KR100223057B1 - Manufacture or field emission device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a field emission device, wherein an oxide pattern and a gate are inclined to etch a silicon wafer surface to form a tip, and the surface is thermally oxidized to sharpen the tip, and then an oxide film and a gate for insulating the gate. A metal film is deposited, and is deposited while spreading about 20 to 40 ° about a vertical axis so that the mask oxide film pattern and the portions formed on the thermal oxide film are not connected to each other, and a beam is sent in an oblique direction to deposit a sacrificial film. After the inner surface of the hole and the bottom of the silicon tip are deposited, the exposed thermal oxide layer is removed to remove the layers on the mask oxide pattern by lift-off, so that only the tip portion is exposed, and a protective film is formed on the front surface. After removing the sacrificial aluminum film and the protective film thereon, the gate is insulated from the gate covering only the tip. Since the field emission device having the arc film is formed, the protective film is coated on the silicon negative electrode tip to extend the life of the silicon tip, and the gate and the silicon negative electrode are electrically disconnected, thereby reducing the gate leakage current and increasing the voltage applied to the gate. Therefore, process yield and device operation reliability can be improved.

Description

Method of manufacturing a field emission device.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a silicon field emission device. In particular, a protective film is formed by depositing a protective film of diamond-like carbon, silicon carbide, diamond, or molybdenum after covering a gate thin film and an insulating layer with a sacrificial layer on a silicon tip. The silicon field is deposited only on the tip and does not remain on other parts of the device, so that the electrical resistance between the gate and the silicon tip remains the same as before the protective film was deposited, resulting in higher voltages across the device and preventing device destruction by dielectric breakdown. A method for manufacturing an electron emitting device.

A field emission device uses a field emission characteristic in which electrons are released into a vacuum across a potential barrier when a strong electric field is applied to the conductor, and a phenomenon in which an electric field is concentrated at an angled portion sharpens a cathode conductor to which electrons are emitted and gates at a short distance. When the device is installed, the device emits cold electrons by applying a relatively low gate voltage and cathode voltage, and the field emission current can be adjusted to a voltage applied to the gate.

Such field emission devices can be used for high speed devices with high switching speed, pressure sensors, amplification and mixing of microwaves, infrared detectors, and the like, and emit light when the emitted electrons strike the fluorescent film. Field emission displays (FEDs), which are bright, low power consumption, low production costs, and wide viewing angles, can be manufactured. The FED is a CRT high-definition and liquid crystal display (liquid crystal). Display (hereinafter referred to as LCD) has all the advantages of the light and thin type, attracting attention as a next-generation display device. In particular, the FED can not only manufacture the thin and thin, but also solve the problems of process yield, manufacturing cost, and enlargement, which are crucial disadvantages of the LCD. That is, in case of LCD, even if one unit pixel is defective, the whole product is treated as defective. However, FED has a smaller number of unit pixels in one pixel group, so even if one or two unit pixels are defective, There is no abnormality in the operation of the product, the overall yield is improved, and compared with the LCD, the structure is simple, the power consumption is small, the unit cost is low, and is suitable for the portable display device.

Initially, the FED is exposed to the outside by a cavity, and is composed of a conical cathode having a vertex, a gate arranged on both sides of the cathode, and an anode spaced apart from the gate, each of which includes a cathode, a grid, and a cathode. Corresponds to the anode.

In the FED, a voltage is applied to the cathode, and electrons are emitted by the electric field concentrated at the tip of the cathode, and the emitted electrons are guided by the anode to which a positive voltage is applied to emit the fluorescent material applied to the anode. The gate controls the direction and amount of electrons.

In the field emission device according to the prior art, if silicon is used as a cathode to make a field emission device, a highly developed semiconductor process technology can be applied, so that there is convenience such as high integration of the device and ease of processing. Disadvantages such as weakness, poor thermal conductivity, etc. make the life of the cathode not long. Therefore, a protective film is coated on the silicon anode needle with a hard, low electrical resistance and good thermal conductivity such as molybdenum, chromium, diamond-like carbon, and diamond.

In the method of manufacturing a field emission device according to the prior art as described above, after completing the triode structure of the tip-shaped cathode, the insulating film, and the gate film, the protective film is deposited, and the low-resistance protective film evenly covers all surfaces of the device. The tip and gate film are connected through a protective film, which lowers the electrical resistance between the cathode and the gate, limiting the voltage across the gate, making it difficult to properly regulate the current from the cathode, and the current leaking into the gate through the protective film increases power consumption. Increasing the temperature, increasing the temperature of the device, the operating characteristics of the device is lowered, the gate voltage is increased, the dielectric breakdown through the protective film is easy to break the device has a problem of lowering the process yield and the reliability of the device operation.

