JP2000243331A - Driving method and manufacturing method of cold cathode electron-emitting device - Google Patents

Abstract

[PROBLEMS] To stabilize the electron emission characteristics of an electron-emitting device. SOLUTION: A cold cathode electron-emitting device driven at a normal driving voltage of _Vf or less is controlled by a driving method,
First, peak value by applying a pulse voltage peak value is V _f voltage less than V _s, then peak value V _f above voltage V
_The pulse voltage whose peak value changes is applied until the pulse voltage reaches the _maximum , and the pulse voltage whose _peak value is Vmax is applied once or more, and then the normal driving is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method and a manufacturing method of a cold cathode electron-emitting device.

[0002]

2. Description of the Related Art Conventionally, two types of electron-emitting devices using a thermionic electron-emitting device and a cold-cathode electron-emitting device have been known. The cold cathode electron emission device includes a field emission type (hereinafter, referred to as “FE type”), a metal / insulating layer / metal type (hereinafter, referred to as “MIM type”), a surface conduction type electron emission device type, and the like.

As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Field emissi
on ", Advance in Electron
Physics, 8, 89 (1956) or C.I. A. Spindt, "PHYSICAL Pro
parties of thin-film field
de emission cathodes with
molybdeniumcones ", J. App.
l. Phys. , 47, 5248 (1976).

As an example of the MIM type, C.I. A. Mea
d, “Operation of Tunnel-Em
issue Devices ", J. Apply. P.
hys. , 32, 646 (1961).

As an example of the surface conduction electron-emitting device,
M. I. Elinson, Radio Eng. El
electron Phys. , 10, 1290, (196
5) and the like.

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, a device using a SnO ₂ thin film by Elinson et al. [M. I. Elins
on, Radio Eng. ElectronPh
ys. , 10, 1290, (1965)], based on an Au thin film [G. Dittmer, "Thin Sol
id Films ", 9, 317 (1972)], In
_{By a 2} O ₃ / SnO ₂ thin film [M. Hartwel
l and C. G. FIG. Fonstad, "IEEE T
rans. ED Conf. ", 519 (197
5)], using a carbon thin film [Hisashi Araki et al .: Vacuum,
26, No. 1, p. 22 (1983)].

The above-mentioned electron-emitting devices of the FE type, the MIM type, the surface conduction type, and the like have an advantage that a large number of devices can be arranged on a substrate, and various image display devices using these devices have been proposed.

A surface conduction type electron-emitting device that emits electrons from an electron-emitting portion formed in a conductive thin film by passing a current through a small-area conductive thin film formed on a substrate in parallel with the film surface. Has a simple structure and is easy to manufacture, so a large number of elements can be formed over a large area,
For example, application to an image display device or the like has been studied.

An example in which the surface conduction electron-emitting device is applied to an image display device is disclosed in US Pat.
6,883 and JP-A-6-342636. In these publications, two-dimensionally a plurality of surface conduction electron-emitting devices including a pair of device electrodes provided on a substrate, a conductive film connected to these device electrode pairs, and an electron-emitting portion formed in the conductive film. The document describes a means for arranging and electrically selecting means for individually selecting emitted electrons emitted from each electron-emitting device, and forming an image in accordance with an input signal and a manufacturing method.

[0010] Further, Japanese Patent Application Laid-Open No. 7-2352 by the present applicant.
In 55, a deposit mainly composed of carbon is formed in the vicinity of the electron emission portion by applying a voltage to the surface conduction electron-emitting device in the presence of an organic substance, and the electron emission characteristics of the surface conduction electron-emitting device are improved. Techniques for improving are disclosed.

Further, Japanese Patent Application Laid-Open No. Hei 7-2352 by the present applicant
No. 75 discloses a technique for stabilizing the electron emission characteristics by, for example, reducing the residual partial pressure of the organic substance in the environment where the electron-emitting device is formed to 1.3 × 10 ⁻⁶ Pa or less.

Further, Japanese Patent Application Laid-Open No. 9-2597 by the present applicant is disclosed.
In 53, the partial pressure of the organic gas is 1.3 × 10 3 for each of the surface conduction electron-emitting devices arranged two-dimensionally.
^In an atmosphere of ^-6 Pa or less, by applying a voltage pulse higher than the voltage obtained by adding the maximum value of the normal driving voltage in advance and the noise voltage that can enter the surface conduction electron-emitting device,
There has been disclosed a method of suppressing irreversible instability of emission current generated by a temperature characteristic or a disturbance of a driving circuit at the time of normal driving and reducing uneven brightness.

An image display device using a surface conduction electron-emitting device manufactured by applying the above-described method is expected to have more excellent characteristics than other conventional image display devices.
For example, in comparison with liquid crystal display devices that have become widespread in recent years,
It does not require a backlight because it is a self-luminous type,
The wide viewing angle is excellent.

[0014]

As described above, the surface conduction electron-emitting device has a simple structure and is easy to manufacture.
Further, since it has excellent electron emission characteristics, it is an electron emitting element suitable for forming an image forming apparatus using a phosphor as an image forming member, for example, a large self-luminous flat display. In addition, application to various analyzers, processing devices, and the like using an electron source is also expected. As described above, in consideration of application to an image forming apparatus or the like, the electron-emitting device is required to continuously emit an expected amount of an electron beam. In order to provide a more reliable image forming apparatus, analyzer, and the like, an electron-emitting device having more stable electron-emitting characteristics has been demanded in comparison with a conventional electron-emitting device.

Accordingly, an object of the present invention is to provide a driving method and a manufacturing method of an electron-emitting device, which further stabilize the electron-emitting characteristics of the electron-emitting device.

[0016]

The driving method and the manufacturing method of the present invention for achieving the above object are as follows. That is, the driving method of the present invention is a method of driving a cold cathode electron emitting element, and is a method of driving a cold cathode electron emitting element driven at a normal driving voltage of _Vf or less, and includes a normal driving voltage. the prior, first, peak value by applying a pulse voltage is V _s, then the peak value is equal to or higher than V _f voltage V _max
And until the pulse voltage peak value varies by applying, after the peak value has been applied at least once a pulse voltage is V _max,
This is a method of driving an electron-emitting device that performs normal driving.

