JP2004158470A - Horizontal type field emission cold cathode device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal type field emission cold cathode device capable of attaining low driving voltage, high field emission efficiency, and high integration. <P>SOLUTION: The horizontal type field emission cold cathode device has cathode electrodes 22 and gate electrodes 24 laterally formed on a main surface of a supporting substrate 16. The cathode electrode 22 has a side surface 22a and the gate electrode 24 has a side surface 24a facing each other, and an emitter 26 is formed on the side surface 22a of the cathode electrode 22. The emitter 26 is composed of a metal-plated layer 42 formed on the cathode electrode 22 and a plurality of grain-shaped or stick-shaped fine bodies 44, supported on the metal plated layer 42 in a scattered state, made of a material chosen from fullerene, carbon nanotube, graphite, a material with a low work function, a material with negative electron affinity force, and a metallic material. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a horizontal field emission cold cathode device.

  In recent years, field emission cold cathode devices utilizing Si semiconductor processing technology have been actively developed. As a typical example, a vertical field emission cold cathode device proposed by Spindt (C. A. Spindt) and the like is known (for example, see Non-Patent Document 1). This field emission cold cathode device has a conical emitter on a Si single crystal substrate, and a gate electrode provided so as to surround the tip of the emitter.

  On the other hand, in view of the problems of the vertical field emission cold cathode device, a horizontal field emission cold cathode device proposed by Green (R. Green), Gray (HF Gray), and the like is also known. (For example, see Non-Patent Document 2). This field emission cold cathode device has an emitter and a gate electrode which are disposed on the same substrate so as to face each other. The horizontal field emission type cold cathode device has the advantages of being easy to manufacture and increasing the yield.

  In the case of a horizontal field emission type cold cathode device, the emitter end face facing the gate electrode has a sharpness of about 80 to 500 nm corresponding to the thickness of the emitter and a tip radius of curvature of 40 to 250 nm in a direction perpendicular to the substrate surface. It has considerable sharpness. However, the emitter end face is parallel to the gate electrode in a direction parallel to the substrate surface, and the sharpness is zero. That is, the emitter end face facing the gate electrode has only a two-dimensional sharpness, not a three-dimensional one, and has a drawback that the driving voltage is high. Even if the emitter end face is sharpened three-dimensionally, a sharpness higher than that of lithography cannot be obtained, and usually the sharpness is about 50 to 100 nm in a direction parallel to the substrate surface. In addition, when the number of precise lithography steps increases, the merit of simplifying the manufacturing method diminishes.

  On the other hand, a device using fullerene or carbon nanotube as an emitter has been proposed as a field emission cold cathode device (for example, see Patent Document 1). Since fullerenes and carbon nanotubes have a small tip radius of curvature, the driving voltage can be reduced and the field emission efficiency can be improved. In addition, since the atmosphere dependency and the influence of residual gas are small, operation at a low degree of vacuum can be expected.

  In the case of this type of cold cathode device, the emitter can be formed by a method in which fullerene or carbon nanotubes are dispersed in an organic solvent, passed through a ceramic filter, and then pressed on a substrate. Further, the emitter can be formed by a method of directly depositing fullerene or carbon nanotube on a substrate by a CVD method or the like. Further, the emitter can be formed by a method in which fullerene or carbon nanotube is dispersed in a thick film paste, printed, and fired at a high temperature (about 500 to 800 ° C.).

  However, in the method in which fullerenes or carbon nanotubes are pressed or deposited on a substrate, the adhesion of the emitter is weak, and the emitter is easily peeled off by a strong electric field applied to the emitter. In addition, the method of forming fullerenes or carbon nanotubes by printing has a problem in that performance is reduced or deteriorated due to high-temperature baking or the like. Further, in both the pressure bonding and the printing, the orientation of the carbon nanotubes to the extraction electrode is not good, and there are problems such as an increase in driving voltage and non-uniformity of electron emission.

  Further, in the pressure bonding method, there is a problem that patterning corresponding to the cathode wiring is extremely difficult because carbon has high chemical resistance and etching is difficult. Further, the deposition method by the CVD method or the like requires a catalyst of a transition metal and needs to be finely divided, resulting in a problem that a resistance value is increased and a signal delay or the like is likely to occur. Further, in the printing method, since the film has a high resistance and it is difficult to form a thick film, it is difficult to form a low-resistance wiring, and there is also a problem that a signal delay or the like easily occurs.