The present invention is to solve the above problems, an object of the present invention is to cover all the surface of the device, including the gate film with a thin film of aluminum, leaving only the tip of the silicon cathode needle before depositing the cathode tip protective film, diamond-like carbon After depositing a protective film such as diamond or molybdenum and wet etching the device in an acidic solution, as the aluminum thin film is dissolved, the protective film deposited on the aluminum thin film is also removed, leaving the protective film deposited at the tip of the silicon tip. The protective film is covered only on the silicon tip to prevent the reduction of the electrical resistance between the cathode and the gate, which makes the tip harder and improves the thermal conductivity to prolong the life of the tip, and prevents leakage current and dielectric breakdown, resulting in process yield and device Method for manufacturing field emission device that can improve the reliability of operation To provide.

1A to 1J are manufacturing process diagrams of the field emission device according to the present invention.

* Description of symbols for the main parts of the drawings;

101 silicon wafer 102a mask oxide film

102b: thermal oxide film 103: interlayer insulating oxide film

104: metal film 105: aluminum film

106: protective film

Features of the method for manufacturing a field emission device according to the present invention for achieving the above object

Forming a mask oxide film pattern on a silicon substrate;

Etching the silicon substrate exposed by the mask oxide film pattern to form an inclined tip;

Thermally oxidizing the surface of the silicon substrate on which the tip is formed to form a thermal oxide film to determine the size of the tip;

Forming an interlayer insulating film for insulating the gate and the tip on the thermal oxide film and the mask oxide film, but spreading at a predetermined angle with respect to the vertical axis so that the portion formed on the mask oxide film pattern and the thermal oxide film is not connected to each other and,

Forming a metal layer serving as a gate on the interlayer insulating layer, wherein the metal oxide layer is formed so that the portions formed on the mask oxide layer pattern and the thermal oxide layer are not connected to each other;

Forming an easy-to-remove sacrificial film on the entire surface of the structure, and sending a beam in an oblique direction to be deposited to the inner surface of the gate hole and the bottom of the silicon tip;

Removing the exposed thermal oxide layer and removing the layers on the mask oxide layer pattern to expose the silicon tip;

Forming a protective film on the entire surface of the structure;

And removing the sacrificial layer and the protective layer thereon to form a protective layer pattern insulated from the gate surrounding the silicon tip.

Hereinafter, a method of manufacturing a field emission device according to the present invention will be described in detail with reference to the accompanying drawings.

First, phosphorus is doped to increase electrical conductivity in a predetermined single crystal silicon wafer, for example, in the crystal direction 100, a 4 inch n-type wafer 101, and then the oxide film 102a to be used as a mask is oxidized. Grow in. (See FIG. 1A).

Thereafter, a photoresist pattern (not shown) is formed on the oxide film 102a by a photoexposure process, and then anisotropic etching of the exposed oxide film 102a using the photoresist pattern as a mask is performed by dry etching to form the oxide film 102a. Form a pattern. (See FIG. 1B).

Thereafter, using the oxide film 102a as a mask, the exposed silicon wafer 101 is isotropically etched by a dry etching method to form an inclined tip shape. (See FIG. 1C).

Then, when the surface of the wafer 101 is oxidized to form the oxide film 102b to make the silicon tip more sharp, 45% of the thickness of the oxide film grown in the oxidation furnace penetrates under the silicon so that the silicon tip is inclined. Knowing the exact thickness of the neck, this property can be used to form a sharp tip. (See FIG. 1D).

Thereafter, an oxide film 103 is deposited on the oxide film 102a and the oxide film 102b to insulate the silicon wafer 101 from the gate metal film by an electron beam deposition method. At this time, the deposited oxide film 103 is deposited while being spread at approximately 20 to 40 degrees around the vertical axis, and is not connected to a portion formed on the oxide film 102a and a portion formed on the oxide film 102b. (See FIG. 1E).

Next, a metal film 104 to be used as a gate is deposited on the oxide film 103 by electron beam deposition. In this case, the portions formed on the oxide film 102a and the portions formed on the oxide film 102b are not connected to each other by being spread out at about 20 to 30 ° around the vertical axis as in the case of depositing the oxide film. (See FIG. 1F).

