KR20080108960A - Ferroelectric material and method of forming ferroelectric layer using the same - Google Patents

Abstract

A ferroelectric material and the ferroelectric layer formation method using the same are provided to implement the ferroelectric material possible for forming at the temperature of 200‹C or less with excellent ferroelectric property. A ferroelectric material is comprised of the mixture of the organic compound and the inorganic material ferroelectric material. The inorganic material ferroelectric material includes at least one of the oxide ferroelectric, fluoride ferroelectric, and the mixture of the ferroelectric semiconductor or these inorganic materials. The inorganic material ferroelectric material has the hysteresis characteristic according to the change of the applied voltage. The silicide, silicate or another metal is added to the ferroelectric material.

Description

Ferroelectric material and method of forming ferroelectric layer using the same

The present invention relates to a ferroelectric material that can be efficiently used in the manufacture of various electrical and electronic devices, and a ferroelectric layer forming method for forming a ferroelectric layer using the ferroelectric material.

Currently, ferroelectric materials are used as materials for various electronic and electrical devices. There are many kinds of electronic devices using ferroelectric materials, including piezoelectric devices and pyroelectric devices. In particular, recently, attempts to manufacture nonvolatile memories using polarization characteristics of ferroelectric materials have been made at various angles.

Currently ferroelectric materials are largely divided into organic and inorganic materials. Since the inorganic ferroelectric has a very high dielectric constant as compared with the organic ferroelectric, most inorganic ferroelectrics are used in various electronic and electrical devices.

However, in the case of the inorganic ferroelectric, for example, a high temperature treatment of 500 degrees or more is required. Therefore, in the formation of the ferroelectric layer using the ferroelectric, there is a problem that expensive equipment is required, manufacturing costs are high, and many restrictions are placed on the material of the substrate forming the ferroelectric layer.

In particular, in constructing a ferroelectric memory using an inorganic ferroelectric material, a fatal problem is caused in which the data retention characteristics of the memory are deteriorated by the high temperature forming conditions.

1 is a cross-sectional view showing a typical structure of a metal-ferroelectric-semiconductor (MFS) type memory device using a ferroelectric material.

In FIG. 1, source and drain regions 2 and 3 are formed in a predetermined region of the silicon substrate 1, and a ferroelectric film or a ferroelectric layer 5 is formed on the channel region 4 between the source and drain regions 2 and 3. ) Is formed. At this time, as the ferroelectric layer 5, inorganic materials having ferroelectric characteristics, such as PZT (PbZr _x Ti _1-x O ₃ ), SBT (SrBi ₂ Ta ₂ O ₉ ), BLT ((Bi, La) ₄ Ti ₃ O ₁₂ ), and the like. This is used. The source and drain regions 2 and 3 and the ferroelectric layer 5 are respectively provided with a source electrode 6, a drain electrode 7 and a gate electrode 8 made of metal.

In the ferroelectric memory having the above-described structure, the ferroelectric layer 5 exhibits polarization characteristics according to the voltage applied through the gate electrode 8, and the conductive channel is formed between the source region 2 and the drain region 3 by this polarization characteristic. Is formed so that a current flows between the source electrode 6 and the drain electrode 7. In particular, in the above structure, even when the voltage applied through the gate electrode 8 is interrupted, the polarization characteristic of the ferroelectric layer 5 is continuously maintained. Therefore, the above structure is attracting attention as a structure in which a nonvolatile memory can be configured by only one transistor without having a separate capacitor.

However, in the ferroelectric memory having the above structure, the use of the inorganic ferroelectric material causes the following problems. That is, when the ferroelectric layer 5 made of an inorganic material is formed on the silicon substrate 1, for example, the ferroelectric layer 5 and the silicon are generated by CVD or sputtering at 500 to 800 degrees. A low quality transition layer is formed on the interface with the substrate 1 and elements such as Pb and Bi in the ferroelectric layer 5 are diffused in the silicon substrate 1, making it difficult to form a high quality ferroelectric layer. Therefore, there is a problem that the polarization characteristic of the ferroelectric layer 5, that is, the data holding time of the ferroelectric memory becomes very short.

Accordingly, an object of the present invention is to provide a ferroelectric material capable of forming a ferroelectric layer at low temperature while having good ferroelectric characteristics.

In addition, another object of the present invention is to provide a method of forming a ferroelectric layer for forming a ferroelectric layer using the ferroelectric material.

