JPH05243076A - Capacitor - Google Patents

Abstract

(57) [Abstract] [Purpose] The insulating layer on the surface of the lower electrode is composed of a chemical adsorption film containing a water-repellent group and silicon in the molecule, and is directly or indirectly fixed to the surface of the lower electrode by a covalent bond. ,
Further, by providing the upper electrode made of conductive molecules on the insulating layer, a substantially pinhole-free high capacity capacitor is realized. A capacitor having a lower electrode 2 on the surface of a substrate 1, an insulating layer 3 on the surface, and an upper electrode 4 on the surface, wherein the insulating layer 3 contains a water-repellent group and silicon in the molecule. A chemical adsorption film containing the chemical adsorption film, which is directly or indirectly fixed to the surface of the lower electrode 2 by a covalent bond, and the upper electrode 4 made of conductive molecules is formed on the insulating layer 3. .. As an example, a conductive molecule 34 including a cyclic carbon structure having a larger molecular size than a chemisorption single molecule is used for the upper electrode 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor using an organic thin film as an insulator.

[0002]

2. Description of the Related Art Conventionally, polyethylene terephthalate (PET), poly (ethylene-2,
An electrode of aluminum (Al) or the like is formed on a plastic film of 6-naphthalate), polyimide, polypropylene, or the like by vapor deposition or plating, and this is overlapped and wound, and heat fusion is performed to form a capacitor. Also,
The capacitor using a chemisorption monomolecular film containing a linear carbon chain in the insulating layer, which has been already proposed by the present inventors, has an insulating layer thickness of an atom defined by the length of the chemisorption monomolecule. It has a uniform thickness depending on the size, an extremely thin and uniform insulating layer can be realized, the capacitance per unit electrode area increases in inverse proportion to the film thickness, and a micro capacitor can be realized (Japanese Patent Application No. 3-1443498).

[0003]

The capacitance per unit electrode area of the capacitor is inversely proportional to the thickness of the insulating layer. However, in the conventional structure using a plastic film for the insulating layer,
It is difficult to reduce the thickness of the insulating layer to 1 μm or less because pinholes are generated, and the capacitance per unit electrode area has an upper limit (about 2.7 nF / cm ² ). It was difficult to realize. Furthermore, in a capacitor using a chemisorption monomolecular film containing a linear carbon chain in the insulating layer, the insulating layer has a constant thickness of about the atomic size defined by the length of the chemisorption monomolecule, Although an extremely thin and uniform insulating layer can be realized, and the capacitance per unit electrode area increases in inverse proportion to the film thickness, a microminiature capacitor can be realized, but the chemisorption monomolecular film of the insulating layer sometimes has When a metal electrode is formed on the upper electrode by a method such as vacuum deposition, a short circuit may occur at the pinhole of the molecular order, resulting in a leak current density of a conventional PET film, etc. In some cases, there were problems such as a phenomenon in which the capacitor was higher than that of the capacitor using 2 to 3 orders of magnitude, and the withstand voltage dropped to about 1V.

In view of the above problems of the prior art, it is an object of the present invention to provide a capacitor using a chemical adsorption film capable of substantially eliminating molecular-order pinholes.

[0005]

To achieve the above object, a capacitor of the present invention comprises a lower electrode on the surface of a substrate, an insulating layer on the surface of the lower electrode, and an upper electrode on the surface of the insulating layer. Wherein the insulating layer comprises a chemical adsorption film containing a water-repellent group and silicon in the molecule, and the chemical adsorption film is directly or indirectly fixed to the surface of the lower electrode by a covalent bond. Further, an upper electrode made of conductive molecules is provided on the insulating layer.

In the above structure, the covalent bond is preferably a siloxane bond. Further, in the above structure, the chemisorption film is preferably chemically bonded to the surface of the lower electrode through at least the siloxane-based monomolecular film.

Further, in the above structure, the water-repellent group is preferably a fluorine-containing hydrocarbon group. Further, in the above structure, the conductive molecule is preferably a molecule containing a cyclic carbon structure.

In the above structure, it is preferable that the conductive molecule having a cyclic carbon structure is at least one selected from alkyl-substituted oligothiophene, polypyrrole and polyaniline.

