KR100312187B1 - Method for fabrication field emission devices with diamond - Google Patents

Abstract

The present invention relates to a method for manufacturing a field electron emission device using diamond.

The manufacturing method of the present invention comprises the steps of pre-treating the surface of the substrate to finely scratch, depositing an insulating film and the first photosensitive film on the substrate in turn, patterning the first photosensitive film, the first photosensitive film as a mask Etching the insulating film, removing the first photoresist film, depositing diamond on the substrate, plasma etching the diamond to generate a whisker, removing the etched insulating film, gate insulating film on the whisker Depositing a gate metal film and a second photoresist film in sequence, patterning the second photoresist film, etching the gate metal film using the second photoresist film as a mask, removing the second photoresist film, and removing the second photoresist film. And removing the gate insulating film.

Another manufacturing method of the present invention comprises the steps of pre-treating the surface of the substrate to finely scratch, depositing a gate insulating film, a gate metal film, an insulating film and a photoresist film in sequence on the substrate, patterning the photoresist film, and masking the photoresist film Etching the insulating film, the gate metal film, and the gate insulating film, removing the photoresist film, depositing diamond on the substrate, plasma etching the diamond to generate a whisker, and removing the insulating film. It is configured to include. If the diamond is in the form of a tip instead of a whisker, depositing the diamond on the substrate, removing the insulating film, depositing an insulating film on the gate metal film and the diamond, patterning the insulating film, And etching the insulating film and the diamond using a facetting phenomenon to form a conical diamond tip.

The field emission device manufactured in this way can emit the maximum current with the minimum voltage, and the gate insulating current can be reduced by increasing the voltage applied to the gate by making the gate insulating film thickest.

Description

Method for fabricating field electron emitting devices using diamonds {Method for fabrication field emission devices with diamond}

The present invention relates to a method for manufacturing a field electron emission device using diamond, and more particularly, depositing diamond in a gate hole and etching with a gas plasma containing air or oxygen to obtain the maximum field emission electron with a minimum gate voltage. It relates to a method for manufacturing a field electron emission device.

Generally, molybdenum, silicon, and the like have been used as a cathode material in the manufacture of the field electron emission device, but there are problems such as oxidation of the surface, abrasion by ion collision, and difficulty in reproducible processes. For this reason, diamond, which is hard and does not react with surrounding gas, has been studied as a cathode material of a new field emission device.

The cathode material of the field electron emission device generally takes the form of a thin film, which is difficult to use in an electronic device due to the uneven position of the field emission, and is difficult to attach the gate. Attempts are being made to sharpen. Etching the silicon wafer into an inverted pyramid shape and filling the hole with diamond by chemical vapor deposition followed by melting the silicon to form pyramid-aligned diamond needles, but this method is difficult to make the diamond sharp enough. It can be used only once, so it is expensive.

In order to solve this problem, U.S. Patent 4,957,591 proposes a method for manufacturing diamond into dry needles by dry etching with oxygen plasma, etc.The density of diamond needles is randomly generated only at grain boundaries of polycrystalline thin films. There is a problem that it is difficult to obtain a high and uniform needle. In US Patent 5,844, 252, which is proposed by another method, it is proposed to dry-etch a diamond needle to process the device with a gate. However, since a diamond thin film is also present in the lower portion of the gate film, the thickness of the gate insulating film cannot be applied. Even when a voltage is applied, there is a problem that the insulating film is broken or a current is likely to leak to the gate.

Accordingly, the present invention provides a method for manufacturing a field electron emission device having an optimal structure that emits a maximum current at a minimum voltage and reduces the gate leakage current while increasing the gate voltage in order to solve the above problems. It is aimed.

In accordance with another aspect of the present invention, there is provided a method of preliminarily treating a surface of a substrate, applying a fine scratch, depositing an insulating film and a first photoresist film on the substrate, and patterning the first photoresist film. 1, etching the insulating film using a photoresist film as a mask, removing the first photoresist film, depositing diamond on the substrate, and plasma-etching the diamond to form a whisker; Generating the same pointed shape), removing the etched insulating film, depositing a gate insulating film, a gate metal film, and a second photosensitive film on the whisker in turn, patterning the second photosensitive film, and forming the second photosensitive film. Etching the gate metal layer using the photosensitive layer as a mask; And removing the photoresist film and the gate insulating film over the whisker.