The ferroelectric material according to the first aspect of the present invention for achieving the above object is characterized by consisting of a mixture of inorganic ferroelectric material and organic material.

In addition, the ferroelectric material according to the second aspect of the present invention is characterized by consisting of a mixture of a solid solution of an inorganic ferroelectric material and an organic material.

The inorganic ferroelectric material may include at least one of an oxide ferroelectric, a fluoride ferroelectric, a ferroelectric semiconductor, and a mixture of these inorganic materials.

In addition, the inorganic ferroelectric material is characterized in that the PZT.

In addition, the ferroelectric material is characterized in that the silicate, silicate or other metal is further mixed.

In addition, the organic material is characterized in that the polymer ferroelectric.

In addition, the polymeric ferroelectric includes at least one or more of polyvinylidene fluoride (PVDF), a polymer, a copolymer, or a terpolymer comprising the PVDF, an odd number of nylon, a cyano polymer, and polymers or copolymers thereof. Characterized in that.

In addition, the polymer ferroelectric is characterized in that the PVDF-TrFE.

In addition, the ferroelectric material is characterized in that it is produced by heating and firing a mixed solution of the inorganic ferroelectric material and the organic solution.

In addition, the ferroelectric material is used as a material of a ferroelectric transistor or a ferroelectric memory.

In addition, the method of forming a ferroelectric layer according to the third aspect of the present invention comprises the steps of preparing a mixed solution of an inorganic ferroelectric material and an organic material, applying the mixed solution on a substrate to form a ferroelectric film, and heating the ferroelectric film Firing to form a ferroelectric layer.

In addition, the ferroelectric layer forming method according to the fourth aspect of the present invention comprises the steps of preparing a mixed solution of an inorganic ferroelectric material and an organic material, forming a ferroelectric film by applying the mixed solution on a substrate, and the ferroelectric film And heating and firing to form a ferroelectric layer.

In addition, the mixed solution is characterized in that after mixing the inorganic powder and the organic powder, dissolved in a solvent to produce.

In addition, the mixed solution is characterized in that produced by dissolving the organic powder in the inorganic solution.

In addition, the mixed solution is characterized in that produced by dissolving the inorganic powder in the organic solution.

In addition, the mixed solution is characterized in that produced by mixing the inorganic solution and the organic solution.

In addition, the organic material is characterized in that the ferroelectric organic material.

In addition, the mixed solution is characterized in that the mixed solution of the PZT solution and PVDF-TrFE solution.

In addition, the PZT solution is characterized in that it is produced by mixing the PZO solution and PTO solution.

In addition, the PVDF-TrFE solution is PVDF-TrFE powder THF (C ₄ H ₅ O), MEK (C ₄ H ₈ O), acetone (C ₃ H ₆ O), DMF (C ₃ H ₇ NO), DMSO It is characterized by producing by dissolving in at least one of (C ₂ H ₆ OS).

In addition, the ferroelectric film is formed by a spin coating method.

In addition, the ferroelectric film is formed by an inkjet method.

In addition, the ferroelectric film is formed by screen printing.

The method may further include etching a portion of the ferroelectric layer.

In addition, the etching of the ferroelectric layer is characterized in that it is carried out through the BOE.

In addition, the etching of the ferroelectric layer is characterized in that it is carried out through a two-step etching using BOE and gold etchant.

The ferroelectric layer is etched through the RIE method.

Moreover, the said baking temperature is 200 degrees or less, It is characterized by the above-mentioned.

In addition, the substrate is polyimide (PI), polycarbonate (PC), polyether sulfone (PES), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polychloride Vinyl (PVC), Polyethylene (PE), Ethylene Copolymer, Polypropylene (PP), Propylene Copolymer, Poly (4-methyl-1-pentene) (TPX), Polyarylate (PAR), Polyacetal (POM) , Polyphenylene oxide (PPO), polysulfone (PSF), polyphenylene sulfide (PPS), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAC), polyvinyl alcohol (PVAL), polyvinyl acetal, polystyrene (PS), AS resin, ABS resin, polymethyl methacrylate (PMMA), fluorine resin, phenol resin (PF), melamine resin (MF), urea resin (UF), unsaturated polyester (UP), epoxy resin ( EP), diallyl phthalate resin (DAP), polyurethane (PUR), polyamide (PA), silicone resin (SI) or mixtures and compounds thereof. It is characterized by.