[0009]

According to the structure of the present invention, the insulating layer on the surface of the lower electrode is made of a chemical adsorption film containing a water-repellent group and silicon in the molecule, and is directly or indirectly fixed to the surface of the lower electrode by a covalent bond. In addition, since the upper electrode made of conductive molecules is provided on the insulating layer, a substantially pinhole-free high-capacity capacitor can be realized. Also, by using a chemical adsorption film containing a linear carbon chain for the insulating layer, the thickness of the insulating layer becomes a constant thickness around the atom size defined by the length of the chemisorption single molecule, and it is extremely thin and uniform. An insulating layer can be realized, the capacitance per unit electrode area increases in inverse proportion to the film thickness, and a microminiature capacitor can be realized.

Further, according to the preferable constitution of the present invention in which the covalent bond is a siloxane bond, the chemisorption film can be firmly bonded to the surface of the lower electrode. Further, according to the preferable constitution of the present invention in which the chemical adsorption film is chemically bonded to the surface of the lower electrode through at least the siloxane-based monomolecular film, the molecular density of the chemical adsorption film can be further increased.

Further, according to the preferred constitution of the present invention in which the water-repellent group is a fluorine-containing hydrocarbon group, the chemisorption film can maintain favorable insulating properties and water repellency. Further, according to a preferred configuration of the present invention in which the conductive molecule is a molecule containing a cyclic carbon structure, by forming an upper electrode made of a conductive molecule such as graphite having a cyclic carbon structure on the insulating layer, for example, Even if a molecular-order pinhole lacking an adsorbed monomolecule exists in a chemisorption monolayer, a cyclic carbon structure conductive molecule having a larger molecular size than a linear carbon chain is You can't go in. Therefore, it is possible to prevent the lower electrode and the upper electrode from being electrically short-circuited via the pinhole. That is, the leakage current density is reduced. Moreover, the potential above the insulating film made of the chemisorption monomolecular film is
Since the voltage is uniformly regulated by the conductive molecules including the cyclic carbon structure formed on the insulating film, a uniform voltage is applied to the insulating layer, and the withstand voltage improves to a value specific to the insulating layer. A capacitor with excellent characteristics can be formed. Further, even when forming a metal-insulating layer-metal (MIM) tunnel element having such a capacitor shape, a pinhole-free insulating layer having a uniform film thickness can be formed, so that there is almost no variation in element characteristics. It is determined by the patterning accuracy of 1 and contributes to the reduction of variations in element characteristics.

By selecting at least one kind of alkyl-substituted oligothiophene, polypyrrole, and polyaniline as the conductive molecule having a cyclic carbon structure, preferable conductive characteristics can be obtained and the occurrence of pinholes can be further reduced.

Furthermore, by using a chemisorption monomolecular film composed of a linear carbon chain containing a water-repellent group, it is possible to prevent the ingress of water and to use a fluorine-containing hydrocarbon group as the water-repellent group to prevent leakage current. Is small and the withstand voltage is improved, so that the applied voltage can be increased even with a thin insulating layer. Therefore, the thickness of the insulating layer can be reduced to several nm, a capacitor having a large capacitance per electrode area can be realized, and the size can be reduced.

When the chemisorption monolayer is fixed to at least one of the superconducting electrodes by a chemical bond,
The mechanical strength is high, and film peeling due to stress is unlikely to occur.

[0015]

The present invention will be described in more detail with reference to the following examples. Conventionally, a substrate is brought into contact with a non-aqueous organic solvent in which a chemical adsorbent is dissolved to cause a chemical reaction in the non-aqueous organic solvent to form a monomolecular film. This reaction is called a chemisorption reaction. The monomolecular film thus obtained is called a chemisorption monomolecular film. Since the chemisorption monomolecular film is connected to the surface of the substrate through a strong chemical bond, the chemisorption monomolecular film generally has such an adhesive strength that it does not peel unless the surface of the substrate is scraped off. In addition to such adsorption in the liquid phase,
There is also a method of chemisorption in the gas phase.

However, when the chemically adsorbed monomolecular film is used as the insulating film of the capacitor, the leak current sometimes becomes higher by two to three orders of magnitude as compared with the capacitor using the conventional PET film or the like. .. Also, withstand voltage is 1
It may be as low as V. The existence of molecular-order pinholes was considered to be the cause of this. The present inventors have studied an upper electrode forming method to solve this problem,
The present invention has been reached.

