JP3142895B2 - Method for manufacturing field emission electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Spindt type field emission electrode which emits an electron beam by field emission.
It relates to a manufacturing method .

[0002]

2. Description of the Related Art When manufacturing this kind of field emission type electrode, there are many types of emitter chips formed by applying a thin film, such as shapes and materials, but it is necessary to increase the current density of electron emission. In this case, a metal material having a high melting point, a carbide, or a boride is preferable.

[0003] On the other hand, it is relatively easy to form a pyramid-type EMI emitter chip by anisotropically etching a single crystal of a semiconductor material such as silicon. On the other hand, when using a metal material or a metal carbide having a high melting point, a method such as sputtering, vacuum evaporation, or various CVD methods is used for film formation, but special conditions are required to obtain a single crystal. Therefore, it is difficult to simultaneously form a large number of emitter chips by anisotropic etching.

[0004]

SUMMARY OF THE INVENTION Spindt type electric field emission
In the method of manufacturing a projection electrode, when forming an emitter tip using the above-mentioned metal material or a material of a metal carbide having a high melting point, when a material such as a single crystal polycrystal or an amorphous body is used, after forming the emitter tip, It was difficult to correct the tip shape to an appropriate shape. The present invention has been made in view of the above points, and has as its object the purpose of spinning.
The method of manufacturing a field emission electrode bets scheme is to provide a method of manufacturing a field emission electrode which is capable of properly correcting the distance the shape and the emitter tip and the gate layers once formed the emitter tip.

[0005]

According to the present invention, in order to achieve the above-mentioned object, a conductive substrate is provided on an electrically conductive substrate via an insulating layer.
A conductive gate layer and pass through the insulating layer and the gate layer.
Forming radiation holes to expose the surface of the substrate
The emitter tip is formed of a metallic material in the radiation hole.
In the field emission electrode of the focus system,
After forming the chip , an oxide film is formed on the surface of the emitter chip and the gate layer, and the oxide film is removed to correct the shape of the emitter chip and adjust the distance between the emitter chip and the gate layer. Features.

[0006]

According to the method of the present invention, Spindt-type field emission
When manufacturing the mold electrode, an oxide film is formed on the surface of the emitter chip and gate layer already formed of a metallic material, and the oxide film is removed to correct the shape of the emitter chip and adjust the distance between the gate layers. Because it does, the conventional spint method
In the field emission electrode of the formula, the shape of the emitter tip formed from a metal material such as a metal material or a metal carbide, whose shape was difficult to modify , the distance between the emitter tip and the gate layer, and the thickness of the oxide film By controlling, it can be easily corrected.

[0007]

FIG. 4 shows a Spindt-type field emission electrode formed primarily, in which a conductive substrate 2 made of fully doped silicon is placed on an insulating substrate 2 made of silicon dioxide. A conductive layer made of metal molybdenum with a layer 3 interposed between the insulating layer 3 and the gate layer 4 to expose a surface of the substrate 2 from the metal molybdenum; Is formed. Emitter tip 1 is an electron beam e ^- is adapted to emit towards the collector 6 through radiating holes 5 a.

The method for producing this primary field emission electrode is described in Dr. Sri International (USA). This is performed by a known method proposed by Spindt et al. According to the method of the present invention, when the shape of the emitter chip 1 which has already been formed is changed, the surface of the emitter chip 1 is oxidized and then the oxide film is removed. This is a method for adjusting the distance between the three, and will be described below with reference to embodiments.

[0009] Example 1 In Example 1, the surface of the emitter tip 1 and the gate layer 3 made of a metallic molybdenum is heated at 530 to about 630 ° C. is oxidized, oxide films of MoO ₃ on the surface as shown in FIG. 1 7 is formed. The thickness of the oxide film 7 was measured while changing the temperature conditions during the oxidation of Mo. The result was as follows.

Temperature condition 535 ° C. Oxidation in air for 1 hour Film thickness measurement 2.5 μm / hr = about 420 ° / min Temperature condition 570 ° C. Oxidation in air flow for 1 hour Film thickness measurement 5 μm / hr = about 840 ° / min In the example, oxidation at 535 ° C.
酸化 A thick oxide film 7 was formed.

