JP3147267B2 - Electron emitting device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device and a method for manufacturing an electron-emitting device capable of efficiently emitting electrons by a simple manufacturing method.

[0002]

2. Description of the Related Art Conventionally, two types of electron-emitting devices, a thermionic electron source and a cold cathode electron source, are known. Field emission type (FE), metal / insulating layer / metal type (hereinafter abbreviated as MIM), and surface conduction type electron emitting device (SC) are used as cold cathode electron sources.
E).

[0003] An example of a field emission type (FE) is disclosed in W.S.
P. Dyke & W. W. Dolan, "Field e
mission ", Advance in Elect
ronPhysics, 8, 89 (1956) and C.I. A. Spindt, “Physical prop
artists of thin film-field
emission cathodes with mo
lybdenum cones ", J. Appl. Ph.
ys. , 47, 5248 (1976).

As an example of the MIM type, C.I. A. Mea
d, "The tunnel-emission am
plier, J. et al. Appl. Phys. , 32, 6
46 (1961) and the like are known.

As an example of the SCE type, M. I. Elin
son, Radio Eng. Electron P
ys. , 10 (1965). The SCE utilizes a phenomenon in which electron emission occurs when a current flows in a small-area thin film formed on a substrate in parallel with the film surface.

As the surface conduction electron-emitting device (SCE), a device using an SnO ₂ thin film by Elinson et al., A device using an Au thin film [G. Dittmer: "T
Hin Solid Films ", 9, 317 (19
72)], a thin film of In ₂ O ₃ / SnO ₂ [M.
Hartwell and C.M. G. FIG. Fonstad:
"IEEE Trans. ED Conf.", 519
(1975)], using a carbon thin film [Hisashi Araki]
Others: Vacuum, Vol. 26, No. 1, p. 22 (1983)] and the like.

As a typical device configuration of these surface conduction electron-emitting devices, the above-mentioned M.D. FIG. 6 shows the device configuration of the Hartwell. FIG. 6A is a plan view of the element, and FIG. 6B is a sectional view taken along the line AA. In FIG. 1, reference numeral 1 denotes an insulating substrate. The electron-emitting portion forming thin film 4 is formed of an H-shaped metal oxide thin film or the like formed by sputtering, and the electron-emitting portion 5 is formed by an energization process called forming described below. Reference numeral 4 denotes a thin film including an electron emitting portion.

Conventionally, in these surface-conduction electron-emitting devices, the electron-emitting portion forming thin film 4 is generally formed with an electron-emitting portion 5 by an energization process called forming before electron emission. . That is, the forming means that an electron is applied by applying a voltage to both ends of the thin film 4 for forming an electron emitting portion, causing the thin film for forming an electron emitting portion to be locally destroyed, deformed or deteriorated, and brought into an electrically high-resistance state. That is, the emission part 5 is formed. In the electron emitting portion 5, a crack may be generated in a part of the thin film 4 for forming the electron emitting portion, and the electron emission may be performed from the vicinity of the crack. Hereinafter, the thin film for forming the electron emitting portion including the electron emitting portion generated by the forming is referred to as a thin film 4 including the electron emitting portion.

In the surface-conduction type electron-emitting device subjected to the forming treatment, a voltage is applied to the thin film 4 including the above-described electron-emitting portion, and a current is caused to flow through the surface of the device, thereby causing the electron-emitting portion 5 to emit electrons. Things.

[0010]

However, in the above-mentioned conventional surface conduction type electron-emitting device,
In particular, the following reasons can be cited as problems that hinder practical application to display devices.

1) Even in a state where electrons are being emitted, a part of the current flowing through the element flows through the insulating substrate 1, which may cause Joule heat. 2) The current flowing in the insulating substrate 1 is greatly affected by impurities and the like adhering to the inside of the insulating substrate 1 and on the insulating substrate 1, so that the variation between elements becomes large. 3) The efficiency of electron emission is not very good. This may be due to a large current flowing through the inside of the substrate 1 as one factor. Due to the above-described problems, the surface conduction electron-emitting device has not been actively used in industry, despite the advantage that the device structure is simple.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. Even when electrons are being emitted, the temperature rise of the device is small, and the variation in the electron emission between the devices. It is an object of the present invention to provide an electron-emitting device having small electron emission efficiency and good electron emission efficiency, and a method for manufacturing the same.

