JP2005032449A - Electron emitting device and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron emitting device capable of reducing a unique capacity of an electron emitting element, reducing a beam diameter of emitted electrons and being manufactured easily. <P>SOLUTION: The electron emitting device has a gate electrode 14, a cathode electrode 13 made of a laminated body of a first electrode 12 and an electron emitting layer 15, and an anode electrode 16 arranged on a substrate 11. An h<SB>2</SB>is set to fulfill a specific relation formula with a film thickness h<SB>1</SB>of the first electrode 12, a film thickness h of the cathode electrode 13, an interval d between the gate electrode 14 and the first electrode, an interval H between the cathode electrode 13 and the anode electrode 16, an electric field intensity E<SB>a</SB>between the anode electrode 16 and the cathode electrode 13, and an electric field intensity E<SB>g</SB>between the cathode electrode 13 and the gate electrode 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron emission device and an image display device.
[0002]
[Prior art]
Examples of the electron-emitting device include a field-emission electron-emitting device (hereinafter referred to as “FE”) and a metal / insulating layer / metal-type electron-emitting device (hereinafter referred to as “MIM”).
[0003]
FIG. 13 shows a schematic cross-sectional structure of the vertical FE. In the figure, 131 is a substrate, 132 is a cathode electrode, 133 is an insulating layer, 134 is a gate electrode, and 135 is a conical emitter. The element has a structure (so-called “spindt type”) in which an opening is formed in a laminated body of an insulating layer 133 and a gate electrode 134 disposed on the cathode electrode 132, and a conical emitter 135 is disposed in the opening. is there. Further, a structure in which a substantially flat emitter is disposed in the opening without disposing a conical emitter is disclosed in, for example, Patent Document 1 and Patent Document 2.
[0004]
The horizontal FE has a structure in which an emitter having a sharp tip and a gate electrode that draws electrons from the tip of the emitter are arranged in parallel on a substrate (Patent Document 3, Patent Document 4, Patent Document 5, and Patent Document). 6).
[0005]
[Patent Document 1]
JP-A-8-96704
[Patent Document 2]
JP-A-8-115654
[Patent Document 3]
U.S. Pat. No. 4,728,851
[Patent Document 4]
US Pat. No. 4,904,895
[Patent Document 5]
Japanese Patent Laid-Open No. 3-46729
[Patent Document 6]
JP 2002-150925 A
[0006]
[Problems to be solved by the invention]
In order to apply the electron-emitting device to an image display device such as a display, it is desired that the electron-emitting device can be driven with low power consumption. Further, in order to increase the definition of the display, it is necessary that the diameter of the electron beam irradiated to the phosphor is small. And it is important that it is easy to manufacture.
[0007]
The above-mentioned Spindt-type device, which is a vertical FE, is difficult to uniformly manufacture the device, so that the electron emission characteristics between the devices are difficult to be uniform. Furthermore, since the cathode electrode and the gate electrode are stacked via the insulating layer, the power consumption increases due to the element capacity of the electron-emitting device during driving as the number of display pixels increases. End up.
[0008]
On the other hand, in the vertical FE using the flat electron-emitting layer disclosed in the above-mentioned Patent Document 2 or the like, the diameter of the electron beam can be reduced, but the vertical type FE increases the number of display pixels. As a result, the power consumption increases due to the element capacitance of the electron-emitting element during driving.
[0009]
Further, in a general lateral type FE, since electrons emitted from the cathode are likely to collide with the opposing gate electrode, efficiency (reaches the anode electrode with respect to the total emitted electron current emitted from the emitter). In addition to a decrease in the ratio of the emitted electron current, electrons emitted from the emitter may be scattered by the gate electrode, and the diameter of the electron beam may be increased when the anode is irradiated.
[0010]
The present invention provides an electron-emitting device that can reduce the capacitance inherent to the electron-emitting device, reduce the beam diameter of the emitted electrons, and can be easily manufactured, and an image display device that uses the device. There is.
[0011]
[Means for Solving the Problems]
The first of the present invention is (a) a gate electrode disposed on a substrate surface;
(B) a cathode electrode composed of a first electrode disposed on the surface of the substrate apart from the gate electrode, and an electron emission layer disposed on the surface of the first electrode;
(C) A voltage V between the cathode electrode and the gate electrode. _g A first voltage applying device for applying
(D) an anode electrode disposed opposite to the electron emission layer at a distance;
(E) A voltage V between the cathode electrode and the anode electrode _a A second voltage application device for applying the electron emission device, wherein the thickness of the cathode electrode and the thickness of the gate electrode are substantially the same,
The thickness of the first electrode is h ₁ , The thickness of the electron emission layer is h ₂ ,
The thickness of the cathode electrode is h (= h ₁ + H ₂ ),
The distance between the gate electrode and the first electrode is d,
The distance between the cathode electrode and the anode electrode is H,
Electric field intensity E between the anode electrode and the cathode electrode _a V _a / H,
Electric field strength E between the cathode electrode and the gate electrode _g V _g / D satisfies the relationship of the following formula (I).