[0017] Here, the following voltage V _s is V _f, is preferably an electron emission threshold voltage or more of the electron emission device. Further, the peak value of the pulse voltage is changed from V _s to V
_{The peak} value of each pulse voltage while changing to _max
Assuming that V ₁ , V ₂ ,..., V _N as the above integers, for 1 ≦ i <N, the peak value of each pulse voltage is

[0018]

(Equation 2) It may be.

[0019] The total application time of the pulse applied by the peak value of V _max is may be more than 500 .mu.sec, may be less 60 sec, also 500 microns
It may be longer than 60 seconds and shorter than 60 seconds. Further, the total of the application time of each pulse applied while the _peak value changes from V _s to V _max may be 500 μsec or more, or may be 60 sec or less,
The time may be 500 μsec or more and 60 sec or less. Further, the sum of the total application time of each pulse to be applied, the sum of the pulse applying time of the applied at the peak value of V _max while the peak value changes from V _s to V _max, 500
The time may be longer than μsec, shorter than 60 sec, or longer than 500 μsec and shorter than 60 sec.

The above driving method may be a driving method of a cold cathode electron-emitting device having a carbon or carbon compound in an electron-emitting portion.
A method of driving a surface conduction electron-emitting device having a conductive thin film formed in contact with the device electrode and an electron-emitting portion formed on a part of the conductive thin film between the pair of device electrodes. Is also good.

Further, the method for manufacturing a cold cathode device according to the present invention comprises:
Forming a film having carbon or a carbon compound in the electron emitting portion, forming a film having the carbon or carbon compound in the electron emitting portion, and forming the film having the carbon or carbon compound, and then applying the driving method. is there.

Further, the present invention is suitably applied to preliminary driving and manufacture of a surface conduction electron-emitting device. This method of manufacturing a surface conduction electron-emitting device includes a step of forming a pair of opposing device electrodes and a conductive thin film connected to the device electrodes on a substrate, and energizing the conductive thin film via the electrode pair. Forming an electron-emitting portion of the surface-conduction electron-emitting device, and activating the surface-conduction electron-emitting device in an environment where an organic substance is present after the forming process is completed. And a stabilizing step of reducing the partial pressure of the organic substance to 1 × 10 ⁻⁶ Pa or less from the environment where the surface conduction electron-emitting device is present after the activation step. This is a manufacturing method in which the above driving method is applied after the forming step.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The means for solving the above-mentioned problems will be described below in detail. Prior to the description of the driving method of the present invention, electric characteristics of a surface conduction electron-emitting device to which the present invention can be applied will be described. FIG. 2 shows a schematic diagram of a typical configuration example of a surface conduction electron-emitting device to which the present invention can be applied. 2A is a plan view of a flat surface conduction electron-emitting device, FIG. 2B is a cross-sectional view of the flat surface conduction electron-emitting device, and FIG. 2C is a vertical surface conduction electron-emitting device. FIG. 2A to 2C, the same symbols indicate the same kind of constituent members. In FIG. 2, 1 is an insulating substrate, 2 and 3 are device electrodes, 4 is a conductive thin film electrically connected to the device electrodes 2 and 3, 5 is an electron emitting portion formed in the conductive thin film, and 21 is This is a step forming portion made of an insulating material.

FIG. 6 is a schematic diagram showing a measuring system for measuring the electrical characteristics of the surface conduction electron-emitting device described below. In FIG. 6, the same symbols as those in FIG. FIG.
The same components as those shown in FIG. The device shown in FIG. 6 may be used in a process of manufacturing a surface conduction electron-emitting device described later. Here, reference numeral 54 denotes an anode electrode for capturing electrons emitted from the electron-emitting portion 5, 51 denotes an element electrode 2,
A power supply for generating a voltage (hereinafter, referred to as an element voltage _Vf ) applied between the three electrodes, 50 is an ammeter for measuring an element current _If flowing between the element electrodes 2 and 3, and 53 is an anode electrode. A high-voltage power supply for generating a high voltage to be applied, 52 is an ammeter for measuring an emission current _Ie flowing through the anode electrode, 55 is a vacuum tank, 57 is a vacuum tank 55 and a vacuum pump 5
6 is a gate valve provided between the first and second gate valves. When the apparatus is also used in an activation step to be described later, the apparatus includes a storage container 58 for the activation substance and a control valve 59 for controlling the amount of the activation substance introduced into the vacuum chamber.

The electrical characteristics of the surface conduction electron-emitting device are typically represented by the relationship between the emission current _Ie and the device voltage _Vf, and the relationship between the device current _If and the device voltage _Vf .
In order to determine these relationships, as shown in FIG. 6, the surface conduction electron-emitting device is placed in an environment evacuated to vacuum, and the anode electrode is placed 2 mm to 8 mm above the device. Then, 100 V to 10 kV with respect to the anode electrode
A voltage of the order of magnitude is applied, an element voltage _Vf is applied between the element electrodes, and an element current _If and an emission current _Ie flowing at this time are measured.

Representative of the electrical characteristics obtained as described above
FIG. 7 shows a simple example. Here, the emission current I_e Is the element current I
_f Since it is significantly smaller than, it is shown in arbitrary units.
Note that both the vertical and horizontal axes are linear scales. Shown in the figure
As described above, the surface conduction electron-emitting device has a certain voltage (
Threshold voltage V _th) The above element voltage V_f When applied,
Intense emission current I_e Increases monotonically, and stabilization described later
In the processed surface conduction electron-emitting device, the device
Current I _f Also element voltage V_f Increase monotonically with the increase of
You.

The stabilizing process is a process for suppressing the phenomenon that new carbon or a carbon compound is further deposited in an electron emitting portion or its vicinity by energizing a surface conduction type electron emitting device as seen in an activation process described later. Therefore, it is a process for reducing the residual amount of the organic gas existing in the space around the surface conduction electron-emitting device or adsorbed on the surface. As a specific method of the stabilization process, for example, the stabilization process can be performed by continuing evacuation while heating the vacuum chamber and the surface conduction electron-emitting device in a state where no new organic gas flows.