[0013]

That is, the present invention has a conductive film between a pair of electrodes on an insulating substrate , and a voltage is applied to a part of the conductive film between the electrodes. Formed by
In an electron-emitting device having a crack, the substrate is made of a conductive material.
An electron-emitting device having a groove in a crack of the film .

Further, according to the present invention, there is provided a method of manufacturing an electron-emitting device, comprising: forming a pair of electrodes on an insulating substrate; forming a conductive film between the electrodes; A step of forming a crack in a part of the conductive film by applying a pressure, and a step of removing a part of the substrate in the crack and forming a groove in the crack. This is a method for manufacturing an electron-emitting device.

Hereinafter, the present invention will be described in detail. The present inventors have studied in view of the above-mentioned problems, and as a result, in order to remove the influence of the insulating substrate during the electron emission of the element as much as possible, the conductive film is formed of a conductive thin film or a conductive film formed of an island-like film of fine particles. In an insulating substrate holding a discontinuous film, an electron-emitting device having a structure in which a groove is formed in the substrate at the position of the discontinuous portion of the conductive film was found.

The basic structure, manufacturing method and characteristics of the new electron-emitting device according to the present invention will be outlined.
FIG. 1 is a configuration diagram showing the configuration of a basic electron-emitting device according to the present invention. FIG. 1A is a plan view of the device, and FIG.
(B) is a BB line sectional view. In the figure, 1 is an insulating substrate, 2 and 3 are device electrodes, 4 is a thin film formed of an electron emitting material, and 5 is an electron emitting portion. Reference numeral 6 denotes a groove formed in the insulating substrate.

In the present invention, the electron emitting portion 5 of the thin film 4 including the electron emitting portion is made of conductive fine particles having a particle diameter of several tens of mm, and includes the electron emitting portion other than the electron emitting portion 5.
Consists of a fine particle film. Note that the fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure not only in a state in which the fine particles are individually dispersed and arranged, but also in a state in which the fine particles are adjacent to each other or overlapped (island shape). Inclusive). Alternatively, the thin film 4 including the electron-emitting portion may be a carbon thin film in which conductive fine particles are dispersed.

Pd, Ru, Ag, Au, Ti, In, Cu, C
metals such as r, Fe, Zn, Sn, Ta, W, Pb, Pd
Oxides such as O, SnO ₂ , In ₂ O ₃ , PbO, Sb ₂ O ₃ , HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB
_4, GdB boride such as _{4, TiC, ZrC, HfC,} T
carbides such as aC, SiC, WC, TiN, ZrN, Hf
Nitride such as N, semiconductor such as Si and Ge, carbon, Ag
Mg, NiCu, Pb, Sn and the like.

The thin film 4 including the electron-emitting portion is formed by a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like.

Next, a method for manufacturing the electron-emitting device of the present invention will be described. There are various methods for manufacturing an electron-emitting device having the electron-emitting portion 5 of the present invention. FIG. 2 shows a manufacturing process diagram of one example. Reference numeral 4 denotes a thin film for forming an electron emitting portion, for example, a fine particle film.

Hereinafter, the manufacturing method will be described in order with reference to FIG. 2 and FIG. 1) After sufficiently washing the insulating substrate 1 with a detergent, pure water and an organic solvent, the device electrodes 2 and 3 are formed on the surface of the insulating substrate 1 by vacuum deposition technology and photolithography technology (FIG. 2A). reference). Any material may be used as the material of the device electrode as long as it has conductivity. For example, a nickel metal may be used, and the device electrode interval L1
Is 2 μm, the element electrode length W1 is 300 μm, and the film thickness d of the element electrodes 2 and 3 is 1000 °.

2) An organometallic solution is applied between the device electrodes 2 and 3 provided on the insulating substrate 1 so as to cover the device electrodes 2 and 3 and is allowed to stand. To form In addition, the organic metal solution refers to the Pd,
Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Z
A solution of an organic compound containing a metal such as n, Sn, Ta, W, or Pd as a main element is used.

Thereafter, the organic metal thin film is subjected to a heating and baking treatment,
Patterning is performed by lift-off, etching, or the like to form a thin film 4 for forming an electron-emitting portion. (See FIG. 2 (b))

3) Subsequently, when an energizing process called forming is applied between the element electrodes 2 and 3 by applying a voltage from a power supply (not shown), the electron emitting portion having a changed structure is formed at the portion of the thin film 4 for forming the electron emitting portion. 5 is formed (see FIG. 2C). The portion where the thin film 4 for forming an electron emission portion is locally broken, deformed or deteriorated by this energization treatment and the structure is changed is referred to as an electron emission portion 5. As described above, the present applicant has observed that the electron-emitting portion 5 is made of fine metal particles.

