JPH02247939A - Surface conductive electron emission element, image formation apparatus using it and manufacture of element - Google Patents

Abstract

PURPOSE:To largely improve reliability in the production of a surface conductive electron emission element by means of a fine-grain beam spraying process by leaning a substrate in a certain angle from the direction of the fine-grain beam radiated thereon and rotating the substrate at the same time. CONSTITUTION:Disclosed here is the production of a surface conductive electron emission element for dispersing and accumulating fine grains between a pair of or among a plurality of electrodes on the same substrate. The substrate is leant in a certain angle and turned at the same time to improve accumulation states at the end of a gap and ensure contact of end portions of electrodes 10 and 11 with the fine-grains. An angle theta between the direction of fine-grain beam and the substrate is set to 2 to 30 degrees. A rotation introduction section 12 applies forming movement to the substrate. With its speed of 5 to 60rpm. The minimum film thickness (a) of a fine-grain particle film and the film thickness A at the contact between both end electrodes shows mutual relationship a/A=0.6 to 0.7.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for manufacturing an electron-emitting device, specifically a surface conduction type electron-emitting device, particularly a fine particle beam spraying method, and an electron-emitting device obtained by this method. It is related to.

[Prior Art] Conventionally, as an element that can emit electrons with a simple structure,
For example, M.I. Ellingson (N, I.

A cold cathode device announced by Elinaon et al. is known. [Radio Eng, Elect
Ron.

Phya,) Volume 10, 12H=1298 pages%1-
11851 This utilizes the phenomenon in which electrons are emitted by passing a current parallel to the film surface through a small-facet thin film formed on a substrate, and is generally called a surface conduction electron-emitting device. being called.

These surface conduction electron-emitting devices include those using the 5nap (Sb) thin film developed by Ellingson et al., and those using an Au thin film [G.
Solid Films°' (G, Dittmer:
“Th1n 5 Solid Films”), vol. 9, p. 317, (1972) 1. ITO thin film [M. Hartwell and C.F.
Day-Confaln (M, Hartwell and
C., G., Fonstad: “IEEE Trans.
ED Conf,” ) 519 pages, (1975
2006)], by carbon thin film [Hisashi Araki et al.: “Vacuum”
, Vol. 26, No. 1, p. 22, (1983)].

These devices require electrical heating treatment called forming before they emit electrons. In other words, the Joule heat generated by energization locally destroys, deforms, or alters the film, creating an electrically high-resistance region, and emitting electrons from that region.

[Problems to be Solved by the Invention] One possible device is one in which fine particles are dispersed or deposited on an electrode substrate that has been patterned on an insulating substrate such as quartz glass using a technique such as photolithography. . A schematic diagram of this electrode substrate is shown in FIG. 2. In other words, electrodes 10 and 11 made of a low-resistance material for voltage application are provided at a minute interval on an insulating substrate 9t. During this time, electron-emitting material fine particles are dispersed or deposited. One of the methods for this dispersion or deposition is the particle beam spraying method. Here, fine particles refer to particles with a particle size of 100 OA or less (-order particles), and fine particle beam refers to a jet containing fine particles that flows in a fixed direction with directionality at a higher density than the surrounding space. The cross-sectional shape does not matter. Since this fine particle beam spraying method is relatively easy to produce, it can be used for all materials that can be made into fine particles by methods such as resistance heating, sputtering, and laser melting.

However, in general, the particle beam spraying method has a major problem in terms of reliability during device fabrication due to geometrical problems in dispersing and depositing particles on the device substrate.

In other words, as shown in Figure 3, the probability of contact between the electrode end and the particles is low, resulting in poor reliability in terms of electrical properties.For example, when using the conventional particle beam spraying method, the Also, the inter-electrode resistance shows a variation of one to two orders of magnitude, in some cases three orders of magnitude or more, and not only the variation but also the position of local breakage, deformation, or deterioration that occurs during forming cannot be determined. Both of these naturally pose a major problem when producing a surface conduction electron-emitting device, as they cause variations in electrical properties, that is, a decrease in device reliability.