The oxidation can be represented by the following chemical formula. Mo + 3 / 2O ₂ → MoO ₃ By removing the formed oxide film 7, the tip shape of the emitter chip 1 and the distance between the emitter chip 1 and the gate layer 4 are corrected as shown in FIG. .

[0012] oxide film 7 of MoO ₃ with respect to where NH ₃ water to have a solubility, in the present embodiment, to remove the oxide film 7 with aqueous NH _3. Note that the thickness of the oxide film 7 can be set according to the oxidation conditions (which can be controlled by temperature and time) as described above. For example, the thickness of the metal molybdenum oxide film 7 is set to , Which is approximately proportional to the square of time. Since the diffusion coefficient is represented by an exponential function of temperature, setting the temperature to a high value is effective. However, hexavalent metal molybdenum oxide has the property of sublimating at a relatively low temperature, and its vapor pressure is 0.30 mm / 700 ° C., 10.1 mm / 8.
00 ° C, 476.2 mm / 1100 ° C, 760 mm / 1
155 ° C.

When forming oxide film 7 in this manner,
By controlling the thickness, the sharpness of the emitter chip 1 after removal and the distance between the emitter chip 1 and the gate layer 4 can be made appropriate. Embodiment 2 This embodiment is different from Embodiment 1 in the method of removing the oxide film 7 after forming the oxide film 7 under the same conditions as in Embodiment 1 described above.

That is, in the present embodiment, the oxide film 7 is heated and removed by sublimation utilizing the sublimability of hexavalent metal molybdenum oxide. In this embodiment, the oxide film 7 was heated at 800 ° C. to remove the sublimation. Embodiment 3 In the above Embodiments 1 and 2, the solubility of NH ₃ water and sublimation are used to remove the metal molybdenum oxide film 7. When the oxide film becomes a multivalent oxide film, it loses sublimability and becomes insoluble in NH ₃ water. Therefore, the oxide film 7 cannot be removed by the methods of the first and second embodiments.

The tetravalent oxide film has very good conductivity and remains.
If there is no problem, you can leave it as it is
Increases the work function and raises the threshold for electron beam emission.
Need to be removed. The specific resistance of metallic molybdenum is
5.2 × 10^-6Ωcm, MoO _ThreeHas a specific resistance of 8.8 × 1
0^-FiveΩcm (500 ° C.). Therefore, in this embodiment,
Hydrogen, which is a primary gas, is flowed over the surface of the oxide
Removed by reduction to den. Also an oxide film on the surface
When 7 is oxidized to hexavalent, it is removed by the methods of Examples 1 and 2.
Leave.

When a tetravalent oxide is formed, nitric acid treatment may be performed instead of the reduction as described above to convert the oxide to a hexavalent oxide and sublimate it.

[0017]

According to the present invention, an oxide film is formed on the surface of an emitter chip and a gate layer which are already formed of a metallic material when a Spindt-type field emission electrode is manufactured, and the oxide film is removed. Correction of the shape of the emitter tip,
Since the distance between gate layers is adjusted, the conventional Spindt method
In the field emission type electrode, the thickness of the oxide film is controlled by controlling the shape of the emitter tip formed from a metallic material such as a metal material or a metal carbide, which has been difficult to modify , and the distance between the emitter tip and the gate layer. This has the effect that the correction can be made easily, and in particular, the emitter tip can be easily sharpened.

[Brief description of the drawings]

FIG. 1 is a sectional view of a field emission electrode in an oxide film formation state according to a method of Example 1 of the present invention.

FIG. 2 is a cross-sectional view of the field emission electrode after removing an oxide film by the method according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a field emission electrode at the time of primary formation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Emitter chip 2 Substrate 3 Insulating layer 4 Gate layer 5 Radiation hole 6 Collector 7 Oxide film

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-52274 (JP, A) JP-A-3-71529 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/02

Claims (1)

(57) [Claims] A conductive substrate is provided on a conductive substrate via an insulating layer.
Laminate the gate layer and pass through the insulating layer and the gate layer.
Form radiation holes to expose the surface of the substrate and release
Spin forming emitter tip with metallic material in the hole
In the field emission type electrode of the
Forming an oxide film on the surface of the emitter chip and the gate layer, correcting the shape of the emitter chip and adjusting the distance between the emitter chip and the gate layer by removing the oxide film. Of manufacturing a field emission electrode.