As described above, as the field emission type cold cathode, various types have been proposed, such as a horizontal type in which the disadvantage of the vertical type is improved and a type using carbon nanotube or fullerene as an emitter material. However, the conventionally proposed field emission cold cathodes are not sufficient in terms of sharpness, drive voltage, reliability, yield, ease of manufacture, and the like.
Journal of Applied Physics, Vol. 47, 5248 (1976) Tech.Digest of IEDM 85, p 172 (1985) JP-A-10-149760

  The present invention has been made in view of the above points, and has as its object to provide a horizontal field emission cold cathode capable of achieving low driving voltage, high field emission efficiency, and high integration.

A first aspect of the present invention is a horizontal field emission cold cathode device,
A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , Carbon nanotubes, graphite, a low work function material, a negative electron affinity material, made of a material selected from the group consisting of metal materials, and that the fine body is partially embedded in the metal plating layer, It is characterized.

A second aspect of the present invention is a horizontal field emission cold cathode device,
A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , Carbon nanotubes, graphite, a low work function material, a negative electron affinity material, made of a material selected from the group consisting of metal materials, and that the fine body is entirely embedded in the metal plating layer, It is characterized.

A third aspect of the present invention is a horizontal field emission cold cathode device,
A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , A material selected from the group consisting of carbon nanotubes, graphite, a low work function material, a negative electron affinity material, and a metal material, and the fine bodies are rod-shaped, and 50 to 100% of the fine bodies are: The cathode electrode is oriented within an angle range of ± 20 ° with respect to a main surface of the support substrate on which the cathode electrode is provided.

A fourth aspect of the present invention is a horizontal field emission cold cathode device,
A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. Made of a material selected from the group consisting of carbon nanotubes, graphite, a low work function material, a negative electron affinity material, and a metal material, and the fine body is rod-shaped and hollow, and a conductive material is formed inside the fine body. And a filling layer made of the above material is provided.

A fifth aspect of the present invention is a horizontal field emission cold cathode device,
A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter disposed on the first side surface to face the second side surface for emitting electrons; and the emitter is distributed between a metal plating layer formed on the cathode electrode and the metal plating layer. And a plurality of granular or rod-like fines supported in a state, wherein the fines are selected from the group consisting of fullerenes, carbon nanotubes, graphite, low work function materials, negative electron affinity materials, and metallic materials. Made of materials,
A gate protrusion disposed on the second side surface to face the first side surface, the gate protrusion includes a gate metal plating layer made of the same material as the metal plating layer, and a gate metal plating layer Having a plurality of gate fine bodies supported in a dispersed state and made of the same material as the fine bodies,
It is characterized by having.

  Further, the embodiments according to the present invention include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, when an invention is extracted by omitting some constituent elements from all the constituent elements described in the embodiment, when implementing the extracted invention, the omitted part is appropriately supplemented by well-known conventional techniques. It is something to be done.

  According to the present invention, it is possible to provide a high-performance horizontal field emission type cold cathode device having excellent field emission stability and uniformity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals, and repeated description will be made as necessary.

  FIG. 1 is a cross-sectional view showing a flat panel display which is an example of a vacuum micro device to which a horizontal field emission cold cathode device according to an embodiment of the present invention is applied. FIG. 2 is a partial plan view of the device, and FIG. 3 is a cross-sectional view of a main part of the device.

  This display device has a pair of a cathode electrode 22 and a gate electrode 24 corresponding to each of a large number of pixels arranged in a matrix as shown in FIG. The cathode electrode 22 is connected to the cathode lines 12 arranged in the vertical direction in FIG. 2, and the gate electrode 24 is connected to the gate lines 14 arranged in the horizontal direction in FIG.

  As shown in FIG. 1, all the cathode electrodes 22 and the gate electrodes 24 are disposed on the flat main surface (the upper surface extending in the horizontal direction in FIG. 1) of the insulating support substrate 16 made of glass. In each pixel, the cathode electrode 22 and the gate electrode 24 are arranged side by side on the support substrate 16 with a small gap of 1 μm to 30 μm. On the opposing side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24, an emitter 26 and a gate protrusion 28 having a structure described in detail later are disposed, respectively. The cathode line 12, the gate line 14, and the like are incorporated in a wiring structure 18 provided on a support substrate 16.

  A glass opposing substrate 32 is disposed so as to face the glass supporting substrate 16, and a vacuum discharge space 33 is formed between the substrates 16 and 32. The space between the substrates 16 and 32 is maintained by the peripheral frame and the spacer 34. A transparent common electrode, that is, an anode electrode 36 and a phosphor layer 38 are provided on the surface of the counter substrate 32 facing the support substrate 16.