Thereafter, the aluminum film to be used as a sacrificial layer by sending the flux from the horizontal direction of 20 to 30 ° while rotating the wafer 101 about the vertical axis so that the protective film does not adhere to the gate of the metal film 104 and the lower portion of the silicon tip. 105 is formed on the entire surface of the structure. At this time, the aluminum film formed on the tip is not connected to the aluminum film formed on the inclined portion. (See FIG. 1G).

Then, when the exposed oxide film 102b is removed, all of the aluminum film 105, the metal film 104, and the oxide films 103 and 102a positioned on the silicon tip are removed so that the surface of the silicon tip is removed. Exposed. (See FIG. 1H).

Subsequently, a low-resistance, high-strength protective film 106 such as diamond-like carbon, molybdenum, diamond, or the like is coated on the entire surface of the structure by a line-of-sight electron beam deposition method or laser ablation. To form. At this time, the tip portion and the sacrificial layer portion are not connected to each other. (See FIG. 1I).

Then, the aluminum film 105 is etched by a wet etching method to remove the protective film 106 deposited on the unnecessary portion by a lift-off method to complete the field emission device. (See FIG. 1J).

As described above, in the method of manufacturing the field emission device according to the present invention, the silicon wafer surface is inclined etched using the oxide film pattern as a mask to form a tip, and the surface is thermally oxidized to sharpen the tip, and then insulation from the gate is removed. Depositing an oxide film and a metal film serving as a gate, and being deposited while spreading at about 20 to 40 ° around a vertical axis so that the mask oxide pattern and the portions formed on the thermal oxide film are not connected to each other, and the beam is sent in an oblique direction. The film is deposited so that the inner surface of the gate hole and the bottom of the silicon tip are deposited, and then removing the exposed thermal oxide layer, the layers over the mask oxide pattern are lifted off, leaving only the tip portion exposed, After the protective film is formed on the sacrificial aluminum and the upper protective film is removed, the gay wrap around the tip only Since a field emission device having a protective film insulated from the dielectric layer is formed, a protective film is coated on the silicon negative electrode tip to extend the life of the silicon tip, and the gate and the silicon negative electrode are electrically disconnected, thereby reducing the gate leakage current and the voltage applied to the gate. There is an advantage that can be increased to improve the process yield and the reliability of device operation.

Claims (10)

In the method of manufacturing a silicon field emission device, Forming a mask oxide film pattern on a silicon substrate; Etching the silicon substrate exposed by the mask oxide film pattern to form an inclined tip; Thermally oxidizing the surface of the silicon substrate on which the tip is formed to form a thermal oxide film to determine the size of the tip; Forming an interlayer insulating film for insulating the gate and the tip on the thermal oxide film and the mask oxide film, but spreading at a predetermined angle with respect to the vertical axis so that the portion formed on the mask oxide film pattern and the thermal oxide film is not connected to each other and, Forming a metal layer serving as a gate on the interlayer insulating layer, wherein the metal oxide layer is formed so that the portions formed on the mask oxide layer pattern and the thermal oxide layer are not connected to each other; Forming an easy-to-remove sacrificial film on the entire surface of the structure, and sending a beam in an oblique direction to be deposited to the inner surface of the gate hole and the bottom of the silicon tip; Removing the exposed thermal oxide layer and removing the layers on the mask oxide layer pattern to expose the silicon tip; Forming a protective film on the entire surface of the structure; And removing the sacrificial layer and the protective layer thereon to form a protective film pattern insulated from the gate surrounding the silicon tip. The method of manufacturing a field emission device according to claim 1, wherein the silicon substrate has a crystal direction (100) and a 4 inch diameter n-type silicon wafer is used. The method of manufacturing a field emission device according to claim 1, further comprising a step of doping phosphorus to increase electrical conductivity of the silicon substrate. The method of manufacturing a field emission device according to claim 1, wherein the interlayer insulating film is formed of an oxide film by electron beam deposition. The method of manufacturing a field emission device according to claim 1, wherein the metal film is deposited by electron beam deposition. The method of manufacturing a field emission device according to claim 1, wherein the interlayer insulating film and the metal film are deposited so as to spread at 20 to 40 degrees about a vertical axis. The method of manufacturing a field emission device according to claim 1, wherein the sacrificial film is formed of aluminum. The method of manufacturing a field emission device according to claim 1, wherein in the sacrificial film deposition process, plasma is sent from a horizontal direction from 20 to 30 ° while the substrate is rotated about a vertical axis. The method of manufacturing a field emission device according to claim 1, wherein the protective film is formed by an electron beam deposition method or a laser ablation method. The method of manufacturing a field emission device according to claim 1, wherein the protective film is formed of diamond-like carbon, molybdenum or diamond.

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