FIG. 8 shows an example in which the above-mentioned electric characteristics are displayed by a display method different from the method shown in FIG.
The method of expressing the graph shown in FIG. 8 is a so-called Fowler-N
This is an expression method called an ordheim plot. When electrons emitted from the electron-emitting device are caused by field emission, a straight line descends to the right.

A surface conduction electron-emitting device to which the present invention can be applied.
The electrical characteristics of the element were measured using Fowler-Nordhei in FIG.
When expressed in m-plot, as shown in FIG.
Style I _e And element current I_f Both become straight lines going down to the right
expressed. Note that the straight line obtained from the device current and the emission current
The slopes of the straight lines obtained from the above are almost the same value. Than this,
Element current I_f Conduction mechanism is due to field emission.
A. Asai et al. [SID Intl. Sym
p. Digest Tech. Papers, 127
(1997)], the emission current I_e Is the element current I_f 
Part of the light reaches the anode electrode after performing multiple elastic scattering.
Since it has reached the element current I_f of
The emission current I reflects the conduction mechanism_e Also Fowler-N
as a straight line descending to the right in the ordheim plot
Can be said. Element current I_f Is due to field emission,
If φ is the work function of the electron emission part,

[0030]

(Equation 3) It can be expressed as. Here, α is an electron emission region, β is an electric field conversion coefficient, and is a parameter that reflects the shape near the electron emission portion. Note that βV _f corresponds to the electric field intensity in the field emission field. Therefore, if the value of the work function φ is designated, the emission region α and the electric field conversion coefficient β can be obtained from the intercept between the slope of the straight line and the y-axis in FIG.

Here, the electron-emitting device is operated at a constant device voltage V
_When driving with _f , work function φ and electric field conversion coefficient β during driving
Does not change, the fluctuation of the device current _If changes in the emission region α.
It can be said that it is a fluctuation of. Further, the emission current I _e
Is a part of the device current _If , and it can be said that the variation of the emission current _Ie is caused by the variation of the emission region α. As will be described in detail later, the driving method of the present invention is a driving method in which the emission current _Ie is stabilized by suppressing the fluctuation of the emission region α.

Next, another characteristic of the surface conduction electron-emitting device to which the present invention can be applied, that is, “memory characteristic” will be described. "Memory characteristics" means that the electric characteristic curve (relationship between emission current and drive voltage and between device current and drive voltage) of a surface conduction electron-emitting device is higher than the maximum applied voltage experienced so far. In this case, the characteristic shifts to a different characteristic, and thereafter, the characteristic is maintained until a larger driving voltage is experienced.

The memory characteristics are subjected to the aforementioned stabilization processing.
Characteristics that are notable for surface-conduction electron-emitting devices
You. This will be described with reference to FIG. FIG. 9A shows a table.
Device voltage V applied to surface conduction electron-emitting device_f And Ano
Emission current I captured by the cathode electrode_e Diagram showing the relationship with
It is. In the figure, the horizontal axis of the graph is the element voltage V_f And the vertical axis is
Emission current I_e Represents the size of Electric characteristic curve A in the figure
Is the maximum value of the device voltage applied for the first time after stabilization.
(Hereafter, the maximum element voltage V _max V)_f3V_f1Is
Characteristic curve at the time. Similarly, the characteristic curve B_{ma x} Is V
_f2(> V_f1), The characteristic curve C is V_max Is V_f3(>
V_f2) Is a characteristic curve.

As shown in the figure, when the maximum device voltage is V _f1 and the applied voltage is V _f1 or less, the device voltage V _f and the emission current I _e are within a time period in which deterioration with time can be ignored.
Is always on the characteristic curve A. However, once a maximum device voltage of V _f1 or more, for example, V _f2 is experienced,
The characteristic curve shifts to B, and the emission current _Ie becomes a smaller value than the value obtained from the characteristic curve A even when an element voltage lower than _Vf1 is applied again. When a larger maximum device voltage, for example, V _f3 is experienced, the characteristic curve shifts to C and shows a similar tendency. Note that the relationship between the element current _If and the element voltage _Vf has similar characteristics.

[0035] The characteristic curve A, B, relationship Fowler-Nord device current corresponding to C I _f and the element voltage V _f
It is represented by a heim plot, and the electric field conversion coefficient β
_{When A} , β _B , and β _C are obtained, β _A > β _B > β _C is obtained, and the following result is obtained: β _A V _f1 ≒ β _B V _f2 ≒ β _C V _f3 . This means that, with the maximum device voltage V _max increases, so that the maximum field strength .beta.v _max of the electron-emitting portion near becomes constant, changes the shape of the electron-emitting portion near it as a change in β Indicates that it is appearing.

Thus, after the stabilization step,
V which has never been tested_max Electron emission when you first experience
Accompanied by a shape change near the part. In addition, once V_max experienced
Later, V _max The following element voltage V_f When driven by
There is almost no change in the conversion coefficient β.
The shape change in the vicinity is also small. Also, V_f <V_max Element
Electric field applied near the electric emission part because it is driven by voltage
Intensity βV_f Is the electric field strength specified when the maximum element voltage is applied.
Degree βV_max Lower than.

On the other hand, in a cold cathode electron-emitting device having a carbon or carbon compound film in the electron-emitting portion, in particular, in a surface conduction type electron-emitting device, driving is performed while maintaining the maximum electric field intensity experienced by the electron-emitting portion. When the electron emission region α is continued, the electron emission region α decreases with driving under the influence of the strong electric field intensity.

[0038] As done in the driving method of the present invention, since the driving of the electron-emitting device, when driven at a low electric field intensity than the maximum field strength .beta.v _max, it is possible to suppress the reduction in the emission area α with the drive, The emission current _Ie can be stabilized.

On the other hand, the V experienced first after the stabilization step
_{When max} is equal to or higher than a certain value (for example, equal to or higher than the electron emission threshold voltage), a large device current _If and an emission current _Ie may flow instantaneously. This is shown in FIG. FIG. 10A shows a time change of the element voltage _Vf .
FIG. 10B shows a time change of the element current _If corresponding thereto. Although not shown in the figure, the emission current I _e
Also shows the same tendency as the element current _If . As described above, when an extremely large current flows at the initial stage of the voltage application, the vicinity of the electron emission portion may be damaged, and the emission current may be reduced or the element may be destroyed.

