JPH11214768A - Thin-film diode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a thin-film diode, wherein either an alignment process can be dispensed with as much as possible or an alignment process is not required to be high in accuracy, capable of coping with an enlargement of the diode in area or micronization of the diode in size at a high level, without deteriorating the diode in characteristics and dealing with a roll-to-roll production method, where a plastic board is used. SOLUTION: A lower electrode 2 is formed on a lower board 10, and a nonlinear resistive film 4 is formed thereon. An insulating film which contains, for instance, conductive particles 18 is formed on the nonlinear resistive film 4, and an upper electrode 8 is formed thereon. In a figure, codes 12, 14, and 16 denote a liquid crystal, a counter electrode, and an upper board respectively. Only the micro-regions of the nonlinear resistive film 4 corresponding to the conductive particles 18 contained in the film 4 function as a resistive film, so that the regions where the nonlinear resistive film 4 function can be adjusted, by changing them in conductive particle density without micro-processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin film diode used for driving a liquid crystal display panel or the like.

[0002]

2. Description of the Related Art As a driving method of a liquid crystal display panel, there are a passive matrix method and an active matrix method. The passive matrix system can be manufactured at low cost because of its simple structure, but is inferior to the active matrix system in terms of display quality and multi-segmentation (high definition). Therefore, there is a demand for a technology capable of realizing the active matrix system at a manufacturing cost comparable to that of the passive matrix system. Conventionally, switching elements used in the active matrix method include a thin film diode (TFD) having a two-terminal drive element and a thin film transistor (TFT) having a three-terminal drive element. As can be seen from the fact that a three-terminal drive element requires three terminals in principle, one element requires three wirings, and therefore a large aperture ratio cannot be obtained. Also,
Due to the complexity of the structure, the manufacturing process has a factor of increasing the manufacturing cost, such as requiring six or more masks in the manufacturing process.

On the other hand, the two-terminal drive element has an advantage that the aperture ratio can be increased, and the manufacturing cost can be reduced particularly because the structure of the diode is simple. The two-terminal drive element has a simple structure in which a non-linear resistance film is sandwiched between electrodes. However, the process of forming the two-terminal drive element also requires about three masks, and A highly accurate alignment process of the mask was indispensable. This will be specifically described below.

At present, the only commercialized two-terminal driving element is a tantalum oxide MIM diode formed by anodizing tantalum. As shown in FIG. 9, the structure for one pixel includes a lower electrode 100 and a non-linear resistance film 102 provided on the lower electrode 100.
And the upper electrode 10 provided on the nonlinear resistance film 102
4, the portion where the lower electrode 100 and the upper electrode 104 overlap, that is, the three-layer structure portion 106 indicated by hatching becomes a thin film diode. FIG. 10 is a plan view in the case where this is an array. The manufacturing process of this MIM type diode array is as follows.

[0005] First, a lower electrode 100 is formed on a substrate and patterned by photolithography.
Next, a non-linear resistance film 102 is formed on the lower electrode 100, and is positioned and patterned on the lower electrode 100. Next, an upper electrode 104 is formed on the non-linear resistance film 102, and the lower electrode 100 and the lower non-linear resistance film 102 are positioned and patterned. Since high-precision alignment using three masks is thus required, a technique that can eliminate the step of aligning the terminal drive elements is required to approach the manufacturing cost level of the passive matrix system.

[0006] Japanese Patent Publication No. 5-8808 discloses a drive element for a transmission type liquid crystal display which does not require an alignment step.
A structure of a terminal driving element has been proposed. This is shown in FIG.
As shown in (1), a non-linear resistance film 110 is formed on the entire upper surface of the lower electrode 108, and the entire surface of the lower electrode 108 is a thin film diode. 11, reference numeral 112 denotes a lower substrate, 114 denotes an upper substrate, 116 denotes a counter electrode, and 118 denotes a liquid crystal. Since only the non-linear resistance film 110 needs to be formed on the upper surface of the lower electrode 108, an alignment step is not required.

