JP3762032B2 - Method for forming antistatic film and method for manufacturing image display device - Google Patents

Description

【０１７３】
【表２】

【０１７４】
【表３】

【０１７５】
【発明の効果】
以上説明したように、素子基板とフェースプレート間に配置された絶縁性部材表面に、アルミと遷移金属との合金窒化膜として、例えば、クロム−アルミ合金ターゲットから形成された金属クロムとアルミ合金窒化膜を帯電防止膜として用いることにより、組立て工程中に抵抗値の変化がほとんど起こらず安定した値が得られた。
【０１７６】
これにより、スペーサ近傍でのビームの電位の乱れは抑止され、ビームが蛍光体に衝突する位置と、本来発光するべき蛍光体との位置ずれの発生が防止され、輝度損失を防ぐことができ鮮明な画像表示が可能となった。
【０１７７】
また、ターゲットに、アルミと遷移金属との合金として、例えば、Ｃｒ−Ａｌ合金を用いることにより、予め、Ｃｒ−Ａｌ合金ターゲットのＣｒ量を調整することで、成膜中のＣｒ含有量を正確に調整することができるとともに、短い時間で成膜することができるようになった。
【図面の簡単な説明】
【図１】本発明の帯電防止膜の概略断面図である。
【図２】本発明の実施例である画像表示装置の、表示パネルの一部を切り欠いて示した斜視図である。
【図３】表示パネルのフェースプレートの蛍光体配列を例示した平面図である。
【図４】平面型表面伝導型電子放出素子の構成を示す模式的平面図及び断面図である。
【図５】平面型表面伝導型電子放出素子の形成工程図である。
【図６】電子ビーム源のフォーミング形成印加パルス波形図である。
【図７】通電活性化工程印加パルス波形図である。
【図８】垂直型表面伝導型電子放出素子の断面図である。
【図９】表面伝導型電子放出素子の素子電圧と素子電流、放出電流の関係図である。
【図１０】単純マトリクス配置したマルチ電子源の構成を示す平面図である。
【図１１】単純マトリクス配置したマルチ電子源の構成を示す断面図である。
【図１２】他のスペーサ形状の例を示す斜視図である。
【図１３】従来例の平面型画像表示装置を示す模式的断面図である。
【図１４】本発明の他の実施例に用いられるスパッタ装置の構成を示す模式図である。
【符号の説明】
１ 電子源
２ リアプレート
３ 側壁（支持枠）
４ ガラス基板
５ 蛍光膜
６ メタルバック
７ フェースプレート
８ 外囲器
９ Ｘ方向配線
１０ スペーサ
１１ 電極
１２ Ｙ方向配線
１３ 基板
１４，１５ 素子電極
１６ 導電性薄膜
１７ 電子放出部
１８ 通電活性化処理により形成した薄膜
１９ フォーミング用電源
２０ 電流計
２１ 活性化用電源
２２ 表面伝導型放出素子から放出される放出電流Ｉｅを捕捉するためのアノード電極
２３ 直流電圧電源
２４ 電流計
２５ 基板
２６，２７ 素子電極
２８ 段差形成部材
２９ 微粒子膜を用いた導電性薄膜
３０ 通電フォーミング処理により形成した電子放出部
３１ 通電活性化処理により形成した薄膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antistatic film, a film forming method thereof, and an image display device to which the antistatic film is applied.
[0002]
[Prior art]
Thin flat display is space-saving and lightweight, and is attracting attention as a replacement for CRT display. Currently, flat-panel displays include liquid crystal displays, plasma emission displays, and multi-electron sources. Plasma emission type and multi-electron source displays have a large viewing angle and image quality comparable to that of a cathode ray tube, so that high-quality images can be displayed.
[0003]
FIG. 13 is a schematic cross-sectional view of a display using a large number of minute electron sources. 51 is an electron source formed on the rear plate 52, and 54 is a face plate on which a phosphor 55 is formed. As the electron source, cold cathode electron-emitting devices such as a field-emission electron device or a surface conduction electron-emitting device that emit electrons from a conical or needle-shaped tip capable of increasing the density have been developed. In this figure, wiring for driving the electron source is omitted.
[0004]
As the display area of the display increases, it is necessary to increase the thickness of the substrate and the front glass plate in order to suppress the deformation of the substrate due to the difference between the internal vacuum and the external atmospheric pressure. This not only increases the weight of the display, but also causes image distortion when viewed from an angle. Therefore, in order to support atmospheric pressure using a relatively thin glass plate, a structural support called a spacer or a rib is used between the substrate and the front glass. The space between the substrate on which the electron source is formed and the front glass on which the phosphor is formed is usually maintained at a submillimeter to several millimeters, and the interior is maintained at a high vacuum as described above.
[0005]
In order to accelerate the electrons emitted from the electron source, a high voltage of several hundred volts or more is applied between the electron source and the phosphor. That is, since a strong electric field exceeding 1 kV / mm is applied between the phosphor and the electron source, there is a concern about discharge at the spacer portion.
[0006]
In addition, the spacer causes charging when a part of electrons emitted from a nearby electron source hits or positive ions ionized by emitted electrons adhere to the spacer. The electrons emitted from the electron source due to the charging of the spacer are bent in their trajectories, reach a place different from the normal position on the phosphor, and when the display image is viewed through the front glass, the image near the spacer is Displayed distorted. In order to solve this problem, proposals have been made to remove the charge by allowing a minute current to flow through the spacer. There, a high resistance thin film is formed on the surface of the insulating spacer so that a minute current flows on the spacer surface. The antistatic film used here is tin oxide, or a mixed crystal thin film or metal film of tin oxide and indium oxide.
[0007]
[Problems to be solved by the invention]
The semiconductor type thin film such as tin oxide used in the conventional example is more sensitive to a gas such as oxygen as it is applied to a gas sensor, so that its resistance value easily changes in the atmosphere.
[0008]
In addition, since these materials and metal films have a small specific resistance, it is necessary to form them into islands or to make them extremely thin in order to increase the resistance.
[0009]
That is, the conventional high-resistance film has drawbacks that the reproducibility of film formation is difficult, and the resistance value is likely to change in a heat process such as frit sealing or baking in a display manufacturing process.
[0010]
It is an object of the present invention to provide a spacer antistatic film that overcomes the drawbacks of the conventional spacers and has high stability and good reproducibility, and a display device using the same.
[0017]
[Means for Solving the Problems]
  The present inventionAs a means to solve the above-mentioned problems, CrFilm forming method for forming an antistatic film made of an alloy nitride film of Al and Al, wherein the antistatic film is formed by sputtering an alloy target of Cr and Alsois there.
[0018]
The target is preferably a Cr—Al alloy target having a Cr composition of less than 15 at%.
[0019]
Further, in a film forming method of forming an alloy nitride film of Cr and Al by sputtering an alloy target of Cr and Al,
Ar and N as sputtering gas₂As a means for controlling the specific resistance value of the alloy nitride film of Cr and Al using
(1) To increase the specific resistance value, increase the total sputtering pressure or N₂Increase the partial pressure;
(2) In order to reduce the specific resistance value, the sputtering total pressure is reduced or N₂Reduce the partial pressure;
It is also a film forming method characterized by this.
[0020]
  N₂The partial pressure is preferably 50% or less. Also,The present inventionAn image display device having a structure in which a substrate on which a plurality of cold cathode electron-emitting devices are formed and a substrate on which a light emitting material is formed are opposed to each other via a spacerManufacturing methodInUsing the film formation method on the surface of the spacer,Antistatic filmThe process of film formationImage display apparatus characterized by havingManufacturing methodIs realized.
