JPS63229483A - Matrix type display device - 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 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.

2. Description of the Related Art Conventionally, in matrix display devices using nonlinear elements that have been proposed, the display medium is most often liquid crystal. Therefore, in the following description, a matrix type liquid crystal display device will be taken 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 (2a) a method using a three-terminal element such as a thin film transistor (TPT), and (2b) a method using a nonlinear two-terminal element. Each method has its advantages and disadvantages, (11 has a problem with display quality, (2a) has a disadvantage of high cost due to complicated manufacturing process, (2b) has a disadvantage of high cost due to complicated manufacturing process.
It can be manufactured through a simpler process than (2a), and costs can be reduced.

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

First, the first one is a device using an element as shown in FIG. 3 (for example, I-Triple E).

Transaxilon. Electron, dehysis.

Edie Volume 28, No. 6, Page 736 (1981)
(IEEETRANSACTION ON ELECT
RON DEVICES Vol, ED-28°N [
L6.7'36 (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. The same figure (a
), 101 is a substrate, 102 is tantalum (Ta)
The layer 103 is tantalum oxide (Tazos) obtained by anodic oxidation with a thickness of about 400 to 700 people, 104 is a display electrode or pixel electrode, and 105 is tantalum oxide (Ta2os), which is the cause of nonlinear characteristics, and the display electrode. In the figure (bl), 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. It is an electrode.

The second type is a device using an element as shown in FIG. 4 (for example, Technical Report of the Television Society, published on May 25, 1980). This device has a configuration in which two amorphous silicon (a-5t) PIN diodes are connected in parallel in opposite directions in a ring shape to realize a nonlinear element. FIG. 4 (Ta) is a sectional view of the structure of this element, and FIG. 4 (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 N-type a-Si, 204 is I-type a-Si, and 205 is P-type a-3.
i, 206 is a chromium (Cr) layer, 207 is a protective layer made of an insulator, 208 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. be.

The third type is a device using an element as shown in Fig. 5 [for example, Proceedings of the Sixth International Display Research Conference, page 72 (Proc, 6THInt,
Display Research Conf, ＋
pp72]. FIG. 5(a) is a cross-sectional view of the structure of a nonlinear two-terminal element, and FIG. 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 30
3 is a nonlinear layer having a thickness of approximately 1000 nm and is made of a compound of silicon (St), nitrogen (N), and hydrogen (H); 304 is a display electrode or pixel electrode; 305 is a connection between the nonlinear layer and the display electrode; 306 is a nonlinear two-terminal element, and is made of a chromium (Cr) layer.
307 is a lead wiring or bus bar, 308 is a terminal,
309 is a display electrode or a 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, and silicon compound needs to be produced by plasma chemical vapor deposition (plasma CVD) or sputtering 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. and a composite layer interposed between the lead wiring and each of the display electrodes and electrically connected in series, and the composite layer includes a silicon (St) layer and an amorphous layer. The amorphous semiconductor layer is made of amorphous semiconductor layer and silicon (Si) layer stacked in this order, and the amorphous semiconductor layer is made of arsenic (As) and sulfur (S). Arsenic (A
s), selenium (Se), and sulfur (S).

Operation The present invention realizes nonlinear current-voltage characteristics by the composite layer, that is, by the nonlinear element portion having a conductor-composite layer-conductor structure, particularly by the amorphous semiconductor layer included in the composite layer. It is currently assumed that this nonlinearity is caused to a large extent by the amorphous semiconductor layer. When the current-voltage characteristics of an actual element are measured, they show characteristics that can be approximated in the form I=A*Vα. 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 forming the amorphous semiconductor layer is
Although it varies slightly depending on the composition ratio, it is relatively small at 20 or less. Therefore, the shape of the nonlinear element according to the present invention can be relatively thick. This can lead to an improvement in manufacturing yield.

The nonlinearity that the present invention expects from the composite layer can also be achieved by a composite layer that is easily formed by, for example, electron beam heating evaporation and resistance heating evaporation without intentional substrate heating. I can do it.

That is, the manufacturing method is essentially simpler than that of the third embodiment.

Hydrogen is not intentionally mixed in when forming the composite layer. As a result, changes in properties over time due to the separation of hydrogen atoms from the composite layer were significantly reduced. To create a substrate on the nonlinear element side for a matrix display device, photolithography is performed three times or less times.
It is possible with lithography. As mentioned above, considering that the shape of the nonlinear element can be relatively large and that substrate heating is not necessarily required when forming the composite layer 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 is to place a composite layer on top of a bottom conductor layer (usually this is the lead wiring) patterned on the substrate, then a top conductor layer (usually this may also be part of the display electrodes). However, it is possible to stack the layer (which is sometimes a connection wiring connecting the composite layer and the display electrode) in one process of three film formations and three photolithography steps. From the above considerations, a patterned bottom conductor layer on the substrate (usually this is lead trace N1A)
Forming a composite layer on the substrate is easily accomplished using a metal mask and a single deposition process of the metal mask and substrate. 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.
It is speculated that the cause is to a small extent due to the contact portion between the amorphous semiconductor layer and the silicon layer, and that the cause is mainly within the amorphous semiconductor layer.

According to the authors' experiments, the arsenic content ratio in the amorphous semiconductor layer was preferably in the range of 10% to 90%, considering the temperature required during manufacturing of the matrix display device.

