KR19980037809A - Manufacturing method of silicon tip field emitter coated with diamond carbon thin film - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tripolar silicon tip field emitters used in field emission display devices, and more particularly by uniformly coating a diamond-like carbon thin film on the silicon tip surface of a tripolar silicon tip field emitter without breaking the tip. The present invention relates to a method for fabricating a silicon tip field emitter with improved current-voltage characteristics, emission current density and lifetime.

Description

Fabrication method of silicon tip field emitter coated with diamond carbon thin film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a silicon tip field emitter that emits electrons by an electric field in a field emission display device, and in particular, a RPCVD method on a silicon tip of a tripolar silicon tip field emitter. The present invention relates to a method of manufacturing a silicon tip field emitter coated with a diamond carbon thin film coated with diamond carbon to prevent breakage of the tip and to improve electron emission characteristics.

Conventional tripolar silicon tip field emitters were fabricated in a process as shown in FIGS. 1A-1G. First, FIG. 1A illustrates a phosphorus ion diffusion layer 11 by implanting phosphorous ions into a P-type silicon wafer 10 to have a height sufficient to form a cathode electrode and a silicon tip. 11) After the silicon oxide film is formed on the upper portion, the silicon oxide film other than the portion where the tip is to be formed is etched to form the oxide mask 12. Next, FIG. 1B etches the exposed phosphorus ion diffusion layer 11 other than the oxide mask of FIG. 1A by reactive ion etching to form a silicon tip emitter 14 and a cathode electrode 13. The tip of the cathode electrode 13 and the silicon tip emitter 14 is sharpened by a sharp oxidation process. Next, FIG. 1C illustrates the removal of the sharpening oxide film (not shown) and the oxide mask 12 of FIG. 1B by wet etching, and then the cathode 16 and the silicon tip 13 to be selectively etched with the insulator 16 to be described later. 14) A silicon nitride film 15 is formed on the surface, and an insulator 16 is formed conformally on the silicon nitride film 15 along the shape of the tip 14. At this time, the thickness of the insulator 16 determines the distance between the gate electrode 17 and the tip emitter 14 which will be described later. In addition, the material of the insulator 16 is SOG (Spin-On-Glass), BPSG (Borophosphosilicate Glass), polyimide, etc. to facilitate the planarization through a reflow process, which is a post-process. . Next, FIG. 1D shows that the insulator 16 of FIG. 1C is planarized to expose the tip of the silicon nitride film 15 through a reflow process. At this time, when the insulator 15 is BPSG, the reflow step is performed in the range of 700 to 1,000 ° C. 1E shows the formation of a gate metal layer 17 or gate electrode at an equiangular surface along the surfaces of the planarized insulator 16 and exposed silicon nitride film 15 of FIG. 1D. Next, FIG. 1F illustrates that the conformal gate metal layer 17 of FIG. 1E is etched by a chemical mechanical polishing (CMP) process to expose the silicon nitride film 15 on the silicon tip emitter 14. 1G is a three-pole type fabricated by wet etching the exposed silicon nitride film 15 by planarizing the gate metal layer 17 of FIG. 1F, and subsequently wet etching the insulator 16 so that the silicon tip 14 is completely exposed. Silicon tip field emitters are shown.

The silicon tip field emitter manufactured by the above process is aligned with the upper substrate 30 on which the anode electrode 31 and the phosphor 32 are formed as shown in FIG. The display element is completed. When the gate voltage 35 of about 100 V is applied to the gate electrode 17 and the cathode electrode 13 of the field emission display device having the silicon tip field emitter manufactured as described above, the gate electrode 17 and the tip emitter ( An electric field is formed between the layers 14 and electrons 33 are emitted from the tip of the silicon tip emitter 14 by the electric field. At this time, when the anode voltage 34 is applied to the anode electrode 31 and the cathode electrode 13, the electrons 33 emitted by the anode electrode 31 are accelerated to stimulate the phosphor 32 to function as a field emission display device. Will be performed.

The conventional silicon tip field emitter described above has a problem in that the luminance is lowered when the silicon tip field emitter is used in the field emission display device because the emission current density is smaller than that of the metal. Since it is very sharp as about 400 kPa, there is a problem in that when the ionized gas collides with the electrons emitted during operation, it is easily broken.

In order to solve the above problems, there has been an effort to coat diamond films having high hardness and high hardness on the surface of silicon tip emitters with improved conventional techniques. However, in general, polycrystalline diamond thin films manufactured by thermal filament CVD or microwave CVD have island growth, so that uniform deposition is not possible at a thickness of less than 100 μs, resulting in uneven emission characteristics when applied to field emitters. As a result, it is difficult to apply to the field emission display device.

Accordingly, the present invention provides uniform deposition of diamond-like carbon on the tip and cathode electrode surfaces of silicon tip field emitters without rupturing the silicon tip emitters. The purpose is to improve the life of the emitter.

1A to 1G are cross-sectional views sequentially illustrating a manufacturing process of a conventional tripolar silicon tip field emitter.

FIG. 2 is a cross-sectional view showing a field emission display device using a tripolar silicon tip field emitter manufactured by the process of FIGS. 1A to 1G;

3A to 3F are cross-sectional views sequentially illustrating a manufacturing process of a tripolar silicon tip field emitter coated with a diamond-like carbon thin film according to the present invention.