4) The electron emitting portion 5 formed by the above-described method has a crack in a part of the thin film 4, and the inside of the crack is in a discontinuous state composed of fine metal particles. Further, thereafter, the trench 6 is formed by removing the insulating substrate 1 in the portion of the electron emitting portion 5 by a dry etching process or a wet etching process using the island structure of the electron emitting portion forming thin film 4 as a mask. Thus, the electron-emitting device of the present invention is manufactured (see FIG. 2D).

The basic characteristics of the electron-emitting device according to the present invention produced by the above-described device structure and manufacturing method will be described with reference to FIGS.

FIG. 3 is a schematic configuration diagram of a measurement and evaluation device for measuring the electron emission characteristics of the electron-emitting device having the configuration shown in FIG. In FIG. 3, 1 is an insulating substrate, 2
Reference numerals 3 and 3 denote device electrodes, 4 a thin film , and 5 an electron emitting portion.
8 is a power supply for applying an electron voltage Vf to the element,
Reference numeral 9 denotes an ammeter for measuring a device current If flowing through the thin film 4 including an electron-emitting portion between the device electrodes 2 and 3. Reference numeral 10 denotes an anode electrode for capturing an emission current Ie emitted from the electron-emitting portion of the device. , 11 are high voltage power supplies for applying a voltage to the anode electrode 10, and 12 is an ammeter for measuring an emission current Ie emitted from the electron emission portion 5 of the device.

In measuring the device current If and the emission current Ie of the electron-emitting device, a power supply 8 and an ammeter 9 are connected to the device electrodes 2 and 3, and a power supply 11 is provided above the electron-emitting device.
And an ammeter 12 connected to the anode electrode 10. The electron-emitting device and the anode electrode 10 are installed in a vacuum device, and the vacuum device is provided with equipment necessary for a vacuum device such as an exhaust pump (not shown) and a vacuum gauge. The device can be measured and evaluated. The voltage of the anode electrode is 1 kV to 1 kV.
0 kV, distance between anode electrode and electron-emitting device is 3 mm
It was measured in a range of ８8 mm.

FIG. 4 shows a typical example of the relationship between the emission current Ie, the device current If, and the device voltage Vf measured by the measurement and evaluation apparatus shown in FIG. FIG. 4 is shown in arbitrary units, and the emission current Ie is about one thousandth of the device current If.

As is clear from FIG. 4, the electron-emitting device has three characteristics with respect to the emission current Ie. First, the emission current Ie of the present device rapidly increases when a device voltage higher than a certain voltage (referred to as a threshold voltage, Vth in FIG. 4) is applied. Ie is hardly detected. That is, the emission current I
This is a non-linear element having a clear threshold voltage Vth for e.

Second, since the emission current Ie depends on the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf. Third, the emission charge captured by the anode electrode 10 depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 10 can be controlled by the time during which the electron voltage Vf is applied. Because of the above characteristics, the electron-emitting device according to the present invention can be expected to be applied to various fields.

FIG. 4 shows an example of the (MI) characteristic in which the element current If monotonically increases with respect to the element voltage Vf. It may exhibit negative resistance (VCNR) characteristics. Also in this case, the electron-emitting device has the above three characteristics.

The surface conduction electron-emitting device in which the conductive fine particles are dispersed in advance can be constituted by partially changing the basic manufacturing method of the basic device structure of the present invention. . Further, as disclosed by the present inventors in US Pat. No. 5,066,883, a vertical surface conduction electron device in which device electrodes are provided above and below a step on a substrate, and a thin film including an electron emitting portion is arranged between the electrodes. Similar characteristics can be obtained in the emission element.

[0034]

In the electron-emitting device of the present invention described above, Joule heat generated in the device can be reduced, and as a result, the reliability of the device can be improved. Further, it is possible to suppress the variation between the devices and increase the efficiency of electron emission. Therefore, when a large number of electron-emitting devices of the present invention are arranged in a panel to be used as an electron source of a display device,
Significant effects can be expected on improving the uniformity of the image of the display device, the power consumption of the display device, and the reliability.