  In this flat panel type image display device, lighting and blinking of pixels are selected by arbitrarily setting a voltage between the gate electrode 24 and the cathode electrode 22 in each pixel via the gate line 14 and the cathode line 12. can do. That is, the selection of the pixel is performed by so-called matrix driving, for example, by applying a predetermined potential as a selection signal to the cathode line 12 in synchronization with line-sequentially selecting the gate line 14 and applying a predetermined potential. It can be done by doing.

  When a certain gate line 14 and a certain cathode line 12 are selected and given a predetermined potential, respectively, only the emitter 26 at the intersection of the gate line 14 and the cathode line 12 operates. The electrons emitted from the emitter 26 are attracted by the voltage applied to the anode electrode 36, reach the phosphor layer 38 at a position corresponding to the selected emitter 26, and emit light.

  As shown in FIG. 3, the emitter 26 includes a metal plating layer 42 selectively formed in the vicinity of the opposite side surface 22 a of the cathode electrode 22, and a granular or conductive material supported by the metal plating layer 42 in a dispersed state. A plurality of rod-shaped fine bodies 44. In this embodiment, the metal plating layer 42 functions as a resistance ballast layer for improving current emission stability and in-plane uniform field emission, and the fine body 44 functions as a terminal for emitting electrons.

That is, the metal plating layer 42 is desirably formed to have a resistance ballast effect. For this reason, the resistivity of the metal plating layer 42 is set to 10 ⁻⁸ to 10 ⁻⁴ Ω, preferably 10 ⁻⁷ to 10 ⁻⁴ Ω. For this reason, the metal plating layer 42 contains an additive substance for increasing its resistance, for example, B and P, or PTFE (polytetrafluoroethylene). Here, when a Ni-BP-based Ni plating layer is used as the metal plating layer 42, the B concentration is set to 3 to 40%, and the P concentration is set to 7 to 40%. When a PTFE-containing Ni plating layer is used as the metal plating layer 42, the PTFE concentration is set to 0.1 to 30%.

  The metal plating layer 42 is formed only on the opposing side surface 22a of the cathode electrode 22, or in addition thereto, as shown in FIG. 3, the upper surface of the cathode electrode 22 near the opposing side surface 22a (opposing the anode electrode 36). The surface 22b is also additionally formed. However, in this case, the length L1 (see FIG. 3) of the additional portion 22b is set to be 25% or less of the length L0 of the entire upper surface of the cathode electrode 22. This is because only the portion near the gate electrode 24 can substantially function as an emitter, so that extending the metal plating layer 42 further has no effect.

  On the other hand, the fine body 44 is formed of a rod-like body such as a carbon nanotube (in FIG. 3, the fine body 44 has a rod-like shape) or a granular body such as fullerene. FIG. 4A shows a case where the fine body 44 is a rod-like body 44a such as a carbon nanotube. In this case, most of the rod-like bodies 44a are fixed such that the base is embedded in the metal plating layer 42 and the upper part is exposed on the surface of the emitter 26. Alternatively, the rod-like body 44a is completely covered with the metal plating layer 42 and a state is formed in which the projections appear on the surface of the emitter 26 correspondingly. On the other hand, FIG. 4B shows a case where the fine body 44 is a granular body 44b such as fullerene. In this case, the granular body 44b is embedded and fixed in the metal plating layer 42 so that a part thereof is exposed, or is entirely covered with the metal plating layer 42 thinly and correspondingly protrudes from the surface of the emitter 26. A state is formed in which a part appears.

  The granular or rod-shaped fine body 44 needs to have a small radius or radius of curvature in order to improve the electron emission characteristics of the emitter 26. Specifically, when the fine body 44 is granular, the radius is set to 100 nm or less, preferably 30 nm or less. When the fine body 44 has a rod shape, the radius of curvature of the tip is set to 50 nm or less, preferably 15 nm or less.

  When the fine body 44 is formed of a rod-shaped body such as a carbon nanotube, it is desirable that the rod-shaped fine body 44 be oriented toward the gate electrode 24 in order to improve electron emission characteristics. Specifically, the ratio of the rod-shaped fine body 44 oriented within an angle range of ± 20 ° with respect to the spreading direction of the flat main surface of the support substrate 16 (horizontal direction in FIGS. 1 and 3) is described. Desirably, it is 50 to 100%.

  As described later, the orientation of the rod-shaped fine body 44 is performed by performing a plating process using a suspension plating solution in which the fine body 44 is suspended, between the cathode electrode 22 and the gate electrode 24. This can be achieved by forming an electric field between them. In other words, when a positive potential is applied to the gate electrode 24 with respect to the cathode electrode 22 during the plating process, the conductive fine body 44 moves along the lines of electric force of the electric field between the cathode electrode 22 and the gate electrode 24. It is mainly oriented.