In addition, the substrate is characterized in that it is made of a material containing paper.

As described above, according to the present invention, a ferroelectric material capable of being formed at a low temperature of 200 degrees or less while having good ferroelectric properties can be realized.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.

First, the basic concept of the present invention will be described.

Currently, various materials are known as ferroelectric properties. These substances are largely divided into inorganic and organic substances. Examples of the inorganic ferroelectric include oxide ferroelectrics, fluoride ferroelectrics such as BMF (BaMgF ₄ ), ferroelectric semiconductors, and the like, and polymer ferroelectrics as organic ferroelectrics.

As the oxide ferroelectric, for example, Pseudo-ilmenite ferroelectric such as Perovskite ferroelectric such as PZT (PbZr _x Ti _1-x O ₃ ), BaTiO ₃ , PbTiO ₃ , LiNbO ₃ , LiTaO _3, and the like , Tungsten-bronze (TB) ferroelectrics such as PbNb ₃ O ₆ , Ba ₂ NaNb ₅ O ₁₅ , SBT (SrBi ₂ Ta ₂ O ₉ ), BLT ((Bi, La) ₄ Ti ₃ O ₁₂ ), Bi ₄ Ti ₃ Ferroelectrics of bismuth layer structure such as O ₁₂ and Pyrochlore ferroelectrics such as La ₂ Ti ₂ O ₇ and solid solutions of these ferroelectrics, as well as Y, Er, Ho, Tm, Yb, Lu, etc. RMnO ₃ , PGO (Pb ₅ Ge ₃ O ₁₁ ), and BFO (BiFeO ₃ ) containing a rare earth element (R).

Examples of the ferroelectric semiconductors include Group 2-6 compounds such as CdZnTe, CdZnS, CdZnSe, CdMnS, CdFeS, CdMnSe, and CdFeSe.

In addition, the polymer ferroelectric includes, for example, polyvinylidene fluoride (PVDF), a polymer, a copolymer, or a terpolymer containing PVDF, and an odd number of nylons, cyano polymers, and polymers thereof. Copolymers and the like.

In general, inorganic ferroelectrics such as oxide ferroelectrics, fluoride ferroelectrics, and ferroelectric semiconductors have a higher dielectric constant than organic ferroelectrics. Therefore, in the case of piezoelectric elements, pyroelectric elements, ferroelectric field effect transistors, ferroelectric memories, and the like, which are generally proposed, an inorganic ferroelectric material is used as a material of the ferroelectric layer.

However, in the case of the inorganic ferroelectric described above, a high temperature treatment of, for example, 500 degrees or more is required when forming it on a substrate.

The ferroelectric material according to an embodiment of the present invention is composed of a mixture of inorganic ferroelectric material and organic material.

In addition, the ferroelectric material according to another embodiment of the present invention is composed of a mixture of inorganic ferroelectric material and organic ferroelectric material.

According to the inventors' research, the inorganic ferroelectric material has a high dielectric constant while its formation temperature is high. In addition, the organic material including the organic ferroelectric material has a low dielectric constant while its formation temperature is very low. Therefore, when the inorganic ferroelectric material and the organic or organic ferroelectric material are mixed, the ferroelectric material having a very high dielectric constant and having a very low formation temperature can be obtained.

Herein, the following method may be used as a method of mixing an inorganic ferroelectric material and an organic or organic ferroelectric material.

1. After mixing inorganic powder and organic powder, dissolve it in solvent to produce mixed solution.

2. Dissolve organic powder in mineral solution to produce mixed solution.

3. Dissolve the inorganic powder in the organic solution to produce a mixed solution.

4. Mix the inorganic and organic solutions to form a mixed solution.

In addition, in the method of mixing the inorganic ferroelectric material and the organic material, it is possible to adopt the following method.

1. Mix ferroelectric minerals and organics.

2. Mix ferroelectric minerals with ferroelectric organics.

3. Mix solid solution of organic fertilizer with organic material.

4. Mix solid solution of ferroelectric mineral with ferroelectric organic material.

5. Mixing silicide, silicate or other metals into the mixture according to the first to fourth manners.

Of course, the mixing method and method of the said inorganic substance and organic substance are not limited to a specific thing, Any arbitrary method which can mix an inorganic substance and an organic substance suitably can be employ | adopted here.

