrS: Ce pellet can be avoided. .

On the other hand, the amount of Ce in the SrS: Ce light emitting layer is 1 mol% or less. It is difficult to accurately control the amount of the luminescent center by controlling the respective metal sources of the base metal and the luminescent center substance by the co-evaporation method. For example, to make the molar ratio of Sr and Ce 99.5: 0.1 and to make the variation of the amount of 0.1 0.1% or less,
It is almost impossible with current deposition processes. By the way, in a deposition process of Al or the like whose deposition source is relatively stable, Al
The variation in the thickness of the thin film is about 5%. Therefore C
It is extremely difficult to make e an accuracy of 5% or less.

Therefore, the above-described various methods of vapor deposition cannot be said to be a method of forming a light emitting layer in which impurities are small and the amount of light emission center can be controlled at a practical level.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for producing a SrS-based light-emitting layer, which have a small amount of impurities and can control the amount of light-emission centers at a practical level.

[0011]

This and other objects are achieved by any one of the following constitutions (1) to (4). (1) A method for producing a sulfide light emitting layer formed by a vapor deposition method, comprising at least a strontium evaporation source and a zinc sulfide evaporation source to which a luminescence center is added, and strontium and sulfide from each of these evaporation sources. A method for producing a sulfide light-emitting layer in which a zinc raw material is evaporated and the respective raw materials are combined when deposited on a substrate to obtain a sulfide light-emitting layer. (2) The method for producing a sulfide light-emitting layer according to the above (1), wherein the substrate temperature is 350 ° C. or higher to form a sulfide light-emitting layer. (3) The method for producing a sulfide light-emitting layer according to (1) or (2), wherein the substrate is rotated during film formation. (4) A vacuum chamber, a Knudsen cell evaporation source for evaporating at least strontium in the vacuum chamber, an electron beam evaporation source for evaporating zinc sulfide, and a substrate on which materials evaporated from these evaporation sources are deposited. And a heating means for heating the temperature of the substrate to 350 ° C. or higher.

[0012]

Embodiments of the present invention will be described below in detail. The present invention is a manufacturing method for forming, by vapor deposition, a light-emitting layer composed of a base material containing SrS as a main component by vapor deposition, wherein ZnS to which highly purified Sr metal and a luminescent center substance are added is added. The present invention is characterized by a method of co-evaporation using as an evaporation source and an apparatus using the same.

Here, high purity metal Sr is obtained by a metal refining method. In the present invention, this high purity Sr is directly sulfided on a substrate to synthesize SrS, so that impurities are not mixed. Few.

As a sulfur source for sulfurization, ZnS is used. Compared with SrS, ZnS makes it easier to synthesize powder and provides a raw material with a high degree of wear. ZnS powder is less likely to react with moisture than SrS, and does not contain impurities when pelletized.

An emission center is added to ZnS. Emission centers of several mol% or less can be uniformly added to ZnS, and pellets, powders, compacts, agglomerates, and the like using the same are evaporated. The luminescent center substance evaporates together with ZnS and reaches the substrate, and a small amount of luminescent center can be added to the SrS-based luminescent layer with good controllability. That is, ZnS has a function as a carrier of the impurity substance (emission center), and SrS
A luminescent center of 1 mol% or less can be accurately and uniformly added therein.

The luminescent center may be added with existing transition metals and rare earths in existing amounts. For example, rare earth elements such as Ce and Eu, Cr, Fe, Co, Ni, Cu, Bi, and Ag are added to the raw material in the form of metal, fluoride or sulfide.
Since the amount of addition differs depending on the raw material and the thin film to be formed, the composition of the raw material is adjusted so as to be an appropriate addition amount.

As an evaporation method and an evaporation source, known methods such as EB (electron beam), resistance heating, laser, K-cell (Knudsen Cell), and an evaporation source may be used. In particular, Sr is preferably formed by resistance heating and a K-cell, and ZnS is preferably evaporated by EB. The evaporation rate of each material depends on the composition of the film to be formed, but Sr: 1 to 10 nm / sec, ZnS: 5 to 5 nm.
It is about 50 nm / sec.