FIG. 1 is a sectional view of a capacitor according to an embodiment of the present invention. The lower electrode 2 is formed on the substrate 1,
An upper electrode 4 is formed on top of this with an insulating layer 3 in between, and is cut into a desired shape to form a capacitor 5. Insulation layer 3
Is a monomolecular film made of a linear carbon chain containing a water-repellent group such as fluorine and silicon for chemically bonding, and is chemically bonded to the lower electrode 2 by, for example, a siloxane bond. Further, this chemical bond may be a chemical bond via a siloxane-based monomolecular film. The insulating layer 3 is formed by chemically adsorbing a chemical adsorbent on the lower electrode. The chemisorption monomolecular film that is the material of the insulating layer of the present invention may be a monolayer film or a monomolecular cumulative film, but in the case of a monomolecular cumulative film, it is chemically bonded between the cumulative layers. Is required.

There are various methods for chemisorption, but one is
As an example, a chemical adsorbent may have chlorosilyl (-Si
Cl_nX_3-n) Group or alkoxysilane (-Si (O
A)_nX_3-n) Group and a hydrocarbon group or
Using Silane-based Surfactant Containing Monosubstituted Carbon
The case will be described. However, n in the formula is an integer of 1 to 3
And X is hydrogen, a lower alkyl group or a lower alkoxy group
And A represents a lower alkyl group. Above silane
Of the surfactants, chlorosilane-based surfactants
A chemisorption reaction can be performed, and a chemisorption monomolecular film can be reliably formed.
It is preferable because it is possible. Among chlorosilane-based surfactants
Trichlorine-silicon chemical bond (ie, n in the formula is 3)
And, it is preferable because the siloxane bond is also used between adsorbed molecules.
Yes. In addition, the silane-based surfactant used in the present invention does not absorb
In order to improve the density of adsorbed molecules, straight chain is preferable. concrete
To CH₃-(R)_m-SiCl_nX_3-n, CF₃−
(CF₂)_p-(R)_m-SiCl_nX_3-nRepresented by
Chlorsilane-based surfactants are preferred. Where p is
0 or an integer, m is 0 or 1, R is a carbon number of 1 or more.
A methylene group having 1 or more carbon atoms such as a tylene group or a vinylene-containing group,
Methylene group having 1 or more carbon atoms of silicon-containing atom or acid-containing
Any of methylene groups having 1 or more carbon atoms in the elementary atom, X is hydrogen
Atom, lower alkyl group or lower alkoxy group, n is 1
Is an integer of ~ 3. More specifically, for example, CH₃(CH
₂)₉SiCl₃, CH₃(CH₂)₁₅SiCl₃, C
H₃CH₂O (CH₂)₁₅SiCl₃, CH₃(C
H₂)₂Si (CH₃)₂(CH₂)₁₅SiCl₃, C
F₃(CF₂)₇(CH₂)₂SiCl₃, CF₃CH
₂O (CH₂)₁₅SiCl₃, CF₃(CH₂)₂Si
(CH₃) ₂(CH₂)₁₅SiCl₃, F (CF₂)_Four
(CH₂)₂Si (CH₃)₂(CH₂)₉SiC
l₃, CF₃COO (CH₂)₁₅SiCl₃, CF
₃(CF₂) _Five(CH₂)₂SiCl₃Etc.
It Further, when the R group in the above formula contains a vinylene group,
The unsaturated bonds are polymerized by irradiation with a medium, light or high energy rays.
By binding, a strong bond between the molecules occurs
It is preferable because it forms a film. In addition, fluorocarbon silane
Water-repellent effect is great when using surfactant, and electrical insulation characteristics
Is also preferable because it is also good. In addition, especially Chlorcilla
When using a surfactant,
Generally, a chemisorption monolayer is formed due to its high reactivity.
After that, the chemisorption monolayer is washed without contact with water.
Need to If this washing process is not performed, unreacted black
The rusilane-based surfactant reacts with water to become cloudy and
It becomes contaminants and adheres to the chemisorption monolayer, and
Cause characteristic deterioration such as increase in
Become. In addition, these surfactants are suitable for non-aqueous organic solvents.
It is necessary to dissolve, and examples of such a solvent include
Cyclohexane, n-hexadecane, toluene, xyle
, Dicyclohexyl, carbon tetrachloride, chloroform, etc.
They may be used alone or in combination of two or more. Chlorsilane-based
In the case of other silane-based surfactants, other than this, for example,
Methyl alcohol, ethyl alcohol and the like can also be applied.