  In addition, if the rod-shaped fine body 44 is long enough to bridge between the cathode electrode 22 and the gate electrode 24, the electrodes 22 and 24 are short-circuited. For example, as described above, if the distance between the electrodes 22 and 24 is 1 μm to 30 μm, it is desirable to use a rod-shaped fine body 44 shorter than this. For this reason, when preparing the suspension plating solution, the fine particles 44 that have been classified based on a predetermined length can be used. However, as described later, a gap can be formed between the emitter 26 and the gate protrusion 28 after the fine body 44 is provided, and thus the length before the fine body 44 is provided is not limited. .

The fine body 44 is preferably made of carbon nanotube or fullerene, but the fine body 44 can be formed from other materials. As other materials for the fine body 44, graphite, a low work function material, a negative electron affinity (NEA) material, a metal material, or the like can be used. Specifically, LaB ₆ , AlN, GaN, Mo, Ta, W, Ta, Ni, Cr, Au, Ag, Pd, Cu, Al, Sn, Pt, Ti, Fe, carbon, graphite, diamond, Si, TiN, TiC, beta W, SiC, Al ₂ O ₃ , ZnO, in particular, zinc oxide in the shape of a mold, aluminum borate (9Al ₂ O ₃ .2B ₂ O ₃ ), particularly aluminum borate in the form of a filler, potassium titanate, etc. Can be used. When the fine body 44 is hollow, a filling layer 45 made of a conductive material can be formed inside the fine body 44 as shown in FIG.

The above-mentioned carbon nanotube and fullerene are allotropes of the same carbon, and are basically of the same quality. An extremely long fullerene having a unique shape becomes a carbon nanotube. The basic type of fullerene is C ₆₀ composed of a 6-membered ring and a 5-membered ring of carbon, and its diameter is about 0.7 nm. C ₆₀ puts carbon atoms of sp ² orbital hybrids on all the vertices of truncated icosahedron (and consequently icosahedron) by cutting off all 12 pentagonal vertices of icosahedron. It has a structure. Besides C _60, higher fullerenes is more than 60 carbon atoms, for example _{C 70, C 76, C 82} , C 84, C 90, C 96, ..., C 240, C 540, C 720 and the like virtually unlimited Exists in

Further, since the inside of the fullerene is hollow, there are onion-type fullerenes in which several layers of low-order fullerenes are bundled like onions in higher-order fullerenes, and these are called superfullerenes. The distance between the layers in the superfullerene is 0.341 nm. For example, contains the C ₂₄₀ in the C _540, further fullerene containing the C ₆₀ therein is represented by C ₆₀ @C ₂₄₀ @C _540. Here, the symbol “＠” indicates that the molecule or atom described above is an endohedral fullerene.

In addition, fullerene can take in metal in its hollow interior. Examples of such metal-containing fullerenes are La @ C ₆₀ , La @ C ₇₆ , La @ C ₈₄ , La ₂ @C 80, Y ₂ @C ₈₄ , Sc ₃ @C _{82, and the} like. Further, heterofullerenes in which elements other than carbon, such as N, B, and Si, are incorporated into the skeleton portion of fullerenes have also been studied.

  Fullerene vaporizes carbon by applying laser irradiation, arc discharge, resistance heating, etc. to graphite, cooling, reacting and coagulating while vaporizing carbon passes through helium gas, and collecting this with a collection member Can be prepared.

  On the other hand, the gate protrusion 28 facing the emitter 26 is made of a metal plating layer 46 selectively formed on the opposite side surface 24 a of the gate electrode 24 and a conductive material supported in a dispersed state by the metal plating layer 46. And a plurality of granular or rod-shaped fine bodies 48. The metal plating layer 46 and the fine body 48 of the gate projection 28 are made of the same material as the metal plating layer 42 and the fine body 44 of the emitter 26, respectively. However, when a positive potential is applied to the gate electrode 24 with respect to the cathode electrode 22 during the plating process for forming the emitter 26 and the gate protrusion 28, the thickness of the metal plating layer 46 of the gate protrusion 28 is reduced. The density of the fine body 48 is smaller than the thickness of the metal plating layer 42 of the emitter 26 and the density of the fine body 44.

  In the horizontal field emission cold cathode device according to the present embodiment, the fine body 44 of the emitter 26 is supported on the cathode electrode 22 via the metal plating layer 42. Therefore, the fine body 44 is firmly fixed to the cathode electrode 22, and an emitter having a high adhesion strength that can withstand a strong electric field is obtained, and the stability of field emission can be improved.

