KR101303086B1 - Data Storage Device Using Ferroelectric Polymer Thin Film and Method of Manufacturing for the Same - Google Patents

Abstract

The present invention relates to an information storage medium using a ferroelectric polymer thin film and a method of manufacturing the same, and more particularly, to form a ferroelectric polymer thin film on the upper surface of the electrode layer formed on one side of the substrate to store and store information, the information using the ferroelectric polymer thin film A storage medium and a method of manufacturing the same.
An information storage medium using the ferroelectric polymer thin film of the present invention includes a substrate, an electrode layer formed on one surface of the substrate, and a VDF-TrFE ferroelectric polymer thin film having a VDF and TrFE of 70:30 to 80:20 at an upper surface of the electrode layer. It features.
In addition, the present invention comprises the steps of forming an electrode layer on one surface of the substrate, and preparing a VDF-TrFE pellets mixed with VDF and TrFE in a ratio of 70:30 to 80:20, and the VDF-TrFE pellets methyl ethyl ketone ( Methylethylketone) is dissolved in a solvent, coating the dissolved solution on the upper surface of the electrode layer, and annealing (Annealing) the coated substrate.

Description

Data Storage Device Using Ferroelectric Polymer Thin Film and Method of Manufacturing for the Same}

The present invention relates to an information storage medium using a ferroelectric polymer thin film and a method of manufacturing the same, and more particularly, to form a ferroelectric polymer thin film on the upper surface of the electrode layer formed on one side of the substrate to store and store information, the information using the ferroelectric polymer thin film A storage medium and a method of manufacturing the same.

In general, ferroelectrics have two states of spontaneous polarization that exist inside a material as bit data of 0 and 1, respectively. Therefore, the ferroelectric can be applied to memory devices used for data writing, recording holding, reading and writing. However, since the information storage medium using the same is generally applied based on an oxide ferroelectric, there is a problem in that the manufacturing method is complicated and must be manufactured at a high temperature of 550 ° C. or higher.

In the ferroelectric recording medium and a method of manufacturing the same, a ferroelectric recording medium for information storage includes sequentially forming a buffer layer, a lower electrode, a ferroelectric layer, and an upper electrode on a substrate, and etching predetermined regions of the upper electrode. After exposing the ferroelectric layer, an insulating layer is formed on the front surface including the upper electrode, and the surface is planarized by etching the insulating layer by CMP (Chemical Mechanical Polishing) method until the upper electrode is exposed. After the insulating layer is formed, the substrate is heat treated at a temperature of 600 ° C or higher.

As described above, since the information storage medium using the ferroelectric has to go through the formation of the buffer layer, the electrode layer, the dielectric layer, the etching process, the surface planarization, and the heat treatment process, the manufacturing method is complicated.

In addition, the high temperature heat treatment process should be at least 550 ° C or higher, so a high temperature process environment is required, thereby increasing the manufacturing cost.

The present invention is to solve the above-described problems, using a ferroelectric polymer thin film having a ferroelectric property annealing of the information storage medium is performed within 120 to 140 ℃ lower than the existing process temperature, using an oxide An object of the present invention is to provide a method of manufacturing an information storage medium having higher information storage reliability than a ferroelectric medium.

In order to achieve the above object, the present invention comprises the steps of forming an electrode layer on one surface of the substrate, preparing a VDF-TrFE pellets mixed with VDF and TrFE in a ratio of 70:30 to 80:20, and the VDF- Dissolving the TrFE pellets in a methyl ethyl ketone solvent, coating the dissolved solution on the upper surface of the electrode layer, and annealing the coated substrate.

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In the step of dissolving the ferroelectric polymer pellets VDF-TrFE in a methyl ethyl ketone solvent, the concentration of the solution of the ferroelectric polymer pellets (VDF-TrFE) dissolved in a methyl ethyl ketone solvent is 0.1 to 10 wt%.

In addition, coating the dissolved solution on the upper surface of the electrode layer may include spin coating, spray coating, flow coating, dip coating, or dip-drawing coating. It can be made of either.

When the spin coating, the solution may be dropped onto the substrate and coated while rotating at 1000 to 2000 rpm for 5 to 15 seconds.

Finally, annealing the coated substrate is characterized by annealing the substrate at 120 to 140 ° C. for 0.5 to 1.5 hours.