Further, the chemisorption monomolecular film used as the insulating film of the capacitor of the present invention is brought into contact with the surface of the lower electrode 2 with a substance containing a chlorine-silicon chemical bond, and then contains an unreacted chlorine-silicon chemical bond. The substance is washed and reacted with water to form a chemisorption monomolecular film having a silanol group on the surface of the lower electrode 2, or a chemisorption monomolecular film accumulated by repeating this chemisorption monomolecular film forming step a plurality of times. It is obtained by forming. Alternatively, when the method of chemically adsorbing a silane-based surfactant containing fluorocarbon after forming the chemisorption monolayer in this way is adopted, in the case of the lower electrode 2 having less hydrophilic groups exposed on the surface, However, a silane-based surfactant containing a water-repellent group can be chemically adsorbed at a high density, which is preferable. Examples of the material having a chlorine-silicon chemical bond include SiCl ₄ , SiHCl ₃ , and SiH ₂ C.
l ₂ , Cl (SiCl ₂ O) _n SiCl ₃ , H
_k (R ¹ ) _3-k Si (R ² ) _n SiCl _m (R ³ ) _3-m
In general, it is preferable that the number of Cl—Si bonds is large because the silane-based surfactant can be chemically adsorbed at a high density. However, in the formula, n is an integer, l and m are integers of 1 to 3, k is an integer of 1 to 10, R ¹ and R ³ are lower alkyl groups, R ²
Is a methylene group having 1 or more carbon atoms. In particular, if SiCl ₄ is used as the substance containing a chemical bond of chlorine-silicon, the molecule is small and the activity for hydroxylation is large, and therefore the effect of uniformly hydrophilizing the surface of the lower electrode 2 is large and preferable.

The chemisorption monomolecular film used in the capacitor of the present invention may be a monolayer film of a single layer or a monomolecular cumulative film, but in the case of a monomolecular cumulative film, it is chemically bonded between the cumulative layers. Is required.

Next, specific examples of the method of manufacturing the insulating layer 3 will be described. Example 1 FIG. 2 is a process sectional view showing an example of a manufacturing process of a capacitor of the present invention. As the substrate 11, a PET film having a thickness of 1 μm is used. An Al thin film having a thickness of 100 nm is formed on the substrate 11 by an electron beam evaporation method or the like to form the lower electrode 12. The substrate 11 and the lower electrode 12 thus formed are taken out into the atmosphere and the surface of the lower electrode 12 is oxidized to form a thin natural oxide film. After that, the PET film of the substrate 11 is passed through pure water and then sufficiently dried to form a hydroxyl group 14 on the surface of the lower electrode 12, and the following chemical adsorption treatment is performed. As a substance containing a fluorocarbon group and a chlorine-silicon chemical bond, CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si
Cl ₃ is used as the chemical adsorbent 15 and is a non-aqueous solvent 8
0wt% cyclohexane, 12wt% carbon tetrachloride, 8w
A solution prepared by dissolving 10% by weight of a mixed solvent of t% chloroform was prepared, and the substrate 11 was immersed for about 2 hours. Since a large number of hydroxyl groups 14 are formed on the surface of the lower electrode 12 by the above-described treatment, chlorine in the -SiCl group of the substance containing a fluorocarbon group and a chlorine-silicon chemical bond and the hydroxyl group undergo a dehydrochlorination reaction to cause the lower portion. As shown in FIG. 2, the surface of the lower electrode 12 is formed as shown in FIG. 2 in a state where the bond shown in (Chemical Formula 1) is formed over the entire surface of the electrode 12 and the monomolecular film 2 containing fluorine is chemically bonded to the surface of the lower electrode 12. An insulating layer 13, which is a chemisorption monomolecular film, could be formed through the siloxane bond 18.

