JP3192194B2 - Capacitor - Google Patents

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 such as 6-naphthalate), polyimide, or polypropylene by vapor deposition or plating, and the electrodes are stacked and wound, and heated and fused to form a capacitor. Also,
The capacitor using a chemisorbed monolayer containing a linear carbon chain in the insulating layer, which the present inventors have already proposed, has a thickness of the insulating layer defined by the length of the chemisorbed monomolecule. It has a constant thickness in the order of size, and can realize an extremely thin and uniform insulating layer, and the capacitance per unit electrode area increases in inverse proportion to the film thickness. No. 3-143498).

[0003]

The capacitance per unit electrode area of the capacitor is inversely proportional to the thickness of the insulating layer. 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 due to the occurrence of pinholes, and there is an upper limit (approximately 2.7 nF / cm ² ) in the capacitance per unit electrode area. Had become difficult. Furthermore, in a capacitor using a chemisorption monomolecular film containing a linear carbon chain in the insulating layer, the thickness of the insulating layer becomes a constant thickness of about the size of an atom defined by the length of the chemisorption monomolecule, Although 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 very small capacitor can be realized. When a metal electrode is formed by vacuum evaporation or the like on the upper electrode, a short circuit occurs at the molecular order pinhole and the leakage current density becomes lower than that of a conventional PET film. In some cases, such a phenomenon may occur as to be two to three orders of magnitude higher than that of a capacitor using, or the dielectric strength voltage may be reduced to about 1 V.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, an object of the present invention is to provide a capacitor using a chemisorption film which can substantially eliminate pinholes on the order of molecules.

[0005]

In order to achieve the above object, a capacitor according to the present invention includes 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 comprises a chemically adsorbed film made of a substance containing a water-repellent group composed of a hydrocarbon group or a fluorocarbon group and silicon in the molecule. The adsorption film is fixed directly or indirectly to the surface of the lower electrode by a covalent bond, and includes an upper electrode formed by using conductive organic molecules on the insulating layer.

In the above structure, the covalent bond is preferably a siloxane bond. Further, in the above configuration, it is preferable that the chemically adsorbed film is chemically bonded to the lower electrode surface via at least a siloxane-based monomolecular film.

In the above structure, the conductive organic molecule is preferably a molecule having a cyclic carbon structure.

In the above structure, the conductive molecule having a cyclic carbon structure is preferably made of at least one of 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 composed of a chemical adsorption film containing water-repellent groups and silicon in the molecule, and is fixed directly or indirectly to the surface of the lower electrode by covalent bonding. In addition, the provision of the upper electrode made of conductive molecules on the insulating layer makes it possible to realize a substantially pinhole-free high-capacity capacitor. In addition, by using a chemisorption film containing linear carbon chains for the insulating layer, the thickness of the insulating layer becomes a constant thickness of about the size of the atoms defined by the length of the chemisorbed single molecule, and 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 very small capacitor can be realized.

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

According to the preferred structure of the present invention in which the water-repellent group is a fluorine-containing hydrocarbon group, the chemically adsorbed film can maintain preferable insulating properties and water repellency. According to a preferred configuration of the present invention in which the conductive molecule is a molecule containing a cyclic carbon structure, the upper electrode made of a conductive molecule such as graphite containing a cyclic carbon structure is formed on the insulating layer. Even if there is a pinhole in the molecular order where the adsorbed monomolecule is missing in the chemisorbed monomolecular film, the cyclic carbon structure conductive molecule having a molecular size larger than that of the linear carbon chain remains in the molecular order pinhole. 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 leak current density decreases. In addition, the potential on the upper part of the insulating film composed of a chemisorbed monomolecular film is
The voltage is uniformly applied to the insulating layer because it is fixed by the conductive molecules including the cyclic carbon structure formed on the insulating film, and the withstand voltage is improved to a value specific to the insulating layer. A capacitor having good characteristics can be formed. Also, when a metal-insulating layer-metal (MIM) tunnel element having such a capacitor shape is formed, a pinhole-free insulating layer having a uniform thickness can be formed. Is determined by the patterning accuracy, thereby contributing to a reduction in variation in element characteristics.

Further, by selecting the conductive molecule having a cyclic carbon structure from at least one of alkyl-substituted oligothiophene, polypyrrole, and polyaniline, preferable conductive characteristics can be obtained, and furthermore, generation of pinholes can be reduced.

Furthermore, the use of a chemically adsorbed monomolecular film composed of a linear carbon chain containing a water-repellent group prevents the penetration of moisture, and the use of a fluorinated hydrocarbon group as the water-repellent group results in leakage current. And the withstand voltage is also 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 monomolecular film is fixed to at least one superconducting electrode by chemical bonding,
The mechanical strength is high, and film peeling due to stress is unlikely to occur.