[0012]
Formula (I)
0 <h ₂ / H ≦ {A × (E _a / E _g ) + B} × {C × log (d / h) + D},
And h ₂ / H ≦ 1
(In the above equation, E _a / E _g (≧ 0.057, A = 2.45, B = −0.1, d / h ≧ 1, C = 0.658, D = 0.35)
[0013]
The electron emission device of the present invention includes the following configuration as a preferred embodiment.
[0014]
In the formula (I),
0.057 ≦ E _a / E _g <0.346, A = 2.45, B = −0.14,
0.346 ≦ E _a / E _g At this time, A = 0.082, B = 0.68,
When 1 ≦ d / h <10, C = 0.658, D = 0.239,
When 10 ≦ d / h <50, C = 0.352, D = 0.543,
C = 0 and D = 1.15 when 50 ≦ d / h.
[0015]
The d / h is 10 ≦ d / h <1000.
[0016]
E _a / E _g But E _a / E _g ≧ 0.1.
[0017]
The difference between the thickness of the gate electrode and the thickness of the cathode electrode is 5% or less of the thickness of the cathode electrode.
[0018]
The position of the edge of the electron-emitting layer facing the gate electrode is equal to or farther from the gate electrode than the position of the edge of the first electrode facing the gate electrode.
[0019]
The gate electrode includes a second electrode disposed on the substrate surface and a layer made of the same material as the electron emission layer disposed on the second electrode.
[0020]
A second aspect of the present invention is an image display device comprising a plurality of the electron-emitting devices of the present invention.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the present embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.
[0022]
In the present invention, a structure in which a gate electrode and a cathode electrode are provided on a substrate is referred to as an electron-emitting device, and a structure in which an anode electrode, a first voltage application device, and a second voltage application device are incorporated in the device. It is called an electron emission device.
[0023]
The electron emission device of the present invention is characterized by using a lateral FE [electron emission device having a cathode electrode (including an electron emission layer) and a gate electrode spaced apart from the substrate surface] and a gate electrode. The thickness of the electrode is substantially the same, and the thickness of the electron emission layer in the cathode electrode satisfies the following formula (I).
[0024]
Formula (I)
0 <h ₂ / H ≦ {A × (E _a / E _g ) + B} × {C × log (d / h) + D},
And h ₂ / H ≦ 1
[0025]
In the above formula,
h: thickness of cathode electrode
h ₂ : Thickness of electron emission layer
d: the distance between the gate electrode and the cathode electrode (in other words, d is the distance between the gate electrode and the electron emission layer),
H: Distance between cathode electrode and anode electrode (more specifically, distance between electron emission layer and anode electrode)
E _a : Anode voltage is V _a The electric field strength between the anode electrode and the cathode electrode when V = V _a / H
E _g : Gate voltage is V _g The electric field strength between the gate electrode and the cathode electrode when V = V _g / D
In the above formula (I), E _a / E _g ≧ 0.057, A = 2.45, B = −0.1, d / h ≧ 1, C = 0.658, and D = 0.35.
[0026]
In general, in the lateral FE, the gate voltage V is applied to the gate electrode. _g Is applied, a radial equipotential surface is formed so as to wrap around the tip of the cathode electrode (if there is a layer made of an electron emitting member on the cathode electrode), the cathode electrode ( An electric field is applied to the electron emission member. Electrons are emitted from the cathode electrode (electron emission member) by this electric field, but since the equipotential surface is wound around the cathode electrode tip (electron emission member tip), the substrate within the cathode electrode (electron emission member) Electrons emitted from the side are also applied in the direction of the substrate, and there are many electrons that collide with the substrate or collide with the gate electrode. Especially anode voltage V _a Than the electric field formed by _g This tendency is remarkable when the electric field formed by is large, and it is easy to collide with the opposing gate electrode. As a result, the electron emission efficiency (ratio of the electrons reaching the anode with respect to the electrons emitted from the cathode) is decreased, and further, the electrons incident on the gate electrode are scattered, so that the electron beam when irradiated onto the anode is reduced. The diameter may increase.
[0027]
The emission position of the electrons colliding with the gate electrode at the cathode electrode (electron emission layer) is the film thickness h of the cathode electrode (including the electron emission layer), and between the gate electrode and the cathode electrode. Interval d, gate voltage V _g The electric field strength E between the gate electrode and the cathode electrode _g (Ie V _g / D), the anode voltage is V _a , Electric field strength E between the anode electrode and the cathode electrode when the distance H between the cathode electrode and the anode electrode is H _a (Ie V _a / H) strongly. Therefore, if the electron emission part on the cathode electrode is within a range where the electrons emitted from the electron emission part do not collide with the gate electrode, the electron emission efficiency is dramatically improved, and further, the electrons when the anode is irradiated It is possible to make the beam small.