[0022]

[Chemical 1]

The thickness of the insulating layer 13 is about 15 angstroms (1.5 nm) due to the molecular structure. Since the monomolecular film was chemically bonded extremely strongly, it never peeled off.

Embodiment 2 FIG. 3 is a process sectional view showing a second embodiment of the manufacturing process of the capacitor of the present invention. Substrate 11 and lower electrode 12,
The surface treatment and the like are the same as those in the concrete example 1. After being sufficiently dried, the following chemical adsorption treatment is performed.

S as a substance containing a trichlorosilyl bond
When the substrate 11 is immersed for about 30 minutes in a solution of iCl ₄ dissolved in a non-aqueous solvent such as chloroform solvent in an amount of 1% by weight, the hydroxyl group 14 and trichlorosilyl group formed on the surface of the lower electrode 12 are removed as shown in FIG. A dehydrochlorination reaction was caused with the chlorine atom of the substance 21 containing the chlorosilyl monomolecular film 22 of the substance containing the trichlorosilyl group. Thus, as a substance containing a trichlorosilyl group, SiCl
_{If 4} is used, a small amount of OH groups 13 will be present on the surface of the lower electrode 12.
Even if only present, the dehydrochlorination reaction occurs on the surface of the lower electrode 12, and the molecule is fixed to the surface via the —SiO— bond as shown in Chemical formula 2.

[0026]

[Chemical 2]

At this time, generally, unreacted SiCl ₄
Since it also exists on the chlorosilyl monomolecular film, if it is subsequently washed with a non-aqueous solvent of chloroform and further washed with water, SiC that has not reacted with the hydroxyl group on the surface of the lower electrode 12
The l ₄ molecule was removed and the lower electrode 12 was removed as shown in FIG.
A siloxane monomolecular film 24 of Chemical formula 3 or the like is obtained on the surface of.

[0028]

[Chemical 3]

Since the monomolecular film 24 formed at this time is completely bonded to the surface of the lower electrode 12 through the chemical bond of -SiO-, it does not peel off at all. Also,
The obtained siloxane monomolecular film 24 has -SiOH on the surface.
Has many bonds. About three times as many as the initial hydroxyl groups are generated.

Next, the substrate 11 having the siloxane monomolecular film 24 formed on the surface of the lower electrode 12 is dipped in the solution described in the concrete example 1 for about 1 hour, and the surface of the siloxane monomolecular film 24 is converted into The bond of 4) is generated, and the chemisorption monomolecular film 25 containing fluorine is formed in a state of being chemically bonded to the lower siloxane monomolecular film 24 as shown in FIG.
The insulating layer 23 covers the entire surface of the lower electrode 12 by about 20
It could be formed with a film thickness of angstrom.

[0031]

[Chemical 4]

The insulating layer 23 was not peeled at all even after the peeling test. In addition, a specific example 1 shows a case of a monomolecular film layer, and a specific example 2 shows a case of accumulating a fluorine-containing silane-based surfactant layer after one layer of a siloxane monomolecular film. The chemisorption monomolecular film of the invention is not limited to one layer, but its effect does not change even if accumulated in multiple layers.

Furthermore, in the above embodiment, CF ₃ (CF ₂ ) is used as the fluorocarbon chlorosilane-based surfactant.
₇ (CH ₂₎ was used _{2 SiCl 3, CF 3 - (} CF
₂ ) If, for example, a vinylene group (-CH = CH-) or an ethynylene group is added to or incorporated in the R portion of the chlorosilane-based surfactant represented by _p- (R) _m -SiCl _n X _3-n , After the monomolecular film is formed, it can be crosslinked by electron beam irradiation at about 5 megarads, so that the hardness of the monomolecular film can be further improved.

