JPH0324526A - Liquid crystal display device of active matrix and production thereof - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal display device of an active matrix for which nonlinear type resistance elements having excellent reliability and display quality are used by forming a layer consisting of silicon oxide of a specific thickness between a nonlinear type resistance film and a 1st driving electrode. CONSTITUTION:An ITO film 2 which is a transparent electrode is formed on a transparent insulating substrate 1 and the nonlinear type resistance films 3 essentially consisting of the silicon oxide are selectively formed thereon; further, signal line electrodes 4 are formed thereon. The silicon oxide films 5 which have <=10 namometer thickness and have the silicon content lower than the silicon content of the resistance elements 3 are formed between the nonlinear type resistance films 3 and the ITO film 2. The silicon oxide films having the good adhesive property to any of compds. of the systems contg. ITO and silicon are placed between the nonlinear type resistance films 3 and the transparent conductive films 2, by which the adhesive property to these films is improved. The influence on the electrical characteristics is substantially eliminated by limiting the thickness of the silicon oxide films 5. The active matrix panel using the nonlinear type resistance elements is obtd. with the stable electrical characteristics at a good yield with substantially no aging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an active matrix liquid crystal display device such as a liquid crystal display device in which a non-linear element is provided for each pixel, and a method for manufacturing the same.

[Summary of the invention]

This invention improves the electrical contact characteristics between the nonlinear resistive film and the display electrode in an active matrix liquid crystal display device using a nonlinear resistive film and its manufacturing method, thereby stabilizing the characteristics and simplifying the manufacturing method. The present invention provides an active matrix liquid crystal display device.

[Conventional technology]

FIG. 3 is an equivalent circuit diagram of an active matrix liquid crystal display device using a conventional two-terminal nonlinear resistance device. In FIG. 3, 6 is a group of row electrodes, and 7 is a group of column electrodes.
It consists of 1000 electrodes from a book.

A liquid crystal 8 and a nonlinear resistance element 9 are formed in series at the intersection of the row electrode and column electrode. By applying a voltage across these ends, the liquid crystal 8
When driven, the rise characteristic of the 7-night crystal 8 becomes much steeper than when the liquid crystal is driven alone due to a rapid change in resistance of the nonlinear element 9 consisting of an equivalent resistance and an equivalent capacitance.
FIG. 4 shows a conventional active matrix liquid crystal display device in which a liquid crystal layer 14 is sandwiched between a glass substrate 13 provided with a non-linear resistance element and a second glass substrate 12 provided with a striped transparent electrode 16. ．． A voltage is applied between liquid crystal drive electrodes 15 and 16 connected to the nonlinear resistance element, and incident light is modulated by the electro-optic effect of the liquid crystal. When a TN type liquid crystal is used, the light that has become linearly polarized by the polarizing plate 10 or the polarizing plate l1 is modulated by the liquid crystal layer 14. Light incident from the outside passes through a polarizing plate 10. Liquid crystal layer 14, polarizing plate 11, reflective layer 21. When passing through the polarizing plate 11, liquid crystal layer 14, and polarizing plate 10,
It is modulated by the electro-optic effect of the liquid crystal layer 14. Figure 5 {(1
) is a perspective view of a conventional substrate provided with a nonlinear resistance element for one pixel in FIG. 4, and FIG. .

A silicon nitride film 18 made of a compound of silicon and nitrogen and having nonlinear current-voltage characteristics is formed on a transparent electrode l7 made of ITO or the like.
A signal electrode 19 is provided on a glass substrate 20.

The current-voltage characteristics between the transparent electrode 17 and the signal electrode 19 of this device are shown in FIG. In FIG. 6, the horizontal axis shows the voltage, and the vertical axis shows the logarithm of the current flowing through the element, and it can be seen that the device has steep current-voltage characteristics. As a result, a crystal display device with an excellent contrast ratio can be realized.

This conventional liquid crystal display device has a problem with the stability of electrical contact between the transparent electrode 17 and the nonlinear resistive film 18. That is,
When a nonlinear resistive film 18 made of silicon, nitrogen, carbon, etc. is formed on the ITO of the transparent electrode 17, the ITO film 17 and the nonlinear resistive film 18 react with each other during the process, causing peeling of the nonlinear resistive film and electrical A phenomenon occurs in which the characteristics are unstable. In other words, the manufacturing yield of the device may decrease or the electrical characteristics may change over time. [Problems to be Solved by the Invention] Therefore, the present invention was developed in order to solve the above-mentioned drawbacks of the conventional technology. An object of the present invention is to provide a structure and manufacturing method for an active matrix liquid crystal display device.

[Means to solve the problem]

In order to solve the above problems, the present invention forms a thin silicon oxide film between the nonlinear resistance film and the transparent electrode film (ITO film).

[Effect]

A silicon oxide film has good adhesion to an ITO film, which is an oxide, and also has good adhesion to a silicon compound such as silicon nitride. Furthermore, silicon oxide adheres stably to the ITO film or nonlinear resistance film without causing any reaction. The thickness of this oxide film is 100
The influence of this layer on the electrical characteristics of the device can be ignored by setting it to less than 300 yen.

(A tunnel current flows through the oxide film, so the resistance due to this part can be ignored compared to the non-linear resistive film part.) [Example] Figure 1 (al is one side of an example of a matrix liquid crystal display device according to the present invention) FIG. 1 shows a perspective view of the substrate shown in FIG. 2. A monocrystalline drive electrode which is a transparent conductive film such as tin oxide) 2. A non-linear resistive film mainly made of silicon selectively formed thereon 3. A layer of chromium, aluminum, etc. formed thereon. The signal line electrode 4 is made of metal.

Between the nonlinear resistive film 3 and the ITO film 2 is formed a silicon oxide film 5 having a thickness of 10 nanometers or less and having a lower silicon content than the resistive film 3. The nonlinear resistance film 3 has a composition containing silicon as a main component and at least one of oxygen, nitrogen, carbon, hydrogen, and the like. This resistive film 3 is I
Silicon oxide rrj. formed on the TO film. Contains silicon in a larger proportion than 5. IT○, the material for transparent electrodes
has poor adhesion to substances containing a large amount of silicon such as silicon nitride and silicon carbide, but ITO. The adhesion between the nonlinear resistive film 3 and the transparent conductive film 2 can be improved by interposing a silicon oxide film that has good adhesion to any silicon-containing compound. By setting the thickness of the silicon oxide film 5 to 10 nanometers or less, there is almost no influence on the electrical characteristics.

FIG. 2 (al to +dl are cross-sectional views of an embodiment showing the order of manufacturing steps of a substrate provided with a non-linear resistance element of an active matrix liquid crystal display device of the present invention, in which a transparent conductive film is formed on a transparent insulating substrate 1. Step of selectively shaping 2 (Fig. 2 fat)
, step of successively depositing a silicon oxide film 5, a non-linear resistance film 3, and a metal film 4 made of chromium, aluminum, etc. (FIG. 2(b)), and forming a signal electrode 4 made of a metal film by photolithography. Selective shaping step (Fig. 2(c)),
This step consists of a step of selectively forming the nonlinear resistance film 3 and the silicon oxide film 5 by photolithography (FIG. 2(d)). Since the selective removal of the oxide film 5 can be performed in the same photolithography process as the selective removal of the nonlinear resistive film 3, only a slight increase in the number of steps is required. Oxidation lI! Methods for forming J5 include plasma CVD, supersolution, and thermal oxidation of CVD silicon. The silicon oxide IIW5 may be formed continuously with the transparent conductive film so that both are in the same planar shape. Furthermore, since the silicon oxide film 5 is transparent, there is no adverse effect on the display characteristics even if it is left without necessarily being selectively removed. Further, the patterning of the metal electrode 4 may be performed again after the patterning of the nonlinear resistive film 3 is completed.

〔Effect of the invention〕

As described above, according to the present invention, an active matrix panel using nonlinear resistance elements can be
Stable electrical characteristics can be obtained with high yield, and C
It has the remarkable effect of being able to provide a flat panel with image quality comparable to RT at a low cost.

[Brief explanation of drawings]

FIG. 1 (fat) is a perspective view of one substrate of the active matrix liquid crystal display device of the present invention, FIG. 1 (b) is a sectional view of one substrate of the active matrix liquid crystal display device of the present invention, and FIG. -(d) are cross-sectional views showing a method of manufacturing one substrate of the active matrix liquid crystal display device of the present invention, FIG. 3 is an equivalent circuit diagram of a conventional active matrix liquid crystal display device, and FIG. 4 is a diagram of a conventional active matrix liquid crystal display device. A cross-sectional structural diagram of the display device, FIG. 5 (al is a perspective view of one substrate of a conventional active matrix 7-crystal display device, FIG. 5 (bl is a cross-sectional view of one substrate of a conventional active matrix 7 & crystal display device) Figure 6 is a current-voltage characteristic diagram of a nonlinear resistance element. Figure 1 (α) 2...Transparent electrode 3...Nonlinear resistance film 4...Signal electrode 5...Silicon oxide More than membrane

Claims (2)

[Claims] (1) Two opposing substrates, an electro-optic material layer sandwiched between the substrates, a driving electrode provided on each of the two opposing substrates, and a drive electrode provided for each pixel on at least one of the substrates. It consists of a non-linear resistive film mainly composed of silicon sandwiched between a first driving electrode and a signal line electrode, and a thickness of 10 nanometers or less is provided between the non-linear resistive film and the first driving electrode. An electro-optical display device comprising a layer made of silicon oxide. (2) The manufacturing process of a substrate provided with a nonlinear resistance element according to claim 1 includes at least (a) selectively forming a first drive electrode made of a transparent conductive film on a transparent insulating substrate; First step (b) Forming a layer made of silicon oxide with a thickness of 10 nanometers or less Second step (c) Depositing a non-linear resistive film Third step (d) Fourth step depositing a conductive film made of metal (e) a fifth step of selectively forming a metal film; and (f) a sixth step of selectively removing a non-linear resistance film and a silicon oxide film.