JPH02202076A - Non-linear switching element and manufacture thereof - 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 switching element that utilizes nonlinear characteristics, and more particularly to a bidirectional nonlinear switching element that can be used for active matrix driving of liquid crystal.

[Prior art 1] It has been known that a metal-insulator-metal (MIM) thin film laminated structure exhibits bidirectional nonlinear characteristics as shown in Fig. 1, and MIM elements made of TaTaaOsCr have been It has been put into practical use as a switching element for driving the liquid crystals of liquid crystal televisions.

For the performance of an MIM element as a switching element when used to drive a liquid crystal, it is important that the resistance value decreases rapidly and nonlinearly with respect to voltage. It is also necessary to ensure a voltage, that is, when considering a series structure of an MIM element and a liquid crystal, the smaller the capacitance of the element, that is, the capacitance of the insulator of the element, the better.

However, when an insulator is used as an inorganic oxide, its dielectric constant is generally large, and in the case of Ta*Os, it is 25 to 27.

Therefore, in order to reduce capacitance, it is possible to reduce the element area or increase the thickness of the insulator, but increasing the thickness also raises the problem that the resistance value does not become smaller than necessary, making it impractical for practical use. A method is taken to reduce the element area.Actually, the area of elements put into practical use for liquid crystal TVs is 5 μm square.

Extremely advanced manufacturing technology is required.

Further, in manufacturing, there are problems such as poor throughput and high cost due to frequent use of vacuum film forming equipment and dry etching equipment.

[Problem to be solved by the invention]

As described above, the conventional technology has a problem in that bidirectional nonlinear elements used for driving liquid crystal cannot be manufactured easily and at low cost.

The present invention is intended to solve these problems, and by using an organic material with a small dielectric constant as an insulator, a large element area can be formed.

Furthermore, by using a chemically stable phthalocyanine-based organic material and forming the insulator using a wet method, we were able to reduce costs.

Although it has been known that phthalocyanine-type substances exhibit so-called diode characteristics, there have been no reports of bidirectional nonlinear characteristics as shown in Figure 1, and this can be called our new discovery.

[Means for Solving the Problems] In the nonlinear switching element of the present invention, an insulator film is formed on a conductor by a wet method, and a conductor film is further formed on the insulator film. The insulating film is formed by dispersing insulating material particles in an aqueous micelle solution of a surfactant that has the property of being electrolytically charged, and forming a colloid by surrounding the particles with micelles of the surfactant. A conductor, which is the substrate to be film-formed, is immersed as an electrode in the micelle and electrolyzed, thereby electrically destroying the micelles and depositing the insulator material particles surrounding them on the conductor to form a film. be.

As the conductor used for the substrate, metal, oxide conductor (I
nt Os , Snow, etc.) are preferred.

As the insulating material, phthalocyanine substances are preferable, and the particle size is O6005um to 0.5μ as the primary particle size.
m is preferred.

Furthermore, the conductor covering the insulator is preferably a metal or oxide conductor.

[Example 1] Indium tin oxide (ITo), which is an oxide conductor, was formed on a glass substrate to a thickness of 1000 mm.

A photosensitive epoxy acrylate pus was formed as an insulating material that could be patterned on this ITo, and 15X
A minute hole with an area of 15 μm was formed to expose ITOIII (FIG. 2(a)). Note that the material that can be used to form a pattern film is not limited to epoxy acrylate.

Using this substrate as an anode and a platinum electrode as a cathode, electrolysis was carried out in an electrolytic solution containing dispersed colloidal metal-free phthalocyanine.

The charge liquid is metal-free phthalocyanine 5g/surfactant charged by I2 electrolysis 1mM (Doguchi Chemical Co., Ltd. Fe
rroceny l -P EG ) supporting salt (LiB
r) The composition was 0.05M, and metal-free phthalocyanine was colloidally dispersed using an ultrasonic homogenizer, and the supernatant liquid was used.

Electrolysis was carried out for 10 minutes at a constant voltage of +〇, 4V (VS, S, C, E,), and the ITO exposed minute hole part (15X1
A metal-free phthalocyanine film was obtained with a thickness of 3000 μm (Fig. 2(b)).

After drying this film at 150° C. for 15 minutes, ITO was formed on the phthalocyanine film to a thickness of 2000 nm by sputtering (FIG. 2(c)).

Through the above operations, an element having a thin film laminated structure of ITO-metal-free phthalocyanine-ITO was obtained.

Next, when voltage is applied to 22 in Fig. 2 (C) while increasing the voltage sequentially with the positive electrode 25 as the negative electrode, 31 in Fig. 3 is applied.
Nonlinear characteristics like this were obtained.

Next, contrary to the above, connect 25 and 22 in Figure 2 to the positive terminal,
When 22 was set as a negative pole and the voltage was applied while increasing sequentially, a nonlinear characteristic as shown at 32 in FIG. 3 was obtained. This is almost the same characteristic as No. 31, and even if the polarity of the applied voltage is different, this element shows almost the same nonlinear characteristics as that of No. 31, which means that bidirectional nonlinear element characteristics were obtained.

[Example 2] Although metal-free octacyanophthalocyanine was also used as the insulator material, almost the same bidirectional nonlinear characteristics as in Example 1 were obtained.

[Effects of the Invention] As described above, the present invention provides a nonlinear switching element that exhibits characteristics similar to those of conventional MIM elements.

The ability to form patterns using a chemically stable phthalocyanine wet method not only contributes to improved cost performance but also to a larger area that is easier to form than conventional patterns.

This will have a significant effect on the production of future active matrix large color liquid crystal panels.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of nonlinear characteristics. FIG. 2 is a diagram showing the manufacturing process of the nonlinear switching element of the present invention. FIG. 3 is a diagram showing bidirectional nonlinear characteristics of the nonlinear switching element of the present invention. 21...Glass substrate roIll Insulating material organic insulator thin film TOIII capable of pattern deposition Applicant: Seiko Epson Corporation

Claims (1)

[Scope of Claims] 1) A nonlinear switching element characterized in that an organic insulator thin film is formed on a conductor, and a conductor thin film is further formed on the insulator thin film. 2) The nonlinear switching device according to claim 1, wherein the device has bidirectional nonlinear characteristics. 3) The nonlinear switching element according to claim 1, characterized in that a phthalocyanine-based substance is used as the organic insulating film material. 4) As a method of forming an organic insulating thin film, fine particles of an organic insulating film material are solubilized in micelles of a surfactant that is charged by electrolysis, and electrolysis is performed in the micelle solution.
2. The method of manufacturing a nonlinear switching element according to claim 1, wherein the micelles are electrically destroyed and organic insulating film material particles are deposited and formed on the conductor.