[0040] In contrast, the driving method of the present invention is to suppress an instantaneous current increase of the voltage initially applied, after experiencing the maximum device voltage V _max, for driving at low device voltage than V _max This is a driving method for stabilizing the emission current.
Hereinafter, the driving method of the present invention will be described with reference to FIG. FIG.
FIG. 3 is a diagram illustrating an example of a driving method according to the present invention, and is a diagram illustrating a pulse-like voltage applied to an electron-emitting device that has undergone a stabilization step prior to normal driving. As shown in the figure, after applying a pulse voltage of the first V _s becomes the peak value, V
until _max, a pulse is applied while gradually increasing the wave height value, stopping the increase in the peak value when the peak value of the pulse reaches V _max, repeated pulse application one or more times with the peak value of V _max. The application of the voltage pulse up to this point is collectively referred to as pre-driving hereinafter. After performing this preliminary driving, V _max
By driving with a pulse having a peak value of the element voltage V _drv that is lower than the electron emission threshold voltage and higher than that, electron emission can be stably performed.

Where V_s Is the final drive voltage V
_drv And lower than the voltage finally applied during activation.
It is preferable that the voltage is low. With this, the conventional voltage mark
Large current flowing in the initial stage
You. Note that V_s Is the electron emission threshold voltage V_thSet above
May be. The value of the voltage applied for the first time after the stabilization process
Is V_thIf it is below, the presence or absence of voltage application is
And has little effect on the characteristics of subsequent electron-emitting devices.
Because there is no. The peak value is V_s To V_max Change
When changing, the change amount of each peak value is within 20%
Preferably, there is. That is, the peak value is V_s To V_max Ma
With N pulses, V₁ ≤V_Two ≤V_Three ≦… ≦ V _N Composed of
Then, for any i such that 1 ≦ i ≦ N−1,
V_{i + 1} / V_iIt is preferred that ≦ 1.2. This
Abrupt electricity near the electron emission area for each pulse application.
A change in field strength can be suppressed, and damage to the element can be suppressed.
Also, V_max Value damages the surface conduction electron-emitting device.
The upper limit is set to a value that does not cause the problem.

[0042] During preliminary driving, the sum of the time the peak value is driven at V _max, for example, (a pulse width) × (number of pulses)
Is desirably 500 μsec or more. As a result, the emission region α is stabilized during normal driving by V _drv , and thus the emission current _Ie is stabilized. A sum of the time that the peak value is driven by V _max is preferably less 60 sec. Doing driving by this value over time V _max, emission area α is greatly reduced in the pre-drive, because the emission current I _e during normal driving becomes small. The pulse total application time of between the peak value changes from V _s to V _max even, at least 500 .mu.sec 6
It is preferably 0 sec or less.

Hereinafter, the structure and manufacturing method of a surface conduction electron-emitting device to which the present invention can be applied, the structure of an electron source using the same, and an image display device using the electron source will be described. A method for applying the pre-driving process, which is a feature, to the electron source and the image display device will be described.

<Structure and manufacturing method of surface conduction electron-emitting device>
The surface conduction electron-emitting device to which the present invention can be applied will be described with reference to FIG. The basic configuration of the surface conduction electron-emitting device to which the present invention can be applied is roughly classified into a planar type and a vertical type. First, a flat surface conduction electron-emitting device will be described. FIG. 2 is a schematic diagram showing a configuration of a flat surface conduction electron-emitting device to which the present invention can be applied;
FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view.

In FIG. 2, 1 is a substrate, and 2 and 3 are device electrodes.
The poles, 4 are conductive thin films, and 5 is an electron emitting portion. Substrate 1 and
As a result, the content of impurities such as quartz glass and Na was reduced.
Glass, soda lime glass, and soda lime glass
Formed by sputtering or the like _Two Gala laminated
Substrate, ceramic substrate such as alumina, and Si base
A plate or the like can be used.

The materials of the opposing device electrodes 2 and 3 are as follows.
General conductor materials can be used. This includes, for example, Ni, Cr, Au, Mo, W, Pt, Ti, Al, C
metals or alloys such as u, Pd and Pd, Ag, Au, Ru
It is appropriately selected from a printed conductor made of a metal such as O ₂ or Pd-Ag or a metal oxide and glass, a transparent conductor such as In ₂ O ₃ —SnO ₂ and a semiconductor conductor material such as polysilicon. be able to.

The element electrode interval L, the element electrode length W, the shape of the conductive thin film 4 and the like are designed in consideration of the applied form and the like. The element electrode interval L can be preferably in the range of several hundred nm to several hundred μm, more preferably several μm
To several tens of μm. The length W of the device electrode is several μm in consideration of the resistance value of the electrode and the electron emission characteristics.
To several hundred μm. Device electrode 2,
The film thickness d of No. 3 can be in the range of several tens nm to several μm. In addition, not only the configuration shown in FIG. 2 but also a configuration in which a conductive thin film 4 and opposing element electrodes 2 and 3 are laminated on the substrate 1 in this order.

As the conductive thin film 4, a fine particle film composed of fine particles is preferably used in order to obtain good electron emission characteristics. The film thickness is appropriately set in consideration of the step coverage to the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, a forming condition described later, and the like.
It is preferably in the range of several hundreds of pm to several hundreds of nm, more preferably in the range of 1 to 50 nm.
The resistance value is such that Rs is 10 ² to 10 ⁷ Ω / □. Note that Rs is an amount that appears when the resistance R of a thin film having a thickness t, a width w, and a length 1 is R = Rs (l / w). In this specification, the forming process will be described by taking an energizing process as an example, but the forming process is not limited to this, and includes a process of forming a high resistance state by causing a crack in a film. It is.

The material constituting the conductive thin film 4 is Pd, P
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
e, metal such as Zn, Sn, Ta, W, Pd, PdO, S
oxides such as nO ₂ , In ₂ O ₃ , PbO, Sb ₂ O ₃ ,
HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB ₄ , G
dB boride such as _{4, TiC, ZrC, HfC,} Ta,
Carbides such as C, SiC, WC, TiN, ZrN, HfN
Or the like, a semiconductor such as Si or Ge, carbon, or the like.

