JPH03241321A - Production of nonlinear element - Google Patents

Abstract

PURPOSE:To obtain the element which has a nonlinear electric conductivity inducing layer having moldability at and under ordinary temp. and atm. pressure and excellent controllability and operates stably by relieving the edge steps of a lower conductor layer formed on a glass substrate, then forming the nonlinear electric conductivity inducing layer and an upper conductor layer. CONSTITUTION:An insulating resin is applied at nearly the same thickness as the thickness of the lower conductor layer 12. The resin on at least the lower conductor layer 12 is removed by polishing. Alumina powder which is polishing powder is completely removed by washing with running water, ultrasonic cleaning in a neutral detergent and rinsing with pure water to expose the step-relieved insulating layer 15 remaining after the polishing after the edge steps of the lower conductor layer 12 formed on the glass substrate 11 are relieved in such a manner the nonlinear electric conductivity inducting layer 13 and the upper conductor layer 14 are formed. The element which has the nonlinear electric conductivity inducing layer 13 having the moldability at and under ordinary temp. and atm. pressure and the excellent controllability and operates stably is obtd. in this way.

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, devices having a conductor-insulator-conductor structure (hereinafter referred to as an MIM structure in this specification) have also been put into practical use.

[Problem to be solved by the invention] However, conventional nonlinear elements using semiconductors require expensive vacuum equipment such as CVD with poor throughput to form the semiconductor that is the base of the nonlinear element. However, there is a problem in that it becomes extremely expensive, especially for applications that require a large area.

In addition, in nonlinear elements with an M/M structure, the nonlinear electrical conduction inducing layer is formed by 1III anodic oxidation of a metal such as tantalum, so it is difficult to change the characteristics of the anodic oxide film itself, and the device characteristics are almost the same as the film. The only way to control it is by controlling the thickness and element area. For this reason, element characteristics (for example, ○N/○FF
It is difficult to control the ratio, ONE current, and element capacity 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 Problem C] 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 an insulating resin onto the substrate on which the lower conductive layer is formed.

b) A step of removing at least the resin on the lower conductor layer by polishing.

C) Step of removing abrasive material attached to the substrate.

[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 an insulating resin is applied to approximately the same thickness as the lower conductor layer. The resin was made into polyimide by applying polyamic acid with a spin cord and then baking it.

FIG. 3(b) is a cross-sectional view in which at least the resin on the lower conductor layer is removed by polishing. A foamed urethane bat for plastic polishing and alumina powder were used as polishing materials, and only the resin layer was removed by rotating them on a surface plate.

FIG. 3(C) is a cross-sectional view with the abrasive material attached to the substrate removed. Alumina powder, which is polishing powder, is completely removed by washing with running water, ultrasonic washing in a neutral detergent, and rinsing with pure water.
The step-reducing insulator layer 15 remaining after polishing was exposed.

The polymer insulator used for the nonlinear electrically conductive layer was diisopropyl polyfumarate (hereinafter abbreviated as PDiPF). When a polyfumarate ester such as PDiPF is used alone, it is known as a material that allows a thin film with excellent electrical insulation properties to be obtained even in a very thin spin cord film of up to several hundred angstroms. (Jetatsu et al., Polymer Symposium Proceedings Vol. 39. No. 8 (
19891p, 2563) After PDiPF was purified by reprecipitation, it was dissolved in purified chloroform to dissolve PDiPF.
A DiPF solution was made. Furthermore, oxadiazole derivatives (2,5-Bis (4-dieth
ylaminophenyl-L 3+40zadi
axole) was dissolved to form a homogeneous solution. This solution was mixed with 0. Pass through a 5-μm filter to remove dust.
This was used as a raw material solution. The mixing ratio is determined based on the desired ON current value and/or 0FFtIl current value of the nonlinear element and 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 is formed by sputtering or vapor deposition, and an upper conductor 14 is patterned to a width of 20 μm by photoetching.
A nonlinear element with M structure was obtained.

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 more than four digits when the ON voltage is 9 volts and the OFF voltage is 1 volt.

(Example 2) On a substrate on which a lower conductor layer was formed in the same manner as in Example 1,
A siloxane resin was applied to a thickness approximately twice that of the lower electrode. Soft polishing was performed under conditions that allowed almost all of the resin on the lower conductor layer to be removed, and the abrasive was removed by cleaning, exposing the lower conductor layer and the 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. Excess zinc salt was removed by washing the resulting dispersion with water to obtain 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. Also,
Even if a trace of resin remained on the lower conductor layer, almost no difference was observed in the current-voltage characteristics.

(Example 3) On a substrate on which a lower conductor layer was formed in the same manner as in Example 1,
The ester resin was applied to about half the thickness of the lower conductor layer. Soft polishing was performed under conditions that allowed all of the resin on the lower conductor layer to be removed, and the abrasive was removed by washing to expose the lower conductor layer and the step-reducing insulator layer.

Next, PDiPF prepared in the same manner as in Example 1 and poly(3-hexylthiophene) were dissolved in carbon chloride.
A raw material solution was obtained through a 5 μm filter. Using this raw material solution, apply it to the substrate on which the aforementioned lower conductor and step-reducing insulator layer are formed to form a nonlinear electrical conduction inducing layer,
A metal oxide was formed by sputtering or vapor deposition to form the 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 insulating resins, upper and lower conductors, and polymer insulators, various conductors and semiconductors to be dispersed can also 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 room temperature and 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 insulating resin onto the lower conductor layer;
(b) is a cross-sectional view of the step of removing the resin on the lower conductor layer by polishing, and (C) is a cross-sectional view of the step of removing the abrasive material adhering to the substrate. FIG. 4 is a diagram showing current-voltage characteristics of a nonlinear element created in Example 1 of the present invention. 15... Step difference mitigation insulator layer 31...
・・・・・−・・Abrasive material 41・・・・・・・・Current-voltage characteristic curve plate

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 an insulating resin onto the substrate on which the lower conductive layer is formed. b) A step of removing at least the resin on the lower conductor layer by polishing. c) Step of removing abrasive material attached to the substrate.