WO2016171436A1

WO2016171436A1 - Organic memory device and method for preparing same using high-temperature heat treatment

Info

Publication number: WO2016171436A1
Application number: PCT/KR2016/003977
Authority: WO
Inventors: 김영규; 김화정; 정재훈; 서주역
Original assignee: 경북대학교산학협력단
Priority date: 2015-04-20
Filing date: 2016-04-18
Publication date: 2016-10-27
Also published as: KR101672237B1; KR20160124941A

Abstract

The present invention relates to an organic memory device and a method for preparing same using high-temperature heat treatment and, more specifically, to an organic memory device which enables obtaining of thermal stability as well as excellent memory properties even at a low voltage by means of forming a polymer memory insulating layer by means of heat treatment at a high temperature of 80°C or higher. And the present invention enables enhanced stability of a charge transport layer due to low acidity and has applied, to a memory storage layer, a sulfonic acid-based organic material of which the glass transition temperature is very high and thus can be heat treated at a high temperature up to 300°C. In order to attain the purpose, an organic memory device in a transistor that comprises source and drain electrodes and a gate electrode formed on a substrate, according to an embodiment of the present invention, has formed thereon an electrically polarizable polymer memory insulating layer that is formed from a heat treated organic material between the gate electrode and the source and drain electrodes and shows hysteresis.

Description

Organic memory device using high temperature heat treatment and manufacturing method thereof

The present invention relates to an organic memory device using a high temperature heat treatment and a method of manufacturing the same, and more particularly, by forming a polymer memory insulating layer by heat treatment at a high temperature of 80 ℃ or more can exhibit excellent memory characteristics even at low voltage while ensuring thermal stability. Organic memory device using high temperature heat treatment that uses sulfonic acid-based organic material as memory storage layer, which can improve stability of charge transport layer due to low acidity and high glass transition temperature. And a method for producing the same.

With the rapid development of the information and communication industry and portable information devices, the demand for large capacity nonvolatile memory devices is increasing. Currently, such nonvolatile memory devices are mainly made of flash memory based on silicon materials. However, conventional flash memories have a limited number of write / erase times, have a slow writing speed, are highly integrated, and are difficult to miniaturize. As the technical limitations are revealed, researches on various types of next generation nonvolatile memory devices have been conducted.

For example, by using organic materials as a memory layer material of memory devices, technology for overcoming physical limitations of existing silicon memory devices and for implementing next-generation nonvolatile memory devices having ultra-high speed, high capacity, low power consumption, and low cost characteristics This is actively going on.

As such an organic memory device, a technology of an organic memory device having an insulating layer made of polyvinyl alcohol (PVA) having a memory function and having a proper dielectric constant in Korean Patent Nos. 1190570 and Korean Patent No. 1234225 is disclosed. have.

According to the preceding document, the organic memory device includes a polymethyl methacrylate (PMMA), a polyvinyl phenol (PVP), and a polyvinyl alcohol (PVA) between the gate electrode layer and the source and drain electrode layers. It has a structure including a tunneling organic insulating layer consisting of at least one selected from the group consisting of.

The organic memory device having an insulating layer made of such a polyvinyl alcohol (PVA) material has an advantage of increasing charge mobility due to high dielectric constant, but has a disadvantage in that a lot of leakage current is generated. Due to the low glass transition temperature of the high temperature is difficult to drive and has the disadvantage that can be driven only at low temperatures.

In the memory device, which is becoming highly integrated, a heat generation problem may occur in the case of a conventional low temperature heat treated memory device. The heat generation phenomenon adversely affects the deformation of the device and the deterioration of the driving ability. Accordingly, the necessity for a manufacturing technology capable of securing thermal stability of the memory device is increasing.

In addition, since the charge transport layer formed adjacent to the organic insulating layer in the organic memory device is generally a weak acid, it is also important to select an appropriate type of organic material to lower the acidity of the organic insulating layer itself. It is essential to securing.

The present invention has been made to solve the above problems, the object of the present invention is to heat treatment at a high temperature of 80 ℃ or more to form a polymer memory insulating layer to ensure thermal stability high temperature heat treatment that can exhibit excellent memory characteristics even at low voltage An organic memory device using and a method of manufacturing the same are provided.