As the fluorocarbon surfactant, the above
CF other than₃CH₂O (CH₂)₁₅SiC
l₃, CF₃(CH₂)₂Si (CH₃)₂(CH₂)
₁₅SiCl₃, F (CF₂)_Four(CH₂)₂Si (CH
₃)₂(CH₂)₉SiCl₃, CF₃COO (C
H₂)₁₅SiCl₃, CF₃(CF₂)_Five(CH₂)₂
SiCl₃Starting with trichlorosilane-based surfactants such as
CF₃CH₂O (CH₂)₁₅Si (CH₃)₂C
l, CF₃(CH₂)₂Si (CH₃)₂(CH₂)₁₅
Si (CH₃)₂Cl, CF₃CH₂O (CH₂)₁₅S
i (CH₃) Cl₂, CF₃COO (CH₂)₁₅Si
(CH₃)₂Uses chlorosilane-based surfactants such as Cl
did it. CF₃(CF₂)₇(CH₂)₂Si (OC
H₃)₃, CF₃CH₂O (CH₂)₁₅Si (OC
H₃)₃Alkoxysilane-based surfactants such as
Similar effects were obtained by heating the sex agent solution.
CH₃(CH₂) ₉SiCl₃, CH₃(CH₂)₁₅S
iCl₃, CH₃CH₂O (CH₂)₁₅SiCl₃, C
H₃(CH₂)₂Si (CH₃)₂(CH₂)₁₅SiC
l₃Chlorsilane Surfactant Having Hydrocarbon Group
However, similarly, a chemisorption monolayer is formed at room temperature, which is good.
An insulating layer can be formed.

Next, a method for forming the upper electrode 4 after forming the insulating layer 13 or 23 as described in the specific embodiment 1 or 2 will be described. FIG. 6 shows an embodiment showing the manufacturing process of the upper electrode of the capacitor of the present invention. The substrate 1 on which the insulating layer 3 is formed is placed in a vacuum apparatus, evacuated, and then an electric current is passed between two graphite rods in a helium atmosphere having a vacuum degree of about 100 Torr to cause arc discharge. Then, the upper electrode 4 made of a graphite thin film is formed on the insulating layer 3. You can leave it as it is, but further A
The upper electrode may be formed by stacking 1 thin films and vacuum vapor deposition. When the graphite thin film is formed in this manner, the leakage current density is reduced by about one digit or more as compared with the capacitor in which the metal thin film such as Al is directly vapor-deposited on the insulating layer 3, and the leakage current density is 2 × 10 ^-11 A / m
A value of m ² or less was obtained. The withstand voltage was about 4V, which was about 1V higher than that of the capacitor in which the Al upper electrode was formed by the vacuum evaporation method. This is because the conductive molecule 34 including a cyclic carbon structure such as graphite is difficult to enter into the molecular-order pinhole 35 of the chemisorption monolayer due to its large molecular size, which is caused by a short circuit at the pinhole portion. It is considered that the leak current was effectively reduced.
Further, in the graphite thin film formed as described above, fullerenes such as C ₆₀ and C ₇₀ are present, and these have a size of a dozen angstroms, and have a larger steric hindrance, which leads to the formation of molecular pinholes. It is considered to be difficult to enter and is desirable as the upper electrode of the capacitor.

In the method of forming the graphite thin film, the arc discharge method has been described, but the method is not limited to this, and the electron beam evaporation method, the sputtering method, the ion beam sputtering method, the CVD method, the laser ablation method may be used. It goes without saying that methods such as the law are possible.

When an alkyl-substituted oligothiophene is used as the conductive molecule having a cyclic carbon structure of the upper electrode material, for example, diethyl quinkethiophene (C ₂ H ₅ (C ₄ SH ₂ ) ₅ C ₂ H ₅ ) Is dissolved in chloroform at a concentration of about 1 mg / ml, applied and dried to form the upper electrode 4
To form. Or at a vacuum of 10 ^-5 Torr or more,
Diethylquinkethiophene placed on a tungsten boat can be evaporated by resistance heating to form an upper electrode with a thickness of several thousand angstroms. In the former case, when a hydroxyl group is formed at the end of the insulating layer on the upper electrode side and the surface is hydrophilic, the solution can be applied well and can be applied uniformly. In the latter case, a hydroxyl group does not have to be formed at the end on the upper electrode side of the insulating layer, but it is more uniform in the conductive molecule when the end is hydrogen or a methyl group than when it is terminated by a fluorine atom. Adhesion can be achieved. The characteristics of the produced capacitor were similar to those using a graphite thin film for the upper electrode.