The fine particle film described herein is a film in which a plurality of fine particles are aggregated, and has a fine structure in a state in which the fine particles are individually dispersed or arranged or in a state in which the fine particles are adjacent to each other or overlap each other (when some fine particles are formed). To form an island-like structure as a whole). The particle size of the fine particles is in the range of several times to several hundred nm of 0.1 nm, preferably in the range of 1 nm to 20 nm.

The electron-emitting portion 5 is constituted by a high-resistance crack formed in a part of the conductive thin film 4, and depends on the thickness, film quality, material, and the method of energization forming and the like of the conductive thin film 4, which will be described later. It will be. Inside the electron emission unit 5,
In some cases, conductive fine particles having a particle size ranging from several times 0.1 nm to several tens nm are present. The conductive fine particles contain some or all of the elements of the material constituting the conductive thin film 4. The electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof can also contain carbon and a carbon compound.

Next, the vertical surface conduction electron-emitting device will be described. FIG. 2C is a schematic view showing an example of a vertical surface conduction electron-emitting device to which the surface conduction electron-emitting device of the present invention can be applied. In FIG. 2C, FIG.
FIG. 2 shows the same parts as those shown in FIGS.
The same reference numerals as in (a) and (b) are used. In the figure, reference numeral 21 denotes a step forming portion. Substrate 1,
The device electrodes 2 and 3, the conductive thin film 4, and the electron-emitting portion 5 can be made of the same material as in the case of the above-mentioned flat surface conduction electron-emitting device. The step forming portion 21 can be made of an insulating material such as SiO ₂ formed by a vacuum deposition method, a printing method, a sputtering method, or the like. The film thickness of the step forming portion 21 corresponds to the device electrode interval L of the flat surface conduction electron-emitting device described above, and can be in the range of several hundred nm to several tens μm. This film thickness is set in consideration of the manufacturing method of the step forming portion and the voltage applied between the device electrodes, but is preferably in the range of several tens nm to several μm.

The conductive thin film 4 is stacked on the device electrodes 2 and 3 after the device electrodes 2 and 3 and the step forming portion 21 are formed. Although the electron emitting portion 5 is formed in the step forming portion 21 in FIG. 2C, the shape and the position are not limited to this depending on the forming conditions, forming conditions and the like.

There are various methods for manufacturing the above-mentioned surface conduction electron-emitting device, one example of which is schematically shown in FIG. Hereinafter, an example of the manufacturing method will be described with reference to FIGS. 3, the same parts as those shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG. 1) The substrate 1 is sufficiently washed with a detergent, pure water, an organic solvent, and the like, and after the element electrode material is deposited by a vacuum deposition method, a sputtering method, or the like, the element electrode 2 is formed on the substrate 1 using, for example, a photolithography technique. , 3 (FIG. 3A). 2) An organic metal solution is applied to the substrate 1 provided with the device electrodes 2 and 3 to form an organic metal thin film. As the organic metal solution, a solution of an organic metal compound containing the metal of the material of the conductive film 4 as a main element can be used. The conductive thin film 4 is formed by heating and baking the organic metal thin film and patterning it by, for example, a lift-off method using a mask corresponding to the shape of the conductive thin film or by etching or the like (FIG. 3).
(C)). Here, the method of applying the organometallic solution has been described, but the method of forming the conductive thin film 4 is not limited to this, and a vacuum evaporation method, a sputtering method, a chemical vapor deposition method,
A dispersion coating method, a dipping method, a spinner method, or the like can be used, and direct patterning can be performed by an inkjet method or the like.

3) Subsequently, a forming step is performed. As an example of the method of the forming step, a method by an energization process in a vacuum vessel will be described with reference to FIG. 6, reference numeral 55 denotes a vacuum vessel, which is evacuated through a gate valve 57 by a vacuum pump 56 such as a turbo molecular pump, a sputter ion pump, or a cryopump. Note that an auxiliary pump including a scroll pump, a rotary pump, a sorption pump, and the like may be provided as necessary. Reference numeral 58 denotes a container for storing an activation gas used in the activation step described below, and is connected to the vacuum container 55 through an adjustment valve 59 including a slow leak valve such as a variable leak valve or a needle valve.

A voltage applying means is connected to the device electrodes 2 and 3. For example, as shown in FIG. 6, the element electrode 2 is connected to a ground potential, and the element electrode 3 is connected to a power supply 51 through a current introduction terminal. An ammeter 50 is provided to monitor the value of the current flowing between the element electrodes 2 and 3. Reference numeral 54 denotes an anode electrode used in the subsequent steps, and an ammeter 5
2 to a high voltage power supply 53.

After evacuating the inside of the vacuum vessel, the device electrodes 2, 3
In the meantime, when power is supplied using the power supply 51, the electron-emitting portion 5 having a changed structure is formed at the portion of the conductive thin film 4 (FIG. 3C). According to the energization forming, a portion where the structure such as destruction, deformation or alteration is locally formed in the conductive thin film 4 is formed. This portion constitutes the electron emission section 5. FIG. 4 shows an example of the voltage waveform of the energization forming. The voltage waveform is preferably a pulse waveform. The method shown in FIG. 4A in which a pulse having a pulse peak value of a constant voltage is continuously applied and the method shown in FIG. 4B in which a voltage pulse is applied while increasing the pulse peak value are used. There is.

T1 and T2 in FIG. 4A are the pulse width and pulse interval of the voltage waveform. Normally T1 is 1 μs
c to 10 msec, T2 is 10 μsec to 10 msec
It is set in the range of c. The peak value of the pulse is appropriately selected according to the form of the surface conduction electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes.
The pulse waveform is not limited to a rectangular wave, and a desired waveform such as a triangular wave can be adopted.

T1 and T2 in FIG.
It can be similar to that shown in FIG. The peak value of the pulse can be increased by, for example, about 0.1 V steps. The end of the energization forming process can be determined, for example, by reading a change in resistance value caused by local destruction or deformation of the conductive thin film 2. For example, during the pulse interval T2, the conductive thin film 2 Can be detected by applying a voltage that does not cause local destruction or deformation of the device, and measuring the current. For example, an element current flowing by applying a voltage of about 0.1 V is measured, and a resistance value is obtained. When the resistance value indicates 1 MΩ or more, the energization forming is terminated.