[0028]
The range of the emission part where the emitted electrons do not collide with the gate electrode is represented by the hatched range in FIGS. 2 (a) and 2 (b). Therefore, the thickness h of the electron emission layer ₂ Is controlled so as to fall within the range indicated by hatching in the drawing, it is possible to manufacture a lateral electron emission device having an efficiency of almost 100%. The curve in the figure represents the boundary line of whether or not the emitted electrons collide with the gate electrode. According to the following formula (I) that approximately represents this curve, an electron emission device with an efficiency of approximately 100% can be obtained. Become h ₂ Can be defined.
[0029]
Formula (I)
0 <h ₂ / H ≦ {A × (E _a / E _g ) + B} × {C × log (d / h) + D},
And h ₂ / H ≦ 1
Here, in the above formula (I), A, B, C, and D are constants.
[0030]
In the above formula (I),
0.057 ≦ E _a / E _g When <0.346, A = 2.45 and B = −0.14 are satisfied,
0.346 ≦ E _a / E _g When A = 0.082 and B = 0.68,
When 1 ≦ d / h <10, C = 0.658 and D = 0.239 are satisfied,
When 10 ≦ d / h <50, C = 0.352 and D = 0.543 are satisfied,
When 50 ≦ d / h, C = 0 and D = 1.15 are satisfied.
[0031]
In the above formula, E _a = V _a / H, E _g = V _g / D.
[0032]
However, even if the electrons emitted from the electron emitting portion collide with the gate electrode and are scattered, the amount of electrons is sufficiently small compared to the total number of electrons emitted from the electron emitting portion, that is, the efficiency is very high. If it is too high, it does not affect the size of the electron beam when the anode is irradiated.
[0033]
Therefore, in actuality, in the above formula (I), h in the range defined by A = 2.45, B = −0.1, C = 0.658, D = 0.35 ₂ It does not matter.
[0034]
In the present invention, preferably, d / h is 10 ≦ d / h <1000, and E _a / E _g Is E _a / E _g ≧ 0.1.
[0035]
As described above, in the configuration of the electron emission device of the present invention described above, the electrons emitted from the cathode electrode can be reduced from entering the gate electrode, the electron emission efficiency can be dramatically improved, and the anode can be irradiated. It is possible to reduce the electron beam when it is applied.
[0036]
FIG. 1 shows a schematic perspective view of an embodiment of an electron emission device of the present invention. In the figure, 11 is a substrate, 12 is a first electrode, 13 is a cathode electrode, 14 is a gate electrode, 15 is an electron emission layer, 16 is an anode electrode, d is a distance between the cathode electrode 13 and the gate electrode 14, h Is the thickness of the cathode electrode 13, h ₂ Is the thickness of the electron emission layer 15, H is the distance between the cathode electrode 13 and the anode electrode 16, V _g Is the gate voltage, V _a Is the anode voltage. Here, the cathode electrode 13 is composed of a laminate of the first electrode 12 and the electron emission layer 15. Further, like the cathode electrode 13, the gate electrode 14 may be formed of a stacked body of a second electrode and a layer made of the same material as the electron emission layer 15.
[0037]
The distance d between the gate electrode 14 and the cathode electrode 13 depends on the work function of the material constituting the element and the material constituting the electron emission layer 15, the voltage at the time of driving, the required shape of the emitted electron beam, and the like. Set as appropriate. Usually, d is set in the range of several tens of nm to several tens of μm, and preferably selected in the range of about 100 nm to 10 μm.
[0038]
Thickness h of electron emission layer 15 ₂ Is appropriately set from the range represented by the formula (I). By selecting from this range, it is possible to prevent the electrons emitted from the electron emission layer during driving from colliding with the gate electrode, improve the efficiency, and further reduce the electron beam when irradiated to the anode. It is possible. Usually h ₂ Is set in a range of several μm or less, and is preferably selected in a range of 150 nm or less. The total thickness h of the cathode electrode is preferably 1 nm or more and 150 nm or less.
[0039]
The electron-emitting device of the present invention shown in FIG. 1 has an interval between a first electrode 12 and a second electrode (gate electrode 14) facing each other on an insulating substrate (or a laminate in which an insulating layer is laminated on a silicon substrate or the like). The electron emission layer 15 is stacked on at least the first electrode 12, and the cathode 13 is constituted by the first electrode 12 and the electron emission layer 15. At this time, the thickness of the cathode electrode 13 and the thickness of the gate electrode 14 are substantially the same. Preferably, the difference between the thickness of the cathode electrode 13 and the thickness of the gate electrode 14 is 5% or less of the thickness of the cathode electrode 13. is there. In this electron emission device, a voltage higher than that of the cathode electrode 13 is applied to the gate electrode 14 to emit electrons from the electron emission layer 15, and a voltage higher than that of the cathode electrode 13 and the gate electrode 14 is applied to the anode electrode 16. Thus, the electrons emitted from the electron emission layer 15 are collected.
[0040]
An example of the method for manufacturing the electron-emitting device of the present invention described above will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing an example of a manufacturing method of an embodiment of an electron-emitting device constituting the electron-emitting device of the present invention.
[0041]
First, as shown in FIG. 3A, a conductive material layer 31 to be the first electrode 12 and the second electrode 35 and a material layer 32 constituting the electron emission layer 15 are stacked on the substrate 11.