[0035]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 An electron-emitting device of the type shown in FIG. 1 was produced as an electron-emitting device of this example. FIG. 1A is a plan view of the present element,
FIG. 1B shows a cross-sectional view. In addition, FIG.
1 in (b) is an insulating substrate, 2 and 3 are device electrodes for applying a voltage to the device, 4 is a thin film including an electron emitting portion,
Reference numeral 5 denotes an electron emitting portion. L1 in the figure is the element electrode 2
And the element electrode interval between the element electrodes 3, W1 is the width of the element electrode, d
Represents the thickness of the device electrode, and W2 represents the width of the first conductive thin film.

A method for manufacturing the electron-emitting device of this embodiment will be described with reference to FIG. 1) A quartz substrate was used as the insulating substrate 1, and after sufficiently washing with an organic solvent, the device electrodes 2 and 3 made of Ni were formed on the surface of the insulating substrate 1 (FIG. 2A). At this time, the element electrode interval L1 is 3 μm, and the element electrode width W1
Was set to 500 μm, and the thickness d was set to 1000 °.

2) Next, a solution containing organic palladium (ccp-4230, manufactured by Okuno Pharmaceutical Co., Ltd.) was applied between the device electrodes 2 and 3, and then heat-treated at 300 ° C. for 10 minutes to oxidize. Palladium (PdO) fine particles (particle size: 8 to 12)
0 °, average particle size: 70 °) to form a fine particle film,
The thin film 4 for forming an electron-emitting portion was formed (FIG. 2B). Here, the thin film 4 for forming an electron-emitting portion has a width (width of the device) W of 300 μm and is disposed substantially at the center of the device electrodes 2 and 3.

The film thickness of the electron emitting portion forming thin film 4 was 100 ° and the sheet resistance was 5 × 10 ⁴ Ω / cm ² . Note that the fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure not only in a state in which the fine particles are individually dispersed and arranged, but also in a state in which the fine particles are adjacent to each other or overlapped (an island shape). ), And the particle diameter of the fine particles of 8 to 120 ° refers to the diameter of the fine particles in which particle formation can be recognized in the above state.

3) Next, as shown in FIG. 2C, a voltage is applied to the electron emitting portion 5 between the device electrodes 2 and 3, and the thin film 4 for forming the electron emitting portion is energized (forming). It formed by doing. FIG. 5 shows a voltage waveform of the forming process.

In FIG. 5, TI and T2 are the pulse width and pulse interval of the voltage waveform, and in this embodiment, T1 is 1 millisecond,
T2 is set to 10 milliseconds, the peak value of the triangular wave (the peak voltage at the time of forming) is set to 5 V, and the forming process is performed by about 1
This was performed for 60 seconds in a vacuum atmosphere of × 10 ^-6 torr. In the electron-emitting portion 3 thus prepared, fine particles mainly composed of palladium element were dispersed and arranged, and the average particle diameter of the fine particles was 30 °.

4) Finally, as shown in FIG. 2 (d), reactive palladium (Pd) fine particle film is used as a mask.
Insulating substrate 1 by ion etching (RIE)
A groove 6 was formed in the groove. In the present invention, the depth of the groove 6 is not limited, but in this embodiment, the etching is performed to a depth of 200 °. Regarding the depth of the groove, if the groove is formed too deep, there is a risk of damaging the ultrafine particle thin film 4. If the groove is too shallow, the original effect of the present invention is not exhibited.
Preferably, it is in the range of 100 to 500 °.

In this embodiment, the RIE method is used to form the groove in the insulating substrate. However, the present invention is not limited to this, and a wet etching method using an acid or an alkali may be used. Good.

The electron emission characteristics of the device fabricated as described above were measured. FIG. 3 shows a schematic configuration diagram of the measurement evaluation apparatus.

Also in FIG. 3, 1 is an insulating substrate, 2 and 3 are device electrodes, 4 is a thin film including an electron emitting portion , 5 is an electron emitting portion, 8 is a power supply for applying a voltage to the device, 9
Is an ammeter for measuring an element current If, 10 is an anode electrode for measuring an emission current Ie generated from the element, 11 is a high voltage source for applying a voltage to the anode electrode 10, and 12 is an emission current. It is an ammeter for performing.
In measuring the device current If and the emission current Ie of the electron-emitting device, a power supply 8 and an ammeter 9 are connected to the device electrodes 2 and 3, and a power supply 11 and an ammeter 12 are provided above the electron-emitting device.
Are connected to each other. Also,
The present electron-emitting device and the anode electrode 10 are installed in a vacuum device, and the vacuum device is provided with equipment necessary for a vacuum device such as an exhaust pump (not shown) and a vacuum gauge.
The device can be measured and evaluated under a desired vacuum. In this embodiment, the distance between the anode electrode and the electron-emitting device is 4 mm, the potential of the anode electrode is 1 kV, and the degree of vacuum in the vacuum device when measuring the electron emission characteristics is 1 × 10 ⁻⁶ to.
rr.

