JPH0558170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention provides a microcomputer,
The present invention relates to a semiconductor device having non-linear characteristics that is applied to a solid-state display device, an image sensor, or a liquid crystal printer that solidifies the display portion of a word processor or a television.

``Prior Art'' For solid-state display panels, a system in which each picture element is controlled independently is effective for large-area displays. A panel using such active elements is a display with a large area matrix configuration of A4 size or larger, with 640 elements in the horizontal direction (640 x 3 = 1920 elements in the case of full color) or 200 elements or 526 elements in the vertical direction. The device is known. However, in such a large-area display device, each picture element (hereinafter also referred to as a pixel) having an active element has a distance between adjacent pixels arranged in a matrix with a predetermined distance apart. It is easy to cause crosstalk (a phenomenon of weak electrical conduction). Therefore, even if one tried to create an ON function and the other OFF function, each pixel would not be able to turn on or off sufficiently, easily resulting in insufficient contrast.

"Problems to be Solved by the Invention" In such a large-area display device, in order to completely eliminate crosstalk between each pixel, semiconductors including amorphous semiconductors should not exist between adjacent pixels. . Furthermore, it is important to cover the side surfaces of this semiconductor with an insulator to provide electrical isolation. However, when each pixel and the semiconductor constituting the pixel were made to correspond on a 1:1 basis, four types of photomasks were required in the manufacturing process.

If this photomask is made once, it requires seven steps (resist coating, baking, patterning, development, partial removal of resist, selective etching of the workpiece, and removal of resist).
This has become an extremely large hindrance to lowering manufacturing yields. For this reason, there has been a demand for a semiconductor device structure in which the number of mask alignments is only once for every two types, and in which crosstalk between adjacent pixels can be completely prevented.

"Means for Solving the Problem" In order to solve the problem, the present invention provides a display device in which a plurality of active element type pixels are provided in a matrix on a substrate, each pixel has a first electrode, a non-linear material , a non-linear element consisting of a stack of second electrodes, and a third electrode connected to the second electrode of the element and serving as a pixel electrode, the first electrode being provided in each pixel. The display device is characterized in that the non-linear element is provided across a plurality of the third electrodes and is provided in a portion where the first electrode and the third electrode overlap, The display device is characterized in that a second electrode of a pixel and a nonlinear material under the electrode have approximately the same shape.

In the configuration of the present invention, the third electrode, which is a pixel electrode connected to one electrode (second electrode) of the non-linear element, is crossed so as to cross the other electrode (first electrode) of the non-linear element. (electrode) is provided, and a nonlinear element is provided in the portion where the first electrode crosses this third electrode (pixel electrode), that is, the portion where the third electrode and the first electrode overlap. This is a characteristic feature.

Further, the first electrode of the nonlinear element has a plurality of third electrodes.
The pixel electrode (pixel electrode) is provided across the electrodes (pixel electrodes).

That is, as shown in FIG. 4A, the first electrode, which is one wiring of the matrix, is provided so as to cross a plurality of pixel electrodes.

Further, if necessary, an insulating material is provided under the second electrode, which is one electrode of the nonlinear element, to cover the semiconductor and the first electrode thereunder to provide isolation.

As a result, since the mask alignment process uses a self-alignment process, it only needs to be done twice, and no semiconductor remains above the leads between adjacent pixels, making it possible to completely prevent crosstalk.

In addition, the semiconductor's periphery (electrodes on the top and bottom) is covered with an insulating material and is packaged. This passivation film also prevents crosstalk between pixels.

Furthermore, the nonlinear element used in this invention uses a non-single crystal semiconductor, and its material composition is Si(N)−SixC _1- x
(0<X≦1)(I)-Si(N) structure, Si(NIPIN) structure or Si(N)-SixC _1- x(0<X<1)(I)-SixC _1- x
(0<X≦1)(I)−SixC _1- x(0<X<1)(I)−Si
(N) structure (where N is N-type, I is intrinsic or substantially intrinsic, P is P-type, and (I) is a barrier layer) or its tandem laminated structure and modified structure. I am the lord.

The nonlinear element used in the present invention has ohmic contact with a pair of electrodes (first and second electrodes), and is composed of a composite diode that has reverse rectification characteristics. An example is an NIN structure in which an N-type semiconductor (hereinafter referred to as intrinsic or substantially intrinsic) semiconductor-N type semiconductor is stacked, that is, an NI junction and an IN junction are electrically connected in opposite directions, and a semiconductor Semiconductors with integrated NIN junctions as well as their variants NN ^- N, NP ^- N, NIPIN, NIP ^- IN or
It is a composite diode with an NIP ⁺ IN structure (hereinafter, for simplicity, these diodes will be collectively referred to as NIN type diodes).