4) It is preferable to perform a process called an activation step on the device after the forming. The activation process is a process in which the device current _If and the emission current _Ie are significantly changed by this process. The activation step can be performed, for example, by repeatedly applying a pulse in an atmosphere containing a gas of an organic substance, similarly to the energization forming. As the pulse voltage, besides the voltage pulse shown in FIG. 4A, a bipolar voltage pulse shown in FIG. 5 can be used.

The atmosphere in the vacuum vessel during the activation step
For example, using an oil diffusion pump or rotary pump
Organic gas remaining in the atmosphere when exhausting the container
In addition to being able to be formed using
Once a sufficiently exhausted vacuum, a suitable organic gas
Can also be obtained by introducing The preference at this time
The gas pressure of organic substances depends on the form of
Depending on the shape and type of organic substance,
Is set as appropriate. Suitable organic substances include alka
, Alkene, alkyne aliphatic hydrocarbons, aromatic coals
Hydrides, alcohols, aldehydes, ketones,
Organic acids such as mines, phenol, carboxyl, sulfonic acid, etc.
Such as methane, ethanol, etc.
, Saturated hydrocarbons such as propane, ethylene, propylene
Unsaturated hydrocarbons, butadiene, n-hexane, l-
Hexene, benzene, toluene, O-xylene, benzo
Nitrile, tolunitrile, chloroethylene, trichloro
Ethylene, methanol, ethanol, isopropanol
, Formaldehyde, acetaldehyde, acetone,
Methyl ethyl ketone, diethyl ketone, methylamine,
Ethylamine, acetic acid, propionic acid, etc.
Mixtures can be used. Due to this processing, it exists in the atmosphere
Carbon or carbon compounds from organic substances
Deposition and device current I _f And emission current I_e Changes significantly
I will be. The end of the activation step is determined by the device current I
_f And emission current I_e The measurement is performed as appropriate while measuring. Pal
The pulse width, pulse interval, pulse crest value, etc. are set appropriately.
You.

5) It is preferable to perform a stabilizing step on the electron-emitting device obtained through the above steps. This step is a step of exhausting the organic substance in the vacuum container. It is preferable to use a vacuum-evacuation device that does not use oil so that an organic substance such as oil generated from the device does not affect the characteristics of the element. Specifically, a vacuum evacuation device such as a magnetic levitation type turbo molecular pump, a cryopump, a sorption pump, an ion pump and the like can be mentioned.

In the activation step, when an oil diffusion pump or a rotary pump is used as an exhaust device and an organic gas derived from an oil component generated from the oil diffusion pump or the rotary pump is used, the partial pressure of this component must be kept as low as possible. . The partial pressure of the organic component in the vacuum vessel is preferably 1 × 10 ⁻⁶ Pa or less, more preferably 1 × 10 ⁻⁸ Pa or less, at a partial pressure at which the above-mentioned carbon and carbon compounds are not substantially newly deposited. When further evacuating the inside of the vacuum vessel, heat the entire vacuum vessel,
It is preferable to easily exhaust the organic substance molecules adsorbed on the inner wall of the vacuum vessel or the electron-emitting device. The heating conditions at this time are desirably 80 to 250 ° C., preferably 150 ° C. or more, and it is desirable to perform the treatment as long as possible. However, the present invention is not particularly limited to this condition, and the size and shape of the vacuum vessel, the configuration of the electron-emitting device, The conditions are appropriately selected according to the above conditions. The pressure in the vacuum vessel must be as low as possible.
It is preferably at most 10 × 10 ⁻⁵ Pa, particularly preferably at most 1 × 10 ⁻⁶ Pa.

It is preferable that the atmosphere at the time of driving after the stabilization step is performed is the same as the atmosphere at the end of the stabilization treatment, but the present invention is not limited to this. Even if the pressure of the vacuum vessel is slightly increased, stable characteristics can be maintained to some extent. By employing such a vacuum atmosphere, the deposition of new carbon or a carbon compound can be suppressed, and H ₂ O or O ₂ adsorbed on a vacuum vessel or a substrate can be removed. As a result, the device current I _f , The emission current _Ie is stabilized.

6) After performing the above-mentioned stabilizing step, before performing normal driving, a pre-driving step of applying the above-described pre-driving voltage pulse between the element electrodes 2 and 3 is performed. From the above,
The manufacturing process of the surface conduction electron-emitting device to which the present invention can be applied is completed.

[0066] For finished electron-emitting device, between the device electrodes 2 and 3, by applying a V _max or less of the drive voltage V _drv was applied with pre-driving step, the anode electrode 54 disposed above the electron-emitting devices By applying a high voltage using the high-voltage power supply 53, stable electron emission can be obtained.

The pre-driving is usually performed at the final stage of the manufacturing process, for example, after the stabilization process or as a part of the stabilization process. It is also possible to perform an appropriate refresh mode after the start.

[0068]

EXAMPLES The present invention will be described below with reference to specific examples. However, the present invention is not limited to these examples, and each element is set within a range in which the object of the present invention is achieved. And that the design is changed. [Embodiment 1] This embodiment is directed to a surface conduction electron-emitting device having a configuration similar to that schematically shown in FIG.
It is an example to which the driving method of the present invention is applied. Based on FIG.
A method for manufacturing the electron-emitting device used in this embodiment will be described.

Step-a (FIG. 3 (a)) After washing the substrate 1 made of a quartz substrate, 5 nm of Ti and 50 nm of Pt were deposited on the substrate 1 by a sputtering method. Thereafter, a photoresist is applied on the deposited film to form a pattern having a shape corresponding to the device electrode pairs 2 and 3, and unnecessary portions of Pt and Ti are removed by etching, and then the resist is removed to remove the substrate. 1 on the device electrodes 2 and 3
Was formed. The distance L between the device electrodes 2 and 3 is 3 μm,
The length W of the device electrode was 500 μm.