Another manufacturing method of the present invention comprises the steps of pre-treating the surface of the substrate to finely scratch, depositing a gate insulating film, a gate metal film, an insulating film and a photoresist film in sequence on the substrate, patterning the photoresist film, and masking the photoresist film Etching the insulating film, the gate metal film, and the gate insulating film, removing the photoresist film, depositing diamond on the substrate, plasma etching the diamond to generate a whisker, and removing the insulating film. It is configured to include.

Another manufacturing method of the present invention comprises the steps of pre-treating the surface of the substrate to finely scratch, depositing a gate insulating film, a gate metal film, a first insulating film and a photoresist film sequentially on the substrate, patterning the photoresist film, the photosensitive film Etching the first insulating film, the gate metal film and the gate insulating film as a mask, removing the photoresist film, depositing diamond on the substrate, removing the first insulating film, removing the first insulating film, And depositing a second insulating film, patterning the second insulating film, and etching the second insulating film and diamond by using a faceting phenomenon to form a diamond tip.

When the field electron emission device is manufactured in this manner, a relatively sharp needle can be obtained because the metal film is used as a mask without using the lithography method used in the semiconductor device process, and thus a large amount of current can be emitted at a low voltage. By controlling the thickness of the gate insulating film, it is possible to obtain an effect of reducing the gate leakage current while increasing the applied voltage.

1a to 1l is a process diagram of a method for manufacturing a field electron emission device according to Example 1 according to the present invention

Figure 2a to 2g is a process chart of the method for manufacturing a field electron emission device according to the second embodiment of the present invention.

Figure 3a to 3i is a process chart of the method for manufacturing a field electron emission device according to the third embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings the present invention will be described in detail.

Example 1

According to Embodiment 1 of the present invention as shown in FIGS. 1A-1L, a step of pretreating the surface of the silicon or glass substrate 10 to apply a fine scratch to preferentially grow diamond (FIG. 1A), the pretreated Depositing a gate insulating film 11 such as a silicon oxide film and the first photosensitive film 12 in order to pattern a diamond whisker on the substrate 10 (FIG. 1B), and patterning the first photosensitive film 12. Step (FIG. 1C). Etching the gate insulating film 11 using the first photosensitive film 12 as a mask (FIG. 1D), removing the first photosensitive film 12 (FIG. 1E), and the diamond 13 in silicon or glass Depositing on the substrate 10 (FIG. 1F), applying a negative bias to the substrate 10, and etching the diamond 13 with a gas plasma to generate a whisker 13a (FIG. 1G), wherein the whisker ( After the 13a is formed, the insulating layer 11 is removed (FIG. 1H), and the gate insulating layer 14, the gate metal layer 15, and the second photosensitive layer 16 are sequentially deposited on the whisker 13a. (I), patterning the second photosensitive film 16 (FIG. 1J), etching the gate metal film 15 using the second photosensitive film 16 as a mask (FIG. 1K), and the second 2 removing the photoresist film 16 and removing the gate insulating film on the upper portion of the whisker 13a (FIG. 1L) Diamond needles triode device is completed.

Example 2

According to the second embodiment of the present invention as shown in Figs. 2a to 2g, a step of pretreating the surface of the silicon or glass substrate 20 to apply a fine scratch to preferentially grow diamond (Fig. 2a), the pretreatment Depositing a gate insulating film 21, a gate metal film 22, an insulating film 23, and a photosensitive film 24 on the substrate 20 in sequence (FIG. 2B), and patterning the photosensitive film 24 (FIG. 2C). ), Etching the insulating film 23, the gate metal film 22, and the gate insulating film 21 using the photosensitive film 24 as a mask (FIG. 2D), removing the photosensitive film 24, and removing diamond. Depositing 25 on the substrate 20 (FIG. 2E), plasma etching the diamond 25 to generate a whisker 25a (FIG. 2F), and removing the insulating film 23 (2g). The diamond needle triode element is completed.