The threshold voltage of such a composite diode makes the diode characteristics opposite to each other, and the build-in voltage (threshold) determines the conductivity type at or near the NI interface of the NI junction (NIP junction). Impurities such as trace amounts of phosphorus,
It can be determined by the height difference between the energy edges at the NI interface and the IP interface. Therefore, by controlling the manufacturing process, it is possible to determine the threshold voltage of a desired element, and to control how easily current flows below the threshold and how easily current flows above the threshold.

Furthermore, the present invention provides a structure in which the X wiring or the Y wiring (hereinafter referred to as the X wiring as only the X wiring is shown in the drawings) constituting the composite diode and the matrix and the nonlinear element thereon have approximately the same shape. It can be completed by simply performing two mask alignments. A typical example of the structure of the present invention is shown in FIG. 4, and its manufacturing process is shown in FIG.

Furthermore, for solid-state display elements such as liquid crystals, AC bias is applied to the other electrode (fourth electrode) of the liquid crystal, leads are wired in the Y direction, and the electrical level is controlled to achieve full color and gradation. It also has the feature of being controllable.

``Function'' In this way, even when creating a matrix with a large area of A4 size or larger, the leads in the X direction can be arranged closely on the insulator in the stripe section between each pixel, and each pixel can be This made it possible to eliminate electrical leakage from adjacent elements. In addition, by making the second electrode and the lead connected to it the same width, alignment accuracy in the X direction can be reduced to ±200 μm or less (theoretically within ±3 mm). The process is now possible with precision alignment.

In addition, as shown in Figures 1 and 4, the other Y wiring and electrodes of the liquid crystal are divided into three parts, and red (referred to as R) and green (referred to as G) are connected to each electrode or active element. , blue (referred to as B)
By passing the voltage through the filter, voltage can be applied independently to that level on the Y axis. Therefore, it has the feature that it is possible to perform gradations for R, G, and B.

The present invention will be described below with reference to Examples.

Example 1 FIG. 1 shows a circuit diagram using a solid state display device of the present invention.

In the drawing, the pixel is the electrode 2 of the nonlinear element 2.
(second electrode) is connected to one electrode 23 (third electrode) of the liquid crystal 3. The non-linear element is connected to the address lines 4 and 5 of the X wiring that provides the clock signal.
are connected by an electrode 21. On the other hand, the fourth electrode 24 of the liquid crystal 3 is connected to the data lines 6 and 7 of the Y wiring. The Y wiring has a fourth electrode 24 divided into three parts corresponding to one third electrode 23 (Fig.
6-1, 6-2, 6-3, i.e. 6 or 24) in Figure C correspond to the other opposing translucent insulating substrate, typically the glass substrate (20' in Figure 4C). are connected. The fourth electrode 14 has R (red), G (green), and B (blue) filters, making it full-color.

This X wiring is provided on the same insulating substrate, typically a glass substrate (20 in FIGS. 4B, C, and D). As a result, crosstalk 33 is less likely to occur, and the resistance of this part should be set to 10 ⁹ Ω or more, preferably
It is an object of the present invention to set the resistance to 10 ¹⁰ Ω or more.

These picture elements are arranged in a matrix, which is shown in the drawing as 2×2×3 (R, G, B). However, the present invention does not use such a small matrix, but a scaled-up display device, for example (640 pixels x 3 pixels).
It is effective for large matrix panels such as (R, G, B) x 200 or 512).

Examples of the manufacturing process and characteristics of a nonlinear element that is a part of a pixel using such a composite diode are shown in FIGS. 2 and 3.

The manufacturing process in Figure 2 is 3 in Figure 4A.
This corresponds to the case where the 0 area is particularly enlarged and manufactured.

2A, B, C, and D-2 correspond to the longitudinal cross-sectional view of FIG. 4 CC'. FIG. 2D-1 corresponds to the longitudinal sectional view taken along line A-A' in FIG. 4, and shows the device structure.

In FIG. 2A, non-alkali glass 20 was used as the light-transmitting insulating substrate. On this top surface, a conductive film of aluminum 11 and a chromium film 12 on top of the aluminum film 12 are deposited at a rate of 0.1 by sputtering or electron beam evaporation.
They were formed to a thickness of ~0.5 μ and 500-1500 Å, respectively.