[0015]

The present invention will be described more specifically 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. Further, the monomolecular film obtained in this manner is called a chemisorption monomolecular film. Since the chemisorption monomolecular film is connected to the substrate surface through a strong chemical bond, the monomolecular film has an adhesive strength that generally does not peel unless the substrate surface is scraped off. In addition to such liquid phase adsorption,
There is also a method of chemisorption in the gas phase.

However, when a chemically adsorbed monomolecular film is used as an insulating film of a capacitor, the leakage current may sometimes be two to three orders of magnitude higher than that of a capacitor using a conventional PET film or the like. . In addition, the withstand voltage is 1
V or as low as V. This was probably due to the presence of pinholes of molecular order. 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. A lower electrode 2 is formed on a substrate 1,
An upper electrode 4 is formed thereover with an insulating layer 3 interposed therebetween, and cut out into a desired shape to form a capacitor 5. Insulating layer 3
Is a monomolecular film composed of a linear carbon chain containing a water-repellent group such as fluorine and silicon for chemically bonding, and chemically bonded to the lower electrode 2 by, for example, a siloxane bond or the like. 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 to the lower electrode. In addition, the chemisorption monomolecular film which is a material of the insulating layer of the present invention may be a monolayer film or a monomolecular accumulation film. In the case of a monomolecular accumulation film, the monolayer is chemically bonded between the accumulation layers. Is required.

There are various methods for performing chemisorption.
As an example, a 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 iodine-substituted carbon
The case will be described. Where n in the formula is an integer of 1 to 3
X is hydrogen, lower alkyl group or lower alkoxy group
And A represents a lower alkyl group. The above silane type
Of the surfactants, chlorosilane-based surfactants are
Performs chemisorption reaction and ensures formation of chemisorption monolayer
Is preferred. Even among chlorosilane-based surfactants
Is a trichlorine-silicon chemical bond (ie, n in the formula is 3)
And between adsorbed molecules via a siloxane bond
No. In addition, the silane-based surfactant used in the present invention has an absorption property.
In order to improve the deposition molecular density, a straight chain is preferable. concrete
CH_Three-(R)_m-SiCl_nX_3-n, CF_Three−
(CF_Two)_p-(R)_m-SiCl_nX_3-nRepresented by
Chlorosilane-based surfactants are preferred. Where p is
0 or an integer, m is 0 or 1, R is a group having 1 or more carbon atoms.
A methylene group having 1 or more carbon atoms, such as a tylene group and a vinylene-containing group,
Methylene group having 1 or more carbon atoms in silicon-containing atoms or acid-containing
Any of methylene groups having 1 or more carbon atoms of an element atom, X is hydrogen
Atom, lower alkyl group or lower alkoxy group, n is 1
-3. More specifically, for example, CH_Three(CH
_Two)₉SiCl_Three, CH_Three(CH_Two)_FifteenSiCl_Three, C
H_ThreeCH_TwoO (CH_Two)_FifteenSiCl_Three, CH_Three(C
H_Two)_TwoSi (CH_Three)_Two(CH_Two)_FifteenSiCl_Three, C
F_Three(CF_Two)₇(CH_Two)_TwoSiCl_Three, CF_ThreeCH
_TwoO (CH_Two)_FifteenSiCl_Three, CF_Three(CH_Two)_TwoSi
(CH_Three) _Two(CH_Two)_FifteenSiCl_Three, F (CF_Two)_Four
(CH_Two)_TwoSi (CH_Three)_Two(CH_Two)₉SiC
l_Three, CF_ThreeCOO (CH_Two)_FifteenSiCl_Three, CF
_Three(CF_Two) _Five(CH_Two)_TwoSiCl_ThreeEtc.
You. When the R group in the above formula contains a vinylene group,
Unsaturated bonds are polymerized by medium, light or irradiation of high energy rays.
By bonding, a single molecule that is stronger
It is preferable because it becomes a film. The fluorinated carbon silane
Use of a surfactant has a large water-repellent effect and electrical insulation properties
Is also preferable because it is also good. In particular, chlorsila
When using surfactants, surfactants and water
Generally forms a chemisorbed monolayer due to the high reactivity of
And then clean the chemisorbed monolayer without contacting it with moisture.
Need to be If this washing step is not performed, unreacted
The silane-based surfactant reacts with moisture to become cloudy,
It becomes contaminants (contaminants) and adheres to
Cause of characteristic deterioration such as increase of
Become. In addition, these surfactants can be used in non-aqueous organic solvents.
It is necessary to dissolve, for example, such a solvent
Cyclohexane, n-hexadecane, toluene, xylene
, Dicyclohexyl, carbon tetrachloride, chloroform, etc.
They may be used alone or in combination. Chlorsilane-based
In the case of an outside silane-based surfactant, besides this, for example,
Methyl alcohol, ethyl alcohol and the like can also be applied.