In addition, as the organic material mixed with the ferroelectric inorganic material, a general monomer, oligomer, polymer, copolymer, preferably an organic material having a high dielectric constant may be used.

These materials include, for example, polyvinyl pyrrolidone (PVP), polycarbonate (PC), polyvinyl chloride (PVC), polystyrene (PS), epoxy (epoxy), polymethyl methacrylate (PMMA), polyimide (PE), poly (ethylene) (PE), and PVA ( polyvinyl alcohol), nylon 66 (polyhezamethylene adipamide), and PEKK (polytherketoneketone).

In addition, as the organic material, fluorinated para-xylene, fluoropolyarylether, fluorinated polyimide, polystyrene, poly (α-methyl styrene) (poly (α) -methyl styrene), poly (α-vinylnaphthalene), poly (vinyltoluene), polyethylene, cis-polybutadiene, poly Propylene, polyisoprene, poly (4-methyl-1-pentene), poly (tetrafluoroethylene), poly ( Chlorotrifluoroethylene (poly (chlorotrifluoroethylene), poly (2-methyl-1,3-butadiene) (poly (2-methyl-1,3-butadiene)), poly (p-xylylene) (poly ( p-xylylene)), poly (α-α-α'-α'-tetrafluoro-p-xylylene) (poly (α-α-α'-α'-tetrafluoro-p-xylylene)), poly [1,1- (2-methyl propane) bis (4-phenyl) carbonate] (poly [1,1- (2-methyl propane) bis (4-phenyl) carbonate]), poly (cyclohexyl methacrylate), poly (chlorostyrene), poly (2,6- Dimethyl-1,4-phenylene ether) (poly (2,6-dimethyl-1,4-phenylene ether)), polyisobutylene, poly (vinyl cyclohexane), Nonpolar organic substances such as poly (arylene ether) and polyphenylene, poly (ethylene / tetrafluoroethylene), poly (ethylene / chlorotri Poly (ethylene / chlorotrifluoroethylene), fluorinated ethylene / propylene copolymer, polystyrene-co-α-methyl styrene, ethylene / ethyl acryl Ethylene / ethyl acrylate copolymer, poly (styrene / 10% butadiene) (poly (styrene / 10% butadiene), poly (styrene / 15% butadiene) (po ly (styrene / 15% butadiene), poly (styrene / 2,4-dimethylstyrene) (poly (styrene / 2,4-dimethylstyrene), Cytop, Teflon AF, polypropylene-co-1-butene (polypropylene-co- Low dielectric constant copolymers such as 1-butene) and the like can be used.

And other conjugated hydrocarbon polymers such as polyacene, polyphenylene, poly (phenylene vinylene), polyfluorene, and oligomers of such conjugated hydrocarbons. ; Condensed aromatic hydrocarbons such as anthracene, tetratracene, chrysene, pentacene, pyrene, perylene and coronene; oligomeric para substitutions such as p-quaterphenyl (p-4P), p-quinquephenyl (p-5P), p-sexiphenyl (p-6P) Oligomeric para substituted phenylenes; Poly (3-substituted thiophene), poly (3,4-bisubstituted thiophene), polybenzothiophene, poly Isothianaphthene, poly (N-substituted pyrrole), poly (3-substituted pyrrole), poly (3,4-disubstituted pyrrole) ) (poly (3,4-bisubstituted pyrrole)), polyfuran, polypyridine, poly-1,3,4-oxadiazoles, polyiso Polyisothianaphthene, poly (N-substituted aniline), poly (2-substituted aniline), poly (2-substituted aniline), poly (3-substituted aniline) (poly Conjugated heterocyclic polymers such as (3-substituted aniline), poly (2,3-bisubstituted aniline), polyazulene, polypyrene; Pyrazoline compounds; Polyselenophene; Polybenzofuran; Polyindole; Polypyridazine; Benzidine compounds; Stilbene compounds; Triazines; Substituted metallo- or metal-free porphines, phthalocyanines, fluorophthalocyanines, naphthalocyanines or fluoronaphthalocyanines; C ₆₀ and C ₇₀ fullerenes; N, N'-dialkyl, substituted dialkyl, diaryl or substituted diaryl-1,4,5,8-naphthalenetetracarboxylic diimide (N, N'-dialkyl, substituted dialkyl, diaryl or substituted diaryl-1,4,5,8-naphthalenetetracarboxylic diimide) and fluorinated derivatives; N, N'-dialkyl, substituted dialkyl, diaryl or substituted diaryl 3,4,9,10-perylenetetracarboxylic diimide (N, N'-dialkyl, substituted dialkyl, diaryl or substituted diaryl 3,4,9,10-perylenetetracarboxylic diimide); Bathophenanthroline; Diphenoquinones; 1,3,4-oxadiazoles (1,3,4-oxadiazoles); 11,11,12,12-tetracyanonaphtho-2,6-quinodimethane (11,11,12,12-tetracyanonaptho-2,6-quinodimethane); α, α'-bis (dithieno [3,2-b2 ', 3'-d] thiophene) (α, α'-bis (dithieno [3,2-b2', 3'-d] thiophene) ); 2,8-dialkyl, substituted dialkyl, diaryl or substituted diaryl anthrathiothiophenes (2,8-dialkyl, substituted dialkyl, diaryl or substituted diaryl anthradithiophene); Organic groups such as 2,2'-bibenzo [1,2-b: 4,5-b '] dithiophene (2,2'-bibenzo [1,2-b: 4,5-b'] dithiophene) Semi-conducting materials or their compounds, oligomers and compound derivatives can be used.

