JPH0850307A - Display driving element and its production - Google Patents

Abstract

PURPOSE:To unnecessitate a dedicated process to form a pixel electrode for an active matrix type liquid crystal display device. CONSTITUTION:Enough transmittance can be obtd. even when a pixel electrode 15 is formed from a laminated body of a Si layer 4a and a silicide layer 7. Therefore, the pixel electrode 15 is formed by using the Si layer 4a and the silicide layer 7 formed on the Si layer 4a. The Si layer 4a is simultaneously formed when a Si layer 4 to constitute a part of a thin film transistor 14 is formed In this case, the Si layer 4a to form the pixel electrode 15 can be simultaneously formed with the Si layer 4 to constitute a part of the thin film transistor 14. Moreover, when a metal layer to form a source electrode 12 and a drain electrode 13 for the thin film transistor 14 is produced by forming a film of such metal that can be changed into silicide, the silicide layer 7 can be formed on the surface of the Si layer 4a for the pixel electrode 15 at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display driving element and a method of manufacturing the same.

[0002]

2. Description of the Related Art In an active matrix type liquid crystal display device, display driving elements composed of thin film transistors and pixel electrodes are provided in a matrix on a transparent substrate made of glass or the like. Of these, the pixel electrode is a transparent conductive film, for example, ITO (indium tin oxide).
It is formed by a film. Therefore, when forming a pixel electrode, ITO is formed into a film and patterned.

[0003]

As described above, in the conventional display driving element, the transparent conductive film such as ITO is formed and the pixel electrode is formed by patterning the transparent conductive film. There is a problem in that the film cannot be formed at the same time as the formation of another thin film, a dedicated process is required, and the number of processes is large. In addition, ITO, which is generally used as a transparent conductive film, is limited in its application because it causes a battery reaction with Al, which is a wiring material, during etching, or has a problem that it is difficult to handle because the light transmittance changes depending on the film forming conditions. is there. An object of the present invention is to provide a display driving element and a manufacturing method thereof which can reduce the number of steps and facilitate handling during film formation by using a material other than ITO for the pixel electrode.

[0004]

SUMMARY OF THE INVENTION The present invention has been made on the finding that a sufficient transmittance can be obtained even if the pixel electrode is formed of a laminate of a Si layer and a silicide layer. For example, a Si nitride film (a gate insulating film in an embodiment described later) is formed on a glass substrate, and an amorphous Si layer is formed thereon by plasma CVD to a film thickness of 500.
Amorphous Si is formed by depositing a film of about Å and then depositing a metal layer of a silicidable metal such as Cr on it.
When a silicide layer having a film thickness of about 40 to 50 Å was formed on the surface of the layer, the metal layer that did not contribute to silicidation was removed, and the transmittance was measured, the results shown in FIG. 8 were obtained. As is clear from this figure, the wavelength is 55
When it is about 0 nm or more, a sufficient transmittance can be obtained. From this, the present invention provides a pixel electrode
It is formed by a silicide layer formed on the surface of the Si layer forming a part of the thin film transistor.

[0005]

According to the present invention, since the silicide layer serving as the pixel electrode is formed on the surface of the Si layer for forming a part of the thin film transistor, for example, the source electrode and the drain electrode of the thin film transistor or the wiring is formed. When a metal layer for forming a metal film is formed of a metal capable of silicidation, at the same time, a silicide layer is formed on the surface portion of the Si layer for the pixel electrode, and a dedicated process for forming the pixel electrode is performed. It is unnecessary and can be easily handled during film formation.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 7 show respective manufacturing steps of a display driving element in an embodiment of the present invention.
Therefore, the structure of the display drive element of this embodiment will be described together with its manufacturing method with reference to these figures in order.

First, as shown in FIG. 1, a gate electrode 2 made of Cr, Al or the like is provided at a predetermined position on the upper surface of a glass substrate 1.
To form. Next, the gate insulating film 3 made of Si nitride (Si) or Si oxide (Si) is formed on the entire upper surface of the glass substrate 1 including the gate electrode 2. Next, a Si (silicon) layer 4 made of amorphous Si (silicon), poly Si (silicon), or the like is formed on the upper surface of the gate insulating film 3. Next, a channel protection film 5 made of photoresist or the like is formed on the upper surface of the Si layer 4 corresponding to the gate electrode 2.
To form.

Next, as shown in FIG. 2, ions such as phosphorus ions and boron ions are implanted using the channel protection film 5 as a mask, and Si in a region other than under the channel protection film 5 is implanted.
An ion implantation region 4 a is formed in the layer 4. Next, the Si layer 4
After removing the oxide film (not shown) formed on the surface of
As shown in FIG. 3, a metal layer 6 made of a silicidable metal such as Cr, Mo, or Ni is formed on the entire upper surface by sputtering or the like. Then, a silicide layer 7 having a film thickness of about 40 to 50Å is formed on the surface portion of the Si layer 4 in the region not covered with the channel protective film 5, that is, the surface portion of the ion implantation region 4a.