On the other hand, the electrical characteristics of a thin film diode are generally designed by changing the material, thickness, and area of the nonlinear resistance film. Conventionally used tantalum oxide has a large dielectric constant, and the thin-film diode has a large electric capacity. When the electric capacity increases, the voltage applied to the liquid crystal connected in series decreases, and the display function deteriorates. For this reason, it is desired to reduce the area of the thin-film diode as much as possible and to reduce the electric capacity of the thin-film diode. Conventionally, the reduction of the electric capacity has been dealt with by a laterite structure and a fine processing technique.

[0008]

SUMMARY OF THE INVENTION The above Japanese Patent Publication No. 5-880
According to the technique described in Japanese Patent Application Publication No. 8 (1996) -1996, the alignment step can be omitted, so that the manufacturing cost can be reduced accordingly, and the manufacturing cost of the active matrix system can be made closer to the manufacturing cost of the passive matrix system. It can be considered as one of the methods. However, when the area of the non-linear resistance film is increased with respect to the area of the lower electrode, the current amount far exceeds the desired amount. For this reason, in this technology, the amount of current is controlled by changing the oxygen content of a-Si: O: H used for the non-linear resistance film. However, when such measures are taken, Patent Publication No. 2583794. As shown in the figure, the electrical characteristics of the thin film diode are degraded, and the function originally required cannot be sufficiently performed.

Among the electrical characteristics required for a thin film diode, the most important is the sharpness of the IV curve. In other words, it means that the ratio of the current flowing when the switching function is ON and OFF is large. When ON, a large amount of current flows to increase the response speed, and when OFF, it is necessary to prevent unnecessary current from flowing and applying voltage to the liquid crystal. This is because the display contrast, which is important in the display quality, is determined by the amount of current at the time of OFF. If the electric characteristics are reduced and the IV curve required for the active matrix type driving element becomes gentle, the function as the driving element does not work sufficiently. From this perspective,
According to the technique described in Japanese Patent Publication No. 5-8808, although the manufacturing cost can be reduced, the advantage of the active matrix type driving element, that is, “advantage in display quality and multi-segmentation” is sacrificed. Will be.

On the other hand, the reduction of the electric capacity of the thin-film diode has reached the limit in the laterite structure and fine processing in view of the technical trend of large area and high definition. Technology to reduce the electric capacity of thin-film diodes,
That is, a technique for miniaturizing a thin film diode and a technique for eliminating an alignment step are desired for the following reasons. Generally, a liquid crystal display panel is formed of a glass substrate. In recent years, a liquid crystal display panel (PFD) using a film of a plastic or the like as a substrate has been commercialized. PFD is lightweight and hard to break, bendable,
This is a feature that conventional glass does not have. But,
A plastic film serving as a substrate has low heat resistance, so that a conventional manufacturing process for forming on a glass substrate cannot be applied. For this reason, in the conventional PFD, a passive matrix system having no switching element on a substrate is applied. However, this method is considered to be disadvantageous in future technical trends such as high definition and large screen. Therefore, research for applying the active matrix method to the PFD has recently been performed.

In order to apply the active matrix method to a plastic substrate, fine switching elements must be formed on the plastic substrate. However, it is known that plastic substrates undergo expansion and contraction due to heat and dehydration during processing. This expansion and contraction was close to 1000 ppm, and alignment of the mask was very difficult. For this reason, in the past, this was handled by using a loose design or using a unit-size stepper, but it can be said that the limit has been reached in view of a larger screen and higher definition. In addition, the plastic substrate can be produced by a roll-to-roll method due to its characteristic flexibility. The roll-to-roll production method is much more efficient in terms of production cost than the conventional method, but it is impossible with current technology to perform a highly accurate alignment process in this method.

Therefore, the present invention can eliminate the alignment step as much as possible or eliminate the high precision of the alignment, and can cope with a large area and high definition without lowering the diode characteristics at a high level. It is an object of the present invention to provide a thin film diode that can be produced in a roll-to-roll system using a plastic substrate.