  It is desirable that the metal plating layer 42 of the emitter 26 contains impurities for obtaining a so-called resistance ballast effect. For example, as the metal plating layer 42, a Ni-BP-based resistance plating layer having a higher resistance value than the Ni plating layer or a PTFE-containing Ni plating layer is used. Accordingly, a potential drop occurs due to the resistance plating layer 42, and even if there is a difference in the radius of curvature or shape at the tip of each emitter 26, the electric field strength at the tip of the emitter is substantially reduced by the resistance ballast effect, and the field emission of the Stability and non-uniformity are greatly improved. In this regard, in the case of the conventional device, if there is a difference in the radius of curvature or the shape of the tip of each emitter, the electric field intensity distribution is different, so that the non-uniformity of the field emission characteristics becomes significant.

  6 (a) to 6 (c) are views showing a method of manufacturing a horizontal field emission cold cathode device according to another embodiment of the present invention in the order of steps, and this device is applicable to the device shown in FIG. It is.

  First, a metal cathode electrode 22 and a metal gate electrode 24 were formed on a glass support substrate 16. Here, the cathode electrode 22 and the gate electrode 24 were formed to a thickness of 2 μm using a highly conductive Ni plating film in consideration of signal delay in a large field emission display. The gap between the cathode electrode 22 and the gate electrode 24 was formed by lithography using an exposure device such as a stepper.

  Next, both electrodes 22 and 24 were covered with a plating resist film 52 so as to expose only opposing side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24 (FIG. 6A). The plating resist film 52 may be formed so as to additionally expose portions of the upper surfaces of the electrodes 22 and 24 near the opposing side surfaces 22a and 24a. However, in this case, the length L1 (see FIG. 3) of the additional portion 22b is set to be 25% or less of the length L0 of the entire upper surface of the cathode electrode 22. Alternatively, the plating resist film 52 may be formed so as to expose only the opposing side surface 22a of the cathode electrode 22 forming the emitter 26.

Next, in 1 liter of distilled water, dissolve in a ratio of 25 g of nickel sulfate, 40 g of sodium hypophosphite, 10 g of sodium acetate, 10 g of sodium citrate, and 30 g of boric acid, and adjust to about PH5 for metal plating layers 42 and 46. The resulting electroless Ni-BP-based resistance plating solution was formed. Further, about 50 g of fullerene C ₆₀ or carbon nanotubes classified to a predetermined length as the fine bodies 44 are mixed with the plating solution, and suspended in the plating tank 56 by stirring to form the suspension plating solution 54. Prepared. Next, while the temperature of the suspension plating solution 54 is maintained at about 80 ° C., the support substrate 16 on which the cathode electrode 22, the gate electrode 24, and the plating resist film 52 are disposed in the above-described manner is moved to the suspension plating solution 54. It was immersed in the substrate and subjected to electroless plating (FIG. 6B).

  When this electroless plating treatment was performed for about 3 minutes, Ni-BP-based electroless resistance plating layers (metal plating layers 42 and 46) were formed on the exposed side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24. Was formed with a thickness of about 3 μm. At this time, since the fullerenes or carbon nanotubes that become the fine bodies 44 settle down together with the plating material, the metal plating layers 42 and 46 were formed in a state where the fine bodies 44 were embedded in a dispersed state.

  That is, by the electroless plating process, the emitter 26 including the metal plating layer 42 and the fine body 44 and the metal plating layer 46 and the fine body 48 are formed on the opposing side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24, respectively. The gate projection 28 was formed. On the glass supporting substrate 16 between the cathode electrode 22 and the gate electrode 24, the metal plating layer has little adhesion, so that the metal plating layer is hardly formed, or even if formed, it is easily formed by ultrasonic waves. Was peeled off. Therefore, after washing and drying, a horizontal field emission type cold cathode device having a predetermined structure applicable to the device shown in FIG. 1 was obtained (FIG. 6C).

  Here, since the electroless plating process was performed, the thickness of the metal plating layer 42 of the emitter 26 and the density of the fine body 44 and the thickness of the metal plating layer 46 of the gate projection 28 and the density of the fine body 48 were reduced. Became almost equal.

Next, the field emission characteristics of the field emission cold cathode device manufactured by the method shown in FIG. 6 were measured. As a result, the emitter 26 has a strong adhesive force to the cathode electrode 22 even with a strong electric field which is applied to the tip of the emitter 26 at 10 ⁷ V / cm or more, and does not peel off. It showed stable field emission characteristics. When the emitter was formed only of fullerenes or carbon nanotubes without the metal plating layer 42, the peeling phenomenon of the emitter was observed under such a strong electric field, and only unstable field emission characteristics were obtained.

