JPH03241878A - Manufacture of nonlinear element - Google Patents

Abstract

PURPOSE:To obtain a nonlinear element which operates stably and is provided with a nonlinear electric conduction induction layer that is able to be formed at a normal temperature and pressure and excellent in controllability by a method wherein an edge step induced by a lower conductor layer formed on a glass board is relaxed, and then the nonlinear electric conductive induction layer and an upper conductor layer are formed. CONSTITUTION:A Pyrex glass 11 is used as a board, a lower conductor 12 is formed thereon, photosetting resin is applied as thick as the lower conductor layer 12, which is pre-braked, and the lower conductor layer is irradiated from below with light rays of a certain wavelength to which the resin is photosensitive, the uncured resin on the lower conductor layer is removed, the resin left unremoved is post-baked to be fixed to serve as a step relaxing insulator layer 15. Polyfumaric acid di-isopropyl of high molecular insulator and oxadiazole derivative of organic semiconductor are mixed together to form a uniform solution, which is applied onto the board 11 to serve as a nonlinear electrical conduction induction layer 13, an upper conductor 14 is formed thereon, and thus a nonlinear element of MIM structure can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nonlinear element having nonlinear current-voltage characteristics.

[Prior Art] Conventional nonlinear elements have used semiconductor wafers such as Si, or thin film semiconductors formed on glass, single crystal, or the like. Further, those having a conductor-insulator-conductor structure (hereinafter referred to as HIM structure in this specification) have also been put into practical use.

[Problems to be Solved by the Invention] However, conventional nonlinear elements using semiconductors require expensive vacuum equipment with poor throughput, such as CVD, to form the semiconductor that is the base of the nonlinear element.
Therefore, for applications that require a particularly large area,
There was a problem that it became extremely expensive.

In addition, in nonlinear elements with a MIN structure, the nonlinear electrical conduction inducing layer is formed by anodic oxidation of a metal such as tantalum, so it is difficult to change the characteristics of the anodic oxide film itself.
Device characteristics can only be controlled almost exclusively by film thickness and device area. Therefore, it is difficult to control element characteristics (for example, 0N10FF ratio, ON current, and element capacitance) in a well-balanced manner.

On the other hand, although a nonlinear element with excellent controllability can be obtained in principle by using a nonlinear electrical conduction inducing layer composed of at least a polymeric insulator and a conductor or semiconductor dispersed within the polymeric insulator, The nonlinear electrical conduction inducing layer becomes thinner at the edge step portions of the lower conductor layer formed on the glass substrate, causing short-circuit currents to flow, and the upper conductor layer to break, resulting in a lack of reliability and stability.

The present invention aims to solve the above problems by providing a method for manufacturing a nonlinear element that can be formed at room temperature and pressure, has a nonlinear electrical conduction inducing layer with excellent controllability, and operates stably. It is.

[Means for Solving the Problems J] The method for manufacturing a nonlinear element of the present invention is such that the nonlinear electrical conduction inducing layer sandwiched between conductors is made of at least a polymeric insulator and a conductor or semiconductor dispersed within the polymeric insulator. This nonlinear element is characterized in that the edge step of the lower conductor layer formed on the glass substrate is relaxed in the following steps, and then the nonlinear electrical conduction inducing layer and the upper conductor layer are formed.

a) A step of applying a photocurable resin to serve as an insulator to approximately the same thickness as the lower conductor layer.

b) A step of irradiating light of a wavelength to which the resin is sensitive from below the lower conductor layer.

C) Step of removing uncured resin on the lower conductor layer.

[Example] Hereinafter, the details of the present invention will be shown by examples.

(Example 1) FIG. 1 shows the concept of a cross section of a nonlinear element manufactured in this example. Further, FIG. 2 shows the concept of a conventional element in which the edge step of the lower conductor layer is not alleviated.