[0013]

The miniaturization of the element in the prior art is intended to reduce the area of the nonlinear resistive film itself, which limits the approach in the microfabrication and reduces the position with respect to the area. Matching conditions cannot be ruled out. In the case of a small area where a voltage is applied on the nonlinear resistive film, the electric flow can be adjusted regardless of the area of the nonlinear resistive film by manipulating the number or density of these small areas. An extreme level is possible compared to the approach by Further, since it is not related to the area of the nonlinear resistive film itself, the alignment step for aligning the area is meaningless and is unnecessary.
This is the purpose of the present invention. Under such an idea, claim 1
In the invention described, in a thin-film diode including a lower electrode provided on a substrate, a non-linear resistance film provided on the lower electrode, and an upper electrode provided on the non-linear resistance film, any one of the non-linear resistance films Voltage is applied only to a certain area.

According to a second aspect of the present invention, there is provided a thin-film diode comprising: a lower electrode provided on a substrate; a nonlinear resistance film provided on the lower electrode; and an upper electrode provided on the nonlinear resistance film. A film having both a conductive region and an insulating region is provided between the lower electrode and the upper electrode, and a voltage is applied only to a portion of the nonlinear resistance film corresponding to the conductive region.

According to a third aspect of the present invention, there is provided a thin-film diode comprising: a lower electrode provided on a substrate; a nonlinear resistance film provided on the lower electrode; and an upper electrode provided on the nonlinear resistance film. An insulating film containing conductive particles is provided between the lower electrode and the upper electrode, and a voltage is applied only to a portion of the nonlinear resistance film corresponding to the conductive particles. I have.

According to a fourth aspect of the present invention, there is provided a thin-film diode including a lower electrode provided on a substrate, a non-linear resistance film provided on the lower electrode, and an upper electrode provided on the non-linear resistance film. An insulating film having a hole is provided between the lower electrode and the upper electrode, so that a voltage is applied only to a portion of the nonlinear resistance film corresponding to the hole.
The configuration is adopted.

According to a fifth aspect of the present invention, in the configuration of the first aspect, the upper electrode is divided into a plurality of electrode pieces for one pixel.

According to a sixth aspect of the present invention, in the configuration of the second aspect, the upper electrode is divided into a plurality of electrode pieces for one pixel.

According to a seventh aspect of the present invention, in the configuration of the third aspect, the upper electrode is divided into a plurality of electrode pieces for one pixel.

According to an eighth aspect of the present invention, in the configuration of the fourth aspect, the upper electrode is divided into a plurality of electrode pieces for one pixel.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1 (a partially cutaway plan view), the thin-film diode in this embodiment includes a lower electrode 2, a non-linear resistance film 4 provided on the lower electrode 2, Is formed in a four-layer structure including an organic insulating film 6 provided on the insulating film 6 and an upper electrode 8 of a hatched display (not a sectional display) provided on the insulating film 6. The upper electrode 8 is divided into a plurality of electrode pieces 8a. FIG.
FIG. 2 is a plan view showing an arrangement of pixels, which is an array. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line BB in FIG.

3 and 4, reference numeral 10 denotes a lower substrate 10 on which the lower electrode 2 is provided, 12 denotes a liquid crystal, and 14 denotes a liquid crystal.
Denotes an opposing electrode, and 16 denotes an upper substrate on which the opposing electrode 14 is provided. The insulating film 6 includes the non-linear resistance film 4
This is a member for applying a voltage only to an arbitrary region of the conductive particles, and as shown in FIG. 5, the conductive particles 18 are included in a state where the conductive particles 18 are coated. The conductive particles 18 exist in such a state that a part thereof protrudes from the front and back surfaces of the insulating film 6.
The minute region corresponding to each conductive particle 18 in the nonlinear resistance film 4 is a region electrically connected to the upper electrode 8 and a region to which a voltage is applied. Therefore, the insulating film 6
Is a member having both a conductive region and an insulating region.