[0021]
[Action]
The antistatic film is a film that removes charges accumulated on the surface of the insulating material by covering the surface of the insulating material with a conductive film. Usually, the surface resistance (sheet resistance Rs) of the antistatic film is 10¹²Must be Ω or less. Furthermore, a lower resistance value is sufficient to obtain a sufficient antistatic effect.¹¹The resistance is preferably Ω or less, and if the resistance is lower, the charge removal effect is improved.
[0022]
When the antistatic film is applied to the spacer of the display, the surface resistance value Rs of the spacer is set in a desirable range from the antistatic and power consumption. The lower limit of the sheet resistance is limited by the power consumption in the spacer. The lower the resistance, the quicker the charge accumulated in the spacer can be removed, but the power consumed by the spacer increases. The antistatic film used for the spacer is preferably a semiconductive material rather than a metal film having a small specific resistance. The reason is that when a material having a low resistance is used, the antistatic film must be made very thin in order to obtain the desired surface resistance Rs. Although it depends on the surface energy of the thin film material, the adhesion to the substrate, and the substrate temperature, generally, a thin film of 10 nm or less is island-shaped, the resistance is unstable, and the film formation reproducibility is poor.
[0023]
Therefore, a semiconductive material having a specific resistance value larger than that of the metal conductor and smaller than that of the insulator is preferable. However, many of these materials have a negative resistance temperature coefficient. If the temperature coefficient of resistance is negative, the resistance value decreases due to the temperature rise due to the power consumed on the spacer surface, further generates heat and the temperature continues to rise, and an excessive current flows. It causes so-called thermal runaway. However, thermal runaway does not occur in a situation where the amount of heat generated, that is, power consumption and heat dissipation are balanced. Further, if the absolute value of the resistance temperature coefficient TCR of the antistatic film material is small, thermal runaway is difficult.
[0024]
In the experiment, when the power consumption per square centimeter of the spacer exceeds about 0.1 W under the condition of using an antistatic film having a TCR of -1%, the current flowing through the spacer continues to increase, and a thermal runaway state occurs. Admitted. Of course, this depends on the spacer Va and the voltage Va applied between the spacers and the resistance temperature coefficient of the antistatic film. From the above conditions, the value of Rs whose power consumption does not exceed 0.1 W per square centimeter is 10 x Va²Ω or more. That is, the sheet resistance Rs of the antistatic film formed on the spacer is 10 × Va.²It is necessary to set the range from Ω to the 11th power Ω.
[0025]
As described above, the thickness t of the antistatic film formed on the insulating spacer is desirably 10 nm or more. On the other hand, when the film thickness t is 1 μm or more, the film stress increases and the risk of film peeling increases, and the film formation time increases, resulting in poor productivity. Therefore, the film thickness is desirably 10 nm to 1 μm, and more preferably 20 to 500 nm.
[0026]
The specific resistance ρ is the product of the sheet resistance Rs and the film thickness t. From the above-described preferable range of Rs and t, the specific resistance ρ of the antistatic film is 10^-Five× Va²-10⁷Must be Ωcm. Furthermore, in order to realize a more preferable range of sheet resistance and film thickness, ρ is (2 × 10^-Five) Va²~ 5x10⁶It is good to use Ωcm.
[0027]
The acceleration voltage Va of electrons in the display is 100 V or higher, and a voltage of 1 kV is required to obtain sufficient luminance. Under the condition of Va = 1 kV, the specific resistance of the antistatic film is 10-10.⁷Ωcm is a preferred range.
[0028]
As a result of intensive studies on the materials that realize the characteristics of the antistatic film described above, it has been found that aluminum and transition metal alloy nitride films are extremely excellent as antistatic films. The transition metal is selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Hf, Ta, W, etc., and these may be used alone. Two or more transition metals can be used in combination. Transition metal nitride is a good metallic conductor, and aluminum nitride is an insulator.
[0029]
The aluminum transition metal alloy nitride film can control the specific resistance value in a wide range from a good conductor to almost an insulator by adjusting the composition of aluminum and the transition metal. That is, the above-described specific resistance value desirable as the spacer antistatic film can be realized by changing the composition. Further, it was found that the material is a stable material with little change in resistance value in the process of manufacturing a display device described later. In addition, the temperature coefficient of resistance is negative, but the absolute value is less than 1%, and it is a material that is unlikely to cause thermal runaway. Furthermore, since nitride has a low secondary electron emission rate, it is difficult to be charged by electron irradiation, and is a material suitable for a display using an electron beam.
[0030]
Aluminum and transition metal alloy nitride film, which are antistatic films, are formed on an insulating member by thin film forming means such as sputtering, reactive sputtering, electron beam evaporation, ion plating, ion assisted evaporation, and CVD. Can be formed.
[0031]
For example, in the case of the sputtering method, an aluminum transition metal alloy nitride film is obtained by nitriding sputtered metal atoms by sputtering an aluminum and transition metal target in a gas containing nitrogen or ammonia. At this time, the amount of nitrogen in the nitride film changes by adjusting sputtering conditions such as gas pressure, nitrogen partial pressure, and deposition rate. However, sufficient nitridation results in better film stability.
[0032]
According to the present invention, by performing sputtering using an aluminum / transition metal alloy target whose composition has been adjusted in advance, the film-forming composition can be adjusted as compared to the above-described sputtering using an aluminum / transition metal target. Will be easier, more accurate. In addition, the film can be formed in a short time.
[0033]
As described above, the display spacer antistatic film has been described. However, since the aluminum transition metal alloy nitride is a high melting point material and has a high hardness, it is useful not only for display spacers but also for other applications. High material.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
A display device to which the antistatic film of the present invention is applied will be specifically described.
[0035]
FIG. 1 is a schematic cross-sectional view of a display device with a spacer 10 as the center. Reference numeral 1 is an electron source, 2 is a rear plate, 3 is a side wall (support frame), 7 is a face plate, and 2, 3, 7 is an airtight container (envelope 8) for maintaining the inside of the display panel in a vacuum. Is forming.
[0036]
The spacer 10 has an antistatic film 10c of the present invention formed on the surface of an insulating substrate 10a. The spacer 10 is provided in order to prevent the vacuum envelope 8 from being damaged or deformed by receiving atmospheric pressure by evacuating the inside of the envelope 8. The material, shape, arrangement, and number of the spacers 10 are determined in consideration of the atmospheric pressure, heat, and the like received by the envelope, such as the shape of the envelope 8 and the thermal expansion coefficient. The shape of the spacer includes a flat plate shape, a cross shape, an L shape, and the like. The use of the spacer 10 becomes more significant as the image forming apparatus becomes larger.
[0037]
FIG. 12 is a view showing an example of such a spacer. FIG. 12A is a perspective view showing a plate-like spacer opened in a matrix on a plurality of electron sources, and FIG. It is a perspective view which shows the spacer opened in line shape.
[0038]
Since the insulating base material 10a needs to support the atmospheric pressure applied to the face plate 7 and the rear plate 2, a material having high mechanical strength and high heat resistance such as glass and ceramic is suitable. When glass is used as the material for the face plate and rear plate, the spacer insulating base material should be the same as these materials as much as possible, or a material with the same thermal expansion coefficient, in order to suppress thermal stress during the display device manufacturing process. It is desirable to be.
[0039]
When glass containing alkali ions such as soda glass is used for the insulating substrate, the conductivity of the antistatic film may be changed by, for example, Na ions. By forming the Na block layer 10b of Si nitride, Al oxide or the like between the insulating substrate and the antistatic film, it is possible to suppress the entry of alkali ions such as Na into the antistatic film.