Example 3

According to the third embodiment of the present invention as shown in FIGS. 3A to 3, a step of finely scratching the surface of the substrate 30 by pretreatment (FIG. 3A), the gate insulating layer 31 on the substrate 30, Depositing the gate metal film 32, the first insulating film 33, and the photosensitive film 34 in sequence (FIG. 3B), patterning the photosensitive film 34 (FIG. 3C), and using the photosensitive film 34 as a mask. Etching the first insulating film 33, the gate metal film 32 and the gate insulating film 31 (FIG. 3D), removing the photosensitive film 34, and depositing diamond 35 on the substrate (FIG. 3e), removing the first insulating film 33 (Fig. 3f), depositing a second insulating film 36 on the gate metal film 32 and the diamond 35 (3g), and the second insulating film Step 3h of patterning 36, the second insulating layer 36 and the diamond 35 are etched using faceting to form a conical diamond tip 3. A diamond triode element is completed through step 3i of forming 5a).

For the materials used in Examples 1, 2 and 3, the following method is used.

In the gate insulating layers 14, 21, and 31, if the thicknesses of the gate insulating layers 14, 21, and 31 are too thick, the length of the diamond whiskers 13a, 25a and the tip 35a becomes long, which is a problem. If too thin, dielectric breakdown easily occurs, so a sufficient voltage cannot be applied, so a thickness of several micrometers is appropriate.

In addition, the gate metal layers 15, 21, and 31 are sputtered by plasma ions to be an automatic source of mask material during diamond dry etching, and are deposited thinly on the side surfaces of the diamond whiskers 13a, 25a and the tip 35a. Since it serves to form a protective film so as not to be etched any more, it is deposited sufficiently thick in consideration of this. However, if the gate metal films 15, 22, and 31 are too thick, they may adversely affect the amount and trajectory of the emitted electrons, so that the amount of sputtered and lost during diamond needle etching and the optimum thickness of the finished device after the process is finished In consideration of the appropriate deposition.

In this process, the diamonds 13, 25 and 35 are adjusted to grow the diamond to an appropriate height so that the optimum device structure can be obtained to obtain the maximum field emission electrons with the minimum gate voltage in the range where the emitted electron beam does not spread too much. do.

In Examples 1 and 2, a thin film of a metal thin film capable of withstanding oxygen plasma is used as a mask without using a conventional lithography method in the above process. When a small amount of metal is coated on the diamonds 13 and 25 by sputtering or thermal vapor deposition, deposition is performed in the form of clusters. The size of the clusters is several tens of nm, and the interval is less than 100 nm. Diamond whiskers 25a and 35a less than 100 nm apart can be made.

In addition, since the directions of the diamond whiskers 13a and 25a are parallel to the incident angles of the etch ions, the direction of the whiskers can be arbitrarily determined by tilting the substrate or adjusting the direction of the electrode to change the ion incident angle.

During the etching of the diamond whiskers 13a and 25a, a mass of metal made of a metal material such as Mo, which is a mask material, and placed in a proper position near the substrate without depositing the mask metal by the plasma for diamond etching Sputtered to deposit on the whisker side.

To sharpen the diamond whiskers 13a and 25 after removing the mask, the sputtering by ion bombardment is greater than 70 degrees when the ion incidence is 90 degrees, so the diamond needle is sputtered with an ion beam incident in the direction parallel to the diamond whisker. Just do it. At this time, the whisker will be damaged if the ion beam treatment is performed for a long time.

In Examples 1, 2 and 3, after the etching is completed, the mask material is removed on the diamond whiskers 13a, 25a and the tip 35a by a wet or dry method and treated with a plasma or an ion beam to make it more sharp. Handling whiskers and tips in this way can improve the electrical conductivity of diamond whiskers and tips.

In the third embodiment, since the diamond tip is formed by using the faceting phenomenon of the second insulating film 36, by adjusting the thickness of the second insulating film 36, the angle of the conical diamond tip or the side inclination angle is adjusted. It is possible. That is, as the thickness of the second insulating film increases, the time taken for the diamond beneath the second insulating film to be exposed increases, so that the side slope of the conical diamond tip 35a is increased, and as a result, a sharp tip can be obtained.