Such a configuration adjusts the concentration, that is, the content of the conductive particles 18 so that the non-linear resistance film 4 is formed.
Means that the region in which the function of (1) functions can be freely adjusted. In a conventional technique for miniaturizing the element by reducing the entire area of the nonlinear resistance film 4,
Although there is a limit due to the need to rely on microfabrication technology that directly approaches the shape itself of the nonlinear resistance film 4, there is a configuration in which a region to which a voltage is applied is changed according to the number or density of the conductive particles 18 as in this embodiment. Then, the area of the non-linear resistance film 4
Irrespective of the shape, the region where the nonlinear resistance film 4 functions can be formed extremely finely and arbitrarily with a particle size level.

As described above, the adjustment of the region in which the nonlinear resistance film 4 functions is adjusted by the degree of aggregation of the ultra-small regions, so that the adjustment is not roughly related to the shape of the nonlinear resistance film 4. This eliminates the need for the alignment step conventionally associated with the shape, or eliminates the high accuracy of the alignment step due to the looseness in design. This is different from the necessity of the alignment step by forming the non-linear resistance film 4 on the entire surface of the lower electrode 2 as in the technique described in Japanese Patent Publication No. 5-8808, so that the composition of the non-linear resistance film 4 does not need to be changed. Also, the electric characteristics of the nonlinear resistance film 4 are not reduced. Further, even when tantalum oxide is used for the non-linear resistance film 4, its electric capacity can be easily reduced, in other words, the IV characteristics can be varied, thereby optimizing the IV characteristics.

Next, a manufacturing process of the thin-film diode in this embodiment will be described with reference to FIG. First, the lower electrode 2 is formed on the lower substrate 10 (FIG. 6A). As the material of the lower electrode 2, Al, Ni, Cu, Au, A
g, Cr, Mo, Ta, Zn, Fe, Ti, W, Sn,
Examples include Pb, Pt, In, and the like, and a metal of these compounds, an organic substance, and a semiconductor. Since the lower electrode 2 is required to have low resistance and flexibility, Al, Ni, Cu and the like are particularly preferable.

Next, a non-linear resistance film 4 is formed on the lower electrode 2 (FIG. 6B). Examples of the material of the nonlinear resistance film 4 include Si, a-Si, a-Si: H, and a-Si: O:
H, a-Si: N: H, a-Si: F, a-Si: N:
F, a-Si: O: F, porous silicon, SiC, Z
nO, ZnSe, CdTe, AlGa, InP, GaAs
s, InSb, GaP, GaN, AlP, InN, In
Semiconductor material composed of As, NaCl, AgBr, CuCl, etc., or a composite thereof, Si4N3, SiO2, i-C
And the like, or an organic substance. In particular, a-S
Suitable materials include i: O: H and a-Si: N: H. When the lower substrate 10 is made of an organic material such as plastic, it is desirable to use the same material as the lower substrate 10 in consideration of stress and the like. Thus, the nonlinear resistance film 4 conventionally formed of an inorganic material can be formed of an organic material such as 3-alkylthiophene. In this case, there arises a problem that the mobility and hence the amount of current cannot be increased.
Contrary to the tantalum oxide of the M-type diode, the diode area may be increased to some extent. This is insulating film 6
Can be dealt with by increasing the conductive region, that is, by increasing the content of the conductive particles 18.

Next, an insulating film 6 is formed on the nonlinear resistance film 4 (FIG. 6C). Examples of the material of the insulating portion of the insulating film 6 (in other words, the binder material of the conductive particles 18) include organic materials such as polyimide, epoxy resin, PET, PC, and PES, and inorganic materials such as SiO2 and SiN. The material of the insulating portion is selected in consideration of etching simultaneously with the upper and lower layers. The material of the conductive particles 18 is A
1, Ni, Cu, Au, Ag, Cr, Mo, Ta, Z
There are metals such as n, Fe, Ti, W, Sn, Pb, Pt, In and the like and alloys thereof. Examples of the film forming method include coating, spraying, and sputtering. The size of the conductive particles 18 may be about 1 nm to 10 μm, but is preferably about 10 nm to 1 μm in consideration of the film thickness and the electrode area. The particle concentration is 1e-6 to 10,000 particles / μ.
m ² , but the particle size is about 0.1 μm and the upper electrode 8
If it is about 100 [mu] m ^2, the particle concentration 1e-4 to 1 pieces / [mu] m ² is an appropriate amount.