Next, as shown in FIG. 4, the metal layer 6, the silicide layer 7 and the Si layer 4 in the region other than the thin film transistor forming region 8 and the pixel electrode forming region 9 are removed.
Next, as shown in FIG. 5, a photoresist layer 10 is formed on the entire upper surface except the channel protective film 5 and both sides thereof, and then the metal layer 7 is wet-etched with an organic alkaline etching solution such as a TW solution. Remove unnecessary parts. This step is a step for separating the source electrode and the drain electrode, which will be described later. Then, the photoresist layer 10 is removed. Next, as shown in FIG. 6, a passivation film 11 is formed on the entire upper surface except the pixel electrode formation region 9.
Is formed by plasma CVD and then patterning. When the passivation film 11 is formed by plasma CVD, the implanted ions are activated at the same time.

Next, as shown in FIG. 7, the metal layer 6 in the pixel electrode forming region 9 is removed by performing wet etching with an organic alkaline etching solution such as a TW solution using the passivation film 11 as a mask.
In this state, in the thin film transistor formation region 8, a Si layer is formed under the gate electrode 2 and the channel protection film 5 as a channel region including an intrinsic region, and on both sides thereof as a source region and a drain region including the ion implantation region 4a. 4. A thin film transistor 14 including a source electrode 12 and a drain electrode 13 formed of the metal layer 6 remaining on both sides of the channel protection film 5 is formed. In addition, in the pixel electrode formation region 9, S made to have a low resistance by ion implantation is used.
A pixel electrode 15 composed of the i layer 4a and the silicide layer 7 formed thereon is formed. Thus, the display driving element of this embodiment is manufactured.

In the display driving element thus obtained, the Si layer 4a forming the pixel electrode 15 can be formed at the same time as the Si layer 4 forming a part of the thin film transistor 14, and the thin film transistor 14 can be formed. Metal layer 6 for forming source electrode 12 and drain electrode 13
When the metal is formed of a silicidable metal such as Cr, the silicide layer 7 can be formed on the surface of the Si layer 4a for the pixel electrode 15 at the same time. The process is eliminated, and the number of processes can be reduced accordingly.

In the above embodiment, the metal layer 6 for forming the source electrode 12 and the drain electrode 13 of the thin film transistor 14 is formed of a silicidable metal such as Cr and at the same time the Si layer 4a for the pixel electrode 15 is formed. Although the silicide layer 7 is formed on the surface portion of, the present invention is not limited to this. For example, although not shown, when a metal layer for forming the wiring of the thin film transistor 14 is formed of a metal capable of silicidation such as Cr, at the same time, the silicide is formed on the surface portion of the Si layer 4a for the pixel electrode 15. The layer 7 may be formed. Also in this case, a dedicated process for forming the pixel electrode 15 is not necessary.

[0013]

As described above, according to the present invention, since the silicide layer which becomes the pixel electrode is formed on the surface of the Si layer for forming a part of the thin film transistor, the transparent conductive material such as ITO is used. When the film is formed, a dedicated process for forming the pixel electrode, which was necessary when forming the film, can be eliminated, or the handling at the time of film formation can be facilitated.

[Brief description of drawings]

FIG. 1 is a plan view of a display driving element according to an embodiment of the present invention, in which a gate electrode, a gate insulating film, and
Sectional drawing in the state which formed the Si layer and the photoresist layer.

FIG. 2 is a cross-sectional view of a state in which ions are implanted in the same manufacturing process.

FIG. 3 is a cross-sectional view showing a state in which a metal layer capable of silicidation is formed in the same manufacturing process.

FIG. 4 is a cross-sectional view of a state in which element isolation and the like are performed in the same manufacturing.

FIG. 5 is a cross-sectional view showing a state in which an unnecessary portion of the metal layer is removed during the manufacturing.

FIG. 6 is a cross-sectional view showing a state in which a passivation film is formed in the same manufacturing process.

FIG. 7 is a cross-sectional view showing a state in which an unnecessary portion of the metal layer is removed during the manufacturing.

FIG. 8 is a diagram showing an example of the transmittance of a pixel electrode composed of an amorphous Si layer and a silicide layer formed thereon.

[Explanation of symbols]

 4 Si layer 6 Metal layer 7 Silicide layer 12 Source electrode 13 Drain electrode 14 Thin film transistor 15 Pixel electrode

Claims (4)

[Claims] 1. A display driver including a thin film transistor and a pixel electrode, wherein the pixel electrode is formed of a silicide layer formed on a surface of a Si layer forming a part of the thin film transistor. . 2. A method of manufacturing a display driving element comprising a thin film transistor and a pixel electrode, wherein Si is formed in the thin film transistor forming region and the pixel electrode forming region.
A layer, and a silicide layer on the latter Si layer,
A method of manufacturing a display driving element, characterized in that the pixel electrode is formed by the latter Si layer and the silicide layer formed thereon. 3. The silicide layer is formed by depositing a metal layer made of a metal capable of silicidation for forming a source electrode and a drain electrode of the thin film transistor. Manufacturing method of display driving element. 4. The display driving element according to claim 2, wherein the silicide layer is formed by depositing a metal layer made of a silicidable metal for forming the wiring of the thin film transistor. Production method.