JPS5893090A - Matrix type liquid crystal display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to gate electrodes and gate insulators of semiconductor devices such as TFT arrays having storage capacitors, etc., as well as active elements such as TPTs having a plurality of gate lines and source lines. The present invention relates to constituent materials of membranes, storage capacitor electrodes, and Mvt bodies, and methods of manufacturing the same.

FIG. 1 is a cross-sectional structural diagram for explaining the configuration of a TFT array, and FIG. 2 is a cross-sectional structural diagram for explaining the configuration of a matrix type liquid crystal display device. In the figure, (1) is the gate edge, (2) is the source line,
(3) is the drain electrode, (April TFT), (5) is the display electrode, (6) is the storage capacitor, (7) is the liquid crystal, (8
) is TFT array, (9) is TFT array substrate, QO
denotes a transparent conductive i, aa a color filter, (goods) a counter substrate, and (to) a matrix type liquid crystal display device.

Conventionally, there have been devices of this type as shown in Fig. 8 and Fig. 4.・Figure 8 is a plan view of a TPT array pixel.

Figure 4 shows a cross-sectional structural diagram taken along the line mV-W in Figure 8.

In the figure, (1) is a gate line, (2) is a source line, (
3) is the drain electrode, (5th is the display electrode, (8) is the TF
T array.

(9) is a TFT array substrate, a4 is a semiconductor, (2) is a storage capacitor electrode, αQ is a gate insulating film, and O is a dielectric.

First, the structure of a matrix type liquid crystal display device will be explained with reference to FIGS. 1 and 2. Matrix type liquid crystal display! One wheel is equipped with a plurality of gate lines (υ) and a source line (2) that certifies these gate lines, and a TPT wire is connected at the intersection thereof.
Active elements such as (4) are formed, and its drain electrode (3
) 1 display electrode (6), and signal storage capacitor (6)
A TFT array substrate (9) on which a TFT array (8) having a structure is formed, and a transparent conductive 1iQI substrate facing this,
A liquid crystal (7) between the opposing substrate (9), which has color filters (b) such as red, edge, and blue, and this side substrate (9), (b).
It has a sandwiched structure.

Next, the conventional TFT array (8) will be explained with reference to FIGS. 8 and 4. The TFT array (8) is made of an insulating substrate such as glass, on the surface of which is formed an AI or the like that will become the gate line a), for example, by vapor deposition, and a gate insulating film (to) is formed on top of it. 810. For example, after forming A1, etc., which will become the source IIM (2), )' and rain electrode (3), by a vapor deposition method, etc., for example, amorphous silicon, etc., which will become the semiconductor (b), is formed by plasma CVD. The TFT (4) is then formed by a method or the like. After this, the storage capacitor (6) becomes, for example, a storage capacitor electrode) III! 03 etc. by a vapor deposition method, etc., a dielectric material αη, such as StO, is formed by a sputtering method, etc., and then, for example, In2O2, which also serves as the 1 display electrode (5) and the upper electrode of the storage capacitor, is formed by a vapor deposition method, etc. Then, one end of the TFT array (8) is formed first and connected to the NiDrain electrode (3), thereby completing the TFT array (8).

By the way, the characteristics required of a TFT array used in a matrix type liquid crystal display are the drain current (105 (OFF)) when the TPT is OFF and the current (X) when the TPT is ON.
DS(ON)) and specific gravity Di(ON)/ID5(OFF
) is required to be 108 or more, and it is also necessary that the transconductance (pm), which indicates the sensitivity and gain of the TFT, be large. Here, in the case of a half body that can be formed by a low-temperature process of about 600° C. or lower, such as an amorphous TPT using silicon, it is located near the interface between the semiconductor and the gate insulating film. Field effect mobility of carriers in semiconductors (
b) is extremely small (e.g. 0.ii cm"
/ V-s e below) It is difficult to obtain the voltage (current) necessary to drive the liquid crystal, and it is extremely large ('l'
-) Large 1i1/gate length ratio) and large area TP
For example, as shown in Fig. 8, it is necessary to form a large T.
On the other hand, image displays such as matrix type liquid crystal displays have a structure of PT and small d display electrodes.

Due to resolution constraints, the maximum size of a unit pixel is approximately 800
It is necessary to make it as small as 0 or less ichronmeter.

As explained above, in conventional matrix-type liquid crystal displays, the installation area of TPT, which usually causes display defects, increases and the installation area of one display electrode decreases, resulting in a reduction in unit pixel area, which is a measure of one display performance. A matrix-type liquid crystal that has good display performance because the ratio of the display electrode area, that is, the aperture ratio (hereinafter referred to as aperture ratio), is reduced, and the area where a signal storage capacitor, which requires a relatively large capacity, can be formed is reduced. The disadvantage was that the display device was not very attractive.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it uses Ti as the constituent material of the gate electrode and storage capacitor electrode in a TFT array used in a YATRIX type liquid crystal display device, etc. The feature is that the surface is anodized to serve as the gate insulating film and the dielectric of the storage capacitor.