Further, when polypyrrole or polyaniline is used as the conductive molecule containing a cyclic carbon structure of the upper electrode material, a dilute aqueous solution prepared by mixing 30% by weight of FeCl ³ as an oxidizing agent with polyvinyl alcohol (PVA) is chemically adsorbed. After being thinly applied and dried on the insulating layer 3 made of a monomolecular film, pyrrole vapor or aniline vapor is brought into contact with the monomer vapor to polymerize the monomer vapor to form the upper electrode as a polymer. In this case, it is desirable that the end of the insulating layer 3 on the side of the upper electrode of the chemisorption monomolecular film has a hydroxyl group and has a hydrophilic surface. In this case, PV
Since the A-FeCl ³ thin film is a high resistance layer, this layer causes variations in characteristics, so it is preferable that the thin film is as thin as possible. The leak current and the withstand voltage of the produced capacitors were almost the same as those using the graphite thin film for the upper electrode, although there were some variations.

[0039]

As described above, in the capacitor of the present invention, since the chemisorption monomolecular film chemically bonded to the lower electrode is used as the insulating layer, it is mechanically stable and strong. Further, since the thickness of the chemisorption monomolecular film is uniform on the molecular order, a small and lightweight capacitor with little characteristic variation can be realized. Further, since the upper electrode is made of a conductive molecule containing a cyclic carbon structure having a larger molecular size than the chemisorption monomolecule, the leakage current density of the capacitor is small, the withstand voltage is large, and the insulating layer made of the chemisorption monolayer is formed. It is possible to easily manufacture a capacitor making use of the above-mentioned characteristics and to manufacture it with a high yield.

[Brief description of drawings]

FIG. 1 is a sectional structural view showing an embodiment of a capacitor of the present invention.

FIG. 2 is a conceptual sectional process diagram in which the substrate surface is enlarged to the molecular level, showing the manufacturing process in the first embodiment of the capacitor of the present invention.

FIG. 3 is a sectional process conceptual diagram in which a substrate surface is enlarged to a molecular level, showing a manufacturing process in a second embodiment of the capacitor of the present invention.

FIG. 4 is a sectional process conceptual diagram in which a substrate surface is enlarged to a molecular level, showing a manufacturing process in a second embodiment of the capacitor of the present invention.

FIG. 5 is a sectional process conceptual diagram in which a substrate surface is enlarged to a molecular level, showing a manufacturing process in a second embodiment of the capacitor of the present invention.

FIG. 6 is a sectional process conceptual diagram in which the substrate surface is enlarged to the molecular level, showing the manufacturing process of the upper electrode in the embodiment of the capacitor of the present invention.

[Explanation of reference numerals] 1, 11 Substrate 2, 12 Lower electrode 3, 13, 23 Insulating layer 4 Upper electrode 5 Capacitor 14 Hydroxyl group 15 Chemical adsorbent 18 Siloxane bond 21 Substance containing trichlorosilyl group 22 Chlorosilyl monomolecular film 24 Siloxane monolayer Molecular film 25 Chemisorption monomolecular film containing fluorine 34 Conductive molecule containing cyclic carbon structure 35 Pinhole

Claims (6)

[Claims] 1. A capacitor having a lower electrode on a surface of a substrate, an insulating layer on a surface of the lower electrode, and an upper electrode on a surface of the insulating layer, wherein the insulating layer includes a water-repellent group and silicon. A chemical adsorption film containing in the molecule, the chemical adsorption film is directly or indirectly fixed to the surface of the lower electrode by a covalent bond, and an upper electrode made of a conductive molecule is provided on the insulating layer. A capacitor characterized in that. 2. The capacitor according to claim 1, wherein the covalent bond is a siloxane bond. 3. The capacitor according to claim 2, wherein the chemisorption film is chemically bonded to the surface of the lower electrode through at least the siloxane-based monomolecular film. 4. The capacitor according to claim 1, wherein the water-repellent group is a fluorine-containing hydrocarbon group. 5. The capacitor according to claim 1, wherein the conductive molecule is a molecule containing a cyclic carbon structure. 6. The capacitor according to claim 5, wherein the conductive molecule having a cyclic carbon structure is at least one selected from alkyl-substituted oligothiophene, polypyrrole, and polyaniline.