As described above, according to the present invention, the ferroelectric polymer thin film is formed on the upper surface of the electrode layer formed on one surface of the substrate, and then annealed at a temperature relatively lower than that of the conventional oxide ferroelectric material, thereby resulting in a high-temperature processing environment and accordingly It is effective in reducing production costs.

In addition, since the information storage medium using the ferroelectric polymer thin film has higher stability than the oxide ferroelectric, the final elapsed time and the amount of information remaining compared to the same area have an effect.

1 is a cross-sectional view illustrating an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.
2 is a flow chart illustrating a method of manufacturing an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.
3 to 5 are dissolved VDF-TrFE pellets in a methyl ethyl ketone solvent in accordance with an embodiment of the present invention, the dissolved solution is coated on the upper surface of the electrode layer formed on one side of the substrate, annealing (Annealing) A perspective view for explaining the process.
6 is a graph illustrating a reason why a 75:25 ratio of VDF and TrFE is preferable according to an embodiment of the present invention.
FIG. 7 is a graph for explaining why the concentration of a solution in which a VDF-TrFE pellet is dissolved in a methylethylketone solvent according to an embodiment of the present invention is preferably 1wt%.
8 is a graph illustrating information storage characteristics of an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.
9 is a graph showing the amount of information remaining over time of an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily reproduce.

1 is a cross-sectional view illustrating an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.

As shown in FIG. 1, the information storage medium 100 using a ferroelectric polymer thin film includes a substrate 101, an electrode layer 102 formed on one surface of the substrate, and a VDF and TrFE formed on the upper surface of the electrode layer 102. It is composed of a VDF-TrFE ferroelectric polymer thin film 103 having a ratio of: 30 to 80:20.

The ferroelectric polymer thin film 103 is preferably formed using a solution 106 in which a VDF-TrFE pellet 104 having a VDF and TrFE of 75:25 ratio is dissolved in a methylethylketone solvent 105. The concentration of the solution is 0.1 to 10 wt%.

When the concentration is less than 0.1wt%, the ferroelectric polymer thin film 103 formed on the upper surface of the electrode layer 102 becomes too thin, and bit data due to an interface effect existing between the electrode layer 102 and the thin film 103. ) Becomes difficult to record.

In addition, when the concentration of the solution 106 exceeds 10wt%, the thickness of the ferroelectric polymer thin film 103 becomes thick, so that application of a larger voltage is required to record the same amount of bit data. .

The concentration of the solution 106 in which the VDF-TrFE pellet 104 is dissolved in a methyl ethyl ketone solvent 105 is preferably 1 wt%, and the ferroelectric polymer thin film 103 having a thickness of 85 nm to 95 nm is used. Can be obtained.

The electrode layer 102 includes aluminum (Al), iron (Fe), nickel (Ni), chromium (Cr), titanium (Ti), molybdenum (Mo), silver (Ag), platinum (Pt), and tungsten (W). It may be made of one or more materials of gold (Au), iridium (Ir) or copper (Cu).

In addition, the substrate 101 may be made of one or more materials of gold (Au), chromium (Cr), silicon dioxide (SiO ₂ ), or silicon (Si).

2 is a flow chart illustrating a method of manufacturing an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.

As shown in FIG. 2, in the method of manufacturing the information storage medium 100 using the ferroelectric polymer thin film, forming an electrode layer 102 on one surface of the substrate 101 (S101), and VDF and TrFE 70: 30. Preparing a VDF-TrFE pellet 104 mixed at a ratio of 80 to 20:20 (S102), and dissolving the VDF-TrFE pellet 104 in a methyl ethyl ketone solvent 105 (S103). And coating the dissolved solution 106 on the upper surface of the electrode layer 102 (S104) and annealing the coated substrate 101 (S105).

In the step (S101) of forming the electrode layer 102 on one surface of the substrate 101, the electrode layer 102 on the surface of the substrate 101, the thermal evaporation (E-beam evaporation), sputter (RF) or DC sputter, E-beam, Electro-plating or Chemical Vapor Deposition.

In the preparing of the VDF-TrFE pellets 104 in which the VDF and TrFE are mixed at a ratio of 70:30 to 80:20 (S102), preferably, the VDF-TrFE pellets at which the VDF and TrFE are mixed at a ratio of 75:25. (104) is used.