An object of the present invention is to improve this reliability. In other words, the purpose of the fine particle beam spraying method is to greatly improve the reliability of surface conduction type electron-emitting devices when they are produced by the method. The present invention will be explained in detail below.

[Means and effects for solving the problem] According to the present invention, fine particles are dispersed between a pair or a plurality of electrodes on the same substrate,
In the method for manufacturing a surface conduction electron-emitting device, by rotating the device substrate at a certain angle from the direction of the incoming particle beam, contact between the electrode end and the particles becomes more reliable. This greatly improves the reliability of the device when producing the emitting device. In other words, the present invention relates to an improvement of the particle beam deposition method, which is one of the methods for manufacturing surface conduction electron-emitting devices, and electrodes formed on the same substrate created by this method. A schematic diagram of this is shown in Fig. 2, and as mentioned above, it consists of an insulating substrate and low resistance electrodes for voltage application provided at minute intervals.As the insulating substrate, quartz glass, Examples include blue plate glass, silicone, and white plate glass. Also, as a low resistance electrode for voltage application, a general conductive material such as Au, Aj) can be used.

In addition to conductive materials such as Pt, Ag, and old metals, oxides such as SnO2, 1-0, etc., and compound conductive materials such as molybdenum silicide can be used. There is no limit to the thickness for both, but for an insulating substrate it is preferably 0.5 to 51cm, and for a low resistance electrode for voltage application it is preferably 500mm or more, more preferably 100OA to several μm, and The minute spacing is preferably from several to several hundred pm, but of course is not limited to the above for electrodes formed on the same substrate.

Next, the method of particle beam spraying will be explained with reference to FIG. 1, which is a conceptual diagram of the present invention. First, regarding the particle beam generation method, any of the conventionally known methods in which particles are shaped by resistance heating, plasma decomposition, etc. and sprayed onto the substrate together with a carrier gas may be used.Here, the resistance heating method will be explained as an example. Of course, it is not limited to this.

The evaporation source 1 and the crucible 2 are arranged in the upstream chamber 3, and a voltage is applied to the crucible 2 from an external electrode to raise the temperature to the point at which the evaporation source 1 evaporates. The fine particles thus generated are blown onto the substrate 4 together with the carrier gas introduced from the carrier gas inlet 6 using the differential pressure between the downstream chamber 5 and the upstream chamber 3 in which the substrate 4 is disposed. At this time, a beam generating section 7 is provided in which an orifice, a tapered nozzle, a diverging nozzle, a contracting/expanding nozzle, etc. are arranged to form a beam. The crucible 2 is appropriately selected from carbon crucibles, aluminum crucibles, etc., depending on the material of the evaporation source. As the material for the evaporation source, the required 1
Please select as appropriate.

The material of the fine particles used in the present invention is very wide, and almost all conductive materials such as ordinary metals, semimetals, and semiconductors can be used.

Among them, ordinary cathode materials with low work function, high melting point, and low vapor pressure, thin film materials that form surface conduction electron-emitting devices through conventional forming processing, and materials with high secondary electron emission coefficients. is suitable.

Specifically, Lam6. CeB6. YB4. GdB
Borides such as s, TiC, Zr1C, HfC, TaC, S
Carbide such as in, VC.

? Nitride such as iN, ZrN, HfN, Nb, No
, Rh, Hf.

Ta, w, Re+ Ir, pt, Tei, Au, Todoroki g, Cu, Cr, ^
p.

Metals such as Go, Fe, Pb, Pd, Cs, and Ba, metal oxides such as In2O3゜5n02, Sb20:1, and semiconductors such as Si and Ge.

Examples include carbon, AgMg, etc. Note that the present invention is not limited to the above materials.

The carrier gas is appropriately selected from He, Ar, N2, etc. The differential pressure between the upstream chamber and the downstream chamber to be used is preferably 10 to 10,000 in terms of pressure ratio, more preferably 100 to too. The essence of this lies in the board setting method, which will be explained below. That is, by simultaneously rotating the substrate at certain angles from the particle beam direction, the deposition condition at the end of the gap is improved as shown in FIG. 4, and the contact between the electrode end and the particle is ensured.