The device voltage was applied between the device electrodes 2 and 3 of the electron-emitting device using the above-described measurement and evaluation apparatus, and the device current If and the emission current Ie flowing at that time were measured. The current-voltage characteristics as shown in FIG. In this device, the emission current Ie rapidly increases from an element voltage of about 8 V. At an element voltage of 16 V, the element current If becomes 2.2 mA, the emission current Ie becomes 11 uA, and the electron emission efficiency η = Ie / If (%) becomes 0. 0.08%.

The same measurement was carried out on several hundreds of simultaneously manufactured devices.
There was no significant difference in the values of the device current and the emission current when kept at. Further, the temperature of the device was also lower than when the substrate had no groove, and it was confirmed that the reliability when the electron-emitting device was operated for a long time was improved.

Comparative Example 1 The procedure of Example 1 was repeated, except that no groove was formed on the insulating substrate 1, and the solution was oxidized using a solution containing organic palladium (ccp-4230, manufactured by Okuno Pharmaceutical Co., Ltd.). An electron-emitting device in which an electron-emitting portion was formed by forming a palladium (PdO) fine particle film was obtained.

In the same manner as in Example 1, a device voltage was applied between the device electrodes of the electron-emitting device, and the device current If and the emission current Ie flowing at that time were measured. As a result, the electron emission efficiency η = Ie / If (% ) Was 0.05%.

In the embodiment described above, when forming the electron-emitting portion, the forming process is performed by applying a triangular wave pulse between the electrodes of the device, but the waveform applied between the electrodes of the device is limited to a triangular wave. However, a desired waveform such as a rectangular wave may be used, and the peak value, pulse width, pulse interval, and the like are not limited to the above-described values. Can be selected.

[0051]

As described above, according to the present invention, even when electrons are being emitted, the temperature rise of the elements is small, the variation between the elements in the electron emission is small, and the efficiency of the electron emission is good. It is possible to obtain a simple electron-emitting device. Further, according to the manufacturing method of the present invention, an electron-emitting device having the above excellent characteristics can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a basic electron-emitting device according to the present invention.

FIG. 2 is a process chart showing an example of a method for manufacturing an electron-emitting device of the present invention.

FIG. 3 is an explanatory diagram showing a measuring means for measuring an electron emission characteristic of the electron emission element of the present invention.

FIG. 4 is a graph showing current-voltage characteristics of the electron-emitting device of the present invention.

FIG. 5 is a graph showing a voltage waveform of a forming process of the electron-emitting device of the first embodiment.

FIG. 6 is a configuration diagram of a conventional surface conduction electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2, 3 Element electrode 4 Thin film 5 Electron emission part 6 Groove part 7 Pulsed power supply for generating a crack part 8 Power supply for flowing current to an electron emission element 9 Ammeter for measuring element current If DESCRIPTION OF SYMBOLS 10 Anode electrode 11 High voltage power supply for applying high voltage to anode electrode 12 Ammeter for measuring emission current Ie

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Midome 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shigeki Matsuya 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Yoshiyuki Osada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-2-247940 (JP, A) JP-A-64-274047 ( JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 1/316 H01J 9/02 H01J 29/04 H01J 31/12

Claims (5)

(57) [Claims] 1. A conductive film is provided between a pair of electrodes on an insulating substrate , and a voltage is applied to a part of the conductive film between the electrodes.
An electron-emitting device having a crack formed by the above-mentioned method, wherein the substrate has a groove in the crack of the conductive film . 2. The electron-emitting device according to claim 1, wherein the conductive film is formed of a fine particle film. 3. A method for manufacturing an electron-emitting device, comprising: forming a pair of electrodes on an insulating substrate, forming a conductive film between the electrodes, and applying a voltage between the electrodes. Forming a crack in a part of the conductive film, and removing a part of the substrate in the crack to form a groove in the crack. Manufacturing method. 4. The step of removing a part of the substrate in the crack and forming a groove in the crack is a step of etching using the conductive film as a mask. 3. The method for manufacturing an electron-emitting device according to item 1. 5. The method according to claim 1, wherein said etching is a dry etching.
The method according to claim 4, wherein the method is performed by a process or a wet etching process.