The VDF-TrFE pellets 104 in which the VDF and the TrFE are mixed in a 75:25 ratio have a Curie temperature of 130 ° C., which is relatively lower than that of the oxide ferroelectric and obtains a stable ferroelectric phase.

In the step (S103) of dissolving the VDF-TrFE pellet 104 in a methylethylketone solvent 105, a solution 106 in which the VDF-TrFE pellet is dissolved in a methylethylketone solvent 105 The concentration of is characterized in that 0.1 to 10wt%. Preferably, when the concentration of the solution 106 is 1wt% and the concentration is less than 0.1wt%, the ferroelectric polymer thin film 103 formed on the upper surface of the electrode layer 102 becomes too thin, the electrode layer 102 and the thin film The interfacial effect existing between the 103 makes it difficult to write bit data. In addition, when the concentration of the solution 106 exceeds 10wt%, the thickness of the ferroelectric polymer thin film 103 becomes thick, so that application of a larger voltage is required to record the same amount of bit data. .

When the concentration of the solution 106 in which the VDF-TrFE pellet 104 is dissolved in a methyl ethyl ketone solvent 105 is 1 wt%, the ferroelectric polymer thin film 103 having a thickness of 85 nm to 95 nm may be obtained. The 85 nm to 95 nm thickness is a condition in which damage between the electrode layer 102 and the thin film 103 is small, a small amount of voltage can be applied, and bit data is easily recorded.

In the step (S104) of coating the dissolved solution on the upper surface of the electrode layer 102, the solution 106 on the upper surface of the electrode layer 102 (Spin) coating, spray coating, flow coating The coating may be carried out using either a dip coating or dip-drawing coating method.

Preferably, the coating is performed using a spin coating. The spin coating is performed by dropping the solution 106 on the upper surface of the electrode layer 102 and rotating for 5 to 15 seconds at a speed of 1000 to 2000 rpm. Characterized in that.

At this time, when the spin speed is less than 1000rpm, the coating becomes uneven or thick, and when it is more than 2000rpm, the thickness of the thin film 103 may be too thin. Preferably, spin coating is performed at 1500 rpm for 10 seconds, and the thickness of the ferroelectric polymer thin film 103 may be formed to be 85 nm to 95 nm.

In the step of annealing the coated substrate 101 (S105), the substrate 101 coated with the solution 106 is annealed (annealing) for 0.5 to 1.5 hours at 120 to 140 ℃ do.

Preferably, the substrate 101 is annealed in an air atmosphere at 130 ° C. for 1 hour. When the annealing temperature is lower than 120 ° C. or higher than 140 ° C., the crystallinity and ferroelectric properties of the ferroelectric polymer thin film 103 do not increase.

3 to 5 are dissolved VDF-TrFE pellets in a methyl ethyl ketone solvent in accordance with an embodiment of the present invention, the dissolved solution is coated on the upper surface of the electrode layer 102, and annealed (Annealing) A perspective view for explaining the process.

As shown in FIGS. 3 to 5, the VDF-TrFE pellet 104 having a VDF and TrFE of 75:25 ratio was dissolved in a methylethylketone solvent 105, and the solution 106 having a concentration of 1wt%. Get

In addition, the dissolved solution 106 is dropped on the upper surface of the electrode layer 102 formed on one surface of the substrate placed on the spin plate 108 using the dropper 107 and spin-coated for 10 seconds at a speed of 1500 rpm.

In addition, annealing is performed in an air atmosphere at 130 ° C. for 1 hour to increase ferroelectric crystallinity of the 85 nm to 95 nm thick ferroelectric polymer thin film 103 formed on the electrode layer 102.

6 is a graph illustrating a reason why a 75:25 ratio of VDF and TrFE is preferable according to an embodiment of the present invention.

As shown in FIG. 6, when the VDF and the TrFE are 75:25, the Curie temperature is 130 ° C., which is relatively lower than that of the oxide ferroelectric, and thus, a stable ferroelectric phase can be obtained.

7 is a graph for explaining why the concentration of the solution 106 in which the VDF-TrFE pellet 104 is dissolved in a methyl ethyl ketone solvent 105 according to an embodiment of the present invention is preferably 1 wt%. to be.