In the above manner, the mixing ratio of the inorganic material and the organic material can be appropriately set as necessary. If the mixing ratio of the ferroelectric inorganic material is increased, the dielectric constant of the mixture is increased while the formation temperature is high, and if the mixing ratio of the ferroelectric inorganic material is low, the dielectric constant of the mixture is low while the formation temperature is low.

The ferroelectric material according to the present invention has the following characteristics.

1. Since the ferroelectric layer is formed using a mixed solution of an inorganic material and an organic material, the ferroelectric layer can be easily formed using inkjet, spin coating, or screen printing.

2. Since the formation temperature of the ferroelectric layer is lowered to approximately 200 degrees or less, it is possible to form a ferroelectric layer having excellent data retention characteristics on the silicon substrate.

3. Since the formation temperature of the ferroelectric layer is lowered, piezoelectric elements, pyroelectric elements, field effect transistors, and ferroelectric memories can be formed on various kinds of substrates, such as organic materials or paper, instead of conventional silicon substrates.

Since the ferroelectric material according to the present invention has a low forming temperature, organic materials such as conventional Si, Ge wafers, papers, paper coated with a coding material such as parylene, or plastics having flexibility can be used as the substrate. have. In addition, the organic materials usable here include polyimide (PI), polycarbonate (PC), polyether sulfone (PES), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), Polyvinyl chloride (PVC), polyethylene (PE), ethylene copolymer, polypropylene (PP), propylene copolymer, poly (4-methyl-1-pentene) (TPX), polyarylate (PAR), polyacetal ( POM), polyphenylene oxide (PPO), polysulfone (PSF), polyphenylene sulfide (PPS), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAC), polyvinyl alcohol (PVAL), polyvinyl acetal , Polystyrene (PS), AS resin, ABS resin, polymethyl methacrylate (PMMA), fluorine resin, phenol resin (PF), melamine resin (MF), urea resin (UF), unsaturated polyester (UP), epoxy Resin (EP), diallyl phthalate resin (DAP), polyurethane (PUR), polyamide (PA), silicone resin (SI) or mixtures and combinations thereof The can be used.

Meanwhile, FIGS. 2 to 6 illustrate ferroelectric layers formed by mixing inorganic ferroelectric materials and organic ferroelectric materials, such as PZT (PbZr _x Ti _1-x O ₃ ) and PVDF-TrFE, at a predetermined ratio. It is a graph which measured the polarization characteristic after that.

Here, the ferroelectric layer is mixed with the PZT solution and PVDF-TrFE solution in a constant ratio to generate a mixed solution, the mixed solution is applied on the silicon wafer by spin coating method, and then the silicon wafer is fixed on the hot plate for a predetermined time. It was formed by heating to about 150 ~ 200 degrees.

In addition, the PZT solution, for example, by mixing a zirconium propoxide solution with a mixed solution of 2-methoxyethanol solution and lead acetate trihydrate solution to produce a PZO solution Then, a titanium isopropoxide solution was mixed with a mixed solution of 2-methoxyethanol solution and lead acetate trihydrate solution to generate a PTO solution, and then a PZO solution and a PTO solution were mixed.