[0040]
The antistatic film 10c is an alloy nitride film of Cr and Al, and Cr is used as a transition metal. The ratio (transition metal / aluminum) that provides a specific resistance for a display is 6 at% to 15 at% in the case of Cr. When used for applications other than displays, a material having a wide alloy ratio can be used without being limited to the above range. The applicant has already made a proposal to use an alloy nitride film of transition metal and aluminum as an antistatic film.
[0041]
The spacer 10 is electrically connected to the metal back 6 and the X-direction wiring 9 so that an acceleration voltage Va is applied to both ends of the spacer 10. In this example, the spacer is connected to the wiring, but may be connected to a separately formed electrode. Furthermore, in the configuration in which an intermediate electrode plate (grid electrode or the like) is installed between the face plate 7 and the rear plate 2 for the purpose of shaping the electron beam or preventing the charging of the substrate insulating portion, the spacer penetrates the intermediate electrode plate or the like. Alternatively, they may be connected separately via an intermediate electrode plate or the like.
[0042]
Forming the electrodes 11 having good conductivity such as Al and Au at both ends of the spacer is effective in improving electrical connection between the antistatic film and the electrodes on the face plate and the rear plate.
[0043]
Next, a display device using the above-described spacer will be described. FIG. 2 is a perspective view of the display panel used in the example, and a part of the panel is cut away to show the internal structure.
[0044]
In FIG. 2, 2 is a rear plate, 3 is a side wall (support frame), 7 is a face plate, and an airtight container (envelope 8) for keeping the inside of the display panel in a vacuum by 2, 3, and 7 is shown. Forming. When assembling an airtight container, it is necessary to seal the joints of each member in order to maintain sufficient strength and airtightness. For example, frit glass is applied to the joints, and in the air or in a nitrogen atmosphere, Celsius. It seals by baking for 10 minutes or more at 400-500 degree | times. A method for evacuating the inside of the hermetic container will be described later.
[0045]
A substrate 13 is fixed to the rear plate 2, and N × M cold cathode elements 1 are formed on the substrate (N and M are positive integers of 2 or more. For example, in a display device intended for display of a high-definition television, it is desirable to set the numbers N = 3000 and M = 1000 or more in this embodiment. N = 3072 and M = 1024.)
[0046]
The N × M cold cathode elements are simply matrix-wired by M X-direction wirings 9 and N Y-direction wirings 12. A portion constituted by the aforementioned 1, 9, 12, and 13 is called a multi-electron beam source. The manufacturing method and structure of the multi electron beam source will be described later in detail.
[0047]
In this embodiment, the multi-electron beam source substrate 13 is fixed to the rear plate 2 of the hermetic container. However, when the multi-electron beam source substrate 13 has sufficient strength, the hermetic container The substrate 13 itself of the multi-electron beam source may be used as the rear plate.
[0048]
A fluorescent film 5 is formed on the lower surface of the face plate 7. Since this embodiment is a color display device, the phosphor film 5 is coated with phosphors of three primary colors red, green, and blue used in the field of CRT. For example, as shown in FIG. 3A, the phosphors of the respective colors are applied in stripes, and a black conductor 5b is provided between the stripes of the phosphors. The purpose of providing the black conductor 5b is to prevent the display color from being shifted even if there is a slight shift in the irradiation position of the electron beam, and to prevent the reflection of external light and prevent a decrease in display contrast. This is to prevent the fluorescent film from being charged up by an electron beam. For the black conductor 5b, graphite is used as a main component, but other materials may be used as long as they are suitable for the above purpose.
[0049]
Further, the method of separately applying the phosphors of the three primary colors is not limited to the stripe arrangement shown in FIG. 3A, and for example, R, G, B delta shapes as shown in FIG. It may be an array or any other array.
[0050]
When producing a monochrome display panel, a monochromatic phosphor material may be used for the phosphor film 5, and a black conductive material is not necessarily used.
[0051]
Further, a metal back 6 known in the field of CRT is provided on the surface of the fluorescent film 5 on the rear plate side. The purpose of providing the metal back 6 is to improve the light utilization rate by specularly reflecting a part of the light emitted from the fluorescent film 5, to protect the fluorescent film 5 from negative ion collisions, and the electron beam acceleration voltage. For example, to act as an electrode for applying a voltage, or to act as a conductive path for excited electrons in the fluorescent film 5. The metal back 6 was formed by forming the fluorescent film 5 on the face plate substrate 4, smoothing the surface of the fluorescent film, and vacuum-depositing Al thereon. Note that when a low-voltage phosphor material is used for the phosphor film 5, the metal back 6 is not used.
[0052]
Although not used in this embodiment, a transparent electrode made of, for example, ITO is provided between the face plate substrate 4 and the fluorescent film 5 for the purpose of applying an acceleration voltage or improving the conductivity of the fluorescent film. May be.
[0053]
Dx1 to Dxm and Dy1 to Dyn and Hv are electrical connection terminals having an airtight structure provided for electrically connecting the display panel and an electric circuit (not shown). Dx1 to Dxm are electrically connected to the X direction wiring of the multi electron beam source, Dy1 to Dyn are electrically connected to the Y direction wiring of the multi electron beam source, and Hv is electrically connected to the metal back 6 of the face plate.
[0054]
Further, in order to evacuate the inside of the hermetic container to a vacuum, after assembling the hermetic container, an unillustrated exhaust pipe and a vacuum pump are connected, and the inside of the hermetic container is reduced to a degree of vacuum of about 10 7 [Torr]. Exhaust. Thereafter, the exhaust pipe is sealed. In order to maintain the degree of vacuum in the hermetic container, a getter film (not shown) is formed at a predetermined position in the hermetic container immediately before or after sealing. The getter film is, for example, a film formed by heating and vapor-depositing a getter material mainly composed of Ba by a heater or high-frequency heating, and the inside of the hermetic container is 1 × 10 minus 5 to 1 or 1 by the adsorption action of the getter film. The degree of vacuum is maintained at x10 minus 7 [Torr].
[0055]
The basic configuration of the display panel according to the embodiment of the present invention has been described above.
[0056]
Next, the manufacturing method of the multi electron beam source used for the display panel of the above embodiment will be described. The multi-electron beam source used in the image display apparatus of the present invention is not limited in the material, shape or manufacturing method of the cold cathode element as long as it is an electron source in which cold cathode elements are wired in a simple matrix. Therefore, for example, a cold cathode device such as a surface conduction electron-emitting device, FE type, or MIM type can be used.
[0057]
However, a surface conduction electron-emitting device is particularly preferable among these cold cathode devices under the circumstances where a display device having a large display screen and a low price is required. That is, in the FE type, the relative position and shape of the emitter cone and the gate electrode greatly affect the electron emission characteristics, and thus an extremely accurate manufacturing technique is required. This achieves a large area and a reduction in manufacturing cost. This is a disadvantageous factor. Further, in the MIM type, it is necessary to make the insulating layer and the upper electrode thin and uniform, but this is also a disadvantageous factor in achieving a large area and a reduction in manufacturing cost. In that respect, since the surface conduction electron-emitting device is relatively simple to manufacture, it is easy to increase the area and reduce the manufacturing cost. Further, the inventors have found that among the surface conduction electron-emitting devices, those in which the electron emission portion or its peripheral portion is formed of a fine particle film are particularly excellent in electron emission characteristics and can be easily manufactured. Therefore, it can be said that it is most suitable for use in a multi-electron beam source of a high-luminance and large-screen image display device. Therefore, in the display panel of the above embodiment, a surface conduction electron-emitting device in which the electron emitting portion or its peripheral portion is formed from a fine particle film is used. First, the basic configuration, manufacturing method and characteristics of a suitable surface conduction electron-emitting device will be described, and then the structure of a multi-electron beam source in which a number of devices are wired in a simple matrix will be described.