Next, an upper electrode 8 is formed on the insulating film 6 (FIG. 6D). The material of the upper electrode 8 is Al,
Ni, Cu, Au, Ag, Cr, Mo, Ta, Zn, F
e, Ti, W, Sn, Pb, Pt, In and the like, and metals, organic substances, semiconductors and the like of these alloys. Since the upper electrode 8 is used as a reflector, a material having a sufficient reflectance is desired, and Al, Ag, and the like are suitable materials. Further, since a low resistance is not particularly desired for the upper electrode 8, it is desirable to consider not only the film forming method such as sputtering but also the production cost such as the silk printing and the spraying method. In this case, patterning by printing or the like can be considered, and the number of steps can be reduced.

Next, the upper electrode 8 which is the uppermost part of the four-layer structure
Is coated with a resist 20 for photolithography, and is exposed from above a mask (not shown) to pattern the resist 20. (FIG. 6 (e)). This patterning forms a divided structure in the AA direction in FIG. Next, etching is performed from above the patterned resist 20 (FIG. 6F). Usually, wet etching using a solution is mainly used for etching. For example, when the lower substrate 10 is made of plastic or the like, dry etching can reduce damage to the lower substrate 10. Etching is performed on the lower electrode 2 previously formed,
It is desirable to simultaneously etch the four layers of the nonlinear resistance film 4, the insulating film 6, and the upper electrode 8. This makes it unnecessary to perform any conventional alignment with the lower layer.

Finally, when the divided structure of the upper electrode 8 is not patterned by printing or the like, it is necessary to perform patterning in a direction perpendicular to the previously performed etching (the direction BB in FIG. 2). Therefore, the resist 20 is patterned according to the divisional configuration of the upper electrode 8 (FIG. 6G). Next, selective etching is performed from above the patterned resist 20 so as to stop only at the upper electrode 8 (FIG. 6H), and thereafter, the resist 20 is peeled off (FIG. 6I). The number of divisions of the upper electrode 8 is 2 to 1000
Though about 00 is conceivable, about 2 to 1000 is appropriate in consideration of the reflectance of the upper electrode 8 and the like. When the upper electrode 8 is divided into a large number in this manner, as shown in FIG.
Even if there is an electrode piece 8a located immediately below the edge of the counter electrode 14, the influence of the positioning on the counter electrode 14 is neglected because the ratio of the electrode piece 8a to the remaining electrode piece 8a group is small. To the extent possible. Therefore,
Conventionally, it was necessary to position the opposing electrode 14 and the upper electrode 8 with high accuracy. However, by adopting a divided structure as in this embodiment, alignment can be eased. Further, by dividing the upper electrode 8, a region to which a voltage is applied in the nonlinear resistance film 4 is formed by the conductive particles 1.
8 can be varied synergistically in relation to the distribution of 8, and the miniaturization of the thin film diode can be further improved.

Next, another embodiment will be described. The present embodiment is characterized in that a conductive region of a member for applying a voltage only to an arbitrary region of the nonlinear resistance film is formed as a hole. The manufacturing process of the thin-film diode in this embodiment will be described with reference to FIG. First, similarly to the above embodiment, the lower electrode 2 is formed on the lower substrate 10 (FIG. 7).
(A)) Then, a non-linear resistance film 4 is formed on the lower electrode 2 (FIG. 7 (b)). Examples of the material of the nonlinear resistance film 4 include Si, a-Si, a-Si: H, and a-Si: O:
H, a-Si: N: H, a-Si: F, a-Si: N:
F, a-Si: O: F, porous silicon, SiC, Z
nO, ZnSe, CdTe, AlGa, InP, GaAs
s, InSb, GaP, GaN, AlP, InN, In
Semiconductor material composed of As, NaCl, AgBr, CuCl, etc., or a composite thereof, Si4N3, SiO2, i-C
And the like, or an organic substance. In particular, a-S
Suitable materials include i: O: H and a-Si: N: H. When the lower substrate 10 is made of an organic material such as plastic, it is desirable to use the same material as the lower substrate 10 in consideration of stress and the like. Thus, the nonlinear resistance film 4 conventionally formed of an inorganic material can be formed of an organic material such as 3-alkylthiophene. In this case, there arises a problem that the mobility and hence the amount of current cannot be increased.
Contrary to the tantalum oxide of the M-type diode, the diode area may be increased to some extent. This can be dealt with by increasing the conductive region of the insulating film 22 described later.