After that, NIN (N(I)I(I)N, NIPIN, N(I)IPI(I)N) was formed on the entire surface using plasma gas phase reaction method.
A composite diode made of a non-single crystal semiconductor with a structure including That is, a non-single-crystal semiconductor having an amorphous structure is formed on a surface of a substrate maintained at 200 to 300° C. by subjecting an N-type semiconductor to silane and subjecting it to high-frequency glow discharge at 13.56 MHz. Its electrical conductivity is 10 ^-7 to 10 ^-4 (Ωcm)
^-1 and a thickness of 50 to 500 Å. Further next,
Sufficient vacuum was drawn to 10 ^-6 to ^{10 -7} torr. Furthermore, using silane (SimH _2n+2 , e.g. SiH ₄ with m=1), an I-type non-single crystal semiconductor with a thickness of 500 Å to 1 μm and a thickness of 0.1 μm, for example, is laminated on the N-type semiconductor. Formed. Furthermore, sufficient vacuum was drawn to 10 ^-6 to 10 ^-7 torr. Again, B ₂ H ₆ /SiH ₄ =0.1%, and a P-type semiconductor was formed with a thickness of 100 to 500 Å, for example, 200 Å. Similarly, an I-type semiconductor layer (500 to 2000 Å) and an N-type semiconductor layer on top of it to a thickness of 50 to 500 Å are stacked to form a NIPIN junction or an N(I)IPI(I)N junction ((I) is a barrier layer). layer (thickness 5 to 50 Å), but will be omitted below for brevity).

After this, apply chromium (500 to 1500 Å) on this top surface.
15 by electron beam evaporation method or sputtering method
The layers were laminated to a thickness of 0.1 to 0.2 μm.

Furthermore, as shown in FIG. 2B, anisotropic plasma etching was performed using the first photomask so that the peripheral portion 26 was vertical. Next, plasma oxidation is performed on the semiconductor at, for example, 200°C on these entire surfaces.
Silicon oxide was prepared by solid phase-vapor phase oxidation.
Next, silicon nitride or silicon oxide 29 is applied to these entire surfaces.
Coating (particularly the coating on the side surface 26) was performed by plasma CVD method to a thickness of 0.1 to 0.5 μm.

Next, as shown in FIG. The top and the top of the substrate 20 were removed. Thus, Figure 2C was obtained.

Next, CTF was formed on the entire upper surface of FIG. 2C using ITO or tin oxide to a thickness of 0.1 to 0.5 μm. Furthermore, a second photomask is used to
I selectively etched the CTF. In addition to this CTF
Reference numeral 23 constitutes the third electrode for the liquid crystal pixel, and using this CTF as a mask, the unnecessary semiconductor between the pixels 31 was removed as shown in D-1. Thus, the second
Figures D-1 and D-2 were obtained.

Furthermore, after this, an insulator 28 similar to 29 may be formed on the side surface of the semiconductor 31 as well.

If the number of masks is increased, it is also possible to use the method shown in FIG. 2C in which one mask is used and the side surfaces and their vicinity are left by a normal plasma etching method. However, in such a case, the number of masks required to be used is only three.

That is, in FIG. 2, a first electrode 2 made of aluminum and chromium is placed on a glass substrate 20.
1. A composite diode 2 made of NIPIN or NIN semiconductor laminate, a second electrode 15 made of chromium, and a third electrode 23 made of a light-transmitting conductive film closely attached to this second electrode. It was set up so that it would straddle it.

As a result, a nonlinear characteristic 3 as shown in Fig. 3 is obtained.
Embodiment 2 In which the configuration of the present invention is shown in FIG. 4, a plan view A and a longitudinal cross-section of the area 1 surrounded by the broken line in FIG. Figures B, C and D are shown.

Further, FIGS. 4B, C, and D show longitudinal cross-sectional views taken along lines A-A', B-B', and C-C' in A, respectively.
In addition, FIG. 4C shows the liquid crystal 3 and the upper electrodes 6, 7.
and the substrate 20' are also shown, but other A, B,
D shows only the side having the nonlinear element for simplicity.

The manufacturing method of this element is the same as in Example 1.
That is, the first electrode 21, the lead connected thereto, and the semiconductor 2 having the same shape thereon and the conductor constituting the second electrode 15 are formed with a width of 20 μm using the first mask.

Furthermore, a passivation film 29 is provided to insulate the semiconductor and the side surfaces of the lower first electrode.
be configured. Furthermore, it is closely placed on the upper electrode.
CTF is formed on the entire surface so as to straddle this laminate. Next, with a second photomask,
It was formed by etching and removing only the CTF pixels 23 and 23' (420μ x 420μ).

Thus, the electrode 22 of the first pixel and the second pixel next to it
By setting the electrode 22' of the pixel and the lead 4 (FIG. 4B) between them to have the same width, a self-aligned configuration could be achieved even with respect to pattern deviation in the horizontal direction (horizontal direction in the drawing). The semiconductor is removed from the open groove 31 between the two semiconductors 2 and 2', and leads are provided on the substrate 20. That is, since the two semiconductors 2, 2' are isolated by the insulators 28, 28', the equivalent resistance, which is less likely to cause crosstalk, can be reduced to a substantially infinite value of 10 ⁹ Ω or more.