The substrate temperature during the deposition is 200 ° C. to 1000 ° C.
° C, preferably 350 ° C to 800 ° C, more preferably 450 ° C to 700 ° C. ZnS is re-evaporated from the substrate surface at a substrate temperature of around 250 ° C. as described later, so that the supply of sulfur from ZnS of the present invention and the high crystallization of the base material to be obtained are effectively performed. If the substrate temperature is too high, the unevenness of the surface of the thin film of the base material becomes severe, pinholes are generated in the thin film, and a problem of current leakage occurs in the EL element. For this reason, the above-mentioned temperature range is preferable. If the temperature is around 250 ° C. or lower, ZnS itself is also formed into a film while supplying sulfur from ZnS to the base material, and a mixed thin film is formed. Therefore, when a mixed thin film is formed and used for the light emitting layer, the thickness is 250
C. or less is preferred.

When an SrS: Ce thin film is to be obtained as a light emitting layer, if the vapor deposition is performed using pellets obtained by adding Ce to SrS, the composition of the thin film is not S / Sr = 1, but
When S / Sr <1, a stoichiometric shortage of sulfur occurs.

In the present invention, ZnS is a sulfur source for the SrS thin film. That is, S, Zn, Sr, ZnS, SrS produced by the reaction, and these clusters are supplied to the substrate surface from the Sr metal source and the ZnS source. When the temperature of the substrate is high, S, Zn, ZnS, and their cluster adhesion coefficients are 1 or less and re-evaporate on the substrate surface, and ZnS
No thin film is formed. However, the adhesion coefficient of SrS and its cluster is almost 1, and SrS
An rS thin film is formed. At this time, S, Zn, and ZnS are:
Although it flies and diffuses on the substrate surface and re-evaporates, it supplies the S component to the SrS thin film during surface diffusion. Therefore, ZnS
An SrS thin film that does not cause sulfur deficiency without forming a thin film is obtained.

According to the present invention, not only the SrS composition can be controlled, but also the crystallinity of SrS is improved. S of SrS thin film
At the same time, the crystallinity is increased due to the ratio of r and S being 1: 1. At the same time, S, Zn, Sr, ZnS, SrS and the surface diffusion of these clusters on the substrate surface make each element a stable crystal site. Since it is located, a highly crystalline thin film can be obtained. Since EL is a light emission phenomenon under a high electric field, it is necessary to increase the crystal of the base material in order to obtain a high-luminance phosphor thin film. According to the present invention, high crystallization can be easily achieved only by using ZnS as a sulfur supply source. Further, a gas such as H ₂ S or S may be introduced.

In the light emitting layer, in order to increase the luminance, it is necessary to add a light emitting center to a highly crystalline base material in a form containing no defect. For example, taking Ce in SrS as an example, C
e has a trivalent and tetravalent electronic state, and needs to be added as Ce ³⁺ which emits Ce. The SrS host material crystal has a NaCl type crystal structure, and when Ce is added,
It is substituted at the position of Sr and is doped. At this time, S
Since r ²⁺ and Ce ³⁺ have different ionic valencies, vacancies are generated at the Sr position.
e ⁴⁺ doping.

Here, in the present invention, Zn ions, Zn and their clusters supplied from the evaporation source are located at the site of the Sr vacancy generated by Ce substitution, thereby reducing defects and Ce ⁴ which does not emit light. Prevent the occurrence of ⁺ . Excess Z
n is not taken into the film by re-evaporation, and an appropriate amount is doped into the base material. Therefore, there are few defects and C
Since e ³⁺ is effectively doped, a light emitting layer with high luminance can be obtained.

As described above, according to the present invention, ZnS acts as a sulfur supply source with respect to the evaporated high-purity metal Sr, and the carrier of the impurity substance, that is, ZnS vapor is converted into ZnS vapor.
It has the function of mixing and supplying e.

It is possible to form an SrS + ZnS mixed thin film by forming a thin film using the difference in the adhesion coefficient between ZnS and SrS at each temperature and under the substrate temperature condition in which only part of ZnS is re-evaporated.