The gap here refers to a minute gap between the circular electrodes.

Furthermore, since the thickness of the central portion is thinner than that near the electrode end surface, local destruction, deformation, or alteration is likely to occur at the central portion during forming, and the location thereof can be defined.

In addition, the conditions of the rotating part where the board is set are shown in the enlarged view, No. 5.
This will be explained using figures. Here, the angle 0 between the particle beam direction and the substrate is preferably 2° to 30°, more preferably 1°.
It is 0' to 20°. Further, a rotational motion is applied from the rotation introducing portion 12, and the speed thereof is preferably 5 to 60 rpm, more preferably 10 to 40 rpm.Examples will be described below, which were studied based on the concept described above.

[Example] 3,000 Ni electrodes were formed on a quartz insulating substrate that had been thoroughly cleaned, and a pattern as shown in FIG. 2 was formed using a photolithography technique. However, L is 20μ, G is 3
The score was 00 and ended at 1.

Next, the above substrate is placed in the vacuum apparatus shown in FIG.
As mentioned above, the vacuum device is composed of a particle generation chamber (upstream chamber) 3, a particle deposition chamber (downstream chamber) 5, and a contraction/expansion nozzle (beam generation section 7) that connects both chambers.
It was set inside as shown in Figure 5. In this case, θ is lOo
And so. Then, the degree of vacuum is increased to 8 x 10-'T with exhaust system 8.
After exhausting until the temperature was below orr, 60 SCCM of Ar gas was flowed into the particle generation chamber 3 through the inlet 6. At this time, the pressure in the particle generation chamber 3 was 4 x 1G-'' Torr, and the pressure in the particle deposition chamber 5 was 2.3 x 10 = Torr, which was a pressure ratio of more than two digits.The contraction/expansion nozzle at this time The diameter of the nozzle was 41φ, and the distance between the nozzle and the substrate was 200 mm.Furthermore, Pd was used for evaporation 9 and source 1, and a carbon crucible was used for crucible 2.Then, Pd was evaporated under the above-mentioned conditions. .

Pd fine particles were blown out from a contraction/expansion nozzle of 7ffl. At this time, due to the pressure difference between the particle generation chamber 3 and the particle deposition chamber 5, the particle beam as defined above is sprayed onto the substrate from the nozzle. And from the traveling direction of this beam, lθ
The tilted substrates are simultaneously rotated at 20 rpm and the tilted position of the substrate is moved (see Figure 5).The above-mentioned Pd particle beam is blown onto this substrate, and the particles are deposited in the gap. . Of course, due to the spread of the beam, Pd fine particles fly to areas other than the gear part, but since no voltage is applied to unnecessary parts, there is no effect on the device itself.This deposit is removed by high-resolution FE-9EH. When observed, fine particles with a diameter of about 80 to 150 A were deposited. Here, regarding the film thickness of the deposited film (fine particle film), the ratio between the central part and the electrode connection parts at both ends is approximately 0.6 to 0.7.
: It was 1-.

Next, this element was placed at a vacuum level of 5 x 10-' Torr or less with the extraction electrodes spaced 5 mm apart in the vertical direction from the substrate surface, and a voltage of 1.5 KV was applied between the electrodes 10 and 11. The electron emission characteristics were evaluated.

Table 1 shows the results regarding the device resistance emission current value when this device fabrication and evaluation was performed 15 times.

Table 1 Here, R and Ie represent the element resistance and emission current value, respectively, and the subscripts a+ax, sin, and mean represent the maximum, minimum, and maximum, respectively.
Shows average.

In addition, cracks (parts that emit electrons) using FE-3EM
It was confirmed that all of these occurred almost at the center of the gap.

As a result of these factors, 1. Regarding the reliability of characteristics during device manufacturing,
Good characteristics have been obtained. Furthermore, an image forming apparatus was created by providing an electron source with a plurality of these elements arranged, and this was more effective in reducing screen flickering and brightness variations than in the past.

