JP2987372B2 - Electron-emitting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a field emission type electron-emitting device.

[Conventional technology]

2. Description of the Related Art Field emission electron-emitting devices have attracted attention as electron sources for thin displays and for micro vacuum tubes. In particular, the twelfth
Planar electron-emitting devices as shown in the figure have been studied as having high possibility of practical use due to ease of production.

The structure of the electron-emitting device will be described with reference to FIG. 12. First, on an insulating substrate 100, an emitter 102 having a plurality of protruding portions 101 formed in a comb shape is provided. A gate 104 having an opening 103 corresponding to each of the protruding ends 101 is provided adjacent to the emitter 102. An anode 105 is provided in parallel with the gate 104 on the insulating substrate 100 opposite to the emitter 102 with the gate 104 therebetween.

Here, between the emitter 102 and the gate 104, and the gate 10
When a predetermined potential difference is applied between the anode 4 and the anode 105, electrons are emitted from the tip 101 of the emitter 102, and these electrons strike the anode 105 through the opening 103 of the gate 104.

Conventional general steps for forming such a planar electron-emitting device will be described with reference to FIGS.

As shown in FIG. 8, a high melting point metal such as tungsten 11 (W11) is deposited on a glass substrate 10 to a thickness of about 1 μm.

A photoresist is coated on the W11, and prebaking, mask exposure, development, and postbaking are performed to obtain a resist layer 12 having a desired pattern as shown in FIG.

Next, as shown in FIG. 10, W11 is dry-etched. Thereafter, when the resist layer 12 is peeled off, a planar electron-emitting device comprising an emitter and a gate formed in a predetermined pattern as shown in FIG. 11 is obtained.

[Problems to be solved by the invention]

According to the electron-emitting device having the conventional structure in which the electrode portion is formed only of the W layer as described above, the tip of the emitter formed in a comb-like pattern cannot be sufficiently sharpened,
There has been a problem that the electron emission start voltage becomes high and a large current cannot be obtained. This is presumably because in the etching step shown in FIG. 10, because the resistance of the resist layer 12 is not sufficient, the vicinity of the tip of the W layer is easily etched and rounded as shown in FIG.

The present invention has been made in view of the above-described problems, and has as its object to provide an electron-emitting device having a structure capable of sufficiently sharpening a tip of a planar pattern of an emitter from which electrons are emitted. I have.

[Means for solving the problem]

The electron-emitting device of the present invention has a structure in which W, SiN, and Al are formed on an insulating substrate.
Are sequentially laminated.

[Action]

In dry etching during the manufacturing process, the edge of W becomes sharp because Al serves as a mask. Also, since there is SiN as a buffer layer between Al and W, Al and W do not form a compound.

〔Example〕

The structure of the electron-emitting device according to one embodiment of the present invention
The description will be made according to the manufacturing steps shown in FIGS.

After cleaning the insulating substrate 1 made of quartz, glass, or the like,
As shown in FIG. 1, a tungsten layer 2 (W
Layer 2), silicon nitride layer 3 (SiN layer 3) and aluminum layer 4 (Al layer 4) are sequentially deposited. In this embodiment, W
The thickness of the layer 2 was 1 μm, the thickness of the SiN layer was 10 nm, and the thickness of the Al layer was 100 nm.

A photoresist 5 is applied to the surface of the Al layer 4, exposed and developed, and patterned into a planar shape of the electron-emitting device as shown in FIG.

As shown in FIGS. 3 (A) and 3 (B), patterning is performed so that the upper Al layer 4 is etched by wet etching. Here, since the Al layer 4 and the W layer 2 are separated from each other by the SiN layer 3, there is no inconvenience that the Al and W form a solid solution and the wet etching of the Al layer 4 cannot be performed.

FIG. 4 (A), as shown in (B), RIE using SF ₆
(Reactive Ion Etching) dry-etches the lower W layer 2. Here, the upper Al layer 4 functions as a mask having sufficient resistance to dry etching. Therefore, the lower W layer 2 is not rounded at the edges and is etched corresponding to the pattern of the Al layer 4, so that the planar comb-like pattern of the emitter becomes sharp.

As shown in FIGS. 5 (A) and (B), buffered HF
Is used to etch the insulating substrate 1.

As shown in FIGS. 6A and 6B, the resist layer 5 is peeled off to obtain an electron-emitting device.

As shown in FIGS. 7 (A) and (B), the Al layer 4 and the SiN layer 3 can be removed to form an electron-emitting device using only W.

According to the electron-emitting device of the present embodiment configured as described above, the radius of the tip of the comb-shaped emitter is 0.3 μm
When the distance between the gate and the emitter is 10 μm.
Electron emission was obtained from 0V.

For comparison with the above embodiment, when an element having the same structure as that of the embodiment except for SiN was made, it was found that Al and W were dissolved in a solid solution, so that the Al layer could not be wet-etched and was patterned. Could not.

Further, in order to make a comparison with the above embodiment, a W layer was deposited to a thickness of 1 μm, and this was patterned by dry etching with SF ₆ to produce an element having a single-layer structure as in the prior art. The tip has a radius of 0.5 μm, which is considerably rounder than that of the above-described embodiment. When the distance between the gate and the emitter is 10 μm, the voltage is twice that of the above-described embodiment.
Unless a potential difference of 400 V was applied, electron emission could not be obtained.
That is, it was demonstrated that the electron emission start voltage was lower in the example.

〔The invention's effect〕

The electron-emitting device of the present invention has a structure in which W, SiN, and Al are formed on an insulating substrate.
Are sequentially laminated, the following effects can be obtained.

1) The reaction between Al and W is prevented by SiN, and Al etching can be performed as usual.

2) Since Al in the upper layer serves as a mask and the shape of W in the lower layer is maintained in a predetermined pattern, an emitter having a sharp planar pattern can be obtained.

3) From 2), the field emission start voltage can be reduced.

[Brief description of the drawings]

FIGS. 1, 2, 3 (A), 4 (A), 5 (A), 6 (A) and 7 (A) each show one embodiment of the present invention. 3 (B), FIG. 4 (B), FIG. 5 (B), FIG. 6 (B), and FIG. 7 (B) each show a manufacturing process of the example in FIG. A), FIG. 4 (A), FIG. 5 (A), FIG. 6 (A) and FIG. 7 (A)
8, 9, 10 and 11 are cross-sectional views each showing an example of a manufacturing process of a conventional electron-emitting device, and FIG. 12 is an example of a conventional electron-emitting device. FIG. 1. Insulating substrate 2. Tungsten layer (W) made of tungsten (W)
3) Silicon nitride layer (S) composed of silicon nitride (SiN)
iN layer), 4 ... Aluminum layer (Al) made of aluminum (Al)
layer).

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuo Yamaura 629 Oshiba, Mobara-shi, Chiba Examiner at Futaba Electronics Co., Ltd. ) Surveyed field (Int.Cl. ⁶ , DB name) H01J 1/30

Claims (1)

(57) [Claims] 1. A field emission device having a structure in which W, SiN, and Al are sequentially laminated on an insulating substrate.