The device creates multiple diamond whiskers in one gate hole, so electrons from the cathode needle close to the gate can spread to the side. To prevent this, repeat stacking the gate insulating film and the gate metal film two or more times, stacking the multilayer film, and forming a whisker and a tip by depositing diamond only to the gate metal film, which is formed in the bottom layer in the same manner as mentioned above. The metal film can be used as an electronic lens for controlling the trajectory of the field emission electrons by applying an appropriate voltage.

The diamond cathode field emission device fabricated as described above is a triode tube with a gate, so that electrons can be emitted at a lower voltage than the dipole tube, thereby lowering the driving voltage of the device. In addition, since the diamond cathode whisker triode can arbitrarily adjust the height, aspect ratio, sharpness, density, etc. of the diamond whisker, it is advantageous to manufacture a field emission triode having an optimized structure to obtain the maximum current at the minimum voltage. The diamond cathode field emission device manufactured as described above may be used in electron emission devices such as a field emission flat panel display, a rear light emitting device of a liquid crystal display, an ultra small high efficiency microwave amplifier, an ultra small electron gun, and an ion gun.

Claims (9)

Pretreating the substrate surface to apply fine scratches; Sequentially depositing an insulating film and a first photoresist film on the pretreated substrate; Patterning the first photoresist film; Etching the insulating film using the first photosensitive film as a mask; Removing the first photoresist film; Depositing diamond on the substrate; Gas plasma etching the diamond to generate a whisker; Removing the etched insulating film; Sequentially depositing a gate insulating film, a gate metal film, and a second photoresist film on the whisker; Patterning the second photoresist film; Etching the gate metal film using the second photosensitive film as a mask; and And removing the second photosensitive film. Pretreating the substrate surface to apply fine scratches; Depositing a gate insulating film, a gate metal film, an insulating film, and a photoresist film on the pretreated substrate; Patterning the photosensitive film; Etching the insulating film, the gate metal film, and the gate insulating film using the photosensitive film as a mask so that a substrate is exposed; Removing the photosensitive film; Depositing diamond on the substrate and performing plasma etching to produce a whisker; And removing the insulating film. The method according to claim 1 or 2, wherein a negative bias voltage is applied to the substrate, and metal clusters such as Mo are deposited before etching the diamond to be etched by gas plasma. The metal sputtered by plasma ion bombardment according to claim 1 or 2, wherein during the diamond etching, a metal mass such as Mo is placed in an etching chamber so that a metal thin film is deposited on the side of the whisker. Method of manufacturing a field emission device characterized in that deposited on the side of the diamond whisker being etched to form a thin protective film to increase the density of the whisker. Pretreating the surface of the substrate to finely scratch; Sequentially depositing a gate insulating film, a gate metal film, a first insulating film, and a photosensitive film on the substrate; Patterning the photosensitive film; Etching the photosensitive film, the first insulating film, the gate metal film, and the gate insulating film using the photosensitive film as a mask; After removing the photoresist, depositing diamond on the substrate; Removing the first insulating film; Depositing a second insulating film on the gate metal film and diamond; Patterning the second insulating film; And forming a diamond tip by etching the second insulating film and the diamond by using a facetting phenomenon. 6. The method of claim 5, wherein the angle of the diamond tip or the side inclination angle can be adjusted by adjusting the thickness of the second insulating film. The method of claim 1, wherein the contact interface between the substrate, the diamond whisker and the diamond tip is heated to an ohmic contact point through which current can flow in proportion to a given voltage without a potential barrier. A field emission device manufacturing method characterized in that the physicochemical treatment for injecting foreign substances. The method according to any one of claims 1 to 3, wherein after the etching is finished, the mask material is removed by a wet or dry method on the diamond whisker and treated with a gas plasma or an ion beam to make it more sharp. 4. A method according to any one of claims 1 to 3, wherein the gate insulating film and the gate metal film are repeatedly stacked two or more times, and the diamond is deposited only to the gate metal film so as to form the lowest layer.