The formed sulfide fluorescent thin film is preferably a highly crystalline thin film, and although it depends on the material to be formed, it is particularly a (100) -oriented crystalline thin film having a NaCl-type crystal structure. Preferably, there is. Evaluation of crystallinity
For example, it can be performed by X-ray diffraction. In order to increase the crystallinity, the substrate temperature should be as high as possible. In addition, in a vacuum, N ₂ , Ar, S vapor, H ₂ S
Annealing in the middle is also effective.

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 luminous efficiency decreases. Specifically, although it depends on the fluorescent material, it is preferably 100 to 1000 nm, particularly 150 to 70 nm.
It is about 0 nm.

The pressure during the deposition is preferably 1.33 × 10
^{-4 to} 1.33 × 10 ^-1 Pa (1 × 10 ^-6 to 1 × 10 ^-3 Tor
r).

Further, the substrate may be moved or rotated at the time of vapor deposition, if necessary. By moving and rotating the substrate, the film composition becomes uniform, and the variation in the film thickness distribution is reduced.

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

The "crucible" or boat of the resistive heating or K-cell evaporation source is preferably one which does not easily react chemically with the material to be deposited and can withstand a predetermined temperature, for example, pyrolytic boron nitride (PBN). , Alumina, ceramics such as magnesia, quartz and the like,
Particularly, alumina and the like are preferable.

The heating source for heating the evaporation source and the substrate may be any one having a predetermined heat capacity, reactivity, etc., 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
The temperature control accuracy is about ± 1 ° C. at 1000 ° C., preferably about ± 0.5 ° C.

FIG. 1 shows a structural example of an apparatus for forming a light emitting layer of the present invention. In the figure, a vacuum layer 11 includes a substrate 12 on which a light emitting layer is formed, a K-cell 14 as a strontium evaporation source, and an EB evaporation source 15 as a zinc sulfide evaporation source. The vacuum chamber 11 has an exhaust port 11a, and the inside of the vacuum chamber 11 can be set to a predetermined degree of vacuum by exhausting from the exhaust port.

The substrate 12 is fixed to a substrate holder 12a, and a 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 rotating shaft fixing means (not shown). I have. And
Rotation means (not shown) enables rotation at a predetermined rotation number as required. Also, the substrate holder 1
2a is a heating means 1 composed of a heater wire or the like.
3 is closely attached and fixed, and heats the substrate to a desired temperature;
It can be held.

K-cell 14 serving as a strontium evaporation source
Contains a strontium metal material 14a to be an evaporation material. The K-cell 14 is heated by a heating means (not shown) and evaporates the metal material at a desired evaporation rate. EB to be zinc sulfide evaporation means
(Electron beam) The evaporation source 15 has a "crucible" 50 in which zinc sulfide 15a to which an emission center is added is stored, and an electron gun 51 having a built-in filament 51a for emitting electrons. An AC power supply 52 and a bias power supply 53 are connected to the electron gun 51.

Using such a device, the strontium material vapor evaporated from the K-cell 14 and the EB evaporation source 15
The vaporized zinc oxide vapor is deposited and combined on the substrate 12 to form a light emitting layer. At that time, by rotating the substrate 12 as necessary, the composition and the film thickness distribution of the light emitting layer to be deposited can be made more uniform.

As described above, according to the manufacturing method and the manufacturing apparatus by vapor deposition of the present invention, it is possible to easily form a phosphor thin film emitting light with high luminance.

In order to obtain an inorganic EL device using the light emitting layer 3 of the present invention, for example, a structure as shown in FIG. 2 may be used. Substrate 1, electrode 5.6, thick insulating layer 2, thin insulating layer 4
Between them, an intermediate layer such as a layer for increasing adhesion, a layer for relaxing stress, a layer for preventing a reaction, and the like may be provided. The surface of the thick film may be polished or a flattening layer may be used to improve the flatness.

FIG. 2 is a partially 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 a substrate 1, and a thick first insulating layer (thick film dielectric layer) 2 is formed on the lower electrode 5. In addition, the first insulating layer 2
A light emitting layer 3 and a second insulating layer (thin film dielectric layer) 4 are sequentially formed thereon, and an upper electrode 6 is formed on the second insulating layer 4 so as to form a matrix circuit with the lower electrode 5. Are formed in a predetermined pattern.