In addition, the PVDF-TrFE solution may contain PVDF-TrFE powders such as THF (C ₄ H ₅ O), MEK (C ₄ H ₈ O), Acetone (C ₃ H ₆ O), DMF (C ₃ H ₇ NO) It was produced by dissolving in a solvent such as (C ₂ H ₆ OS).

2 to 6, the mixing ratio of PZT and PVDF-TrFE is 1: 1, the mixing ratio of PZT and PVDF-TrFE is 2: 1, and the mixing ratio of PZT and PVDF-TrFE is 3: 1. 5 shows the polarization characteristics when the mixing ratio of PVDF-TrFE is 1: 2 and the mixing ratio of PVDF-TrFE is 1: 3.

2A, 3A and 4A show the film thickness of the ferroelectric layer 50 nm, FIGS. 2B, 3B, 4B, 5 and 6 show the film thickness of the ferroelectric layer 75 nm, and FIG. 2C shows the ferroelectric layer. The case where the film thickness is 100 nm is shown.

2 to 6, the characteristic graph denoted by A is 190 degrees for forming the ferroelectric layer, and the B is for forming the ferroelectric layer at 170 degrees and the C is 150 for forming the ferroelectric layer. The case is shown.

2 to 6, when the mixing ratio of PZT and PVDF-TrFE is 1: 1 or the mixing ratio of PVDF-TrFE is larger, the polarization characteristics are generally good at a temperature of 150 to 190 degrees, and the mixing ratio of PZT is Higher values show good polarization at higher temperatures.

In addition, as the thickness of the ferroelectric layer is increased, the polarization value, that is, the capacitance value is lowered, while the size of the memory window is increased.

In particular, it is noteworthy that the hysteresis characteristics are generally good regardless of changing the mixing ratio of PZT and PVDF-TrFE or setting the formation temperature to a temperature of 200 degrees or less.

As described above, in the case of the conventional inorganic ferroelectric material, since its formation temperature is high, various problems occur when it is formed on a silicon substrate. In contrast, the mixture of the inorganic ferroelectric material and the organic material according to the present invention can be formed at a low temperature of 200 degrees or less, and exhibits good hysteresis characteristics at a voltage between -5 and 5V. This means that by using the ferroelectric material according to the present invention, it is possible to manufacture electronic and electrical devices capable of operating at very low voltage.

Returning to FIG. 1, when the MFS type field effect transistor or the ferroelectric memory as shown in FIG. 1 is produced using the ferroelectric material according to the present invention, first, a predetermined region of the silicon substrate 1 is performed by the same method as in the prior art. The source and drain regions 2 and 3 and the channel region 4 are formed in the substrate.

Then, the ferroelectric material solution according to the present invention is applied to the structure as a whole through spin coating, inkjet printing, or screen printing to form a ferroelectric film, which is baked at a temperature of 200 degrees or less, for example, to form a ferroelectric layer. At this time, the ferroelectric material as described above, the mixture of ferroelectric minerals and organics, the mixture of ferroelectric inorganics and ferroelectric organics, the mixture of solid solutions and organics of ferroelectric inorganics, the mixture of solid solutions and ferroelectric organics of ferroelectric inorganics, and mixtures thereof Use a mixture of silicides, silicates or other metals.

Subsequently, the ferroelectric layer 5 is formed by performing a two-step etching process using BOE (Buffered Oxide Etching) or BOE and Gold etchant to remove the ferroelectric film except for the channel region 4. .

In addition, the source and drain regions 2 and 3 and the ferroelectric layer 5 are respectively formed on the source and drain electrodes 6, the drain electrodes 7, and the gate electrodes 8, respectively.

When the field effect transistor and the ferroelectric memory are implemented using the ferroelectric material according to the present invention, the ferroelectric layer 5 is formed at a low temperature of 200 degrees or less. Therefore, in forming the ferroelectric layer on the silicon substrate, a low quality transition layer is formed at the interface between the ferroelectric layer and the silicon substrate due to the high temperature, and the problem that elements such as Pb and Bi of the ferroelectric material are diffused to the silicon substrate is eliminated. do. That is, a high quality ferroelectric layer can be formed on the silicon substrate. As a result, the data retention time of the ferroelectric memory can be significantly improved.