Further, in the device of the present embodiment, there is also a resistance ballast effect of the Ni-BP-based electroless resistance plating layer 42, the current emission stability is improved by 2 to 30%, and the in-plane uniform field emission is also improved. I could improve it. In addition, the radius of curvature at the tip portion was significantly reduced as compared with the Mo emitter manufactured by the rotary evaporation method. Specifically, it could be reduced from about 70 to 300 nm to about 1 to 30 nm. As a result, the drive voltage was also significantly reduced from about 100 V to about 7 V. Further, when the degree of vacuum is reduced from about 10 ^-9 torr to about 10 ^-7 torr, in the case of the Mo emitter manufactured by the rotary evaporation method, the emission current value becomes about 1/10 or less and the current fluctuation is several hundred%. Although it increased as described above, there was almost no change in the apparatus of the present embodiment.

  FIGS. 7A to 7C are diagrams showing a method of manufacturing a horizontal field emission type cold cathode device according to still another embodiment of the present invention in the order of steps. This device is also the same as the device shown in FIG. Applicable.

  First, similarly to the embodiment shown in FIG. 6, a metal cathode electrode 22 and a metal gate electrode 24 were formed on a glass support substrate 16. Here, the cathode electrode 22 and the gate electrode 24 were formed to a thickness of 1 μm using a highly conductive Ni plating film in consideration of signal delay in a large field emission display. The electrodes 22 and 24 were covered with a plating resist film 52 so as to expose the opposing side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24 (FIG. 7A). The coverage of the electrodes 22 and 24 with the plating resist film 52 can be changed as described above.

  Next, 600 g of nickel sulfamate, 5 g of nickel chloride, 30 g of sodium hypophosphite, 40 g of boric acid, and 1 g of saccharin are dissolved in 1 liter of distilled water at a ratio of about PH4 for the metal plating layers 42 and 46. The resulting resistance plating solution was formed. Further, about 40 g of the carbon nanotubes serving as the fine bodies 44 were mixed with the plating solution, and suspended in the plating tank 66 by stirring to prepare a suspension plating solution 64. Next, while the temperature of the suspension plating solution 64 is maintained at about 50 ° C., the support substrate 16 on which the cathode electrode 22, the gate electrode 24, and the plating resist film 52 are disposed in the above-described manner is moved to the suspension plating solution 64. It was immersed in the substrate and subjected to an electroplating process (FIG. 7B). Here, it was set so that 100 V was applied to the anode 68, 10 V to the gate electrode 24, and 0 V to the cathode electrode 22.

  When this electroplating process was performed for about 4 minutes, Ni-BP-based resistance plating layers (metal plating layers 42, 46) were formed on the exposed side surfaces 22a, 24a of the cathode electrode 22 and the gate electrode 24, respectively. It was formed with a thickness of about 4 μm and 0.5 μm. At this time, since the fullerenes or carbon nanotubes that become the fine bodies 44 settle down together with the plating material, the metal plating layers 42 and 46 were formed in a state where the fine bodies 44 were embedded in a dispersed state.

  That is, by the electroplating process, the emitter 26 composed of the metal plating layer 42 and the fine body 44 and the gate composed of the metal plating layer 46 and the fine body 48 are formed on the opposite side surfaces 22a and 24a of the cathode electrode 22 and the gate electrode 24, respectively. The projection 28 was formed. On the glass supporting substrate 16 between the cathode electrode 22 and the gate electrode 24, the metal plating layer has little adhesion, so that the metal plating layer is hardly formed, or even if formed, it is easily formed by ultrasonic waves. Was peeled off. Therefore, after washing and drying, a horizontal field emission cold cathode device having a predetermined structure applicable to the device shown in FIG. 1 was obtained (FIG. 7C).

  Here, since the electroplating process was performed in a state where a positive potential was applied to the gate electrode 24 with respect to the cathode electrode 22, the thickness of the metal plating layer 46 of the gate protrusion 28 and the density of the fine body 48 were reduced. , The thickness of the metal plating layer 42 of the emitter 26 and the density of the fine body 44 were smaller. The carbon nanotubes were mainly oriented along the electric lines of force of the electric field between the cathode electrode 22 and the gate electrode 24. Specifically, the proportion of the carbon nanotubes oriented within an angle range of ± 20 ° with respect to the spreading direction of the flat main surface of the support substrate 16 (the horizontal direction in FIG. 7C) is 50% to 100%. And could be. Further, this ratio could be changed by adjusting the conditions of the electroplating process (thus, the electron emission characteristics could be improved).