Next, an insulating film 22 is formed on the nonlinear resistance film 4 (FIG. 7C). The insulating film 22 is a member for applying a voltage only to an arbitrary region of the non-linear resistance film 4 similarly to the insulating film 6 in the above embodiment. Examples of the material of the insulating film 22 include oxides such as SiO 2 and inorganic and organic substances such as nitrides. As a film forming method, there are sputtering, vapor deposition, coating and spraying. Although the film thickness varies depending on conditions, it may be about several nm to several μ like the non-linear resistance film 4 below. The material of the insulating film 22 is selected in consideration of etching at the same time as the upper and lower layers.

Next, a resist 24 is applied on the insulating film 22 (FIG. 7D), and the resist 24 is formed by dots (holes) 26.
(FIG. 7E). The size and density of the dots 26 are designed based on the required electrical characteristics of the thin film diode. For example, when the nonlinear resistance film 4 has a film thickness of 1
When a-Si: O: H of 00 nm is used, dots 26
Is about 1 to 10 to 1,000. It is desired that the size of the dot 26 be as small as possible. As a result, the number of dots 26 per element can be increased, and variations in element characteristics due to errors in the number of dots 26 can be reduced. That is,
Variations in the electrical characteristics of the elements can be suppressed to within a certain allowable range without performing high-precision alignment.

After exposing the resist 24, selective etching is performed so as to stop only at the insulating film 22, and holes 30 are formed in the insulating film 22. Thereafter, the resist 24 is peeled off (FIG. 7F). If a photosensitive resist is used for the insulating film 22, the holes 30 can be directly formed by photoetching, and the manufacturing process can be simplified. However, in this case, an etchant to be etched later must be selected. Next, the insulating film 22
The upper electrode 8 is formed on the substrate (FIG. 7 (g)). As a result, the upper electrode 8 is electrically connected to the nonlinear resistance film 4 via the holes 30. Therefore, by changing the diameter and density of the holes 30, the region in which the nonlinear resistance film 4 functions can be freely adjusted regardless of the area of the nonlinear resistance film 4. The material and the like of the upper electrode 8 are as described in the above embodiment.

Next, the upper electrode 8 which is the uppermost part of the four-layer structure
Is coated with a resist 32 for photolithography, and is exposed from above a mask (not shown) to pattern the resist 20. (FIG. 7 (h)). This patterning forms a divided structure in the AA direction in FIG. Next, etching is performed from above the patterned resist 32 (FIG. 7 (i)). Usually, wet etching using a solution is mainly used for etching. For example, when the lower substrate 10 is made of plastic or the like, dry etching can reduce damage to the lower substrate 10. Etching is performed on the lower electrode 2 previously formed,
It is desirable to simultaneously etch the four layers of the nonlinear resistance film 4, the insulating film 22, and the upper electrode 8. This makes it unnecessary to perform any conventional alignment with the lower layer.

Lastly, if the divided structure of the upper electrode 8 is not patterned by printing or the like, it is necessary to perform patterning in a direction orthogonal to the previously performed etching (the direction BB in FIG. 2). Therefore, the resist 32 is patterned according to the divisional configuration of the upper electrode 8 (FIG. 7 (j)). Next, selective etching is performed from above the patterned resist 32 so as to stop only at the upper electrode 8, and then the resist 20 is peeled off (FIG. 7).
(K)). The number of divisions of the upper electrode 8 and the like are as described in the above embodiment. In each of the above embodiments, the film having both the conductive region and the insulating region is provided between the nonlinear resistance film and the upper electrode, but may be provided between the lower electrode and the nonlinear resistance film.