[0058]
(Suitable device configuration and manufacturing method for surface conduction electron-emitting devices)
There are two types of typical structures of the surface conduction electron-emitting device in which the electron emission portion or the peripheral portion thereof is formed of a fine particle film, a planar type and a vertical type.
[0059]
(Planar surface conduction electron-emitting devices)
First, the device configuration and manufacturing method of a planar surface conduction electron-emitting device will be described. FIG. 4 is a plan view (a) and a cross-sectional view (b) for explaining the configuration of a planar surface conduction electron-emitting device. In the figure, 13 is a substrate, 14 and 15 are element electrodes, 16 is a conductive thin film, 17 is an electron emission portion formed by energization forming treatment, and 18 is a thin film formed by energization activation treatment.
[0060]
As the substrate 13, for example, various glass substrates including quartz glass and blue plate glass, various ceramic substrates including alumina, or the above-mentioned various substrates such as SiO 2₂A substrate in which an insulating layer made of a material is stacked can be used.
[0061]
The device electrodes 14 and 15 provided on the substrate 13 so as to face the substrate surface in parallel are formed of a conductive material. For example, metals such as Ni, Cr, Au, Mo, W, Pt, Ti, Cu, Pd, Ag, etc., or alloys of these metals, or In₂O_Three-SnO₂The material may be appropriately selected from metal oxides such as silicon, semiconductors such as polysilicon, and the like. The electrode can be easily formed by using a combination of a film forming technique such as vacuum deposition and a patterning technique such as photolithography and etching. However, the electrode can be formed using other methods (for example, a printing technique). No problem.
[0062]
The shapes of the device electrodes 14 and 15 are appropriately designed according to the application purpose of the electron-emitting device. In general, the electrode interval L is usually designed by selecting an appropriate value from the range of several tens of nanometers to several tens of micrometers, but among them, the preferred one for application to a display device is several micrometers to several tens of micrometers. It is a range. For the element electrode thickness d, an appropriate value is usually selected from the range of several tens of nm to several μm.
[0063]
A fine particle film is used for the conductive thin film 16 portion. The fine particle film described here refers to a film (including an island-like aggregate) containing a large number of fine particles as a constituent element. If the fine particle film is examined microscopically, usually, a structure in which individual fine particles are arranged apart from each other, a structure in which the fine particles are adjacent to each other, or a structure in which the fine particles overlap each other is observed.
[0064]
The particle diameter of the fine particles used in the fine particle film is included in the range of several tenths of nanometers to several hundreds of nanometers, and the preferable range is 1 nm to 20 nm. The film thickness of the fine particle film is appropriately set in consideration of various conditions as described below. That is, the conditions necessary for a good electrical connection with the element electrode 14 or 15, the conditions necessary for a good energization forming described later, and the electric resistance of the fine particle film itself to an appropriate value described later. These are necessary conditions. Specifically, it is set within a sufficient range of several nm to several hundreds of nm. Among them, a range between 1 nm and 50 nm is preferable.
[0065]
Examples of materials that can be used to form the fine particle film include Pd, Pt, Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Zn, Sn, Ta, W, and Pb. Metal, PdO, SnO₂, In₂O_Three, PbO, Sb₂O_ThreeOxides such as HfB₂, ZrB₂, LaB₆, CeB₆, YB_Four, GdB_FourBorides such as TiC, ZrC, HfC, TaC, SiC, WC, and other carbides, TiN, ZrN, HfN, and other nitrides, Si, Ge, etc. A semiconductor, carbon, etc. are raised and it selects from these suitably.
[0066]
As described above, the conductive thin film 16 is formed of a fine particle film, and the sheet resistance value is set so as to fall within the range of 10 3 to 10 7 [Ω / sq].
[0067]
In addition, since it is desirable that the conductive thin film 16 and the device electrodes 14 and 15 are electrically connected to each other well, the conductive thin film 16 and the device electrodes 14 and 15 have a structure in which a part of each other overlaps. In the example of FIG. 4, the layers are stacked in the order of the substrate, the device electrode, and the conductive thin film from the bottom. However, in some cases, the substrate, the conductive thin film, and the device electrode may be stacked in this order. There is no problem.
[0068]
Moreover, the electron emission part 17 is a crack-like part formed in a part of the conductive thin film 16, and has a property of being higher in resistance than the surrounding conductive thin film. The crack is formed by performing an energization forming process to be described later on the conductive thin film 16. In some cases, fine particles having a sufficient particle diameter of several nm to several tens of nm are arranged in the crack. In addition, since it is difficult to accurately and accurately illustrate the actual position and shape of the electron emission portion, it is schematically shown in FIG.
[0069]
The thin film 18 is a thin film made of carbon or a carbon compound and covers the electron emission portion 17 and the vicinity thereof. The thin film 18 is formed by performing an energization activation process to be described later after the energization forming process.
[0070]
The thin film 18 is any one of single crystal graphite, polycrystalline graphite, and amorphous carbon, or a mixture thereof, and the film thickness is 50 nm or less, more preferably 30 nm or less.
[0071]
In addition, since it is difficult to accurately illustrate the position and shape of the actual thin film 18, it is schematically shown in FIG. Further, in the plan view (a), an element from which a part of the thin film 18 is removed is shown.
[0072]
The basic configuration of the preferred element has been described above. In the examples, the following elements were used.
[0073]
That is, blue glass was used for the substrate 13 and Ni thin films were used for the device electrodes 14 and 15. The thickness d of the device electrode was 100 nm, and the electrode interval L was 2 μm.
[0074]
Pd or PdO was used as the main material of the fine particle film, the thickness of the fine particle film was about 10 nm, and the width W was 10 nm.
[0075]
Next, a preferred method for manufacturing a planar surface conduction electron-emitting device will be described. FIGS. 5A to 5D are cross-sectional views for explaining the manufacturing process of the surface conduction electron-emitting device, and the notations of the respective members are the same as those in FIG.
[0076]
1) First, as shown in FIG. 5A, device electrodes 14 and 15 are formed on a substrate 13. In the formation, the substrate 13 is sufficiently cleaned in advance using a detergent, pure water, and an organic solvent, and then a material for the element electrode is deposited. (For example, a vacuum film forming technique such as a vapor deposition method or a sputtering method may be used as a deposition method.) Thereafter, the deposited electrode material is patterned using a photolithography / etching technique, and is shown in (a). A pair of device electrodes (14 and 15) is formed.
[0077]
2) Next, as shown in FIG. 2B, the conductive thin film 16 is formed.
[0078]
In forming the film, first, an organic metal solution is applied to the substrate (a), dried, heated and fired to form a fine particle film, and then patterned into a predetermined shape by photolithography and etching. Here, the organometallic solution is a solution of an organometallic compound whose main element is a fine particle material used for the conductive thin film (specifically, in this embodiment, Pd is used as the main element. In the example, the dipping method is used as the coating method, but other methods such as a spinner method and a spray method may be used.
In addition, as a method for forming a conductive thin film made of a fine particle film, for example, a vacuum evaporation method, a sputtering method, a chemical vapor deposition method, or the like other than the method by application of an organometallic solution used in this embodiment is used. Sometimes used.
[0079]
3) Next, as shown in FIG. 4C, an appropriate voltage is applied between the forming power source 19 between the device electrodes 14 and 15 to perform energization forming processing, thereby forming the electron emission portion 17.