Next, the field emission characteristics of the field emission cold cathode device manufactured by the method shown in FIG. 7 were measured. As a result, the emitter 26 has a strong adhesive force to the cathode electrode 22 even with a strong electric field which is applied to the tip of the emitter 26 at 10 ⁷ V / cm or more, and does not peel off. It showed stable field emission characteristics.

  Further, in the device of the present embodiment, there is also a resistance ballast effect of the highly-oriented carbon nanotubes and the Ni-BP-based resistance plating layer 42, the current emission stability is improved by 4 to 50%, and the in-plane uniformity is improved. The field emission properties were also improved. Further, it is presumed that the orientation of the carbon nanotubes was improved, but the driving voltage was able to be improved by about 3% as compared with the case of non-oriented. Further, as in the embodiment shown in FIG. 6, it is strong against the degree of vacuum, and the emission current value and the current fluctuation hardly change.

  In the embodiment shown in FIGS. 6 and 7, fullerenes or carbon nanotubes are dispersed in a plating solution, and plating is performed so that fullerenes and the like settle and come into contact with the surface of the cathode electrode 22 and the metal plating layer is formed. 42 is generated. Therefore, the metal plating layer 42 is firmly fixed to the cathode electrode 22, and fullerene and the like are firmly fixed to the metal plating layer 42. As a result, the emitter 26 with high adhesion strength that can withstand a strong electric field is obtained, and the stability of field emission is improved. Can be improved. Further, since the plating process is performed at a low temperature of about 100 ° C. or less, the emitter 26 with less damage can be manufactured. In addition, if the cathode electrode 22 and the like are formed on the support substrate 16 in advance, the metal plating layer 42 can be selectively formed on the cathode electrode 22, and the process can be simplified.

  In the embodiments shown in FIGS. 6 and 7, the length of the carbon nanotube or the diameter of the fullerene, the deposited resistance plating layer 42, and the like are determined in advance so that the emitter 26 and the gate projection 28 do not short-circuit due to contact. , 46 were adjusted in advance. However, even if the emitter 26 and the gate projecting portion 28 are short-circuited due to contact, current flows between the cathode electrode 22 and the gate electrode 24 to cut the emitter 26 and the gate projecting portion 28 to form a gap therebetween. can do. According to this method, if the energizing time and the amount of current are appropriately adjusted, it is possible to form a gap between the gate and the emitter that is shorter than in the case of using normal lithography.

  Further, in the embodiment shown in FIGS. 6 and 7, after all the fine bodies 44 and 48 are once thinly covered with the metal plating layers 42 and 46, any one of wet etching, RIE, CDE, sputtering, and sublimation, Alternatively, a part of the surfaces of the fine bodies 44 and 48 may be exposed by using a combination thereof. Further, in the embodiment shown in FIGS. 6 and 7, the Ni-BP-based metal plating layer is used as the metal plating layer 42 of the emitter having the resistance ballast effect. Can be used. In this case, the PTFE-containing Ni plating layer can be formed by suspending PTFE in a Ni plating solution. Further, as the base metal of the metal plating layer, another metal, for example, Cr, Cu, or the like can be used.

  In addition, the horizontal field emission cold cathode device according to the present invention can be used for vacuum micropower devices, environment resistant devices (space devices, nuclear devices, extreme environment devices (radiation resistant devices, It can be used for high-temperature resistant devices, low-temperature devices)), various sensors, and the like.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be variously modified and implemented without departing from the gist thereof.

FIG. 1 is a cross-sectional view showing a flat panel display as an example of a vacuum micro device to which a horizontal field emission cold cathode device according to an embodiment of the present invention is applied. FIG. 2 is a partial plan view of the apparatus shown in FIG. 1. FIG. 2 is a sectional view of a main part of the apparatus shown in FIG. 1. (A) is an enlarged view showing a relationship between a rod-shaped fine body such as a carbon nanotube and a metal plating layer, and (b) is an enlarged view showing a relationship between a granular fine body such as fullerene and a metal plating layer. The enlarged view which shows the relationship between a hollow rod-shaped fine body and a filling layer. (A)-(c) is a figure which shows the manufacturing method of the horizontal field emission type cold-cathode device which concerns on another embodiment of this invention in process order. (A)-(c) is a figure which shows the manufacturing method of the horizontal field emission type cold cathode device which concerns on another embodiment of this invention in order of a process.