Hereinafter, a simple embodiment of this invention will be explained with reference to FIGS. FIG. 6 is a partial plan view of the TFT array pixel of the present invention, and FIG. 61 is a cross-sectional structural diagram taken along line 1--2 in FIG. In the figure, (1) is the gate line, (2) is the source line, (3) is the drain electrode, (5) is the display electrode, and (8) is the drain electrode.
is TFT array% (9) is TFT array substrate, C14
is the semiconductor, c1!1 is the storage capacitor% (m, (I
ll)l! The gate insulating film (17) shows the dielectric material. Next, I will explain its structure.

The TFT array (8) first has a gate line (1) on the surface of a TFT array substrate (9) made of a transparent insulating substrate such as glass.
Ti, which will become the gate line (1) and the storage capacitor electrode), is formed by, for example, vapor deposition, and the solute (ammonium borate) is formed on the gate line (1) and the storage capacitor electrode) as the anode.

Unipolar oxidation is performed using a non-aqueous chemical solution such as a solvent (methanol).

After removing the dielectric material of the product capacitor on the gate insulating films and ', a transparent dielectric film of 1 m 103, etc., which also serves as the display wt electrode (5) and the upper electrode of the storage capacitor, is formed by vapor deposition or the like. First, a source edge (2) and a drain electrode (3), such as Ag, are formed using vaporized M'h or the like and connected to one end of the previously formed display electrode (5).

After this, a semi-dedicated material (b) of amorphous silicon, etc. is formed by, for example, plasma CVD 2, etc., and then a TFT array (
8) is completed.

As described above, in the TFT array according to the present invention, the dielectric material of the gate insulating film and the storage capacitor is formed by oxidizing the surface of the TI, which constitutes the rogate electrode and the storage capacitor electrode, respectively, by anodizing, and forming an insulating film made of TiO2. Formed. The stable oxide film TIO has a large dielectric constant, about 80. Approximately 80. SSO, which is made of rutile and has approximately 100 mag.
The dielectric constant is extremely large compared to about □ (·8 to 4).

This means that the TFT performance index (μ°ε/l-”/L)
(Here, μ is the carrier mobility, ε is the dielectric constant, t is the thickness of the gate insulating film, W is the gate width, and L is the gate length.)
As is clear from the above, the current when the TPT is turned on and the mutual conductance 1m increase, and the performance of the TFT improves, indicating that it can be replaced with a smaller and higher performance TPT compared to the conventional method. ing. In addition, the capacitance per unit area of the storage capacitor, which requires a relatively large capacity to drive the liquid crystal, also increases, indicating that a smaller area is required compared to conventional methods. .

On the other hand, images such as matrix type liquid crystal display! i! In displaying, the maximum size of a unit pixel must be reduced to about 800 t chromedore 0 or less due to resolution constraints.

As explained above, according to the present invention, the installation area of active elements such as TPT is small and the installation area of display electrodes can be increased.1. ,,opening which is a guideline for display performance
11 The number of meshes can be increased, and the storage capacitor can be formed in a small area, so that a matrix type liquid crystal display device with good display quality can be obtained. In addition, since it can be manufactured using a low-temperature process, it is possible to use inexpensive glass substrates, etc., and this has the advantage of producing a large-screen matrix-type liquid crystal display device.

[Brief explanation of the drawing]

Recitation Figure 1 is a diagram for explaining the configuration of the TFT array, Figure 2 is a diagram for explaining the configuration of the TFT array.
The figure is a cross-sectional structural diagram of a matrix type liquid crystal display device, FIG. 8 is a partial plane of a conventional τFT array pixel, and FIG.
FIG. 6 is a partial plan view of a TFT array pixel according to an embodiment of the present invention, and FIG. 6 is a cross-sectional structural diagram taken along line wwm in FIG. In the figure, (1) is the gate edge, M is the storage capacitor electrode, and (G) is the gate insulation lal! ! , aη are dielectrics. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent: Katsura PR letter - (1 other person) Figure 1 σ Figure 2 Figure 3 Figure 4 Figure β Figure 5 Figure 6 θ 1. Indication of incident Patent application 1987-19115!1
No. 1, No. 3, Person making the amendment 5, 1ill Detailed explanation of the invention in the correct subject specification column 6, @Correct contents (1) The description is corrected as follows.

Claims (1)

[Claims] (1) A plurality of gate lines, a plurality of source lines orthogonal to these gate lines, and an active element such as a thin film transistor (hereinafter referred to as TPT) at each intersection of these gate lines and source lines. A substrate on which a TFT array consisting of a signal storage capacitor, etc. is arranged. A matrix type in which a liquid crystal is sandwiched between a transparent transducer film and a counter substrate on which color filters such as red, edge, blue, etc. are formed, and a unit pixel is constituted by the color filter facing the TFT array. In the liquid crystal display device, the gate electrode of the TFT array and the storage capacitor electrode material are T
i, the gate insulator group and the storage capacitor dielectric are T
A matrix type liquid crystal display device characterized by an opening formed by an ie.