[0080]
The energization forming process is a process in which a conductive thin film 16 made of a fine particle film is energized, and a part thereof is appropriately destroyed, deformed or altered, and changed into a structure suitable for electron emission. That is. In the portion of the conductive thin film made of the fine particle film that has changed to a structure suitable for electron emission (that is, the electron emission portion 17), an appropriate crack is formed in the thin film. In addition, compared with before the electron emission part 17 is formed, the electrical resistance measured between the device electrodes 14 and 15 significantly increases after the formation.
[0081]
In order to explain the energization method in more detail, FIG. 6 shows an example of an appropriate voltage waveform applied from the forming power source 19. When forming a conductive thin film made of a fine particle film, a pulsed voltage is preferable. In this embodiment, a triangular wave pulse having a pulse width T1 is continuously applied at a pulse interval T2 as shown in FIG. Applied. At that time, the peak value Vpf of the triangular wave pulse was boosted sequentially. Further, a monitor pulse Pm for monitoring the formation state of the electron emission portion 17 was inserted between the triangular wave pulses at an appropriate interval, and the current flowing at that time was measured by the ammeter 20.
[0082]
In the embodiment, for example, in a vacuum atmosphere of about minus 5 torr, for example, the pulse width T1 is set to 1 millisecond, the pulse interval T2 is set to 10 milliseconds, and the peak value Vpf is increased by 0.1 V for each pulse. did. The monitor pulse Pm was inserted at a rate of once every time 5 pulses of the triangular wave were applied. The monitor pulse voltage Vpm was set to 0.1 V so as not to adversely affect the forming process. Then, when the electrical resistance between the device electrodes 14 and 15 becomes 1 × 10 6 ohms, that is, when the monitor pulse is applied, the current measured by the ammeter 20 becomes 1 × 10 minus 7 A or less. At this stage, the power supply related to the forming process was terminated.
[0083]
The above-described method is a preferable method for the surface conduction electron-emitting device of this embodiment. For example, when the design of the surface conduction electron-emitting device such as the material and film thickness of the fine particle film or the element electrode interval L is changed. Accordingly, it is desirable to change the energization conditions accordingly.
[0084]
4) Next, as shown in FIG. 5D, an appropriate voltage is applied between the activation power supply 21 between the device electrodes 14 and 15 to perform energization activation processing, thereby improving the electron emission characteristics. I do.
[0085]
The energization activation process is a process of energizing the electron emitting portion 17 formed by the energization forming process under appropriate conditions and depositing carbon or a carbon compound in the vicinity thereof (in the figure, carbon Or the deposit which consists of a carbon compound was typically shown as the member 18.) By performing the energization activation process, it is possible to increase the emission current at the same applied voltage typically 100 times or more compared to before the energization activation process.
[0086]
Specifically, carbon originating from an organic compound present in the vacuum atmosphere is obtained by periodically applying a voltage pulse in a vacuum atmosphere within the range of 10 4 to 10 5 torr. Alternatively, a carbon compound is deposited. The deposit 18 is any one of single crystal graphite, polycrystalline graphite, and amorphous carbon, or a mixture thereof, and has a film thickness of 50 nm or less, more preferably 30 nm or less.
[0087]
In order to explain the energization method in more detail, FIG. 7A shows an example of an appropriate voltage waveform applied from the activation power supply 21. FIG. In this embodiment, the energization activation process is performed by periodically applying a rectangular wave having a constant voltage. Specifically, the rectangular wave voltage Vac is 14 V, the pulse width T3 is 1 millisecond, and the pulse interval. T4 was 10 milliseconds. The energization conditions described above are preferable conditions for the surface conduction electron-emitting device according to the present embodiment. When the design of the surface conduction electron-emitting device is changed, it is desirable to change the conditions accordingly.
[0088]
Reference numeral 22 shown in FIG. 5 (d) denotes an anode electrode for capturing an emission current Ie emitted from the surface conduction electron-emitting device, to which a DC high voltage power source 23 and an ammeter 24 are connected (note that the substrate is a substrate). When the activation process is performed after 13 is incorporated into the display panel, the phosphor screen of the display panel is used as the anode electrode 22).
[0089]
While the voltage is applied from the activation power supply 21, the emission current Ie is measured by the ammeter 24 to monitor the progress of the energization activation process, and the operation of the activation power supply 21 is controlled. An example of the emission current Ie measured by the ammeter 24 is shown in FIG. 7B. When the pulse voltage is started to be applied from the activation power supply 21, the emission current Ie increases with time, but eventually becomes saturated. Almost no increase. As described above, when the emission current Ie is almost saturated, the voltage application from the activation power supply 21 is stopped, and the energization activation process is terminated.
[0090]
The energization conditions described above are preferable conditions for the surface conduction electron-emitting device according to the present embodiment. When the design of the surface conduction electron-emitting device is changed, it is desirable to change the conditions accordingly.
[0091]
As described above, the planar surface conduction electron-emitting device shown in FIG.
[0092]
FIG. 8 shows another typical configuration of a surface conduction electron-emitting device in which an electron emission portion or its periphery is formed of a fine particle film, that is, a vertical surface conduction electron-emitting device. FIG. 8 is a schematic cross-sectional view for explaining the basic structure of a vertical type, in which 25 is a substrate, 26 and 27 are element electrodes, 28 is a step forming member, and 29 is a conductive film using a fine particle film. , 30 is an electron emission portion formed by energization forming treatment, and 31 is a thin film formed by energization activation treatment.
[0093]
The vertical type is different from the planar type described above in that one of the element electrodes (26) is provided on the step forming member 28, and the conductive thin film 29 covers the side surface of the step forming member 28. There is in point. 4 is set as the step height Ls of the step forming member 28 in the vertical type. For the substrate 25, the device electrodes 26 and 27, and the conductive thin film 29 using the fine particle film, the materials listed in the description of the planar type can be used similarly. Further, the step forming member 28 includes, for example, SiO.₂ An electrically insulating material such as
[0094]
(Characteristics of surface conduction electron-emitting devices used in display devices)
The element configuration and manufacturing method of the planar and vertical surface conduction electron-emitting devices have been described above. Next, the characteristics of the elements used in the display device will be described.
[0095]
FIG. 9 shows typical examples of (emission current Ie) vs. (element applied voltage Vf) characteristics and (element current If) vs. (element applied voltage Vf) characteristics of the elements used in the display device. The emission current Ie is remarkably smaller than the device current If and is difficult to show on the same scale, and these characteristics are changed by changing design parameters such as the size and shape of the device. Therefore, the two graphs are shown in arbitrary units.
[0096]
The element used in the display device has the following three characteristics with respect to the emission current Ie.
[0097]
First, when a voltage greater than a certain voltage (referred to as a threshold voltage Vth) is applied to the device, the emission current Ie increases abruptly. Not detected.
[0098]
That is, it is a nonlinear element having a clear threshold voltage Vth with respect to the emission current Ie.
[0099]
Second, since the emission current Ie changes depending on the voltage Vf applied to the device, the magnitude of the emission current Ie can be controlled by the voltage Vf.
[0100]
Third, since the response speed of the current Ie emitted from the element is high with respect to the voltage Vf applied to the element, the amount of electrons emitted from the element can be controlled by the length of time for which the voltage Vf is applied.
[0101]
Due to the above characteristics, the surface conduction electron-emitting device can be suitably used for a display device. For example, in a display device in which a large number of elements are provided corresponding to the pixels of the display screen, display can be performed by sequentially scanning the display screen by using the first characteristic. That is, a voltage equal to or higher than the threshold voltage Vth is appropriately applied to the driven element according to the desired light emission luminance, and a voltage lower than the threshold voltage Vth is applied to the non-selected element. By sequentially switching the elements to be driven, it is possible to display by sequentially scanning the display screen.
