CN107367877B

CN107367877B - Liquid crystal display panel and preparation method of pixel unit thereof

Info

Publication number: CN107367877B
Application number: CN201610318473.5A
Authority: CN
Inventors: 肖德元
Original assignee: Zing Semiconductor Corp
Current assignee: Zing Semiconductor Corp
Priority date: 2016-05-13
Filing date: 2016-05-13
Publication date: 2020-12-11
Anticipated expiration: 2036-05-13
Also published as: CN107367877A; TW201740164A; TWI665493B

Abstract

In the liquid crystal display panel and the method for manufacturing the pixel unit thereof provided by the invention, the graphene material is deposited and grown on the glass substrate, and is used as the channel of the field effect transistor and the lower electrode material of the storage capacitor, so that the advantages of light transmittance of glass, electric conductivity, heat conductivity, surface hydrophobicity and the like of graphite are achieved, and the brightness of the display panel is improved.

Description

Liquid crystal display panel and preparation method of pixel unit thereof

Technical Field

The invention relates to the technical field of semiconductors, in particular to a liquid crystal display panel containing a graphene layer and a transparent conducting layer and a preparation method of a pixel unit of the liquid crystal display panel.

Background

A Thin Film Transistor liquid crystal display (TFT-LCD) is provided with a Transistor in each pixel of a picture, so that the display has the advantages of brighter brightness, richer colors, wider visible area, fast response speed, good contrast, high brightness, large visible angle, and the like. The TFT-LCD panel sequentially comprises an upper polarizing plate, an upper glass substrate, a color filter, a common electrode, liquid crystal, a field effect transistor electrode deposited on a bottom glass substrate, a bottom polarizing plate, a backlight plate and a backlight source from the upper surface to the lower surface. The backlight source is emitted from the backlight plate, controlled by the liquid crystal and the upper and lower polarizing plates, and passes through the color filter to generate colorful images.

One important specification in LCDs is brightness. Please refer to fig. 1A, which is a top or bottom view of a pixel unit of an LCD panel of the prior art. As shown in fig. 1A, the pixel unit includes two parallel source lines S and two parallel gate lines G perpendicular to the source lines S, the source lines S and the gate lines G define a pixel region P1, and the pixel region P1 includes a transistor TFT, a display electrode D and a capacitor electrode C. When the backlight source emits light from the backlight panel, not all light can pass through the LCD panel, such as the gate lines G and the source lines S, the transistors TFT and the capacitor electrodes C, and besides the light is not completely transmitted, the light passing through these portions is not controlled by the voltage and cannot display correct gray scale, so that the light needs to be shielded by a black matrix (black matrix) so as to avoid interfering with the correct brightness of other light-transmitting areas in the pixel area P1.

Please refer to fig. 1B, which is a light-transmitting schematic diagram of the pixel region P1 of fig. 1A. As shown in fig. 1B, the ratio of the effective light-transmitting area L1 to the pixel area P1 is the aperture ratio, which is a key factor in determining the LCD panel, and affects the brightness requirement of the backlight source. Therefore, it is an important subject to improve the aperture ratio.

Disclosure of Invention

The present invention is directed to a liquid crystal display panel and a method for manufacturing a pixel unit thereof, so as to solve the problem of low aperture ratio of the liquid crystal display panel in the prior art.

To solve the above problems, the present invention provides a liquid crystal display panel, comprising:

a glass substrate;

a plurality of row scanning lines arranged in parallel on the glass substrate;

a plurality of row scanning lines arranged in parallel on the glass substrate, the row scanning lines and the column scanning lines being arranged perpendicular to each other to define a plurality of pixel regions, each pixel region having a pixel unit, the pixel unit comprising:

the transistor is formed on the glass substrate and comprises a gate electrode, a source electrode and a drain electrode, the gate electrode is electrically connected with one of the row scanning lines, and the source electrode is electrically connected with one of the row scanning lines;

the display electrode is formed on the glass substrate and is electrically connected with the drain electrode;

the storage capacitor is formed on the glass substrate, electrically connected to the display electrode, and provided with a transparent conductive layer as an upper electrode and a graphene layer as a lower electrode;

the transistor further comprises a dielectric layer, the dielectric layer is formed between the grid electrode and the glass substrate, graphene materials are arranged between the dielectric layer and the glass substrate, and the source electrode and the drain electrode are respectively arranged on two opposite sides of the dielectric layer to form a graphene tunneling channel.

Optionally, in the lcd panel, the transparent conductive layer is made of indium tin oxide, aluminum zinc oxide, or gallium zinc oxide.

Optionally, in the liquid crystal display panel, the dielectric layer is made of a high dielectric constant material.