Another object of the present invention is to improve the stability of the charge transport layer due to the low acidity and high glass transition temperature of the high temperature heat treatment applied to the organic storage material of sulfonic acid (sulfonic acid) series that can be heat treated at a high temperature up to 300 ℃ as a memory storage layer An organic memory device using and a method of manufacturing the same are provided.

An organic memory device according to an aspect of the present invention for achieving the above object, in an organic memory device comprising a gate electrode and a source and a drain electrode formed on a substrate, between the gate electrode and the source and drain electrode It is an organic memory device using a high temperature heat treatment, characterized in that the electrically polarizable polymer memory insulating layer formed of a heat-treated organic material exhibits hysteresis.

The organic material may be a sulfonic acid-based material, in particular, the organic material may be a compound represented by Chemical Formula 1 below, or may be a compound represented by Chemical Formula 2 below.

[Formula 1]

(Wherein n is an integer of 2 or more).

[Formula 2]

(Wherein n is an integer of 2 or more).

An organic memory device according to another aspect of the present invention, a substrate; A gate electrode formed on the substrate; An electrically polarizable polymer memory insulating layer formed on the gate electrode and exhibiting hysteresis made of a heat-treated organic material; A charge transport layer formed on the polymer memory insulating layer; And source and drain electrodes formed on the charge transport layer to be spaced apart from each other by a predetermined distance.

Here, the polymer memory insulating layer is characterized in that the heat treatment is performed for 0.4 ~ 0.6 hours at a temperature of 80 ~ 230 ℃ after spin coating the solution of the organic material, the organic material is sulfonic acid (sulfonic acid) It may be a substance, in particular, a compound represented by Chemical Formula 1 or a compound represented by Chemical Formula 2 above.

In addition, the charge transport layer is characterized in that the hole transport layer.

In another aspect, a method of manufacturing an organic memory device includes forming a gate electrode on a substrate; Forming an electrically polarizable polymer memory insulating layer formed on the gate electrode and made of an organic material to exhibit hysteresis; Heat treating the polymer memory insulation layer; Forming a charge transport layer on the polymer memory insulating layer; The method may include forming a source electrode and a drain electrode spaced apart from each other by a predetermined distance on the charge transport layer.

The forming of the polymer memory insulating layer may include spin coating a solution of a sulfonic acid-based organic material to form a polymer memory insulating layer having a thickness of 300 to 800 nm. In the heat treatment of the polymer memory insulation layer, the formed polymer memory insulation layer may be heat treated at a temperature of 80 ° C. to 230 ° C. for 0.4 to 0.6 hours on a hot plate.

The organic material may be a compound represented by Chemical Formula 1 or a compound represented by Chemical Formula 2, and a hole transport layer may be formed as the charge transport layer.

According to the present invention as described above, by heat-treating the organic memory device at a high temperature of 80 ℃ or more to form a polymer memory insulating layer to ensure thermal stability high quality memory device that can exhibit excellent write-read-erase function even at low voltage There is an effect that can be prepared.

The low acidity improves the stability of the charge transport layer and the glass transition temperature is so high that the sulfonic acid-based organic material, which can be heat-treated even at high temperatures up to 300 ° C, is applied to the memory storage layer for durability and safety. Can increase.

1 is a cross-sectional view of an organic memory device according to an exemplary embodiment of the present invention.

2 is a cross-sectional view illustrating an operating principle of an organic memory device according to an exemplary embodiment of the present invention.

3 is a graph illustrating retention test results of a sulfonic acid based organic memory device according to an exemplary embodiment of the present invention.

4 is a gate voltage graph of an organic memory device using a high temperature heat treatment according to an exemplary embodiment of the present invention.

5 is a graph of hysteresis characteristics of an organic memory device subjected to 170 ° C. heat treatment according to an embodiment of the present invention.

6 is a flowchart of a method of manufacturing an organic memory device using high temperature heat treatment according to an embodiment of the present invention.