[0102]
Further, by using the second characteristic or the third characteristic, the light emission luminance can be controlled, so that gradation display can be performed.
[0103]
(Structure of multi-electron beam source with simple matrix wiring of many elements)
Next, the structure of a multi-electron beam source in which the above-described surface conduction electron-emitting devices are arranged on a substrate and simple matrix wiring is described.
[0104]
FIG. 10 is a plan view of the multi-electron beam source used in the display panel of FIG. The surface conduction electron-emitting devices similar to those shown in FIG. 4 are arranged on the substrate, and these devices are wired in a simple matrix by the X-direction wiring electrodes 12 and the Y-direction wiring electrodes 9. An insulating layer (not shown) is formed between the X-direction wiring electrode 12 and the Y-direction wiring electrode 9 so that electrical insulation is maintained.
[0105]
FIG. 11 shows a cross section taken along the line AA ′ of FIG.
[0106]
Note that the multi-electron source having such a configuration includes an X-direction wiring electrode 12, a Y-direction wiring electrode 9, an inter-electrode insulating layer (not shown), and a device electrode and a conductive thin film of a surface conduction electron-emitting device on a substrate in advance. After forming, the power supply energization forming process and the energization activation process were performed on each element via the X direction wiring electrode 12 and the Y direction wiring electrode 9.
[0107]
【Example】
(Example 1)
In this example, first, a plurality of unformed surface-conduction electron sources 1 (FIG. 1) were formed on the rear plate 2. A cleaned blue plate glass was used as the rear plate 2, and 160 or 720 surface conduction electron-emitting devices shown in FIG. 4 were formed in a matrix shape. The device electrodes 14 and 15 are Pt sputtered films, and the X direction wiring 9 and the Y direction wiring 12 are Ag wirings formed by a screen printing method. The conductive thin film 16 is a PdO fine particle film obtained by firing a Pd amine complex solution.
[0108]
As shown in FIG. 3b, the phosphor film 5 serving as an image forming member adopts a stripe shape in which each color phosphor R, G, B extends in the Y direction, and the black conductive material 5b is not only between each color phosphor. The shape which isolate | separated between the pixels of a Y direction and added the part for installing the spacer 10 was used. First, the black conductive material 5b was formed, and each color phosphor 7a was applied to the gap portion to form the phosphor film 5. A material mainly composed of graphite, which is commonly used as a black stripe material, was used. As a method of applying the phosphor 5a to the glass substrate 4, a slurry method was used.
[0109]
The metal back 6 provided on the inner surface side of the phosphor film 5 is subjected to a smoothing process (usually called filming) on the inner surface side of the phosphor film 5 after the phosphor film 5 is formed, and then Al is vacuum deposited. Created by doing. The face plate 7 may be provided with a transparent electrode on the outer surface side of the fluorescent film 5 in order to further increase the conductivity of the fluorescent film 5, but in this embodiment, sufficient conductivity was obtained with only the metal back. I omitted it.
The spacer 10 is formed by forming a silicon nitride film 0.5 μm as an Na block layer on an insulating base material 10a (height 3.8 mm, plate thickness 200 μm, length 40 mm) made of cleaned soda lime glass, A Cr and Al alloy nitride film 5c was formed thereon by a vacuum film formation method.
[0110]
The Cr and Al alloy nitride film used in this example was formed by sputtering an alloy target of Cr (6 at%): Al (94 at%) in an argon and nitrogen mixed atmosphere using a sputtering apparatus.
[0111]
The back pressure of the sputtering chamber was 7 × 10 −5 Pa. N during sputtering₂ Ar and N so that the partial pressure is 20%.₂ The mixed gas was flowed. The total pressure of the spatter gas was 0.4 Pa.
[0112]
A target having a size of 5 inches was provided, and the distance from the substrate holder was 120 mm.
[0113]
The insulating base material 10a made of soda lime glass was fixed to the substrate holder using heat-resistant tape or a fixing jig. The substrate heating up to 350 ° C. may be performed to improve the film quality.
[0114]
The substrate was not heated this time. A high frequency power of 500 W was applied to the target, and an alloy nitrogen film of Cr and Al having a thickness of 200 nm was provided for 50 minutes.
[0115]
The specific resistance value of the Cr and Al alloy nitrogen film was 7.00 × 10 6 Ωcm, and the temperature coefficient of resistance was −0.3%.
[0116]
The surface composition analysis of the film calibrated the composition of each constituent element and the surface nitridation rate using the following apparatus. In the same vacuum chamber with a high vacuum of 10 minus 8 Pa or more, an apparatus equipped with a sputter deposition mechanism, RHEED (reflection high-energy electron diffraction pattern measurement mechanism) and XPS (X-ray photoelectron spectroscopy analysis mechanism) is used. First, Cr and Al alloy nitride film 10c were formed by sputtering, and then it was confirmed that Cr and Al alloy nitride film was formed by RHEED method. Thereafter, XPS measurement was performed. The surface composition of the Al and Cr alloy nitride film was calibrated using the peak area ratio of the A12P spectrum and the N1S spectrum at this time.
[0117]
The ratio “Cr” / “Al” between the Cr element and the Al element was 0.05, which was almost the same as the composition ratio of the target.
[0118]
In addition, Cr is almost an oxide on the surface, but Al is a mixture of nitride and oxide, and the ratio existing as nitride (“aluminum nitride” / “aluminum nitride + aluminum oxide”) is 0.82. there were.
[0119]
Next, the spacer 10 of Example 1 was provided with an electrode 11 made of Al at the connection portion in order to ensure the connection with the X direction wiring or the metal back.
[0120]
The electrode 11 completely covered the four surfaces of the spacer 10 exposed in the envelope 8 within a range of 200 μm from the X-direction wiring to the face plate and 200 μm from the metal back to the rear plate.
[0121]
Here, a voltage of 500 V was applied to both ends of the electrode 11 made of Al, the current value was measured, and the resistance value of the spacer 10 was measured to be 1.6 × 10 9 Ω.
[0122]
The spacer 10 of Example 1 on which the Cr and Al alloy nitride film 10c was formed was fixed on the X-direction wiring 9 at equal intervals.
[0123]
After that, the face plate 7 was disposed 3.8 mm above the electron source 1 via the support frame 3, and the joint portion of the rear plate 2, face plate 7, support frame 3 and spacer 10 was fixed.
[0124]
The joint between the electron source 1 and the rear plate 2, the joint between the rear plate 2 and the support frame 3, and the joint between the face plate 7 and the support frame 3 are coated with frit glass and baked at 430 ° C. for 10 minutes or more in the air. Sealed with things.
[0125]
After this sealing treatment, the specific resistance value of Cr and Al alloy nitride 10c was almost unchanged at 7.2 × 10 6 Ωcm.
[0126]
Further, after the experiment of this example, a part of the spacer 10 was removed, and the surface composition analysis of Cr and Al alloy nitride film 10c was performed.
[0127]
The ratio “Cr” / “Al” between the Cr element and the Al element was 0.05, which was almost the same as the composition ratio of the target.
[0128]
Cr is almost an oxide on the surface, but Al is a mixture of nitride and oxide, and the nitriding rate (“aluminum nitride” / “aluminum nitride + aluminum oxide”) has dropped to 0.49. It was.
[0129]
This surface analysis value was obtained by subjecting Cr and Al alloy nitride film after sputtering formation (after deposition) to a firing temperature of 430 ° C. for 10 minutes or more, and then performing surface analysis in the same manner. Value (anneal value).
[0130]
On the face plate 7 side, the spacer 10 uses conductive frit glass containing silica spheres coated with Au on the black conductive material 5b (line width: 300 μm), thereby ensuring electrical connection between the antistatic film and the face plate. .