Step-b ((b) of FIG. 3) Cr having a thickness of 50 nm is deposited on the substrate 1 provided with the device electrodes 2 and 3 by vacuum evaporation, and the Cr film is formed by photolithography. Forming an opening corresponding to the position where the conductive thin film is to be formed. Thereafter, a solution of an organic Pd compound (ccp-4230: manufactured by Okuno Pharmaceutical Co., Ltd.) was applied, and subjected to a heat treatment at 300 ° C. in the air. Step-c ((c) in FIG. 3) Next, the Cr film formed in step-b was removed by wet etching, washed with pure water and dried to form a conductive thin film 4.

As shown in FIG. 6, the subsequent steps were performed after the electron-emitting devices in the manufacturing process were placed in the vacuum vessel 55 and electrical connection was made. As shown in FIG.
Is connected to a ground potential, and the element electrode 3 is connected to an ammeter 50 and an element voltage power supply 51 through a current introduction terminal. An anode electrode 54 is disposed 5 mm above the substrate 1, and the anode electrode 54 is connected to an ammeter 52 and a high-voltage power supply 53 through a current introduction terminal. Step-d The inside of the vacuum vessel 55 is controlled to 1 × 10 ⁻³ by using a scroll pump (not shown) and a magnetically levitated turbo molecular pump 56.
After the gas was evacuated to about Pa or less, a voltage generated by the device voltage power supply 51 was applied to the device electrode 3 and a forming process was performed to form the electron-emitting portion 5. The applied voltage is a pulsed voltage as shown in FIG. 4B, and is a pulse whose peak value gradually increases with time. Pulse width T1
Is 1 msec, and the pulse interval T2 is 16.7 msec.
And During the forming process, the value of the current flowing through the ammeter 50 sharply decreased when the pulse peak value reached 5V. Then, after applying a pulse voltage until the pulse peak value became 5.5 V, the application of the voltage was stopped, and the resistance value between the device electrodes 2 and 3 was measured.
The forming process has been completed.

Step-e The evacuation of the vacuum vessel 55 is further continued until the pressure in the vessel becomes 10
After the pressure decreased to ^-6 Pa or less, the activation process was performed by adjusting the slow leak valve 59 and introducing benzonitrile gas from the activation gas storage container 58 into the vacuum container 55.
The activation step was performed by adjusting the pressure in the vacuum vessel into which the activation gas was introduced to 10 ⁻⁴ Pa, and applying a voltage generated by the element voltage power supply 51 to the element electrode 3. The applied voltage is a bipolar pulsed voltage as shown in FIG. 5, and is a constant pulse in which the absolute values of _Vfp and _Vfn are equal. The pulse peak value is 16 V, and the pulse width T3 is 1 ms
ec, and the pulse interval T4 was 16.7 msec.
The activation process is performed for one hour, and then the application of the voltage is stopped.
The introduction of the activation gas was stopped, and the activation gas was exhausted from the vacuum vessel.

Step-f The entire vacuum vessel 55 and the electron-emitting device are once heated to 250 ° C. for 10 hours using a heater (not shown), and further evacuated, so that the pressure in the vacuum vessel at room temperature thereafter becomes 1 ×. The pressure was reduced to about 10 ⁻⁸ Pa.

As described above, the pressure in the vacuum vessel was adjusted.
Thereafter, preliminary driving, which is a feature of the driving method of the present invention, was performed.
FIG. 1 shows a pulse voltage waveform at the time of pre-driving. In FIG. 1, V
_s Is 1V and V_max Was set to 16V. The pulse crest value
V_s To V _max The pulse width is 20 μsec
And the pulse interval was 100 msec. Also pal
The peak value is increased every pulse in 0.2V steps.
Was. Pulse peak value is V_s To V_max Sign while changing
The total application time of each applied pulse is 500 μsec.
It is. Pulse peak value is V_max After reaching the peak value,
_max The pulse voltage was applied while maintaining the state. here
And the pulse width is 100 μsec and the pulse interval is 100 m
sec and the pulse peak value is V_max Pulse voltage
A total of 5 shots were applied.

Thereafter, driving was performed with the device voltage set to _Vf = 15 V. On the other hand, for comparison, an electron-emitting device manufactured by exactly the same manufacturing method was driven by setting the driving voltage to 15 V from the beginning without performing preliminary driving.
As a result of comparison between the two devices, a stable electron emission characteristic was obtained in the element subjected to pre-driving with less decrease and fluctuation in emission current and element current during driving than in the element not subjected to pre-driving.

When the emission region α and the electric field conversion coefficient β were observed from the electric characteristics of the device current during driving of the electron-emitting device, the electron-emitting device to which the present invention was applied showed that both of them varied during the driving period. And the stability of the emission region α was particularly superior to that of the comparative electron-emitting device.

[Embodiment 2] This embodiment is a second example in which the driving method of the present invention is applied to an element which has been subjected to the same steps up to the step -f of the embodiment 1. The following preliminary driving was applied to the device that was completed up to the stabilizing step (step-f) in Example 1. The peak value of the pulse voltage applied during the activation step performed in step-d was 15 V.

FIG. 1 shows a pulse voltage waveform at the time of pre-driving. In Figure 1, V _s is the 8V, V _max was 15.5V. While a pulse peak value is changed from V _s to V _max, the pulse width is set to 1 msec, the pulse interval was 10 msec. The pulse peak value was increased every 800 pulses in 0.1 V steps. The total application time of each pulse is applied between the pulse peak value is changed from V _s to V _max is 60 sec.

[0079] After the pulse peak value has reached the V _max, was the application of the pulse voltage to maintain the peak value remains at V _max. Here, the pulse width is 1 msec, and the pulse interval is 10 msec.
As c, a total of 60,000 pulse voltages having a pulse _peak value of V _max were applied. Total pulse applying time pulse height is V _max is 60 sec.

Thereafter, driving was performed with the device voltage set at V _f = 15 V. On the other hand, for comparison, an electron-emitting device manufactured by exactly the same manufacturing method was driven by setting the driving voltage to 15 V from the beginning without performing preliminary driving.
As a result of comparison between the two devices, a stable electron emission characteristic was obtained in the element subjected to pre-driving with less decrease and fluctuation in emission current and element current during driving than in the element not subjected to pre-driving.