7A to 7D are cross-sectional views sequentially illustrating a method of manufacturing an organic memory device using high temperature heat treatment according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention. It should be noted that the same elements in the figures are denoted by the same reference signs wherever possible. On the other hand, the terms or words used in the present specification and claims are not to be construed as limiting the ordinary or dictionary meanings, the inventors should use the concept of the term in order to explain the invention in the best way. It should be interpreted as meanings and concepts corresponding to the technical idea of the present invention based on the principle that it can be properly defined. Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only the most preferred embodiments of the present invention, and do not represent all of the technical ideas of the present invention, and various alternatives may be substituted at the time of the present application. It should be understood that there may be equivalents and variations.

1 is a cross-sectional view of an organic memory device according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating an operating principle of an organic memory device according to an exemplary embodiment of the present invention.

1 and 2, the organic memory device using the high temperature heat treatment according to the present invention may include a substrate 100, a gate electrode 110 formed on the substrate, and a polymer memory insulating layer 120 formed on the gate electrode 110. ), The charge transport layer 130, the source electrode 140, and the drain electrode 150.

The present invention utilizes the fact that the insulating layer 130 located between the gate electrode 110 and the charge transport layer 130 can function as a memory when the insulating layer 130 is made of an electrically polarizable organic material exhibiting hysteresis. The memory device using the hysteresis characteristic stores each quadrant of the hysteresis curve using a hysteresis curve having a different current change curve when the voltage is increased and a current change curve when the voltage is decreased (00,01,10,11). ) Is a technology used for.

First, the substrate 100 may be a silicon substrate, a glass substrate, a plastic substrate, or the like.

For example, the gate electrode 110 may be formed of a conductive material such as gold (Au), silver (Ag), copper (Cu), nickel (Ni) / aluminum, or a polymer.

The polymer memory insulating layer 120 is made of an organic material and is in a heat-treated state. After spin coating the organic material solution, the polymer memory insulating layer 120 is preferably heat-treated at a temperature of 80 to 230 ° C. for 0.4 to 0.6 hours. Particularly, according to the experiment of the applicant, when the heat treatment was performed at about 170 ° C., the most excellent thermal stability and memory characteristics were obtained. This will be described in detail with reference to FIG. 5.

The organic material may be a sulfonic acid-based material that does not damage the material even at high temperature heat treatment, and among the sulfonic acid-based materials, a compound represented by the following Chemical Formula 1 or a compound represented by the following Chemical Formula 2 may be used. It is preferable to use.

[Formula 1]

[Formula 2]

(In the above formulas, n is an integer of 2 or more.)

The two sulfonic acid-based organic materials have a glass transition temperature of about 300 ° C., so that when the polymer memory insulating layer 120 is formed and heat-treated with these materials, heat treatment is possible up to 300 ° C. Applicants' experiment according to this was found to be most preferable to heat treatment for 0.4 ~ 0.6 hours at a temperature of 80 ~ 230 ℃.

Meanwhile, the charge transport layer 130 is formed on the polymer memory insulating layer 120, and may be formed as a hole transport layer to increase charge transport efficiency. For example, the charge transport layer 130 may be formed of poly (3-hexylthiophene) (P3HT). have.

Since the charge transport layer 130 is generally an acid weak material, it is important to appropriately select a type of organic material so as to lower the acidity of the adjacent polymer memory insulating layer 120, which is represented by

Chemical Formulas

1 and 2 above. The sulfonic acid-based organic material is a material having a pH of about 1.5 or more, and in this respect, it can be seen that it is a suitable material for the organic memory device.

The source electrode 140 and the drain electrode 150 are formed to be spaced apart from each other on the charge transport layer 130 by a predetermined distance, and include gold (Au), silver (Ag), copper (Cu), nickel (Ni) / aluminum, and polymers. It may be formed of a conductive material such as.

When a voltage is applied to the gate electrode 110 in the organic memory device of the present invention formed as described above, as shown in FIG. 2, the polymer memory insulating layer 120 is electrically polarized to generate a hysteresis phenomenon, thereby causing a charge transport layer. Hole hysteresis is also induced at 130.