Optionally, in the liquid crystal display panel, the dielectric layer is made of any one of titanium dioxide, hafnium dioxide and zirconium dioxide, or any combination thereof.

Optionally, in the liquid crystal display panel, the gate electrode, the source electrode, and the drain electrode are made of any one or any combination of chromium, gold, nickel, tungsten, titanium, or titanium nitride.

Correspondingly, the invention also provides a preparation method of the pixel unit of the liquid crystal display panel, which comprises the following steps:

providing a glass substrate;

forming a graphene layer on the glass substrate, the graphene layer having a first opening exposing the glass substrate, the first opening dividing the graphene layer into a first region and a second region;

forming a dielectric layer, wherein the dielectric layer is provided with a third region covering the first region, a fourth region covering a part of the glass substrate exposed to the first opening and a fifth region covering a part of the second region so as to form a second opening exposing the glass substrate, and a third opening and a fourth opening exposing the second region, the third region and the fourth region are connected, and the third opening and the fourth opening are respectively arranged at two opposite sides of the fifth region;

forming a transparent conductive layer having a sixth area covering the third area and a seventh area covering the fourth area to form a fifth opening exposing the second, third, fifth and fourth openings; and

forming an electrode layer including a drain electrode, a gate electrode, and a source electrode, the drain electrode having an eighth region covering a portion of the seventh region, a ninth region covering the glass substrate exposed to the second opening, and a tenth region covering the graphene layer exposed to the third opening, the gate electrode being formed on the fifth region, the source electrode covering the graphene layer exposed to the fourth opening, the eighth, ninth, and tenth regions being connected to each other;

the transparent conductive layer is used as an upper electrode of the storage capacitor, and the graphene layer is used as a lower electrode of the storage capacitor.

Optionally, in the method for manufacturing a pixel unit, the dielectric layer is made of a high dielectric constant material.

Optionally, in the preparation method of the pixel unit, the material of the dielectric layer includes any one of titanium dioxide, hafnium dioxide, and zirconium dioxide, or any combination thereof.

Optionally, in the method for manufacturing a pixel unit, the transparent conductive layer is made of indium tin oxide, aluminum zinc oxide, or gallium zinc oxide.

Optionally, in the preparation method of the pixel unit, the material of the electrode layer is any one of chromium, gold, nickel, tungsten, titanium, or titanium nitride, or any combination thereof.

Optionally, in the method for manufacturing a pixel unit, the step of forming a graphene layer on the glass substrate includes: the first opening is formed through a first photolithography etching process.

Optionally, in the method for manufacturing a pixel unit, the step of forming the dielectric layer includes: and forming the second opening, the third opening and the fourth opening by a second lithography etching process.

Optionally, in the method for manufacturing a pixel unit, the step of forming the transparent conductive layer includes: and forming the fifth opening through a third lithography etching process.

Optionally, in the method for manufacturing a pixel unit, the step of forming the electrode layer includes: and forming the drain electrode, the gate electrode and the source electrode by a fourth lithography etching process.

In summary, in the liquid crystal display panel and the method for manufacturing the pixel unit of the liquid crystal display panel provided by the invention, the graphene material is deposited and grown on the glass substrate, and the graphene material is used as the lower electrode material of the channel and the storage capacitor of the field effect transistor, so that the advantages of the light transmittance of the glass, the electrical conductivity, the thermal conductivity, the surface hydrophobicity and the like of the graphite are achieved, and the brightness of the display panel is improved.

Drawings

FIG. 1A is a top or bottom view of a pixel unit of a prior art LCD panel;

FIG. 1B is a schematic diagram of a light-transmitting region of a pixel unit of the LCD panel shown in FIG. 1A;

FIG. 2A is a top or bottom view of a pixel unit of an LCD panel according to an embodiment of the present invention;

FIG. 2B is a schematic diagram of a light-transmitting region of a pixel unit of the LCD panel shown in FIG. 2A;

FIG. 3 is a flowchart illustrating a method for fabricating a pixel unit of an LCD panel according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view illustrating a glass substrate of a pixel unit of an LCD panel according to an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view illustrating the formation of a graphene layer according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a dielectric layer formed in accordance with an embodiment of the present invention;

FIG. 7 is a cross-sectional view illustrating a transparent conductive layer formed according to an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view illustrating the formation of an electrode layer according to an embodiment of the invention.

Detailed Description

The following describes the liquid crystal display panel and the method for manufacturing the pixel unit thereof in detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

The following describes a method for manufacturing a liquid crystal display panel and a pixel unit thereof according to the present invention with reference to the accompanying drawings.