Furthermore, if the second electrode is placed in the center from its original position, the electrode area of the nonlinear element will not change even if it is shifted up or down by ±200μ (maximum), and the electrical characteristics (current value) will not be affected. It is possible to create a pattern without giving it. In other words, in a 640 x 512 element, for example, the upper right edge and lower left edge of a glass substrate (30 cm x 20 cm) will cause a mask misalignment that is 10 times that of the conventional mask, for example, one side will be 200μ on the + side and the other will be 200μ on the - side. Mask alignment is now possible even with poor accuracy due to misalignment.

Furthermore, as is clear from FIG. 4B, crosstalk resistance exists between the second electrode 22 of the element that controls one pixel and the second electrode 22' of the element that controls the adjacent pixel. 33 has an insulator separation with no semiconductor remaining at a distance of 15 μm, so it has a high resistance type of 10 ¹⁰ Ω or more (lead 4
width of 20 μm).

Furthermore, the other fourth electrode 24 of the opposing liquid crystal,
24' and leads 6 and 7 were formed as wiring in the Y direction using another first mask.

After this, for each wiring in the Y direction,
By a known electrodeposition method, red filters were applied to the electrodes 6-1 and 7-1, green filters were applied to electrodes 6-2 and 7-2, and blue filters were applied to electrodes 6-3 and 7-3. formed. Then polyimide e.g.
In addition to coating PIQ as a protective film, this
Orientation treatment was applied to PIQ.

For this full coloring, a dyeing method may be used instead of the electrodeposition method. In this method, R, G, and B filters are first formed on a glass substrate, then a passivation film is formed, and 6-1, 6-2,
Electrodes were formed by dividing it into three parts: 6-3, 7-1, and so on.

In this way, three electrodes could be provided corresponding to one lower electrode.

From the above, it is only necessary to use three types of masks to form one active picture element on this surface, and especially in that case, two overlapping masks (one
It has the advantage of requiring only 10 times).

Furthermore, another opposing insulating substrate 20' is
They were separated by a width of 10 μm, and after evacuating the space, a known liquid crystal 10 was sealed.

For the display panel, a reflective plate is then provided for the reflective type, a light source is provided on the back side for the transmissive type, and a first
The peripheral circuits 8 and 9 shown in the figure were arranged on a printed circuit board, and the leads of the printed circuit board and the leads of the display element were connected in correspondence with each other.

In this way, it has become possible to pattern an active element type panel using only three masks.

"Effects" As described above, the present invention eliminates crosstalk between a pixel made of a nonlinear element and a liquid crystal and an adjacent pixel. In addition, the electrode area (current value when applying a predetermined voltage) of a nonlinear element changes even if it is shifted up to ±200 μm vertically from the center of the rectangular electrode, or by several mm left and right. has certain nonlinear characteristics,
It was possible to prevent variations in the electrical characteristics of the active drive throughout the matrix.

It is an alternating current drive system, and in particular, the threshold value of the diode can be controlled by the process conditions during stacking of semiconductor layers using a gas phase reaction method, making it easy to control gradation.

In the present invention, a nonlinear element NIN junction or
NIPIN joint was used.

Furthermore, NIPIN, which sets up a tandem,
The threshold value may be increased as a NIPINIPIN junction.

However, on the other hand, diode rings with multiple PIN junctions in parallel, or BACK with multiple PIN junctions in series,
The present invention is also effective for other nonlinear semiconductor devices having the origin symmetric characteristic shown in FIG. 3 using the -TO-BACK method and other Zener characteristics or avalanche characteristics. In the present invention, when the non-linear element is non-photosensitive, it is possible to provide the first electrode with only a light-transmitting conductive film and provide a semiconductor closely thereto. In addition, when the device is photosensitive and uses the dark state of the device, it is necessary to provide a light-shielding conductor, such as chromium, in the same shape as the semiconductor between the rectangular transparent conductive film and the semiconductor. Needless to say. Of course, the nonlinear element has photosensitivity,
The present invention may also be applied in accordance with the application when the photosensitive characteristics thereof are utilized.

[Brief explanation of the drawing]

FIG. 1 shows a circuit diagram of a liquid crystal display panel which is an application example of the present invention. FIG. 2 is a longitudinal sectional view showing the manufacturing process of a composite diode, which is a nonlinear element. FIG. 3 shows the operating characteristics of a composite diode, which is a nonlinear element. FIG. 4 shows a plan view and a vertical sectional view of a display panel according to an embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. In a display device in which a plurality of active element type pixels are provided in a matrix on a substrate, each pixel is a nonlinear element consisting of a stack of a first electrode, a nonlinear material, and a second electrode. and a third electrode serving as a pixel electrode connected to the second electrode of the element, and the first electrode is provided across the plurality of third electrodes provided in each pixel. A display device characterized in that the non-linear element is provided in a portion where the first electrode and the third electrode overlap. 2. A display device according to claim 1, wherein the second electrode of each pixel and the nonlinear material under the electrode have approximately the same shape.