[0037]

According to the first, second, third, or fourth aspect of the present invention, a voltage is applied only to an arbitrary area (a minute area) of the nonlinear resistance film, and the nonlinear resistance is determined by the number and density of the area. Because it was configured to adjust the area where the membrane functions,
It is possible to miniaturize the element beyond the limit of fine processing. This makes it possible to respond to a large area and high definition at a high level. In addition, since an alignment step can be omitted or high precision of alignment can be eliminated, manufacturing cost can be reduced, and roll-to-roll production using a plastic substrate can be performed.

According to the fifth, sixth, seventh or eighth aspect of the present invention, the upper electrode is divided into two parts.
Or, in addition to the effects described in 4, the alignment accuracy with respect to the counter electrode can be reduced, and the need for alignment can be further reduced.

[Brief description of the drawings]

FIG. 1 shows a thin film diode 1 according to an embodiment of the present invention.
FIG. 3 is a partially cutaway plan view showing a configuration for pixels.

FIG. 2 is a plan view when the configuration shown in FIG. 1 is used as an array.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a sectional view taken along line BB in FIG. 2;

FIG. 5 is a perspective view of an insulating film.

FIG. 6 is a cross-sectional view showing a manufacturing process of the thin-film diode shown in FIG.

FIG. 7 is a cross-sectional view illustrating a manufacturing process of a thin-film diode according to another embodiment.

FIG. 8 is a plan view of an exposure mask used in the embodiment shown in FIG.

FIG. 9 is a plan view showing a configuration of one pixel of a conventional thin film diode.

FIG. 10 is a plan view when the configuration shown in FIG. 9 is used as an array.

FIG. 11 is a sectional view of another conventional thin film diode.

[Explanation of symbols]

 2 Lower electrode 4 Nonlinear resistance film 6 Insulating film 8 Upper electrode 8a Electrode piece 18 Conductive particle 22 Insulating film 30 Void

Claims (8)

[Claims] 1. A thin-film diode comprising: a lower electrode provided on a substrate; a non-linear resistance film provided on the lower electrode; and an upper electrode provided on the non-linear resistance film. A thin-film diode characterized in that a voltage is applied only to a certain region. 2. A thin-film diode comprising: a lower electrode provided on a substrate; a non-linear resistance film provided on the lower electrode; and an upper electrode provided on the non-linear resistance film. A thin film diode having a film having both a conductive region and an insulating region provided between the non-linear resistive film and a voltage applied only to a portion of the non-linear resistance film corresponding to the conductive region. 3. A thin-film diode comprising: a lower electrode provided on a substrate; a non-linear resistance film provided on the lower electrode; and an upper electrode provided on the non-linear resistance film. A thin film diode characterized in that an insulating film containing conductive particles is provided between the non-linear resistance film and the portion of the nonlinear resistance film corresponding to the conductive particles. 4. A thin-film diode comprising a lower electrode provided on a substrate, a non-linear resistance film provided on the lower electrode, and an upper electrode provided on the non-linear resistance film, wherein the lower electrode and the upper electrode A thin film diode, wherein an insulating film having a hole is provided between the non-linear resistance film and the voltage applied only to the portion corresponding to the hole in the non-linear resistance film. 5. The thin film diode according to claim 1, wherein said upper electrode is divided into a plurality of electrode pieces for one pixel. 6. The thin-film diode according to claim 2, wherein said upper electrode is divided into a plurality of electrode pieces for one pixel. 7. A thin film diode according to claim 3, wherein said upper electrode is divided into a plurality of electrode pieces for one pixel. 8. The thin film diode according to claim 4, wherein said upper electrode is divided into a plurality of electrode pieces for one pixel.