The material used for the substrate is a thick film forming temperature,
A substrate having a heat-resistant temperature or a melting point of not less than 600 ° C., preferably not less than 700 ° C., especially not less than 800 ° C., which can withstand the formation temperature of the EL fluorescent layer and the annealing temperature of the EL element, is used to form the EL element formed thereon. It is not particularly limited as long as it can maintain a predetermined strength. Specifically, alumina (Al ₂ O ₃ ), forsterite (2MgO.SiO ₂ ), steatite (MgO.Si)
O ₂ ), mullite (3Al ₂ O ₃ .2SiO ₂ ), beryllia (BeO), aluminum nitride (AlN), silicon nitride (SiN), ceramic substrate such as silicon carbide (SiC + BeO), heat-resistant glass substrate such as crystallized glass Can be mentioned. Each of these heat-resistant temperatures is 10
It is about 00 ° C or more. Among these, an alumina substrate and crystallized glass are particularly preferable, and when thermal conductivity is required, beryllia, aluminum nitride, silicon carbide and the like are preferable.

In addition, a metal substrate made of titanium, stainless steel, inconel, iron, or the like, such as quartz or thermally oxidized silicon wafer, can also be used. When a conductive substrate such as a metal substrate 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, materials such as lead titanate, lead niobate, and barium titanate can be used.

The resistivity of the dielectric thick film is 10 ⁸ Ω ·
cm or more, particularly about 10 ¹⁰ to 10 ¹⁸ Ω · cm. It is also preferable that the material 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 from 5 to 50 μm, particularly preferably from 10 to 30 μm.

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

In the case of the printing and baking 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 a 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 (ZrO ₂ ), silicon oxynitride (SiON), alumina (A
l ₂ O _3), lead niobate, PMN-PT based material and can be exemplified these multilayer or mixed thin film, as a method of forming an insulating layer with these materials, vapor deposition, sputtering, CVD An existing method such as a sol-gel method or a printing and baking method may be used. In this case, the thickness of the insulating layer is preferably 50 to 1000 nm, particularly 100 to 500 nm.
It is about nm.

The electrode (lower electrode) is formed at least on the substrate side or in the first dielectric. When forming a thick film, the electrode layer exposed to the high temperature of the heat treatment together with the light emitting layer further includes palladium, rhodium, iridium, rhenium, ruthenium, platinum, tantalum, nickel, chromium, as a main component.
A commonly used metal electrode such as titanium may be used.

The other electrode layer serving as the upper electrode has
Normally, the light emission is taken out from the opposite side of the substrate,
A transparent electrode having a light-transmitting property in a wavelength range is preferable. Transparent
The pole takes out the emitted light from the substrate side if the substrate is transparent
It may be used for the lower electrode because it can be used. This place
In particular, it is particularly preferable to use a transparent electrode such as ZnO or ITO.
preferable. ITO is usually In_TwoO_ThreeChemistry with SnO
Although it is contained in a stoichiometric composition, the O content is slightly deviated from this.
You may. In_TwoO_ThreeSnO against_TwoIs 1
-20 wt%, more preferably 5-12 wt%. Also,
In at IZO_TwoO _ThreeThe mixing ratio of ZnO to
Usually, it is about 12 to 32% by weight.

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

The electrodes are doped with impurities in order to ensure conductivity, in addition to silicon as the main component. The dopant used as the impurity only needs to be able to secure predetermined conductivity, and a normal dopant used for a silicon semiconductor can be used. Specifically, B,
Examples thereof include P, As, Sb, and Al. Among them, B, P, As, Sb, and Al are particularly preferable. The concentration of the dopant is preferably about 0.001 to 5 at%.

As a method for forming an electrode layer from these materials, existing methods such as a vapor deposition method, a sputtering method, a CVD method, a sol-gel method, and a printing and baking method may be used. In particular, an electrode is formed inside a substrate. When fabricating a structure having a thick film having the same, the same method as that for forming a dielectric thick film is preferable.