[0042]
Specifically, the surface is thoroughly cleaned in advance, quartz glass, glass with reduced impurity content such as Na, blue plate glass, SiO 2 ₂ A conductive material layer 31 and an electron emission layer are formed on the substrate 11 using any one of a laminated body obtained by laminating a silicon substrate or the like by a sputtering method or the like, or an insulating substrate made of ceramics such as alumina as the substrate 11. The material layer 32 to be laminated is laminated.
[0043]
The conductive material layer 31 is formed by a general vacuum film forming technique such as vapor deposition or sputtering. The material of the conductive material layer 31 is, for example, a metal or alloy material such as Be, Mg, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, Cu, Ni, Cr, Au, Pt, or Pd. Etc. are appropriately selected. The thickness of the conductive material layer 31 to be the first electrode 12 and the second electrode 35 is set in the range of several tens of nanometers to several millimeters including the electrode line portion, and is preferably selected in the range of 10 nm to 50 μm. The
[0044]
The material layer 32 constituting the electron emission layer can be formed by a general vacuum film forming technique such as a CVD method, a vapor deposition method, or a sputtering method. Examples of the material constituting the electron emission layer 15 include graphite, fullerene, fiber-like conductive materials (including carbon fibers such as carbon nanotubes), amorphous carbon, diamond-like carbon, carbon in which diamond is dispersed, and carbon compounds. Is appropriately selected. A carbon compound having a low work function is preferable. The film thickness of the material layer 32 constituting the electron emission layer is set within a range of several μm or less, and is preferably selected within a range of 150 nm or less.
[0045]
In particular, when using carbon fibers such as carbon nanotubes, the cathode should be parallel to the surface of the cathode electrode (surface facing the anode electrode) (so that the fiber lies on the cathode electrode surface). It is preferable to arrange on the surface of the electrode (surface facing the anode electrode). Furthermore, it is more preferable to place a plurality of the carbon fibers on the surface of the cathode electrode. In addition, when using carbon fiber in this way, it is preferable to arrange | position so that the front-end | tip of a fiber may face the gate electrode side. In the case of using a plurality of carbon fibers, it is preferable to arrange the carbon fibers at intervals so that the tips of the fibers face the gate electrode side.
[0046]
Next, as shown in FIG. 3B, a mask pattern 33 is formed on the material layer 32 constituting the electron emission layer by photolithography. The mask pattern 33 is formed except for a portion to be etched to form a gap between the cathode electrode 13 and the gate electrode 14.
[0047]
As shown in FIG. 3C, an interval 34 is formed to separate the stacked body of the material layer 32 and the conductive material layer 31 constituting the electron emission layer into the left and right. Thereby, the first electrode 12 and the second electrode 35 are formed. In the production method described here, the cathode electrode 13 is composed of the first electrode 12 and the electron emission layer 15, and the gate electrode 14 is composed of the second electrode 35 and the electron emission layer 15. The gate electrode 14 in the present invention can be composed of only the second electrode 35. Therefore, the electron emission layer 15 on the second electrode 35 left in the above manufacturing method is not necessarily required.
[0048]
The interval 34 can be formed by etching, and this etching process may be performed so as to dig the substrate 11. This etching method may be selected according to the material of the conductive material layer 31 to be etched and the material layer 32 constituting the electron emission layer.
[0049]
Finally, as shown in FIG. 3D, the mask pattern 33 is removed, and the electron-emitting device according to the present invention can be formed.
[0050]
An electron source or an image display device can be configured by arranging a plurality of the electron emission devices of the present invention on a substrate. In this case, the anode electrode is arranged as one continuous electrode for a plurality of electron-emitting devices.
[0051]
An electron source obtained by arranging a plurality of electron-emitting devices of the present invention will be described with reference to FIG. In the figure, 41 is an electron source substrate, 42 is an X direction wiring, 43 is a Y direction wiring, and 44 is an electron-emitting device according to the present invention.
[0052]
X direction wiring 42 is D _x1 , D _x2 ... D _xm And can be formed of a conductive metal or the like formed by vacuum deposition, printing, sputtering, or the like. The wiring material, film thickness, and width are appropriately designed. The Y-direction wiring 43 is D _y1 , D _y2 ... D _yn And can be formed in the same manner as the X-direction wiring 42.
[0053]
The X direction wiring 42 and the Y direction wiring 43 intersect. For this reason, an interlayer insulating layer (not shown) is provided between the m X-direction wirings 42 and the n Y-direction wirings 43 to electrically isolate them. Here, m and n are both positive integers. The interlayer insulating layer (not shown) is formed of SiO formed by vacuum deposition, printing, sputtering, or the like. ₂ Etc.
[0054]
The cathode electrode 13 constituting the electron-emitting device 44 is electrically connected to one of the m X-direction wirings 42, and the gate electrode 14 is electrically connected to one of the n Y-direction wirings 43. Has been.