As the hysteresis characteristic is generated in the hole movement of the charge transport layer 130 as described above, the charge mobility from the source electrode 140 to the drain electrode 150 is increased, so that the drain current has the hysteresis characteristic. It will be able to function as a volatile memory.

Referring to FIG. 3, it can be seen that the organic memory device using the high temperature heat treatment according to the exemplary embodiment of the present invention shows stable results even after retention tests of about 10,000 times.

As described above, since the charge transport layer formed on the polymer memory insulating layer is generally weak in acidity, it is important to lower the acidity of the adjacent polymer memory insulating layer. The organic material of sulfonic acid type represented by

Chemical Formulas

1 and 2 is used. As a result, a test was conducted on an organic memory device in which a polymer memory insulating layer was formed, thereby achieving the purpose.

The graph shows that the current value is kept uniform over time, especially because it is stable in each of the write-read (read1, read2) -erase items of each memory device. You can expect quality memory features.

4 is a gate voltage graph of an organic memory device using a high temperature heat treatment according to an embodiment of the present invention, and FIG. 5 is a graph of hysteresis characteristics of an organic memory device subjected to 170 ° C. heat treatment according to an embodiment of the present invention.

4 and 5, it can be seen that the organic memory device using the high temperature heat treatment according to the embodiment of the present invention shows high thermal stability after heat treatment at high temperature. In particular, as shown in FIG. 4, the smooth operation of the organic transistor device is performed, and it is shown that it is operated without problems even at a low voltage.

In FIG. 5, a graph of hysteresis characteristics of an organic memory device heat-treated at 170 ° C. according to the applicant's experiment can be seen. When voltage is applied to the gate electrode, the heat-treated polymer memory insulating layer is electrically polarized to generate a hysteresis phenomenon. As a result, a hole hysteresis phenomenon is induced in the charge transport layer, and the charge mobility from the source electrode to the drain electrode is increased, so that the drain current has hysteresis characteristics, thereby enabling a nonvolatile memory function having a transistor structure. will be.

That is, since the hysteresis characteristic of the drain current is clearly indicated, it means that the voltage difference due to hysteresis is large. Therefore, when the 170 ° C. heat-treated polymer memory insulating layer having the large voltage difference due to hysteresis is used, the threshold voltage difference of the memory device increases. Therefore, driving at low voltage becomes possible.

6 is a flowchart illustrating a method of manufacturing an organic memory device using a high temperature heat treatment according to an embodiment of the present invention, and FIGS. 7A to 7D are process cross-sectional views sequentially illustrating a method of manufacturing an organic memory device using a high temperature heat treatment according to an embodiment of the present invention. to be.

6 and 7, the method of manufacturing an organic memory device using a high temperature heat treatment according to an embodiment of the present invention includes forming a gate electrode on a substrate (S10), and formed on the gate electrode and made of an organic material. Forming an electrically polarizable polymer memory insulation layer exhibiting hysteresis (S20), heat treating the polymer memory insulation layer (S30), forming a charge transport layer on the polymer memory insulation layer (S40) and on the hole transport layer Forming a source electrode and a drain electrode spaced apart from each other by a predetermined distance (S50).

In the step S10 of forming the gate electrode on the substrate, the gate electrode 110 is formed on the substrate 100 as shown in FIG. 7A. The gate electrode 110 is formed by thermal evaporation of a conductive material and then patterned. The conductive material may include, for example, gold (Au), silver (Ag), copper (Cu), nickel (Ni) / aluminum, Polymers and the like can be used.

In the forming of the polymer memory insulating layer (S20), the polymer memory insulating layer 120 is formed to have a thickness of 300 to 800 nm on the substrate 100 on which the gate electrode 110 is formed as shown in FIG. 7B.

The polymer memory insulating layer 120 is formed of an electrically polarizable material that exhibits hysteresis. In the present invention, a sulfonic acid-based organic material solution is used. Specifically, it is preferable to use the compound represented by the following general formula (1) or the compound represented by the following general formula (2) among sulfonic acid series materials.

[Formula 1]

[Formula 2]

(In the above formulas, n is an integer of 2 or more.)