Referring to fig. 2A and fig. 2B in combination, fig. 2A is a top view or a bottom view of a pixel unit of a liquid crystal display panel according to an embodiment of the invention, and fig. 2B is a light-transmitting schematic diagram of a pixel region of the pixel unit of the liquid crystal display panel in fig. 2A. Fig. 2A shows only one pixel unit of the lcd panel according to an embodiment of the invention, and in practice, the lcd panel includes a matrix of a plurality of pixel units.

As shown in fig. 2A, the lcd panel includes a glass substrate (not shown), a plurality of row scan lines GG and a plurality of column scan lines GS, the plurality of row scan lines GG are formed on the glass substrate, the plurality of row scan lines GG are m and are arranged in parallel, the plurality of row scan lines GS are formed on the glass substrate, the plurality of column scan lines GS are n and are arranged in parallel, the plurality of row scan lines GG and the plurality of column scan lines GS are perpendicular to each other to define a plurality of pixel regions P2, each pixel region P2 has a pixel unit, and the pixel unit includes a transistor TFT ', a display electrode D ' and a storage capacitor C '.

In this embodiment, the transistor TFT 'is formed on the glass substrate, and the transistor TFT' includes a gate electrode, a source electrode and a drain electrode, the gate electrode is electrically connected to one of the plurality of row scanning lines GG, and the source electrode is electrically connected to one of the row scanning lines GS.

In this embodiment, the display electrode D 'is formed on the glass substrate, and the display electrode D' is electrically connected to the drain electrode.

In this embodiment, the storage capacitor C ' is formed on the glass substrate, and the storage capacitor C ' is electrically connected to the display electrode D '. In this embodiment, the upper electrode of the storage capacitor C 'is a transparent conductive layer, and the lower electrode of the storage capacitor C' is a graphene layer.

In this embodiment, the transistor TFT' further includes a dielectric layer (not shown), the dielectric layer is formed between the gate electrode and the glass substrate, the source electrode and the drain electrode are respectively disposed on two opposite sides of the dielectric layer, and a graphene material is disposed between the dielectric layer and the glass substrate to form a graphene tunneling channel.

Preferably, the material of the transparent conductive layer is Indium Tin Oxide (ITO), Aluminum Zinc Oxide (AZO), or Gallium Zinc Oxide (GZO).

Preferably, the material of the dielectric layer is a high dielectric constant material, such as any one of titanium dioxide (TiO2), hafnium dioxide (HfO2) or zirconium dioxide (ZrO2) or any combination thereof.

Preferably, the gate electrode, the source electrode, and the drain electrode are made of any one of chromium (Cr), gold (Au), nickel (Ni), tungsten (W), titanium (Ti), and titanium nitride (TiN), or any combination thereof.

Therefore, the effective transparent area in the pixel region P2 can be additionally added with two effective transparent areas L2 and L3 on the basis of the conventional effective transparent area L1, that is, the aperture ratio is increased.

FIG. 3 is a flowchart illustrating a method for fabricating a pixel unit of an LCD panel according to an embodiment of the present invention. FIGS. 4 to 8 are schematic structural diagrams of the steps in FIG. 3, and the manufacturing process includes the following steps

Step S1 is executed, as shown in fig. 4, a glass substrate 100 is provided. Preferably, the material of the glass substrate 100 is silicate (SiO 2).

Step S2 is performed, as shown in fig. 5, forming a graphene layer 300 on the glass substrate 100, wherein the graphene layer 300 has a first opening 310 exposing the glass substrate 100, and the first opening 310 divides the graphene layer 300 into a first region 330 and a second region 350.

The step of forming the graphene layer 300 includes depositing a graphene material on the glass substrate 100, and forming the first opening 310 in the graphene material by using a first photolithography and etching process.

Step S3 is performed, as shown in fig. 6, a dielectric layer 500 is formed, wherein the dielectric layer 500 has a third region 550 covering the first region 330 (shown in fig. 5), a fourth region 570 of the glass substrate 100 exposed to the first opening 310 (shown in fig. 5) of the cover portion, and a fifth region 590 of the second region 350 (shown in fig. 5) of the cover portion, so as to form a second opening 520 exposing the glass substrate 100 and third and

fourth openings

530 and 540 exposing the graphene layer 300. More specifically, the third region 550 and the fourth region 570 are connected to each other, the second opening 520 is adjacent to the third opening 530, and the third opening 530 and the fourth opening 540 are respectively located at two opposite sides of the fifth region 590.

The step of forming the dielectric layer 500 includes depositing a dielectric material, which is selected from any one of or any combination of high-k materials, such as titanium dioxide (TiO2), hafnium dioxide (HfO2) or zirconium dioxide (ZrO2), and forming the second opening 520, the third opening 530 and the fourth opening 540 in the dielectric layer 500 by using a second photolithography and etching process.