[0055]
A scanning signal applying unit (not shown) for applying a scanning signal for selecting a row of the electron-emitting devices 44 arranged in the X direction can be connected to the X-direction wiring 42. On the other hand, the Y-direction wiring 43 can be connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 44 arranged in the Y direction according to an input signal. The drive voltage applied to each electron-emitting device 44 is supplied as a difference voltage between the scanning signal and the modulation signal applied to the electron-emitting device 44.
[0056]
In the above configuration, the individual electron-emitting devices 44 can be selected and driven independently using a simple matrix wiring.
[0057]
An image display apparatus configured using such a matrix-arranged electron source will be described with reference to FIG. FIG. 5 is a schematic perspective view showing an example of the image display device of the present invention. 41 is an electron source substrate on which a plurality of electron-emitting devices are arranged, 51 is a rear plate on which the electron source substrate 41 is fixed, 56 is a fluorescent film 54 as a phosphor as an image forming member on the inner surface of the glass substrate 53, a metal back 55, etc. Is a face plate formed. Reference numeral 52 denotes a support frame, and a rear plate 51 and a face plate 56 are connected to the support frame 52 using frit glass or the like. Reference numeral 57 denotes an envelope. The support frame 52 is not necessarily required when the distance between the face plate 56 and the rear plate 51 is smaller than 1 mm. In that case, the face plate 56 and the rear plate 51 are directly connected with a bonding material such as a frit. May be. Since the rear plate 51 is provided mainly for the purpose of reinforcing the strength of the base body 41, if the base body 41 itself has sufficient strength, the separate rear plate 51 can be omitted. That is, the support frame 52 may be sealed directly to the base body 41, and the envelope 57 may be configured by the face plate 56, the support frame 52, and the base body 41.
[0058]
On the other hand, by installing a support body (not shown) called a spacer between the face plate 56 and the rear plate 51, the envelope 57 having sufficient strength against atmospheric pressure can be configured. FIG. 6 is a schematic plan view showing the fluorescent film 54. In the case of a color fluorescent film, the fluorescent film 54 is composed of the black conductive material 61 called the black stripe shown in FIG. 6A or the black matrix shown in FIG. .
[0059]
The image display device as described above can be used as an image display device as an optical printer configured using a photosensitive drum or the like in addition to a display device for a television broadcast, a video conference system, a computer, or the like. Can do.
[0060]
【Example】
Hereinafter, examples of the present embodiment will be described in detail.
[0061]
[Example 1]
(Process 1)
As shown in FIG. 3 (a), quartz is used for the substrate 11, and after sufficient cleaning, a 40 nm thick W as a conductive material layer 31 is formed on the substrate 11 by a sputtering method. Amorphous carbon having a thickness of 60 nm was sequentially deposited as the material layer 32 constituting the emission layer. The reaction gas in the CVD method is CH ₄ And H ₂ And N ₂ The mixed gas was used.
[0062]
(Process 2)
Next, as shown in FIG. 3B, the positive photoresist spin coating and photomask pattern were exposed and developed by photolithography to form a mask pattern 33. The mask pattern 33 is formed except for a portion that is dry-etched to form the first electrode 12 and the second electrode 35 in the next step.
[0063]
(Process 3)
As shown in FIG. 3C, using the mask pattern 33 as a mask, ₄ Was used to dry-etch the material layer 32 and the conductive material layer 31 constituting the electron emission layer, and the interval 34 separating the material layer 32 and the conductive material layer 31 constituting the electron emission layer left and right was formed. In this embodiment, the distance d between the first electrode 12 and the second electrode 14 is 2 μm. Here, the cathode electrode 13 is composed of the first electrode 12 and the electron emission layer 15, and the gate electrode 14 is composed of the second electrode 35 and the electron emission layer 15.
[0064]
(Process 4)
Finally, as shown in FIG. 3 (d), the mask pattern 33 is completely removed and connected in combination with the anode electrode 16 as shown in FIG. 1, thereby constituting the electron emission device of the present invention and emitting electrons. I let you. In this device, V _g Electrons emitted from the electron emission layer 15 by the electric field formed by _a Is attracted to the anode electrode 16 by the electric field formed by. In this embodiment, V _g = 40V, V _a = 5 kV, H = 1 mm.
[0065]
A device capable of measuring a current is disposed between the gate electrode 14 and the cathode electrode 13 and between the anode electrode 16 and the cathode electrode 13, and a current that flows through the gate electrode 14 during electron emission (hereinafter referred to as “gate current”). ) And the current flowing through the anode electrode 16 were measured, and the efficiency was calculated. As a result, the efficiency of the electron-emitting device of this example was 94.4%.
[0066]
The diameter of the electron beam when electrons emitted from the electron emission layer 15 reach the anode electrode 16 is as follows: W having a thickness of 60 nm as the conductive material layer 31 and thickness as the material layer 32 constituting the electron emission layer. This was the same as that of the electron-emitting device manufactured by depositing 40 nm of amorphous carbon in the same manner as the electron-emitting device of this example.
[0067]
The diameter of the electron beam referred to here is a size up to a region of 10% of the peak luminance of the emitted phosphor.