When the emission region α and the electric field conversion coefficient β were observed from the electrical characteristics of the device current during driving of the electron-emitting device, the electron-emitting device to which the present invention was applied showed that both of them varied during the driving period. And the stability of the emission region α was particularly superior to that of the comparative electron-emitting device.

[0082]

As described above, according to the present invention,
The emission current from the electron-emitting device can be stabilized for a long time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating voltage pulses used in a driving method and a manufacturing method according to the present invention.

FIG. 2 is a schematic plan view and a schematic sectional view showing an electron-emitting device to which the present invention can be applied.

FIG. 3 is a diagram showing a manufacturing process of an electron-emitting device to which the present invention can be applied.

FIG. 4 is a diagram showing voltage pulses used during a forming process of an electron-emitting device to which the present invention can be applied.

FIG. 5 is a diagram showing voltage pulses used during an activation step of an electron-emitting device to which the present invention can be applied.

FIG. 6 is a diagram showing a vacuum device and a driving and measuring device used for manufacturing an electron-emitting device to which the present invention can be applied and measuring electric characteristics.

FIG. 7 is a diagram showing electric characteristics of an electron-emitting device to which the present invention can be applied.

FIG. 8 is a diagram showing electric characteristics of an electron-emitting device to which the present invention can be applied.

FIG. 9 is a diagram illustrating memory characteristics of an electron-emitting device to which the present invention can be applied.

FIG. 10 is a diagram illustrating a change in device current when a voltage is applied to an electron-emitting device to which the present invention can be applied.

[Explanation of symbols]

1: substrate, 2 and 3: element electrode, 4: conductive thin film, 5: electron emitting portion, 21: step forming portion, 50: ammeter, 51: power supply, 52: ammeter, 53: high voltage power supply, 54: Anode electrode, 55: vacuum container, 56: vacuum pump, 57: gate valve, 58: activated gas container, 59: slow leak valve.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Keisuke Yamamoto, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 5C036 EE01 EE02 EE14 EF01 EF06 EF09 EG12 EG48 EH26 5C080 AA08 BB05 CC03 DD05 DD29 FF10 HH17 JJ04 JJ06 KK02 KK43

Claims (16)

[Claims] 1. A driving method of a cold cathode electron-emitting devices are normally applied to V _f less voltage as the drive voltage, prior to the normal drive, the first pulse voltage peak value is V _s applied to, then, until a peak value is V _s and V _f higher voltage V _max, the pulse voltage peak value varies by applying, after the peak value has been applied at least once a pulse voltage is V _max, A method for driving an electron-emitting device, comprising performing normal driving. 2. A driving method of an electron emitting device according to claim 1, wherein the voltage V _s is a voltage below V _f. Wherein the pulse voltage peak value V _s is the driving method of an electron emitting device according to claim 1, wherein the at electron emitters electron emission threshold voltage or more. Wherein V from the peak value of the pulse voltage V _{s
The peak} value of each pulse voltage while changing to _max
Assuming that V ₁ , V ₂ ,..., V _N are integers as described above, the peak value of each pulse voltage is given by 4. The method of driving an electron-emitting device according to claim 2, wherein the following relationship is satisfied. Total 5. A peak value is V _max single or a plurality of pulse applying time of an electron emitting device according to any one of claims 1 to 4, characterized in that at least 500μsec Drive method. Total 6. peak value is V _max single or a plurality of pulse applying time of an electron emitting device according to any one of claims 1 to 5, characterized in that not more than 60sec Drive method. 7. A total application time of each pulse peak value is applied during the change from V _s to V _max is, 500 .mu.s
5. The method for driving an electron-emitting device according to claim 1, wherein the value is ec or more. 8. The total application time of each pulse between the peak value changes from V _s to V _max is, 60 sec
5. The method according to claim 1, wherein:
5. A method for driving an electron-emitting device according to any one of the above. 9. The total application time of each pulse between the peak value changes from V _s to V _max is, 500 .mu.s
5. The method according to claim 1, wherein the driving time is not shorter than ec and not longer than 60 sec. 6. 10. The sum of the application time of each pulse applied while the _peak value changes from V _s to V _max and the total application time of one or more pulses applied at the peak value of V _max 5. The method according to claim 1, wherein the sum of the driving times is 500 μsec or more. 6. 11. The sum of the application time of each pulse applied while the _peak value changes from V _s to V _max and the total application time of one or more pulses applied at the peak value of V _max 5. The method according to claim 1, wherein the sum of the driving times is 60 seconds or less. 6. 12. The sum of the application time of each pulse applied while the _peak value changes from V _s to V _max and the sum of the application time of one or more pulses applied at the peak value of V _max Is more than 500 μsec and 60 sec
5. The method of driving an electron-emitting device according to claim 1, wherein c is equal to or less than c. 13. A cold cathode electron emitting device comprising: a pair of opposing device electrodes on a base; a conductive thin film formed in contact with the device electrodes; and a conductive film between the pair of device electrodes. A surface conduction electron-emitting device having an electron-emitting portion formed on a part of the thin film.
13. The method for driving an electron-emitting device according to any one of the above items 12. 14. The electron emission device according to claim 1, wherein the cold cathode electron emission device is a cold cathode electron emission device having carbon or a carbon compound in an electron emission portion. Element driving method. 15. A method for manufacturing a cold cathode electron emitting device, comprising: a step of forming an electron emitting portion; and a step of forming a film having a carbon or carbon compound in the electron emitting portion. A method for manufacturing a cold cathode electron-emitting device, comprising: applying a current by the driving method according to claim 1, after forming a film having: 16. A method for manufacturing a surface conduction electron-emitting device, which is one type of cold cathode electron-emitting device, comprising: forming a pair of opposing device electrodes and a conductive thin film connected to the device electrodes on a substrate. A forming step, a forming step of applying an electric current to the conductive thin film through the electrode pair to form an electron emitting portion of the surface conduction electron-emitting device, and an organic substance present after the forming step is completed. An activation step of energizing the surface conduction electron-emitting device in an environment; and, after the activation step, reducing the partial pressure of the organic substance to 1 × 10
^And a stabilizing step for reducing the current to ^-6 Pa or less, and after the stabilizing step, energization is performed by the driving method according to claim 1. Manufacturing method.