The preferable resistivity of the electrode layer is 1 Ω · cm or less, 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 from 50 to 200.
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 device has been described above. However, as long as the light emitting layer of the present invention can be used, the present invention can be applied to other types of devices and displays. It is possible.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention. Embodiment 1 FIG. 1 shows an example of a vapor deposition apparatus that can be used in the manufacturing method of the present invention. An EB source 15 containing ZnS pellets containing 0.04 mol% of Ce and a K-cell 14 containing metal Sr are provided in the vacuum chamber 11 and are simultaneously evaporated from the respective sources, heated to 650 ° C., and rotated. An SrS: Ce layer was formed on the substrate thus formed. The evaporation rate of each evaporation source was adjusted so that the ratio of ZnS: Sr was 3: 1 in mol / sec.

As a result of composition analysis of the SrS: Ce thin film by X-ray fluorescence analysis, Sr: Zn: S: Ce = 4 in atomic ratio.
9.74: 0.10: 50.10: 0.11.
According to X-ray diffraction, it has a NaCl-type crystal structure, and (10
0) It was found that the crystal thin film was oriented.

Further, an EL device using the light emitting layer was manufactured. By applying a 1 KHz electric field having a pulse width of 50 μS to the electrode, a light emission luminance of 300 cd / m ² was obtained with good reproducibility.

For comparison, the conventional S
The light emitting layer formed using rS: Ce pellets while introducing S gas at a substrate temperature of 650 ° C. was 15 cd / m ² , and the effect of the present invention was clearly exhibited.

As is clear from the above examples, it can be understood that a sulfur deficiency as a base material of the phosphor thin film and the incorporation of impurities can be solved and a light emitting layer with high luminance can be obtained.
An EL element using such a thin film has excellent light-emitting characteristics,
In particular, when a multicolor EL element or a full-color EL element is formed, a light-emitting layer can be manufactured with good reproducibility, which is of great practical value.

[0060]

As described above, according to the present invention, it is possible to obtain a sulfide thin film in which sulfur deficiency and contamination of impurities are suppressed.
It is possible to provide a method and an apparatus for manufacturing a light-emitting layer having excellent light-emitting luminance, efficiency, and color strength.

[Brief description of the drawings]

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

FIG. 2 is an inorganic EL that can be manufactured by the method and apparatus of the present invention.
FIG. 3 is a partial cross-sectional view illustrating a configuration example of an element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st insulating layer (dielectric layer) 3 Phosphor thin film (light emitting layer) 4 2nd insulating layer (dielectric layer) 5 Lower electrode 6 Upper electrode (transparent electrode) 11 Vacuum tank 12 Substrate 13 Heating means 14 K-cell 15 EB evaporation source

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/10 H05B 33/10 33/14 33/14 Z F-term (Reference) 3K007 AB02 AB03 AB04 AB15 BA06 CA01 CA02 CA04 CB01 DA05 DB01 DB02 DC01 DC04 EA04 EC01 EC02 EC03 EC04 FA00 FA01 FA03 4H001 CF01 XA16 XA38 YA58 4K029 AA24 BA02 BA51 BB02 CA02 DB03 DB05 EA08 JA08

Claims (4)

[Claims] 1. A method for producing a sulfide light emitting layer formed by a vapor deposition method, comprising: at least a strontium evaporation source; and a zinc sulfide evaporation source to which a luminescent center is added. And a method for producing a sulfide light-emitting layer by evaporating a zinc sulfide raw material and combining the respective raw materials when depositing on a substrate to obtain a sulfide light-emitting layer. 2. The method for producing a sulfide light emitting layer according to claim 1, wherein the sulfide light emitting layer is formed at a substrate temperature of 350 ° C. or higher. 3. The method for producing a sulfide light emitting layer according to claim 1, wherein the substrate is rotated during film formation. 4. A vacuum chamber, a Knudsen cell evaporation source for evaporating at least strontium, an electron beam evaporation source for evaporating zinc sulfide, and materials evaporated from these evaporation sources are deposited in the vacuum chamber. An apparatus for producing a sulfide light-emitting layer, comprising: a substrate to be heated; and heating means for heating the temperature of the substrate to 350 ° C. or higher.