[0068]
The electron-emitting device of this example has a film thickness h of the first electrode 12. ₁ Is 40 nm, and the film thickness h of the electron emission layer 15 is ₂ Is 60 nm, the film thickness h of the cathode electrode 13 is 100 nm. Therefore, h ₂ / H is 0.6, and A, B, C, D described in claim 1 in Formula (I), and V in this embodiment _a , V _g , H, d, h substituted ₂ /H≦0.618 is satisfied.
[0069]
In addition, the electron emission device used for comparison with the electron emission device of this example is the film thickness h of the first electrode 12. ₁ Is 60 nm, and the film thickness h of the electron emission layer 15 is ₂ Is 40 nm, the thickness of the cathode electrode 13 is 100 nm. Therefore h ₂ / H is 0.4, and A, B, C, D described in claim 2 in the formula (I), and V in this embodiment _a , V _g , H, d, h substituted ₂ /H≦0.473 is satisfied.
[0070]
Further, in this embodiment, both the first electrode 12 and the second electrode 35 and the electron emission layer 15 are simply laminated, and the cathode electrode 13 and the gate electrode 14 are formed by dry etching. is there.
[0071]
[Example 2]
FIG. 7 shows a schematic cross-sectional view of the electron-emitting device of this example. In this embodiment, an example in which the position of the edge (end part) facing the cathode electrode 14 of the electron emission layer 15 is provided at a position farther from the cathode electrode 14 than the edge (end part) of the first electrode 12 is provided. Indicates. 8 and 9 show the manufacturing process.
[0072]
(Process 1)
As shown in FIG. 8A, after quartz was sufficiently washed for the substrate 11, Ti having a thickness of 100 nm was laminated as the conductive material layer 31 on the substrate 11 by sputtering.
[0073]
(Process 2)
Next, as shown in FIG. 8B, a positive photoresist was spin-coated by photolithography, the mask pattern was exposed and developed, and a mask pattern 81 was formed. The mask pattern 81 is formed except for a portion that is dry-etched to form the first electrode 12 and the second electrode 35 in the next step.
[0074]
(Process 3)
As shown in FIG. 8C, using the mask pattern 81 as a mask, CF ₄ Using a gas, the conductive material layer 31 is dry-etched, and the conductive material layer 31 is divided into left and right (an interval 34 separating the conductive material layer 31 is formed), and the first electrode 12 and the second electrode 35 are separated. Formed. In this embodiment, the distance d between the first electrode 12 and the second electrode 35 is 3 μm.
[0075]
(Process 4)
As shown in FIG. 8D, the mask pattern 81 was completely removed.
[0076]
(Process 5)
Next, as shown in FIG. 9E, a positive photoresist was spin-coated by photolithography, the photomask pattern was exposed and developed, and a mask pattern 82 was formed. The mask pattern 82 is formed except for a portion where the electron emission layer 15 is finally formed.
[0077]
(Step 6)
Subsequently, as shown in FIG. 9F, diamond-like carbon having a thickness of 20 nm was deposited as a material layer 32 constituting the electron emission layer by a CVD method. The reaction gas is CH ₄ And H ₂ And N ₂ The mixed gas was used.
[0078]
(Step 7)
Finally, as shown in FIG. 9G, the mask pattern 82 is completely removed, and the anode electrode 16 is arranged and connected in the same manner as in the configuration of FIG. 1, and the first electrode 12 side is used as the cathode electrode 13. And emitted electrons. In this embodiment, V _g = 60V, V _a = 5 kV, H = 1 mm.
[0079]
In the electron emission device of this example, no gate current was observed.
[0080]
It is considered that the larger the gate current is, the more electrons emitted from the electron emission layer 15 collide with the gate electrode 14. Therefore, the electrons are scattered by the gate electrode 14 and reach the anode electrode 16. The diameter is also expected to widen. If the gate current flows, power consumption may increase, so it is desirable that the gate current is small.
[0081]
The electron-emitting device of this example has a film thickness h of the first electrode 12. ₁ Is 100 nm and the film thickness h of the electron emission layer 15 is ₂ Is 20 nm, the thickness h of the cathode electrode is 120 nm. Therefore, h ₂ / H is 0.167, and A, B, C, D described in claim 2 in Formula (I), and V in this embodiment _a , V _g , H, d, h substituted ₂ /H≦0.489 is satisfied.
[0082]
[Example 3]
FIG. 10 shows an example of a schematic cross-sectional view of the electron-emitting device of this example. In this embodiment, the material layer (electron emission layer) constituting the electron emission layer 15 is laminated only on the first electrode 12, and the electron emission layer 15 is laminated on the second electrode (gate electrode 14). No examples. 11 and 12 show the manufacturing process.
[0083]
(Process 1)
As shown in FIG. 11 (a), quartz is used for the substrate 11, and after sufficient cleaning, an electron is formed on the substrate 11 as a conductive material layer 31 with a thickness of 80 nm by a sputtering method and an electron by a CVD method. Diamond-like carbon having a thickness of 20 nm was deposited as the material layer 32 constituting the emission layer. The reaction gas is CH ₄ And H ₂ And N ₂ The mixed gas was used.