Step S4 is performed, as shown in fig. 7, a transparent conductive layer 700 is formed, wherein the transparent conductive layer 700 has a sixth region 710 covering the third region 550 (shown in fig. 6) and a seventh region 730 covering the fourth region 570 (shown in fig. 6) to form a fifth opening 750 exposing the second opening 520 (shown in fig. 6), the third opening 530 (shown in fig. 6), the fifth region 590 (shown in fig. 6), and the fourth opening 540 (shown in fig. 6).

The step of forming the transparent conductive layer 700 includes depositing a transparent conductive material, such as Indium Tin Oxide (ITO), Aluminum Zinc Oxide (AZO), or Gallium Zinc Oxide (GZO), and forming the fifth opening 750 by using a third photolithography and etching process. It is noted that the transparent conductive layer 700, the dielectric layer 500 and the graphene layer 300 form a storage capacitor (not shown), the transparent conductive layer 700 serves as an upper electrode of the storage capacitor, and the first region 330 of the graphene layer 300 serves as a lower electrode of the storage capacitor.

Step S5 is performed, as shown in fig. 8, an electrode layer 900 is formed, the electrode layer 900 includes a source electrode 910, a gate electrode 930 and a drain electrode 950, the source electrode 910 covers the graphene layer 300 exposed to the fourth opening 540 (shown in fig. 6), the gate electrode 930 is formed on the fifth region 590 (shown in fig. 6), the source electrode 910 covers the fourth opening 540 (shown in fig. 6), the drain electrode 930 has an eighth region 951 covering a portion of the seventh region 730 (shown in fig. 7), a ninth region 955 covering the glass substrate 100 exposed to the second opening (shown in fig. 6), and a tenth region 955 covering the graphene layer 300 exposed to the third opening 530 (shown in fig. 6). More specifically, the eighth region 951, the ninth region 953, and the tenth region 955 are connected to each other.

The step of forming the electrode layer 900 includes depositing an electrode material, such as one or a combination of conductive metals, e.g., chromium (Cr), gold (Au), nickel (Ni), tungsten (W), titanium (Ti), titanium nitride (TiN), etc., and forming the source electrode 910, the gate electrode 930, and the drain electrode 950 by a fourth photolithography and etching process.

To this end, a pixel unit 1 of a liquid crystal display panel is formed.

In this embodiment, the deposition steps of steps S2 to S5 are performed by Chemical Vapor Deposition (CVD), Metal Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), Atomic Layer Deposition (ALD), or the like.

It is noted that the dielectric layer 500 is formed between the gate electrode 930 and the glass substrate 100, the second region 350 of the graphene layer 300 is formed between the dielectric layer 500 and the glass substrate 100, and the source electrode 910 and the drain electrode 950 are respectively disposed on two opposite sides of the dielectric layer 500 to form the graphene tunneling channel 990.

According to the invention, the graphene transistor is adopted to replace an amorphous silicon thin film transistor, and the transparent conductive material and the graphene material are adopted as electrode materials of the storage capacitor, so that the effective light-transmitting area can be increased, namely, the aperture opening ratio is improved, the brightness of the liquid crystal display panel is increased, the brightness requirement of a backlight light source is reduced, and further, the power consumption of the LCD panel is saved.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, it is intended that the present invention also include such modifications and variations.

Claims

1. A method of making a pixel cell of a liquid crystal display panel, comprising:

providing a glass substrate;

2. The method of claim 1, wherein the dielectric layer is made of a high dielectric constant material.

3. The method of claim 1, wherein the dielectric layer comprises any one or any combination of titanium dioxide, hafnium dioxide, and zirconium dioxide.

4. The method according to claim 1, wherein the transparent conductive layer is made of indium tin oxide, aluminum zinc oxide, or gallium zinc oxide.

5. The method for manufacturing the pixel unit according to claim 1, wherein the material of the electrode layer is any one or any combination of chromium, gold, nickel, tungsten, titanium or titanium nitride.

6. The method of manufacturing a pixel cell of claim 1, wherein the step of forming a graphene layer on the glass substrate comprises: the first opening is formed through a first photolithography etching process.

7. The method of manufacturing a pixel cell of claim 1, wherein the step of forming the dielectric layer comprises: and forming the second opening, the third opening and the fourth opening by a second lithography etching process.

8. The method of manufacturing a pixel cell of claim 1, wherein the step of forming the transparent conductive layer comprises: and forming the fifth opening through a third lithography etching process.

9. The method of manufacturing a pixel cell of claim 1, wherein the step of forming the electrode layer comprises: and forming the drain electrode, the gate electrode and the source electrode by a fourth lithography etching process.