Explanation of reference numerals

  Reference numeral 12: cathode line; 14: gate line; 16: support substrate; 18: wiring structure; 22: cathode electrode; 24: gate electrode; 26: emitter; 28: gate protrusion; 32: counter substrate; Spacer 34 Spacer 36 Anode electrode 38 Phosphor layer 42 Metal plating layer 44 Fine body 52 Plating resist film 54 and 64 Suspension plating solution 68 Anode.

Claims (14)

A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , Carbon nanotubes, graphite, a low work function material, a negative electron affinity material, made of a material selected from the group consisting of metal materials, and that the fine body is partially embedded in the metal plating layer, A horizontal field emission cold cathode device characterized by the following.   The horizontal field emission type cold cathode device according to claim 1, wherein the fine body is rod-shaped and has a tip having a radius of curvature of 50 nm or less.   The fine body is rod-shaped, and 50 to 100% of the fine body is oriented within an angle range of ± 20 ° with respect to a main surface of the support substrate on which the cathode electrode is provided. The horizontal field emission type cold cathode device according to claim 1 or 2, wherein:   4. The horizontal field emission type according to claim 1, wherein the fine body is rod-shaped and hollow, and a filling layer made of a conductive material is disposed inside the fine body. 5. Cold cathode device.   The horizontal field emission type cold cathode device according to claim 1, wherein the fine body is granular and has a radius of 100 nm or less.   6. The horizontal field emission cold cathode device according to claim 1, wherein the metal plating layer is formed of a resistance ballast layer containing an additive for increasing resistance. 7. The horizontal field emission cold cathode device according to claim 6, wherein the metal plating layer has a resistivity of 10 ^<-8 > to 10 <^{-4> [} Omega].   The semiconductor device further includes a gate protrusion disposed on the second side surface to face the first side surface, wherein the gate protrusion includes a gate metal plating layer made of the same material as the metal plating layer; 8. The horizontal field emission cold cathode device according to claim 1, further comprising a plurality of gate fine bodies supported in a dispersed state on a metal plating layer and made of the same material as the fine bodies.   A surrounding member forming a vacuum discharge space surrounding the cathode electrode, the gate electrode and the emitter in cooperation with the support substrate, and a surrounding member disposed on the surrounding member at a position facing the cathode electrode and the gate electrode; The horizontal field emission cold cathode device according to any one of claims 1 to 8, further comprising an anode electrode provided.   The surrounding member includes a transparent counter substrate facing the support substrate, and the anode electrode including a transparent electrode and the phosphor layer are stacked on the counter substrate in the vacuum discharge space. The horizontal field emission type cold cathode device according to claim 9, characterized in that: A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , Carbon nanotubes, graphite, a low work function material, a negative electron affinity material, made of a material selected from the group consisting of metal materials, and that the fine body is entirely embedded in the metal plating layer, A horizontal field emission cold cathode device characterized by the following. A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. , A material selected from the group consisting of carbon nanotubes, graphite, a low work function material, a negative electron affinity material, and a metal material, and the fine bodies are rod-shaped, and 50 to 100% of the fine bodies are: A horizontal field emission type cold cathode device characterized in that the cathode electrode is oriented within an angle range of ± 20 ° with respect to a main surface of the support substrate on which the cathode electrode is provided. A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter for emitting electrons disposed on the first side surface so as to face the second side surface;
Wherein the emitter comprises a metal plating layer formed on the cathode electrode, and a plurality of granular or rod-like fine bodies supported in a dispersed state on the metal plating layer, wherein the fine bodies are fullerenes. Made of a material selected from the group consisting of carbon nanotubes, graphite, a low work function material, a negative electron affinity material, and a metal material, and the fine body is rod-shaped and hollow, and a conductive material is formed inside the fine body. A horizontal field emission cold cathode device, characterized in that a filling layer made of the above material is provided. A support substrate;
A cathode electrode disposed on the support substrate and having a first side surface;
A gate electrode disposed on the support substrate so as to be laterally arranged with respect to the cathode electrode and having a second side surface facing the first side surface;
An emitter disposed on the first side surface to face the second side surface for emitting electrons; and the emitter is distributed between a metal plating layer formed on the cathode electrode and the metal plating layer. And a plurality of granular or rod-like fines supported in a state, wherein the fines are selected from the group consisting of fullerenes, carbon nanotubes, graphite, low work function materials, negative electron affinity materials, and metallic materials. Made of materials,
A gate protrusion disposed on the second side surface to face the first side surface, the gate protrusion includes a gate metal plating layer made of the same material as the metal plating layer, and a gate metal plating layer Having a plurality of gate fine bodies supported in a dispersed state and made of the same material as the fine bodies;
A horizontal field emission cold cathode device comprising:

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