[0084]
(Process 2)
Next, as shown in FIG. 11B, a positive photoresist was spin-coated, the photomask pattern was exposed and developed, and a mask pattern 111 was formed. The mask pattern 111 is formed except for a portion that is dry-etched in order to form the cathode electrode 13 including the first electrode 12 and the electron emission layer 15 in the next step.
[0085]
(Process 3)
As shown in FIG. 11C, using the mask pattern 111 as a mask, ₄ Was used to dry-etch the material layer 32 and the conductive material layer 31 constituting the electron emission layer to form the cathode electrode 13.
[0086]
(Process 4)
As shown in FIG. 11D, the mask pattern 111 was removed, followed by spin coating with a positive photoresist, and exposure and development of the photomask pattern to form a mask pattern 112. The mask pattern 112 is formed except for a portion where the gate electrode 14 is formed in the next process.
[0087]
(Process 5)
As shown in FIG. 12E, W having a thickness of 100 nm was deposited as the conductive material layer 113.
[0088]
(Step 6)
Finally, as shown in FIG. 12F, the mask pattern 112 was completely removed, and the anode electrode 16 was disposed in the same manner as in the configuration of FIG. In this embodiment, d = 10 μm, V _g = 200V, V _a = 5 kV, H = 1 mm.
[0089]
No gate current was observed in the electron emission device of this example. The gate current here is the same as that described in the first embodiment. The electron-emitting device of this example has a film thickness h of the first electrode 12. ₁ Is 80 nm, and the film thickness h of the electron emission layer 15 is ₂ Is 20 nm, the film thickness h of the cathode electrode 13 is 100 nm. Therefore, h ₂ / H is 0.2, and A, B, C, D described in claim 2 in the relational expression represented by the formula (I), and V in the present embodiment _a , V _g , H, d, h substituted ₂ /H≦0.543 is satisfied.
[0090]
Since the electron-emitting device of this embodiment does not have the electron-emitting layer 15 stacked on the gate electrode 14, when a plurality of elements are arranged and driven in matrix, the gate voltage V for some reason. _g And even if the potential of the gate electrode 14 instantaneously becomes lower than the potential of the cathode electrode 13, no electrons are emitted.
[0091]
[Example 4]
In this embodiment, a case where the electron emission layer 15 constituting the cathode electrode 13 is very thin is shown.
[0092]
(Process 1)
Quartz was used as the substrate 11, and after sufficient cleaning, W having a thickness of 30 nm was deposited as the conductive material layer 31 on the substrate 11 by sputtering. Thereafter, the surface of the conductive material layer 31 is subjected to hydrogen termination treatment by lamp heating in a mixed gas atmosphere of methane and hydrogen in a vacuum chamber at 630 ° C. for 1 hour. The surface of the conductive material layer 31 terminated with hydrogen becomes a later electron emission layer 15.
[0093]
(Process 2)
Next, the conductive material layer 31 is etched by a general laser processing method, a space is formed between the conductive material layers 31, and the cathode electrode 13 and the gate electrode 14 are formed, as shown in FIG. An anode electrode 16 was disposed on the substrate to emit electrons. In this embodiment, d = 5 μm, V _g = 25V, V _a = 5 kV, H = 1 mm.
[0094]
No gate current was observed in the electron emission device of this example. The gate current here is the same as that described in the first embodiment. The electron-emitting device of this example has a film thickness h of the first electrode 12. ₁ Is 30 nm and the thickness h of the electron emission layer 15 is ₂ Is almost zero, so h ₂ / H is a value close to 0 as much as possible. Therefore, A, B, C, D described in claim 2 and V in the case of the present embodiment are added to the relational expression represented by the formula (I). _a , V _g , H, d, h substituted ₂ /H≦0.876 is satisfied.
[0095]
In the electron emission device of this embodiment, a hydrogen termination layer is formed on the surface of the cathode electrode 13 on the side facing the anode electrode 16. The portion is in a state in which electrons are emitted in a lower electric field than the surface of the first electrode 12 facing the gate electrode 14 and where the hydrogen termination layer is not formed. Therefore, the diameter of the electron beam when the anode electrode is irradiated becomes small.
[0096]
[Example 5]
In this example, an image display device was produced using the electron emission device produced in Example 3.
[0097]
Using a manufacturing method similar to that of Example 3, 100 electron-emitting devices whose cross-sectional views are shown in FIG. As shown in FIG. 4, the X direction wiring 42 is connected to the cathode electrode 13, and the Y direction wiring 43 is connected to the gate electrode 14. Each electron-emitting device 44 was arranged at a pitch of 150 μm in width and 300 μm in length. Further, as shown in FIG. 5, a glass substrate 53 having a fluorescent film 54 and a metal back 55 made of aluminum is disposed on the upper portion of the element at a distance of 1 mm. A voltage of 5 kV was applied to the metal back 55. As a result, matrix driving is possible, and the display consumes less power and a high-definition image display device can be formed.