Example 1 except that the angle between the particle beam and the substrate was 2°.
The results of an experiment conducted in exactly the same manner as above are described below. The deposition condition and cracks were almost the same as in Example 1. Table 2 shows the obtained element characteristic values.

Table 2 Also, the pressure in the particle generation chamber 3 and the pressure in the particle deposition chamber 5 at this time were, of course, exactly the same as in Example 1 since they did not depend on the state of the element substrate.

EXAMPLE 1 The results of an experiment conducted in exactly the same manner as in Example 1 except that Au was used as the evaporation source are described below. Regarding the deposition status and cracks, the particle size was 120 to 250 particles, which was somewhat larger than that of Pd, but no major difference was observed.Table 3 shows the obtained device characteristic values.

Table 3 As in the case of Pd, good characteristics were obtained with respect to the reliability of characteristics during device manufacturing with respect to Au.

In addition, in the above examples, the particle generation method is not limited to the resistance heating method, nor is the particle beam generation method limited to the contraction/expansion nozzle. Write down.

[Ratio] Example L The traveling direction of the beam was perpendicular to the substrate, and the rotation speed was also set to Orpm. This is typical of conventional particulate beam deposition methods. The results of an experiment conducted in exactly the same manner as in Example 1 except for the above are described below.

The state of fine particle deposition is almost the same as in Example 1, and the particle size is also the same as 80 to 150 people.

However, as shown in Table 4, there was a large difference in the variation in device characteristics. In addition, some of the cracks were located quite far from the center.

Table 4 As is clear from Table 4, the conventional technology has very poor characteristic reliability during device manufacturing.

[Effects of the Invention] As explained above, in a method for manufacturing a surface conduction electron-emitting device in which particles are dispersed and deposited between a pair or a plurality of electrodes in the same plane, there is By tilting the angle and rotating it, variations in characteristics from element to element are reduced, and the crack generation site can be defined to a certain extent, which has the effect of greatly improving reliability during manufacturing. This is thought to be because the contact between the electrode end surface and the fine particles is ensured, the electrical characteristics of the device are stabilized, and the reliability is greatly improved.In addition, the film thickness at the center of the gap is smaller than that at the periphery compared to the conventional technology. Because it is thinner, cracks tend to occur in the center during the forming process, and the location where cracks occur can be defined to some extent.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the device used in the present invention, Fig. 2 is a schematic diagram of an electrode substrate, Fig. 3 is a conceptual cross-sectional diagram of the deposition state of fine particles when the substrate is not tilted, and Fig. 4 is a conceptual diagram of the device used in the present invention. FIG. 5 is a cross-sectional conceptual diagram of the deposition state of fine particles according to the method, and FIG. 5 is an enlarged view of the substrate rotation part. DESCRIPTION OF SYMBOLS 1... Evaporation source, 2... Crucible, 3... Upstream chamber (fine particle generation chamber), 4.9... Insulating substrate, 5... Downstream chamber (fine particle deposition chamber), 6... carrier gas inlet, 7...beam generation section,
8... Exhaust system, 10.11... Voltage application electrode, 12... Rotation introduction part.

Claims (3)

[Claims] (1) In a surface conduction electron-emitting device having a particulate film formed by dispersing and depositing particulates between a pair or a plurality of electrodes, the relationship between the minimum film thickness a of the particulate film and the film thickness A of the electrode connecting portions at both ends is A surface conduction electron-emitting device characterized by a fine particle film having a/A=0.6 to 0.7. (2) An image forming apparatus characterized in that an image forming member is irradiated with electrons emitted from the surface conduction type electron-emitting device according to claim 1. (3) In a method for manufacturing a surface conduction electron-emitting device in which fine particles are dispersed and deposited between a pair or a plurality of electrodes on the same substrate, the substrate is tilted at a certain angle from the direction of the incoming fine particle beam and rotated. A method for manufacturing a surface conduction electron-emitting device, characterized in that: