JPS63294529A - Matrix type display device - Google Patents

Abstract

PURPOSE:To obtain an element having a sufficiently large nonlinear current- voltage characteristic by providing plural lead wirings, display electrodes and semiconductor layers on a substrate constituting a display device and forming the semiconductor layers of a compd. of silicon and nitrogen. CONSTITUTION:This display device has at least the plural lead wirings 2, the display electrodes 5 provided by plural pieces each with each of the lead wirings 2, and the semiconductor layers 3 which are interposed between the lead wirings 2 and the respective display electrodes 5 and are electrically cascade-connected on a substrate 1. The semiconductor layers are formed of the compd. consisting of the two elements; silicon and nitrogen. Namely, the nonlinear current-voltage characteristic is realized and the contrast characteristic is improved by the nonlinear element parts consisting of the conductor-seimiconductor layer- conductor structure. In addition, the elements can be formed to a relatively large size, since the specific dielectric constant of the compd. consisting of the two elements; silicon and nitrogen forming the semiconductor layers is small. The display device which is simple in the structure, can be produced at a high yield and has the excellent linearity concerning the current-voltage characteristic is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a matrix type display device that has high display quality and is capable of displaying a large capacity.

Furthermore, specifically, it relates to a matrix type display device using nonlinear elements.

BACKGROUND OF THE INVENTION Hitherto, in matrix type display devices using nonlinear elements that have been proposed, the display medium is most often liquid crystal. Therefore, the following description will take the matrix type liquid crystal display device as an example.

The field of application of liquid crystal display devices is expanding from displays for watches, calculators, etc. to displays for terminals and video displays, but what is required is the ability to realize high-quality, large-capacity displays. The methods include (1) simple matrix method;
(2) There is an active matrix method, and (2)
There are two methods: (2a) *method using a three-terminal element such as a membrane transistor (TPT), and (2b) method using a nonlinear two-terminal element. Each method has its advantages and disadvantages, (1)
(2a) has the drawback that the manufacturing process is complicated and the cost is high. (
2b) can be manufactured through a simpler process than (2a), and it is possible to reduce costs.

There are three types of matrix type liquid crystal display devices with nonlinear elements.

The first one is a device using an element as shown in FIG. [Ali Triple E, Transaction,
Electron, Devices, Edie Volume 28, No. 6, 7
36 pages (1981) (IEEE TRA-NS
ACTION ON ELECTRON DEV
ICES Vol, HD-28, No6゜736 (
1981)). FIG. 3(a) is a cross-sectional view of the structure of a nonlinear two-terminal element, and FIG. 3(b) is a layout diagram of a liquid crystal display substrate using this. In the same figure (a), 101 is a substrate, 102 is a tantalum (Ta) layer, and 103 is about 40 mm thick.
Tantalum oxide (Tag's) obtained by anodic oxidation by 0 to 700 people, 104 is a display electrode or picture element electrode, 1
05 is tantalum oxide (Tail), which is the cause of nonlinear characteristics.
s) and the display electrode, which is made of chrome <
In the figure (b), 106 is a nonlinear two-terminal element, 107 is a lead wiring or bus bar, 108 is a terminal, and 109 is a display electrode or picture element electrode.

The second type is a device using an element as shown in Figure 4 [Television Society Technical Report, May 2, 1980]
Announced on the 5th]. This consists of two pieces of amorphous silicon (a
-3i) A nonlinear element is realized by configuring PIN diodes connected in a ring shape in parallel and opposite directions. Fourth
Figure (al is a cross-sectional view of the structure of this element, and figure (b)
is a layout diagram of a liquid crystal display substrate using this element. In this figure, the PIN diode is shown with a symbol representing a normal PN diode. In FIG. 4, 201 is a substrate, 202 is a first electrode, 203 is an N-type a-3i, 20
4 is I type a-3t, 205 is P type a-3i, 206 is a chromium (Cr) layer, 207 is a protective layer made of an insulator, 20
8 is a second electrode, 209 is a PIN diode connected in a ring shape, 210 is a bus bar, and 211 is a display electrode or picture element electrode.

The third type is a device using an element as shown in FIG. [Proceedings of the International Display Research Conference, p. 72 (Proc.

6Tll Int, Display Re5earc
h Conf, pp72) 6 Figure 5(a) is a cross-sectional view of the configuration of a nonlinear two-terminal element, and Figure 5(b) is a layout diagram of a liquid crystal display substrate using this. In the same figure (al), 301 is a substrate, 302 is a lead wiring made of a transparent conductor layer, etc., and 303 is a silicon (S) with a thickness of about 1000.
i), a nonlinear layer made of a compound of nitrogen (N), and hydrogen (H), 304 a display electrode or a pixel electrode, and 305 a connection wiring connecting the nonlinear layer and the display electrode, which is made of chromium (Cr). lii, in the same figure), 306
is a nonlinear two-terminal element, and 307 is a lead wiring or bus terminal.
The bar, 308 is a terminal, and 309 is a display electrode or picture element electrode.

By using these nonlinear resistance elements, it is possible to realize a display capacity much larger than that of a normal liquid crystal display. Expressed in terms of duty ratio, display with sufficiently high contrast is possible even when driving with a duty ratio of about 1/1000.

Problems to be Solved by the Invention When considering driving a display device using a nonlinear two-terminal element, it is necessary to apply a sufficient voltage to the nonlinear element. It must be designed to be about 1/10 or less of that of the part. However, the first aspect of the nonlinear element according to the prior art described above is
As for tantalum oxide, the dielectric constant of tantalum oxide is as high as 20 or more, so the shape of the element can be made fine.
This causes a significant deterioration in yield.

Then, for a second example of a non-linear element, at least five to six photolithography steps are included. This reduces the yield in production and increases production costs.

A third case of the conventional example will be described. According to known literature, the layer from which the nonlinear characteristics originate is composed of an amorphous compound of hydrogen, nitrogen, and silicon. It is generally said that an amorphous compound of hydrogen, nitrogen, and silicon has better semiconductor properties than an amorphous compound of nitrogen and silicon. However, it seems that there is not much correspondence between the magnitude of electrical nonlinear characteristics and semiconductor properties. In any case, the amorphous hydrogen-nitrogen-silicon compound needs to be produced by plasma chemical vapor deposition (plasma CVD) or by the swafting method in a hydrogen atmosphere. This method has many problems, including being dangerous, requiring base heating at a fairly high temperature, and the need to create a uniform plasma.

Further, since the amorphous compound of hydrogen, nitrogen, and silicon contains hydrogen, the change in properties due to the elimination of hydrogen is relatively large.

Therefore, there is a need for a device that can be manufactured through a simple process, is stable, and has sufficiently large nonlinear current-voltage characteristics.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a plurality of lead wirings on at least one substrate constituting the display device, and a plurality of lead wirings for each of the lead wirings. The display electrode includes at least a semiconductor layer interposed between the lead wiring and each of the display electrodes and electrically connected in series, and the semiconductor layer is made of silicon (Si) and nitrogen (N).
The present invention provides a matrix type display device formed from a compound consisting of two elements.

Operation The present invention realizes nonlinear current-voltage characteristics by the semiconductor layer, that is, by the nonlinear element portion having a conductor-semiconductor layer-conductor structure. It is currently assumed that this nonlinearity is caused to a large extent by the semiconductor layer. Measuring the current-voltage characteristics of an actual element! =AlkV'. Here, A and α are constants. By interposing this element between the lead wiring and the display electrode, it is possible to increase the ratio between the on voltage and the off voltage applied to the picture element portion, and it is possible to improve contrast characteristics.

In addition, the dielectric constant of the compound consisting of the two elements silicon and nitrogen that forms the semiconductor layer varies slightly depending on the composition ratio, but 2
The shape of the nonlinear element according to the present invention can therefore be relatively large. This can lead to an improvement in manufacturing yield.

The nonlinearity that the present invention expects from the semiconductor layer can also be achieved by a semiconductor layer that is easily formed by, for example, an electron beam heating evaporation method without intentional substrate heating. That is, the manufacturing method is essentially simpler than that of the third embodiment.

The compound consisting of the two elements silicon and nitrogen that forms the semiconductor layer is not intentionally mixed with hydrogen, and therefore no matter what manufacturing method, e.g., electron beam heating evaporation method or sputtering method, there is no possibility of containing hydrogen atoms. The amount was less than 0.5 at.%. As a result, changes in characteristics over time due to the separation of hydrogen atoms from the semiconductor layer are significantly reduced.

The substrate on the nonlinear element side for a matrix display device can be fabricated by performing photolithography three times or fewer times. As mentioned above, considering that the shape of the nonlinear element can be relatively large and that substrate heating is not necessarily required when the semiconductor layer is formed by vapor deposition, the nonlinear element used in the display device according to the present invention can be The manufacturing method can be simple. Common sense suggests that a patterned bottom conductor layer (usually
This consists of a semiconductor layer on top (lead wiring), then an upper conductor layer (
Usually, this is a part of the display electrode, and sometimes it is a connection wiring connecting the semiconductor layer and the display electrode). - Possible with a single lithography process. Based on the above idea, the semiconductor layer is formed on the lower conductor N (usually lead wiring) patterned on the substrate using a metal mask, and the metal mask and the substrate are combined in a single vapor deposition process. Therefore, it is easily achieved. Further, the upper conductor layer may also be easily formed by subsequent mask deposition depending on what constitutes the upper conductor layer.

From this as well, improvement in manufacturing yield can be expected.

As mentioned earlier, this nonlinear effect is based on experiments.
The contact area between the semiconductor layer and the electrode is small;
It is presumed that the cause is mainly within the semiconductor layer.

Embodiments Hereinafter, embodiments of the matrix type display device of the present invention will be described with reference to the drawings.

As mentioned above, since liquid crystal is the most commonly used display medium in matrix display devices using nonlinear elements, the following description will mainly focus on liquid crystal display devices.

As mentioned above, one conductor connected to the semiconductor layer is a lead wiring or a part thereof branched from a lead wiring, and the other conductor is a part of a display electrode or is intended for connection to a display electrode. This is the connection wiring. Although it has been confirmed that the effects of the present invention are exhibited in any case, in this example, the case where one conductor is used as a lead wiring and the other conductor is a connecting wiring will be described below. do.

FIG. 1 (al is a cross-sectional view of the configuration of the nonlinear two-terminal element according to the present example, and FIG. 1(b) is a plan view. In the same figure,
1 is a substrate, 2 is a lower conductor layer, that is, a lead wire, 3 is a semiconductor layer, 4 is an upper conductor layer, that is, a connection wire, and 5 is a display electrode, that is, a picture element electrode. FIG. 2 is a layout diagram of a substrate for a matrix type display device according to this embodiment, and 11
1 is a lead wiring, 12 is a nonlinear two-terminal element, and 13 is a display electrode, that is, a picture element electrode.

In the following embodiments, the lead wires 2 to 11 are
Indium oxide transparent electrode (ITO) doped with tin (Sn)
i5 pole) or chromium (Cr) or titanium (Ti)
, a tin oxide transparent electrode doped with aluminum (At>, antimony (Sb)), a chromium (Cr)-gold (Au) multilayer film, and the connection wiring 4 is made of titanium (Ti), chromium (Cr).
, the picture element electrode 13 is made of aluminum (AI), and the picture element electrode 13 is made of tin (Sn).
) was formed from an indium oxide transparent electrode (ITO electrode). Particularly when voltage attenuation due to electrode resistance is a problem, it is desirable to use a highly conductive material such as aluminum (AI) for the lead wires 2 to 11.

First, an example of the manufacturing process of a matrix type liquid crystal display panel with a nonlinear two-terminal element will be described.
A case where it is formed using TO will be explained.

A soda glass with ITO etched into a predetermined pattern is obtained, and this substrate is immersed in fuming nitric acid, washed with water, and dried.

Next, a mask made of magnetic stainless steel with a thickness of about 30 micrometers and with holes in a predetermined pattern is aligned with the substrate using an aligner, and a samarium-cobalt magnet is placed on the back side of the substrate. Then, the metal mask and the substrate were brought into close contact. This was placed in a vacuum chamber for vapor deposition, and a semiconductor layer was formed on the substrate by electron beam heating vapor deposition. Furthermore, connection wiring was formed using the same method. Thus, a substrate as shown in FIG. 2 was obtained. When forming a semiconductor layer by vapor deposition, the degree of vacuum is 1*10-hTor.
I made it around r. As a source for forming the semiconductor layer, a commercially available silicon powder and a commercially available silicon nitride powder were mixed at a predetermined ratio and shaped under pressure. In this example, a weight ratio of 1:1.0.5:1.2:1 was prepared.

Before forming this substrate into a panel, the current-voltage characteristics of the device were measured.

Furthermore, after forming alignment films on the substrate on which the nonlinear two-terminal element was formed and the counter substrate on which the strip-shaped ITO was formed, they were subjected to a rubbing treatment, and the two substrates were bonded together to form a panel. Injected liquid crystal. The rubbing direction was such that the liquid crystal molecules had a 90° twisted structure.

Through the above process, a liquid crystal display panel with a nonlinear two-terminal element was obtained.

(Example 1) A liquid crystal display panel with a nonlinear two-terminal element shown in FIG. 1 was manufactured. The manufacturing method is as described above.

Substrate 1 includes silicon dioxide (Si0.) on soda glass.
A material coated with was used. Approximately 20 for lead wiring 2
It is made of ITO with a thickness of 0.00 mm. As a source for forming a semiconductor layer, the weight ratio of silicon powder and silicon nitride powder is o.
, s:i mixture.

Furthermore, the connection wiring 4 is made of chrome (about 700 mm thick).
Cr) film was formed.

The nonlinearity of the current-voltage characteristics of the device was significant with α=7 to 13. Also, its capacity was sufficiently smaller than that of the liquid crystal layer. Also, the nonlinearity was sufficiently stable over a reasonable period of time.

When a liquid crystal display panel was manufactured using this substrate, a display with a contrast of 10:1 or more was realized during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

(Example 2) A liquid crystal display panel with a nonlinear two-terminal element shown in FIG. 1 was manufactured. The manufacturing method is as described above.

Substrate 1 includes silicon dioxide (SiO7) on soda glass.
A material coated with was used. Approximately 60 for lead wiring 2
It is made of titanium (Ti) with a thickness of 0.0 mm. The source for forming the semiconductor layer was obtained from a mixture of silicon powder and silicon nitride powder in a weight ratio of 1=1. Further, as the connection wiring 4, a chromium (Or) film having a thickness of approximately 700 yen was formed.

The nonlinearity of the current-voltage characteristics of the device was significant with α=8 to 13. Also, its capacity was sufficiently smaller than that of the liquid crystal layer. Also, the nonlinearity was sufficiently stable over a reasonable period of time.

When a liquid crystal display panel was manufactured using this substrate, a display with a contrast of 1O:1 or more was realized during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

(Example 3) The manufacturing method for manufacturing the liquid crystal display panel with nonlinear two-terminal elements shown in FIG. 1 was as described above.

Substrate 1 contains silicon dioxide (S10) on soda glass.
A material coated with was used. Approximately 60 for lead wiring 2
It is made of titanium (Ti) with a thickness of 0.0 mm. The source for forming the semiconductor layer was obtained from a mixture of silicon powder and silicon nitride powder in a weight ratio of 2:1. Further, as the connection wiring 4, a chromium (Cr) film having a thickness of approximately 700 mm was formed.

The nonlinearity of the current-voltage characteristics of the device was significant with α=8 to 13. Also, its capacity was sufficiently smaller than that of the liquid crystal layer. Also, the nonlinearity was sufficiently stable over a reasonable period of time.

When a liquid crystal display panel was manufactured using this substrate, a display with a contrast of 10:1 or more was realized during matrix driving with a duty ratio of 1/1000 and a bias ratio of 1/7.

In Examples 1 to 3, a method using a metal mask was adopted as a method of patterning the semiconductor layer and the connection electrode, but a similar effect could also be obtained by a lift-off method using a photoresist.

Furthermore, although liquid crystal is used as an example of the display medium, similar effects can be obtained using electroluminescent devices (EL), electrophoretic devices (EPID), electrochromic devices, plasma light emitting devices, etc. Needless to say.

As described in detail, the nonlinear two-terminal device of the present invention has a simple structure, so it can be manufactured at a high yield, and furthermore,
It has excellent nonlinearity in current-voltage characteristics.

Therefore, a matrix type display device using the element according to the present invention is capable of displaying a large capacity and achieving good display quality.

[Brief explanation of the drawing]

FIG. 1 shows (a) a cross-sectional view of a nonlinear two-terminal element used in a matrix-type display device according to the present invention, a plan view (see FIG. 2), and FIG.
The figure is a layout diagram of a substrate for a matrix type display device according to the present invention, and FIGS. 3(a), 4(a), and 5(a) are nonlinear two-terminal elements used in a conventional matrix type display device. 3) and 4). 5) is a layout diagram of a nonlinear two-terminal element used in a conventional matrix type display device. 1...Substrate, 2...Lower conductor layer, ie, lead wiring, 3...Semiconductor layer, 4...
... Upper conductor layer, i.e., connection wiring, 5... Display electrode, i.e., picture element electrode, 11... Lead wiring, 12... Nonlinear two-terminal element, 13...・・・
...Display electrode, ie, picture element electrode, 101...
Substrate, 102...Tantalum (Ta) layer, 103
...Tantalum oxide (TazOs) obtained by anodizing about 400 to 700 people thick, 104...
...Display electrode or picture element electrode, 105...Tantalum oxide (Tat os), which is the cause of nonlinear characteristics
and a display electrode connection wiring, 106...
Nonlinear two-terminal element, 107...Lead wiring or bus bar, 108...Terminal, 109...
...Display electrode or picture element electrode, 201...Substrate, 202...First electrode, 203...
N type a-31,204・・・■Type a-S i
, 205-...P type a-3i, 206...
-Chromium (Cr) layer, 207... Protective layer made of an insulator, 208... Second electrode, 209...
...PIN diode connected in a ring shape, 210.
... Bus bar, 211 ... Display electrode or picture element electrode, 301 ... Substrate, 302 ...
...Lead wiring made of a transparent conductor layer, etc., 303...
・・・Approximately 1000 silicon (Si) and nitrogen (N)
) and hydrogen (H), 304.
...Display electrode or picture element electrode, 305...
- Connection wiring connecting the nonlinear layer and the display electrode, 30
6...Nonlinear two-terminal element, 307...IJ
+ wire or bus bar, 308...terminal,
309...Display electrode or picture element electrode. Name of agent: Patent attorney Toshio Nakao Haka 1 person 1 = - group
Board 2-bottom @ nose body layer 5 lead li! 3-4 - Body layer 4 - Upper @ fecal body layer 5 Coupling slave 5 ・-Display electrode S', -45 Attached to pry 11- Lead wiring 12-4F- Linear two-dimensional wire Element 13 ~ Display electrode, srl, pattern end ti Fig. 2 73 It 1311 13 Fig. 3 Fig. 4

Claims (1)

[Claims] A plurality of lead wirings, a plurality of display electrodes provided for each of the lead wirings, and electrically conductive electrodes interposed between the lead wirings and each of the display electrodes are provided on at least one substrate constituting the display device. 1. A matrix display device comprising at least a semiconductor layer cascaded with a semiconductor layer, the semiconductor layer being formed of a compound of two elements, silicon (Si) and nitrogen (N).