As shown in FIG. 7, when the concentration of the solution 106 in which the VDF-TrFE pellet 104 is dissolved in the methyl ethyl ketone solvent 105 is 1 wt%, the thickness of the ferroelectric polymer thin film 103 is increased. 85 nm to 95 nm, the thickness of the thin film is formed thinner than when the concentration is increased, such as 2wt%, 3wt%. If the thickness of the thin film is formed thick, a larger voltage is required to record the same amount of bit data. On the other hand, if the thickness of the thin film 103 is formed too thin, it is difficult to write the bit data due to the interface effect existing between the electrode layer 102 and the thin film 103.

Therefore, when the concentration of the solution 106 in which the VDF-TrFE pellet 104 is dissolved in the methyl ethyl ketone solvent 105 is 1 wt%, the ferroelectric polymer thin film 103 can be formed to a thickness of 85 nm to 95 nm. . In addition, such a thickness is a condition in which damage between the electrode layer 102 and the thin film 103 is small, a small amount of voltage can be applied, and bit data is easily recorded.

8 is a graph illustrating information storage characteristics of an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.

As shown in FIG. 8, an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention may compare information with a conventional oxide medium.

In general, the information storage characteristics are better as the time constant (τ) is larger and the smaller the exponential factor is. Therefore, it can be said that the VDF-TrFE pellet in the red circle having the largest time constant (τ) value and the smallest exponential factor value in the graph has the best information storage characteristic. Therefore, conventional oxide media, except for VDF-TrFE pellets, have a relatively small time constant (τ) value and a large exponential factor value compared to ferroelectric polymer media, so that information storage characteristics are relatively poor. I can say no.

9 is a graph showing the amount of information remaining over time of an information storage medium using a ferroelectric polymer thin film according to an embodiment of the present invention.

As shown in FIG. 9, the remaining domain fraction over time (Lapsed time) shows that the VDF-TrFE pellet in the red circle is the most remaining for the longest time compared to the existing oxide medium. It can be seen that it has a (Remained domain fraction).

Therefore, it can be seen that the information storage medium 100 using the ferroelectric polymer thin film has excellent information storage capability compared to the conventional oxide medium.

The terms used throughout the specification of the present invention have been defined in consideration of the functions of the embodiments of the present invention and can be sufficiently modified according to the intentions and customs of the user or operator. It should be based on the contents of.

While the invention has been described with reference to the preferred embodiments, which are referred to by the accompanying drawings, it will be apparent that various modifications are possible without departing from the scope of the invention within the scope covered by the claims set forth below from this description. .

100: information storage medium using a ferroelectric polymer thin film
101: substrate
102: electrode layer
103: ferroelectric polymer thin film
104: VDF-TrFE Pellets
105: methyl ethyl ketone solvent
106: Solution of Ferroelectric Polymer Pellets VDF-TrFE Dissolved in Methylethylketone Solvent
107: dropper
108: spin plate

Claims (9)

delete delete delete Forming an electrode layer on one surface of the substrate;
Preparing a VDF-TrFE pellet in which VDF and TrFE are mixed at a ratio of 70:30 to 80:20;
Dissolving the VDF-TrFE pellets in a methylethylketone solvent to make the concentration of the solution 0.1wt% to 10wt%;
Coating the dissolved solution on an upper surface of the electrode layer; And
Annealing the coated substrate;
Information storage medium manufacturing method using a ferroelectric polymer thin film made of. The method of claim 4, wherein the forming of the electrode layer on one surface of the substrate comprises:
Thermal evaporation, E-beam evaporation, RF or DC sputter, E-beam, Electro-plating, or Chemical Vapor Deposition An information storage medium manufacturing method using a ferroelectric polymer thin film, characterized in that formed in any one way. delete The method of claim 4, wherein the coating of the dissolved solution on the upper surface of the electrode layer,
Manufacture of information storage media using ferroelectric polymer thin film, characterized in that any one of spin coating, spray coating, flow coating, dip coating or dip-drawing coating Way. The method of claim 7, wherein the spin coating (Spin),
Dropping the solution on the substrate and rotating the coating for 5 to 15 seconds at 1000rpm to 2000rpm coating information storage medium using a ferroelectric polymer thin film, characterized in that the coating. The method of claim 4, wherein the annealing of the coated substrate comprises:
Method of manufacturing an information storage medium using a ferroelectric polymer thin film, characterized in that the annealing (annealing) the substrate at 120 ℃ to 140 ℃ for 0.5 hours to 1.5 hours.

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