The substrate used was Pyrex glass 11 with an optically polished surface, a conductor film made of metal or the like was formed by sputtering or vapor deposition, and a pattern was formed by photoetching to form the lower conductor 12. 2
It was patterned to a width of 20 μm so that it was 0 μm square.

FIG. 3 schematically shows a step of alleviating the step difference in the lower conductor layer.

FIG. 3(a) is a cross-sectional view in which a photocurable resin serving as an insulator is applied to approximately the same thickness as the lower conductor layer. As the photocurable resin, a negative resist that is photocrosslinked with light having a wavelength of 300 to 400 nanometers was used. After coating, pre-baking was performed.

FIG. 3(b) is a cross-sectional view in which light of a wavelength to which the resin is sensitive is irradiated from below the lower conductor layer. A mercury lamp was used as a light source, and the light intensity and irradiation time were set to appropriate values so that only the resin on the lower conductor layer that was shielded from light by the lower conductor layer was not cured.

FIG. 3(c) is a cross-sectional view with the uncured resin on the lower conductor layer removed. Removal was performed by development and rinsing. The remaining resin was fixed by boss baking to form a step-reducing insulator layer 15.

The polymer insulator used for the nonlinear electrically conductive layer was diisopropyl polyfumarate (hereinafter abbreviated as PDiPF). When a polyfumaric acid ester such as PDiPF is used alone, it is known as a material that can provide a thin film with excellent electrical insulation properties even in a very thin spin cord film of up to several hundred angstroms. (Shigehara et al., Polymer Symposium Proceedings Yo1.39.Mo, 8 (19g
9j p, 2563) After PDiPF was purified by reprecipitation, PDiPF was dissolved in purified chloroform.
I made a solution. Furthermore, an oxadiazole derivative (2,5-Bis (4-djetb71at
inopbeBI)-1,3゜40zadiazole
) was dissolved to form a homogeneous solution. This solution was mixed with 0. 5
The mixture was passed through a μm filter to remove dust and used as a raw material solution. The mixing ratio is determined based on the desired ON current value and/or OFF current value of the nonlinear element and the film strength.

This raw material solution was coated onto the above-mentioned substrate using a spin coater while controlling the rotation speed and time to obtain a predetermined film thickness, thereby forming the nonlinear electrical conduction inducing layer 13.

On the thus formed nonlinear electrical conduction inducing layer, a metal was formed by sputtering or vapor deposition, and the upper conductor 14 was patterned to a width of 20 μm by photoetching to obtain a nonlinear element with an M-type structure.

The thus obtained nonlinear element did not cause any short circuit or disconnection, and when its current-voltage characteristics were measured in a dark place, it was confirmed that it exhibited stable nonlinearity for a long time as shown in FIG. 4. At this time, if different materials are used for the upper conductor and lower conductor,
In some cases, the characteristics became asymmetric depending on the direction of voltage application.

This nonlinear element has a current 0N10FF ratio of 4 digits or more when the ON voltage is 9 volts and the OFF voltage is 1 volt.

(Example 2) In this example as well, the structure of the -element and the step of reducing the edge step are the same as in Example 1.

On a substrate on which a lower conductor layer was formed in the same manner as in Example 1,
A negative resist sensitive to light with a wavelength of 300 to 450 nanometers was applied to approximately the same thickness as the lower electrode. After prebaking, the lower conductor layer was irradiated with light from a xenon lamp from below, and the resin on the lower conductor layer was removed by development and rinsing.

The remaining resin was fixed by post-baking to form a step-reducing insulator layer.

Next, the zinc salt was dissolved in a PDiPF solution purified and filtered in the same manner as in Example 1.

Hydrogen sulfide gas was bubbled through this solution to generate fine particles of zinc sulfide. The resulting dispersion was washed with water to remove excess zinc salt, thereby obtaining a raw material dispersion in which conductor particles were dispersed. This raw material dispersion liquid was applied to the substrate on which the lower conductor and step-reducing insulator layer described above were formed to form a nonlinear electrical conduction inducing layer, and an upper conductor was formed to produce a nonlinear element.