[0131]
The atmosphere in the envelope 8 completed as described above is exhausted by a vacuum pump through an exhaust pipe, and after reaching a sufficient degree of vacuum, the electron-emitting device 1 of the electron-emitting device 1 is passed through the container outer terminals Dx1 to Dxm and Dy1 to Dyn. An electron emission portion 18 was formed by applying a voltage between the device electrodes 14 and 15 and applying an energization process (forming process) to the electron emission portion forming thin film 16. The forming process was performed by applying a voltage having the waveform shown in FIG.
[0132]
Next, through the exhaust pipe, acetone is introduced into the vacuum container so that the pressure becomes 1 mTorr, and a voltage pulse is periodically applied to the external terminals Dx1 to Dxm and Dy1 to Dyn to deposit carbon or a carbon compound. The treatment was performed. The energization activation was performed by applying a waveform as shown in FIG.
[0133]
Next, the whole container was evacuated for 10 hours while being heated to 200 ° C.^-6The envelope 8 was sealed by welding the exhaust pipe by heating it with a gas burner at a degree of vacuum of about Torr.
[0134]
Finally, in order to maintain the degree of vacuum after sealing, getter processing was performed.
[0135]
In the image forming apparatus completed as described above, electrons are applied to each electron-emitting device 1 by applying scanning signals and modulation signals from the signal generating means (not shown) through the container external terminals Dx1 to Dxm and Dy1 to Dyn, respectively. The emitted electron beam was accelerated by applying a high voltage to the metal back 6 through the high voltage terminal Hv, and the electron was collided with the fluorescent film 5 to excite and emit the phosphor, thereby displaying an image. The applied voltage Va to the high voltage terminal Hv was 1 kV to 5 kV, and the applied voltage Vf between the device electrodes 14 and 15 was 14V.
[0136]
Table 1 shows the resistance value and performance of the antistatic film 10 c for the spacer 10. In Tables 1 to 3, the notation of mE + n is m × 10.ⁿ It shall be shown. “As deposition” means as deposition (after film formation), and in the column showing the results of each example, “good” indicates that the image is less disturbed and “none”. Indicates that the image is not disturbed and is not in a charged state that causes the image to be extremely disturbed.
[0137]
Before the assembly, after sealing to the face plate, after sealing to the rear plate, after vacuum evacuation, and after the device electrode energization treatment, the resistance value hardly changed throughout the entire process.
[0138]
This indicates that Cr and Al alloy nitride film is very stable and suitable as an antistatic film.
[0139]
(Examples 2-9)
Examples 2 to 9 use a Cr (6 at%): Al (94 at%) alloy target.
[0140]
An alloy nitride film of Cr and Al was formed as the conductive film 10C using a Cr (6 at%): Al (94 at%) alloy target in exactly the same manner as in Example 1. However, as shown in Table 1, during the film formation, the total sputtering pressure is 0.4 to 1.0 Pa, N₂ The partial pressure was varied from 10% to 50%.
[0141]
After the formation of the conductive film 10C, a color image was displayed in the image forming apparatus in the same manner as in Example 1, and the disturbance of the image near the spacer was examined.
[0142]
Table 1 summarizes the results of measurement for the spacer 10 of each example.
[0143]
(Examples 1-5)
Examples 1 to 5 are fixed at a total pressure of 0.4 Pa, N₂ The partial pressure is changed. N₂ When the partial pressure is increased, the specific resistance value of the Cr—AlN film increases. Even when the surface is oxidized by the annealing treatment, the specific resistance value hardly changes and it can be seen that this Cr—AlN film is excellent in heat resistance. However, the surface nitridation rate of AlN (“aluminum nitride” / “aluminum nitride + aluminum oxide”) is lowered by the annealing treatment. Especially N₂ It can be seen that the decrease is large when the partial pressure is 30% or more (surface oxidation).
[0144]
(Examples 6 to 9)
In Examples 6 to 9, the total pressure was increased to 0.6 Pa and 1.0 Pa. If the total pressure is increased, the same N₂ The specific resistance value of the Cr—AlN film increases even with partial pressure. However, total pressure, N₂ It can be seen that the surface nitridation rate of AlN decreases as the partial pressure is increased.
[0145]
In the image forming apparatus incorporating the spacers 10 of Examples 7 and 9, image disturbance (shadows) in the vicinity of the spacers due to charging was observed.
[0146]
This is because the surface nitridation rate of AlN is lowered, the charge removal capability of the Cr—AlN film is lowered, and the specific resistance value is too large.
[0147]
(Examples 10 to 15)
In Examples 10 to 15 (Table-2), the target was changed to a Cr (3 at%): Al (97 at%) alloy.
[0148]
As in Examples 1 to 9, the specific resistance value of the Cr—AlN film increases as the total pressure and the partial pressure are increased. A film with a high surface nitridation rate of AlN was obtained even under the same film formation conditions as compared with a Cr (6 at%) target. However, when the specific resistance value increased to about 10 8 Ωcm, the ability to remove electricity was insufficient, and image disturbance (shadow) in the vicinity of the spacer due to charging was observed.
[0149]
(Examples 16 to 19)
In Examples 16 to 19, the target was changed to a Cr (9 at%): Al (91 at%) alloy.
[0150]
As in Examples 1 to 9, the specific resistance value of the Cr—AlN film increases as the total pressure and the partial pressure are increased. However, as in Examples 1 to 9, the surface nitridation rate of the AlN film decreases as the total pressure and partial pressure are increased. In Example 19, the specific resistance value was appropriate at the sixth power of 10, but the surface nitridation rate of the AlN film was as low as 0.33, the charge removal capability was insufficient, and image disturbance (shadow) near the spacer due to charging was observed. It was.
[0151]
(Examples 20 to 22)
Examples 20-22 use what changed the Cr amount of the alloy target from 15% to 50%.
[0152]
When the specific resistance value of the Cr—Al film was smaller than 10 4 Ωcm, Va could not be applied up to 1 kV. When a color image was displayed for a longer time, the specific resistance value of the Cr—AlN film was further reduced due to the heat generated from the spacer 10, and thermal runaway occurred.
[0153]
When the Cr content is up to 9%, the Cr / Al ratio of the formed film is almost equal to the composition of the target, but when it is 15% or more, the Cr content of the formed film is larger than the target composition.
[0154]
This suggests the possibility that the Cr amount of the formed film will change (the Cr amount will gradually decrease) when film formation is continued for a long time. The Cr amount of the alloy target should be less than 15%. is there.
[0155]
(Examples 23 to 26)
In Example 1, a Cr—AlN film was formed by sputtering a Cr—Al alloy target. In Examples 23 to 26, both an Al target and a Cr alloy target were sputtered to form a Cr—AlN film.
[0156]
FIG. 14 is a schematic diagram showing a configuration example of the sputtering apparatus at this time, and includes an Al target 43 and a Cr alloy target 44.
[0157]
Table 3 summarizes the film formation conditions and the results of measurements performed on the spacers 10 of each example.
[0158]
Examples 23 to 26 are examples using a Cr—Al alloy target with 15% Cr and 9% Cr. The Cr content of the Cr—AlN film was adjusted by adjusting the high-frequency power supplied to each target. Similar to Examples 1-22, total pressure, N₂ It is possible to increase or decrease the specific resistance value of the Cr—AlN film having the same Cr content by adjusting the partial pressure.
[0159]
(Comparative Examples 1-6)
In Comparative Examples 1 to 6, both the Al target and the Cr target were sputtered to form a Cr—AlN film. Table 3 summarizes the film formation conditions and the results of measurements performed on the spacers 10 of each example.