After preparing the sulfonic acid-based organic material solution is coated on the substrate 100 on which the gate electrode 110 is formed. At this time, the coating of the organic material solution may be carried out by a spin coating method, and in the step (S30) of heat treating the polymer memory insulating layer after the coating is completed, the polymer memory insulating layer formed is 0.4 at a temperature of 80 ° C. to 230 ° C. on a hot plate. Heat treatment for ~ 0.6 hours.

In the step S40 of forming the charge transport layer on the polymer memory insulation layer, as shown in FIG. 7C, the charge transport layer 130 is formed on the polymer memory insulation layer 120, but the hole transport layer P3HT is used to increase the charge transport efficiency. (poly (3-hexylthiophene)) is coated using a spin coating method or the like.

In this case, the charge transport layer 130 may include a polymer active layer as an organic semiconductor layer.

Finally, in the step S50 of forming the source electrode and the drain electrode, conductive materials on the charge transport layer 130 are illustrated as gold (Au), silver (Ag), copper (Cu), and nickel (Ni) as shown in FIG. 7D. After forming a conductive material such as aluminum and a polymer, a source electrode 140 and a drain electrode 150 spaced by a predetermined distance are formed through a patterning process.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Therefore, the scope of the appended claims will include such modifications and variations that fall within the spirit of the invention.

Claims

An organic memory device comprising a gate electrode and a source and a drain electrode formed on a substrate,

And an electrically polarizable polymer memory insulating layer formed of an organic material heat-treated between the gate electrode and the source and drain electrodes to exhibit hysteresis.
The method of claim 1,

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the sulfonic acid-based material.
The method of claim 2,

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (1).

[Formula 1]

(Wherein n is an integer of 2 or more).
The method of claim 2,

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (2).

[Formula 2]

(Wherein n is an integer of 2 or more).
Board;

A gate electrode formed on the substrate;

An electrically polarizable polymer memory insulating layer formed on the gate electrode and exhibiting hysteresis made of a heat-treated organic material;

A charge transport layer formed on the polymer memory insulating layer; And

And a source and a drain electrode each formed on the charge transport layer at a predetermined distance apart from each other.
The method of claim 5,

The polymer memory insulating layer is an organic memory device using a high temperature heat treatment, characterized in that the heat treatment for 0.4 ~ 0.6 hours at a temperature of 80 ~ 230 ℃ after spin coating the solution of the organic material.
The method of claim 5,

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the sulfonic acid-based material.
The method of claim 7, wherein

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (1).

[Formula 1]

(Wherein n is an integer of 2 or more).
The method of claim 7, wherein

The organic material is an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (2).

[Formula 2]

(Wherein n is an integer of 2 or more).
The method of claim 5,

The charge transport layer is an organic memory device using a high temperature heat treatment, characterized in that the hole transport layer.
Forming a gate electrode on the substrate;

Forming an electrically polarizable polymer memory insulating layer formed on the gate electrode and made of an organic material to exhibit hysteresis;

Heat treating the polymer memory insulation layer;

Forming a charge transport layer on the polymer memory insulating layer;

Forming a source electrode and a drain electrode spaced apart from each other by a predetermined distance on the charge transport layer.
The method of claim 11,

Forming the polymer memory insulating layer,

A method of manufacturing an organic memory device using a high temperature heat treatment, comprising: spin coating a sulfonic acid-based organic material solution to form a polymer memory insulating layer having a thickness of 300 to 800 nm.
The method of claim 11,

The heat treatment of the polymer memory insulating layer,

A method of manufacturing an organic memory device using high temperature heat treatment, wherein the formed polymer memory insulation layer is heat-treated at a temperature of 80 ° C. to 230 ° C. for 0.4 to 0.6 hours.
The method of claim 12,

The organic material is a method of manufacturing an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (1).

[Formula 1]

(Wherein n is an integer of 2 or more).
The method of claim 12,

The organic material is a method of manufacturing an organic memory device using a high temperature heat treatment, characterized in that the compound represented by the formula (2).

[Formula 2]

(Wherein n is an integer of 2 or more).
The method of claim 11,

A hole transport layer is formed as the charge transport layer. A method of manufacturing an organic memory device using high temperature heat treatment.