The nonlinear element produced in this manner did not cause any short circuit or disconnection, and when its current-voltage characteristics were measured in a dark place, it exhibited stable nonlinearity for a long time as in Example 1.

(Example 3) In this example as well, the structure of the element and the step of reducing the edge step difference are the same as in Example 1.

On a substrate on which a lower conductor layer was formed in the same manner as in Example 1,
A polyimide resin that is cured when exposed to light with a wavelength of 300 to 450 nanometers was applied to approximately the same thickness as the lower electrode. After prebaking, the lower conductor layer was irradiated with light from a mercury lamp from below, and the resin on the lower conductor layer was removed with a solvent. The remaining resin was fixed by boss baking to form a step-reducing insulator layer.

Next, PDiPF manufactured by M in the same manner as in Example 1 and poly(3-' bexylthiophene) were dissolved in carbon chloride.
．． A raw material solution was obtained through a 5 μm filter. This raw material solution was applied to the substrate on which the aforementioned lower conductor and step-reducing insulator layer were formed to form a nonlinear electrical conduction inducing layer, and a metal oxide was formed by sputtering or vapor deposition to form an upper conductor layer.

The nonlinear element produced in this manner did not cause any short circuit or disconnection, and when its current-voltage characteristics were measured in a dark place, it exhibited stable nonlinearity for a long time as in Example 1.

Although the embodiments have been described above, the present invention is not limited only to the above embodiments. In addition to photocurable resins, upper and lower conductors, and polymer insulators, various conductors and semiconductors to be dispersed can be considered.

The nonlinear element of the present invention can be widely applied to active matrix display devices, electro-optical devices such as optical shutters, and sensors for temperature, humidity, light, gas, solutions, etc., using the same.

[Effects of the Invention] As described above, the present invention has a nonlinear electrical conduction inducing layer that can be formed at normal pressure and has excellent controllability.
By providing a method for manufacturing a nonlinear element that operates stably, it becomes possible to create an inexpensive and excellent nonlinear element. The nonlinear element of the present invention has a simple element structure and the nonlinear electrical conduction inducing layer can be easily formed, so it is particularly advantageous for manufacturing a large area element.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the concept of a nonlinear element created in Example 1 of the present invention. FIG. 2 is a cross-sectional view showing the concept of a conventional nonlinear element that does not alleviate the edge step of the lower conductor layer. FIG. 3 is a cross-sectional view schematically showing the step of reducing the edge step of the lower conductor layer. (a) is a cross-sectional view of the process of applying photocurable l# resin, which will serve as an insulator, to approximately the same thickness as the lower conductor layer, and (b) is a cross-sectional view of the process in which the resin is exposed to light from below the lower conductor layer. FIG. 6(c) is a cross-sectional view of the step of irradiating light with a certain wavelength; FIG. FIG. 4 is a diagram showing current-voltage characteristics of a nonlinear element created in Example 1 of the present invention. l......Substrate glass 2...Lower conductor 3...Nonlinear electrical conduction inducing layer 4...
・・・・・・Top conductor 5・・・・・・Step difference mitigation insulator layer 1・・・・・・
...More than the current-voltage characteristic curve

Claims (1)

[Claims] A nonlinear element in which a nonlinear electrical conduction inducing layer sandwiched between conductors is composed of at least a polymeric insulator and a conductor or semiconductor dispersed within the polymeric insulator, formed on a glass substrate. 1. A method for manufacturing a nonlinear element, characterized in that a nonlinear electrical conduction inducing layer and an upper conductive layer are formed after the edge step of the lower conductive layer is reduced by the steps described below. a) A step of applying a photocurable resin to serve as an insulator to approximately the same thickness as the lower conductor layer. b) A step of irradiating light of a wavelength to which the resin is sensitive from below the lower conductor layer. c) Step of removing uncured resin on the lower conductor layer.