4 is a cross-sectional view of a field emission display device using a tripolar silicon tip field emitter coated with a diamond-like carbon thin film manufactured by the process of FIGS. 3A to 3F.

Explanation of symbols on the main parts of the drawing

10,20: silicon wafer 11,21: phosphorus ion diffusion layer

12,22 mask 13,23 cathode electrode

14,24 silicon tip 15 silicon nitride film

16,26: insulator 17,27: gate electrode

25 diamondy carbon 28 planarization layer

30: upper substrate 31: anode electrode

32: phosphor 33: electron

34: anode voltage 35: gate voltage

The present invention relates to a method of coating a diamond-like carbon thin film on the surface of a cathode and a tip of a silicon tip field emitter by RPCVD, and is manufactured by a sequential process as shown in FIGS. 3A to 3F.

First, since FIGS. 3A and 3B are the same as those of FIGS. 2A and 2B, the detailed description thereof will be omitted. Next, FIG. 3C shows a diamond-like carbon thin film 25 coated on the cathode electrode 23 and the silicon tip 24 of FIG. 3B with a thickness of about 300 to 600 kPa by RPCVD. Next, 3D forms an insulator 26 and a gate electrode 27 on the diamond-like carbon thin film 25 of FIG. 3C in order to conformally conform to the shape of the tip emitter 24, and the gate formed at the conformal angle. The planarization layer 28 is formed by depositing a photoresist on the electrode 27 by spin coating. 3E shows that the planarization layer 28 of FIG. 3D is etched by argon sputtering etching so as to expose the tip of the gate electrode 27 formed conformally on the tip emitter 24. Next, FIG. 3F etches the exposed gate electrode 27 of FIG. 3E by reactive ion etching, and then wets the insulator with the tip of the silicon tip 24 coated with the diamond-like carbon thin film 25. After etching to expose, the planarization layer 28 remaining above the gate electrode 27 is removed to show a silicon tip field emitter coated with the finished diamondoid carbon thin film.

Using the silicon tip field emitter coated with the diamond-like carbon thin film manufactured by the above-described process, the anode electrode 31 and the phosphor 32 were formed through a spacer (not shown) as shown in FIG. The formed top substrate 30 is aligned and manufactured to manufacture a field emission display device.

When a gate voltage 35 of about 100 V is applied to the gate electrode 27 and the cathode electrode 23 of the field emission display device having the silicon tip field emitter coated with the diamond-like carbon thin film 25 shown in FIG. An electric field of about 1 V / Å or more is generated between the rotor 24 and the gate electrode 27 to emit electrons 33 from the tip 24, which is applied to the anode electrode 31 and the cathode electrode 23. The electrons 33 emitted by the anode voltage 31 are accelerated to the anode electrode 31, and the accelerated electrons 33 stimulate the phosphor 32 to perform the function of the field emission display device.

The present invention can reduce the threshold voltage required for electron emission by coating a diamond-like carbon thin film on the surface of the silicon tip emitter and the cathode as described above to lower the gate voltage, uniform electron emission current density, emission The uniformity of is improved. In addition, the tip of the emitter can be prevented from being damaged by the collision of ions generated during the operation of the silicon tip emitter, which improves the reliability and life of the emitter. Since the gas is generated less, the adsorption and desorption of the gas may be improved to reduce the noise by improving the stability of the discharge current.

In addition, since the diamond-like carbon thin film is coated on the silicon tip surface by RPCVD method, the energy of the deposited material is minimized to prevent the tip of the silicon tip from being damaged by the impact during coating of the diamond-like carbon thin film.

In addition, the manufacturing cost can be lowered by coating the photoresist with the planarization layer and etching it by the argon sputtering method.

Claims (5)

Implanting phosphorus ions into the silicon wafer to form a diffusion layer, and forming a silicon oxide film mast on a portion where the tip of the diffusion layer is to be formed; Etching the exposed diffusion layers other than the oxide mask to form a silicon tip and a cathode electrode under the oxide mask, and then forming a sharp oxide film to sharpen the tip tip; After removing the oxide mask and the oxide oxide which is sharp, coating a diamond-like carbon thin film on the exposed tip and the cathode electrode surface; Forming a planarization layer so as to completely cover the gate metal layer over the gate metal layer and the insulating layer formed on top of the tip; Forming an insulator and a gate metal layer in conformal shape on a tip of the diamond-like carbon thin film along the shape of the tip; Forming a planarization layer on the gate metal layer to completely cover the gate metal layer; Etching the planarization layer over the gate metal layer to expose the tip of the gate metal layer over the tip; Etching the gate metal layer exposed by the etching of the planarization layer, and subsequently etching the insulator such that the tip coated with the diamond-like carbon thin film is exposed at its tip; And removing the planarization layer remaining after etching the insulator. The method of claim 1, A method of manufacturing a silicon tip field emitter coated with a diamond carbon film, characterized in that the diamond electrode is coated with a diamond carbon thin film on the tip and the tip by a Remote Plasma Chemical Vapor Deposition (RPVCD) method. The method according to claim 1 or 2, The diamond-like carbon thin film is coated with a diamond-like carbon thin film, characterized in that the coating of a thickness of about 300 ~ 600Å. The method of claim 1, And a planarization layer formed on the gate metal layer is a photoresist. The method of claim 1, And a planarization layer on the gate metal layer is etched using an argon ion etching method.