[0160]
In Comparative Examples 1 to 3, the back pressure of the sputtering chamber was 7.0 × 10 −5 Pa, which is the same as the previous examples.
[0161]
In Comparative Examples 4 to 6, the film was formed at a sputtering chamber back pressure of 1.3 × 10 minus 3 Pa (this back pressure does not have a pre-exhaust chamber, and the sputtering chamber is kept in the atmosphere for each film formation. This corresponds to a normal back pressure in a batch type film forming apparatus that is opened.)
[0162]
In order to obtain an appropriate specific resistance value of 5 to the 8th power Ωcm, the Cr / Al (atomic) ratio is about 0.03 to 0.12. Cr element is more Ar + N than Al element₂ Since the sputtering rate with the sputtering gas is large, in order to accurately control the small amount of Cr content in the film, it is necessary to accurately control the high-frequency power input to the target with a small value (normally, the setting accuracy is It is about 1% of the power capacity.)
[0163]
In contrast, in Examples 23 to 26, by adjusting the Cr amount of the target of the Cr—Al alloy target, it is possible to make the input high-frequency power substantially equivalent to that of the Al target. Therefore, it can be seen that Examples 23 to 26 are superior to Comparative Examples 1 to 6 in order to accurately adjust the Cr content and form the film in a short time.
[0164]
Comparative Examples 1 to 3 did not disturb the image in the vicinity of the spacer, and showed a good static elimination capability equivalent to the previous examples.
[0165]
In Comparative Examples 4 to 6, the specific resistance value was slightly higher than in Comparative Examples 1 to 3 because the Cr element was oxidized by the residual gas in the chamber during film formation.
[0166]
Furthermore, the nitridation degree of the film surface was greatly reduced by annealing, the charge removal capability was insufficient, and image disturbance (shadow) in the vicinity of the spacer due to charging was observed.
[0167]
Thus, it was found that when the back pressure at the time of film formation decreases, the film has a surface in which the degree of nitridation on the surface is likely to be greatly reduced by annealing.
[0168]
(Examples 27 to 29)
In Examples 1 to 26, the back pressure at the time of film formation was 7.0 × 10 minus 5th power Pa, but in Example 27, the same back pressure 1.3 × 10 minus negative pressure as in Comparative Examples 4 to 6 was used. Film formation was performed at the third power Pa.
[0169]
In Comparative Examples 1 to 6 of co-sputtering film formation from an Al and Cr target, the decrease in the surface nitridation degree after annealing was remarkable when the back pressure was high, but in Examples 27 to 29, the decrease in the surface nitridation degree was small. It showed good static elimination ability.
[0170]
Thus, it was found that when a Cr—Al alloy target was used, a film having a good charge removal capability could be obtained even under apparatus conditions where the back pressure of the sputtering chamber was high.
[0171]
In the image display of the example, the applied voltage Va to the high voltage terminal Hv was 1 kv to 5 kv, and the applied voltage to the device electrode was 14V. The larger the applied voltage Va, the brighter the displayed image and the less disturbed the image near the spacer, but the evaluation of the image did not change. When the voltage applied to the device electrode was changed from 13 V to 15 V, the image was slightly dark at 13 V, and the display image was bright at 15 V, but the image disturbance in the vicinity of the spacer tended to be slightly increased. However, the comparison of the respective examples regarding image disturbance did not change as a trend.
In the above-described embodiments, Cr is used as an example of the transition metal. However, similarly, it is obvious that the effects of the present invention can be obtained even if the above-described transition metals are used. is there.
[0172]
[Table 1]

[0173]
[Table 2]

[0174]
[Table 3]

[0175]
【The invention's effect】
As described above, the alloy nitride film of aluminum and transition metal is formed on the surface of the insulating member disposed between the element substrate and the face plate, for example, metal chromium formed from a chromium-aluminum alloy target and aluminum alloy nitride. By using the film as an antistatic film, the resistance value hardly changed during the assembly process, and a stable value was obtained.
[0176]
As a result, disturbance of the potential of the beam near the spacer is suppressed, the occurrence of misalignment between the position where the beam collides with the phosphor and the phosphor that should originally emit light can be prevented, and brightness loss can be prevented and clear. Image display is now possible.
[0177]
In addition, by using, for example, a Cr—Al alloy as an alloy of aluminum and a transition metal as a target, the Cr content during film formation can be accurately adjusted by adjusting the Cr amount of the Cr—Al alloy target in advance. In addition, the film can be formed in a short time.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an antistatic film of the present invention.
FIG. 2 is a perspective view of the image display apparatus according to the embodiment of the present invention, with a part of the display panel cut away.
FIG. 3 is a plan view illustrating a phosphor array of a face plate of a display panel.
4A and 4B are a schematic plan view and a cross-sectional view showing a configuration of a planar surface conduction electron-emitting device.
FIG. 5 is a process diagram for forming a planar surface conduction electron-emitting device;
FIG. 6 is a waveform diagram of applied pulses for forming formation of an electron beam source.
FIG. 7 is a pulse waveform diagram applied to an energization activation process.
FIG. 8 is a cross-sectional view of a vertical surface conduction electron-emitting device.
FIG. 9 is a diagram showing the relationship between the device voltage, device current, and emission current of a surface conduction electron-emitting device.
FIG. 10 is a plan view showing a configuration of a multi-electron source arranged in a simple matrix.
FIG. 11 is a cross-sectional view showing a configuration of a multi-electron source arranged in a simple matrix.
FIG. 12 is a perspective view showing another example of the spacer shape.
FIG. 13 is a schematic cross-sectional view showing a conventional flat image display device.
FIG. 14 is a schematic view showing a configuration of a sputtering apparatus used in another embodiment of the present invention.
[Explanation of symbols]
1 electron source
2 Rear plate
3 Side wall (support frame)
4 Glass substrate
5 Fluorescent film
6 Metal back
7 Face plate
8 Envelope
9 X direction wiring
10 Spacer
11 electrodes
12 Y-direction wiring
13 Substrate
14,15 Element electrode
16 Conductive thin film
17 Electron emission part
18 Thin film formed by energization activation process
19 Power supply for forming
20 Ammeter
21 Power supply for activation
22 Anode electrode for capturing the emission current Ie emitted from the surface conduction electron-emitting device
23 DC voltage power supply
24 Ammeter
25 substrates
26, 27 Device electrodes
28 Step forming member
29 Conductive thin film using fine particle film
30 Electron emission part formed by energization forming process
31 Thin film formed by energization activation treatment

Claims (5)

In a film forming method for forming an antistatic film made of an alloy nitride film of Cr and Al,
The antistatic film is formed by sputtering an alloy target of Cr and Al. It said target film formation method according to claim 1, wherein the composition of Cr is characterized by using a 15 at% less than Cr-Al alloy target. In a film forming method for forming an alloy nitride film of Cr and Al by sputtering an alloy target of Cr and Al,
As means for controlling the specific resistance value of the alloy nitride film of Cr and Al using Ar and N ₂ as the sputtering gas,
1) To increase the specific resistance value, increase the total sputtering pressure or increase the N ₂ partial pressure;
2) A film forming method characterized by reducing the total sputtering pressure or the N ₂ partial pressure in order to reduce the specific resistance value. The film forming method according to claim 3 , wherein the N ₂ partial pressure is 50% or less. In a method for manufacturing an image display device having a structure in which a substrate on which a plurality of cold cathode electron-emitting devices are formed and a substrate on which a light emitting material is formed are opposed to each other with a spacer interposed therebetween,
Method of manufacturing an image display device characterized by having a using the deposition method according to any one of claims 1-4 to a surface of the spacer, forming an antistatic film process.

Images