Figure 7 is a characteristic graph showing the capacity value variation characteristics with time of the ferroelectric layer formed of a ferroelectric material according to the present invention.

As can be seen in Figure 7, the ferroelectric material according to the present invention has a constant characteristic without a change in its capacity value over time. That is, very good ferroelectric properties.

The embodiment according to the present invention has been described above. However, the above embodiment shows one preferred example of the present invention, which is not intended to limit the scope of the present invention. The present invention can be carried out in various modifications without departing from the spirit thereof.

1 is a cross-sectional view showing a typical MFS type ferroelectric memory device.

2 to 6 is a characteristic graph showing the capacity characteristics according to the voltage of the ferroelectric material according to the present invention.

Figure 7 is a characteristic graph showing the capacity change characteristics with time of the ferroelectric layer formed of a ferroelectric material according to the present invention.

Claims (20)

Consisting of a mixture of inorganic ferroelectric materials and organics, And the inorganic ferroelectric material comprises at least one or more of an oxide ferroelectric, a fluoride ferroelectric, a ferroelectric semiconductor, or a mixture of these inorganic materials, and has a hysteresis characteristic according to a change in applied voltage. The method of claim 1, Ferroelectric material, characterized in that the inorganic ferroelectric material is PZT. The method of claim 1, Ferroelectric material, characterized in that the ferroelectric material is further mixed with silicide, silicate or other metal. The method of claim 1, Ferroelectric material, characterized in that the organic material is a polymeric ferroelectric. The method of claim 4, wherein Wherein the polymeric ferroelectric comprises at least one or more of polyvinylidene fluoride (PVDF), a polymer, a copolymer, or a terpolymer, an odd nylon, a cyano polymer and their polymers or copolymers containing the PVDF A ferroelectric material characterized by the above. The method of claim 1, The ferroelectric material is a ferroelectric material, characterized in that produced by heating and baking a mixture solution of an inorganic ferroelectric material and an organic solution. The method of claim 1, The ferroelectric material is used as a material of a ferroelectric transistor or a ferroelectric memory. Composed of a mixture of organic solids with a solid solution of inorganic ferroelectric materials, Ferroelectric material, characterized in that the mixture is further mixed with silicide, silicate or other metals. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, The mixed solution is a ferroelectric layer forming method, characterized in that by mixing the inorganic powder and the organic powder, and then dissolved in a solvent to produce. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, And the mixed solution is produced by dissolving an organic powder in an inorganic solution. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, The mixed solution is produced by dissolving inorganic powder in an organic solution. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, The mixed solution is a ferroelectric layer forming method characterized in that the mixture is produced by mixing the inorganic solution and the organic solution. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, Ferroelectric layer formation method, characterized in that the organic material is a ferroelectric organic material. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film, Heating and firing the ferroelectric film to form a ferroelectric layer; And etching a portion of the ferroelectric layer. The method of claim 14, And etching the ferroelectric layer through BOE. The method of claim 14, Etching of the ferroelectric layer is performed through a two-step etching using BOE and a gold etchant. The method of claim 14, And the etching of the ferroelectric layer is carried out through a RIE method. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, And the firing temperature is 200 degrees or less. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, The substrate is polyimide (PI), polycarbonate (PC), polyether sulfone (PES), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyvinyl chloride ( PVC), polyethylene (PE), ethylene copolymer, polypropylene (PP), propylene copolymer, poly (4-methyl-1-pentene) (TPX), polyarylate (PAR), polyacetal (POM), Polyphenylene oxide (PPO), polysulfone (PSF), polyphenylene sulfide (PPS), polyvinylidene chloride (PVDC), polyvinyl acetate (PVAC), polyvinyl alcohol (PVAL), polyvinyl acetal, polystyrene ( PS), AS resin, ABS resin, polymethyl methacrylate (PMMA), fluorine resin, phenol resin (PF), melamine resin (MF), urea resin (UF), unsaturated polyester (UP), epoxy resin (EP) ), Consisting of diallyl phthalate resin (DAP), polyurethane (PUR), polyamide (PA), silicone resin (SI) or mixtures and compounds thereof Ferroelectric layer forming method characterized in that. Preparing a mixed solution of an inorganic ferroelectric material and an organic material, Coating the mixed solution on a substrate to form a ferroelectric film; And heating and firing the ferroelectric film to form a ferroelectric layer, And the substrate is made of a material including paper.

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