EXAMPLE Hereinafter, an example of a 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(a) is a cross-sectional view of the structure of the nonlinear two-terminal element according to the present example, and (bl is a plan view. In the same figure,
1 is a substrate, 2 is a lower conductor layer, i.e., lead wiring, 3 is a composite layer, 4 is an upper conductor layer, i.e., connection wiring, 5 is a display electrode, i.e., a pixel electrode, 6 is a silicon layer, and 7 is an amorphous semiconductor. It is a layer. FIG. 2 is a layout diagram of the substrate for a matrix type display device according to this embodiment, in which 11 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)
electrode) or chromium (Cr) or titanium (Ti)
, a tin oxide transparent electrode doped with aluminum (AI), antimony (Sb), and a chromium (Cr)-gold (Au) multilayer film.
), aluminum (AI), and the picture element electrode 13 is made of tin (
The electrode was formed from an indium oxide transparent electrode (ITO electrode) to which Sn) was added. Particularly when voltage attenuation due to electrode resistance is a problem, it is desirable to use a highly conductive material such as aluminum (Al) 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 is placed in a vacuum chamber for evaporation, and a silicon layer is formed on the substrate by electron beam heating evaporation.
An amorphous semiconductor layer was formed by resistance heating vapor deposition, and a silicon layer was further formed as described above. Furthermore, connection wiring was formed in the same manner using a metal mask. Thus, a substrate as shown in FIG. 2 was obtained. In forming the composite layer by vapor deposition, the degree of vacuum was approximately 1*10-'' Torr.

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 (SiO□) 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. An arsenic-selenium compound containing 40 atom % of arsenic was used as a source for forming the amorphous semiconductor layer, and a molybdenum heater was used for vapor deposition. 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=12 to 18. 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 1.081 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 (SiO□) 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.

Arsenic is used as a source when forming an amorphous semiconductor layer.
An arsenic-sulfur compound containing atomic percent was used. 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=12 to 18. 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 3) 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 (StO□) 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.

Arsenic is used as a source when forming a semiconductor layer at 50 atomic%.
, a compound containing 25 atom % of selenium and 25 atom % of sulfur was used. 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 at α-13 to α-24. 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 for patterning the semiconductor layer and the connection electrode, but similar effects could be obtained using a photoresist or a foot-off method.

Furthermore, although liquid crystal is used as an example of the display medium, similar effects can be obtained by 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 is a cross-sectional view and fbl plan view of a nonlinear two-terminal element used in a matrix display device according to the present invention, FIG. 2 is a layout diagram of a substrate for a matrix display device according to the present invention, and FIG. Figures (a), 4 (a), and 5 (a) are cross-sectional views of the structure of nonlinear two-terminal elements used in conventional matrix-type display devices, and Figures 3 (b) and 4 (b). , Figure 5 (b
) is a layout diagram of a nonlinear two-terminal element used in a conventional matrix type display device. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Lower conductor layer, i.e., linear wiring, 3...Composite layer, 4...
- Upper conductor layer, that is, connection wiring, 5...Display electrode, that is, picture element electrode, 6...Silicon layer, 7.
... Amorphous semiconductor layer, 11 ... Lead wiring, 12 ... Nonlinear two-terminal element, 13 ...
...Display electrode, ie, picture element electrode, 101...
Substrate, 102...Tantalum (Ta) layer, 103
...Tantalum oxide (TazO6) obtained by anodic oxidation with a thickness of about 400 to 700 people, 104...
. . . Display electrode or picture element electrode, 105 . . . Connection wiring connecting tantalum oxide (Ta20,), which is the cause of nonlinear characteristics, and the display electrode, 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 Si, 204-...-1 type a-Si, 20
5...P type a-5i, 206...Chromium (Cr) layer, 207...Protective layer made of 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 consisting of a transparent conductor layer, etc., 303...
・Nonlinear layer with a thickness of approximately 100 mm and made of a compound of silicon (Si), nitrogen (N), and hydrogen (H), 304...
...Display electrode or picture element electrode, 305... Connection wiring connecting the nonlinear layer and display light, 306...
...Nonlinear two-terminal element, 307...Lead wiring or bus bar, 308...Terminal, 30
9...Display electrode or picture element electrode. Agent's name: Patent attorney Toshio Nakao 1 person/---A certain salesperson? --- Lower i h\11 books San no kyocho J straw Lee +- (k
iJ%J-Arrival of bow return/7----Lee Y Rooster C side/2-Non-spherical two-terminal element/J-11 display double intestine, that is, bald tremor J reference 2nd figure H// /J /I /J Figure 3 Figure 4

Claims (1)

[Claims] On at least one substrate constituting a display device, a plurality of lead wirings, a plurality of display electrodes provided for each of the lead wirings, and an electrically conductive electrode interposed between the lead wirings and each of the display electrodes are provided. and a composite layer in which a silicon (Si) layer, an amorphous semiconductor layer, and a silicon (Si) layer are laminated in this order, and the composite layer is formed by laminating a silicon (Si) layer, an amorphous semiconductor layer, and a silicon (Si) layer in this order, and the amorphous semiconductor layer Is it composed of arsenic (As) and sulfur (S), or is it composed of arsenic (As) and selenium (Se)?
A matrix display device comprising arsenic (As), selenium (Se), and sulfur (S).