[0098]
【The invention's effect】
As described above, the electron-emitting device of the present invention dramatically improves the efficiency of the lateral FE to almost 100% by forming the electron-emitting layer on the cathode electrode so as to satisfy the formula (I). be able to. Furthermore, since the electrons emitted from the electron emission layer and scattered by the gate electrode can be suppressed, the diameter of the electron beam when the anode electrode is irradiated can be reduced. In addition, the electron emission device of the present invention is easy to manufacture because it has a simple laminated structure.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of an embodiment of the present invention.
FIG. 2 shows h according to the present invention. ₂ / H and E _a / E _g And a schematic graph showing the relationship of d / h.
FIG. 3 is a process diagram showing an example of a method for manufacturing an electron-emitting device according to the present invention.
FIG. 4 is a schematic plan view showing an example of an electron source configured using the electron emission device of the present invention.
FIG. 5 is a schematic perspective view showing an example of an image display device of the present invention.
FIG. 6 is a schematic plan view showing a phosphor film used in the image display device of the present invention.
7 is a schematic sectional view of an electron-emitting device according to Example 2. FIG.
8 is a manufacturing process diagram of the electron-emitting device of Example 2. FIG.
9 is a manufacturing process diagram of the electron-emitting device of Example 2. FIG.
10 is a schematic sectional view of an electron-emitting device according to Example 3. FIG.
11 is a manufacturing process diagram of the electron-emitting device of Example 3. FIG.
12 is a manufacturing process diagram of the electron-emitting device of Example 3. FIG.
FIG. 13 is a schematic cross-sectional view of a conventional vertical FE.
[Explanation of symbols]
11 Substrate
12 First electrode
13 Cathode electrode
14 Gate electrode
15 Electron emission layer
16 Anode electrode
31 Conductive material layer
32 Material layer constituting the electron emission layer
33 Mask pattern
34 intervals
35 Second electrode
41 Electron source substrate
42 X direction wiring
43 Y-direction wiring
44 Electron emitter
51 Rear plate
52 Support frame
53 Glass substrate
54 Fluorescent membrane
55 metal back
56 Face plate
57 Envelope
61 Black conductive material
62 Phosphor
81, 82, 111, 112 Mask pattern
113 Conductive material layer
131 Substrate
132 Cathode electrode
133 Insulating layer
134 Gate electrode
135 emitter

Claims (8)

(A) a gate electrode disposed on the substrate surface;
(B) a cathode electrode composed of a first electrode disposed on the surface of the substrate apart from the gate electrode, and an electron emission layer disposed on the surface of the first electrode;
(C) a first voltage applying device for applying a voltage V _g between the cathode electrode and the gate electrode;
(D) an anode electrode disposed opposite to the electron emission layer at a distance;
(E) _a second voltage application device for applying a voltage Va between the cathode electrode and the anode electrode, wherein the thickness of the cathode electrode and the thickness of the gate electrode are substantially equal to each other. Electron emission devices that are identical in nature,
The thickness of the first electrode is h ₁ , the thickness of the electron emission layer is h ₂ ,
The thickness of the cathode electrode is h (= h ₁ + h ₂ ),
The distance between the gate electrode and the first electrode is d,
The distance between the cathode electrode and the anode electrode is H,
The electric field strength E _a between the anode electrode and the cathode electrode is set to V _a / H,
An electron emission device characterized by satisfying the relationship of the following formula (I) when the electric field strength E _g between the cathode electrode and the gate electrode is V _g / d.
Formula (I)
0 <h ₂ / h ≦ {A × (E _a / E _g ) + B} × {C × log (d / h) + D},
And h ₂ / h ≦ 1
(In the above formula, E _a / E _g ≧ 0.057, A = 2.45, B = −0.1, d / h ≧ 1, C = 0.658, D = 0.35) In the formula (I),
When 0.057 ≦ E _a / E _g <0.346, A = 2.45, B = −0.14,
When 0.346 ≦ E _a / E _g , A = 0.082, B = 0.68,
When 1 ≦ d / h <10, C = 0.658, D = 0.239,
When 10 ≦ d / h <50, C = 0.352, D = 0.543,
2. The electron emission device according to claim 1, wherein C = 0 and D = 1.15 when 50 ≦ d / h. The electron-emitting device according to claim 1, wherein the d / h satisfies 10 ≦ d / h <1000. Wherein _E a / _{E g is} the electron-emitting device according to any one of claims 1 to 3 is _E a / E _g ≧ 0.1. The electron emission device according to any one of claims 1 to 4, wherein a difference between the thickness of the gate electrode and the thickness of the cathode electrode is 5% or less of the thickness of the cathode electrode. The position of an edge of the electron emission layer facing the gate electrode is equal to or farther from the gate electrode than the position of the edge of the first electrode facing the gate electrode. 6. The electron emission device according to any one of 5 above. The gate electrode includes a second electrode disposed on the substrate surface and a layer made of the same material as the electron emission layer disposed on the second electrode. The electron emission device according to claim 1. An image display device comprising a plurality of the electron-emitting devices according to claim 1.

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