Further, the chemically adsorbed monomolecular film used as the insulating film of the capacitor of the present invention is obtained by bringing a material containing a chlorine-silicon chemical bond into contact with the surface of the lower electrode 2 and then containing an unreacted chlorine-silicon chemical bond. The substance is washed and reacted with water to form a chemisorption monolayer having a silanol group on the surface of the lower electrode 2, or a chemisorption monolayer obtained by repeating this chemisorption monolayer formation process a plurality of times. Is obtained. Alternatively, when a method of chemically adsorbing a silane-based surfactant containing fluorocarbon after forming a chemisorption monomolecular film in this manner is adopted, the lower electrode 2 having a small number of hydrophilic groups exposed on the surface is used. However, it is preferable because a silane-based surfactant containing a water-repellent group can be chemically adsorbed at a high density. 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 high density. Wherein n is an integer, l and m are integers from 1 to 3, k is an integer from ^{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, when SiCl ₄ is used as a substance containing a chlorine-silicon chemical bond, the effect of uniformly hydrophilizing the surface of the lower electrode 2 is preferable because the molecules are small and the activity for hydroxylation is large.

The chemically adsorbed monomolecular film used in the capacitor of the present invention may be a monolayer film or a monomolecular accumulation film. In the case of a monomolecular accumulation film, the monolayer is chemically bonded between the accumulation layers. Is required.

Next, a specific example of a method for manufacturing the insulating layer 3 will be described. Embodiment 1 FIG. 2 is a process sectional view showing an example of a manufacturing process of the capacitor of the present invention. As the substrate 11, a PET film having a thickness of 1 μm is used. A lower electrode 12 is formed on a substrate 11 by forming an Al thin film having a thickness of 100 nm by an electron beam evaporation method or the like. 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. Thereafter, the PET film of the substrate 11 is passed through pure water and then sufficiently dried to form hydroxyl groups 14 on the surface of the lower electrode 12, and the following chemical adsorption treatment is performed. CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si as a substance containing a fluorocarbon group and a chlorine-silicon chemical bond
Cl ₃ is used as the chemical adsorbent 15 and the non-aqueous solvent 8
0wt% cyclohexane, 12wt% carbon tetrachloride, 8w
A solution of 10% by weight dissolved in 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, the chlorine of the -SiCl group of the substance containing the fluorocarbon group and the chlorine-silicon chemical bond and the hydroxyl group undergo a dehydrochlorination reaction to form a lower hydrochloric acid. The bond shown in (Formula 1) is formed over the entire surface of the electrode 12, and the fluorine-containing monomolecular film 2 is chemically bonded to the surface of the lower electrode 12, and as shown in FIG. Then, an insulating layer 13 as a chemically adsorbed monomolecular film was formed via the siloxane bond 18.

[0022]

Embedded image

The thickness of the insulating layer 13 is about 15 angstroms (1.5 nm) from the molecular structure. Note that the monomolecular film was extremely strongly chemically bonded, and thus did not peel off at all.

Embodiment 2 FIG. 3 is a process sectional view showing a second embodiment of the manufacturing process of the capacitor of the present invention. A substrate 11 and a lower electrode 12,
The surface treatment and the like are the same as in the specific example 1. After sufficient drying, the following chemical adsorption treatment is performed.

As a substance containing a trichlorosilyl bond, S
When the substrate 11 is immersed for about 30 minutes in a solution in which iCl ₄ is dissolved in chloroform solvent of a non-aqueous solvent at 1% by weight, the hydroxyl group 14 and the trichlorosilyl group formed on the surface of the lower electrode 12 as shown in FIG. A dehydrochlorination reaction occurred with a chlorine atom of the substance 21 containing chlorosilyl, and a chlorosilyl monomolecular film 22 of a substance containing a trichlorosilyl group was formed. As described above, SiCl is used as a substance containing a trichlorosilyl group.
_{If 4} is used, a small amount of OH groups 13
Even if only such a compound exists, a dehydrochlorination reaction occurs on the surface of the lower electrode 12, and the molecule is fixed to the surface via a -SiO- bond as shown in (Chem. 2).

[0026]

Embedded image

At this time, generally, unreacted SiCl ₄
Is also present on the chlorosilyl monomolecular film, and then washed with a non-aqueous solvent of chloroform and further washed with water to obtain SiC that has not reacted with hydroxyl groups on the surface of the lower electrode 12.
l ₄ molecules are removed, the lower electrode 12 as shown in FIG. 4
A siloxane monomolecular film 24 of (Chemical Formula 3) or the like is obtained on the surface of.

[0028]

Embedded image

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

Next, when the substrate 11 having the siloxane monomolecular film 24 formed on the surface of the lower electrode 12 is immersed in the solution described in the first embodiment for about 1 hour, the surface of the siloxane monomolecular film 24 is 4) is generated, and as shown in FIG. 5, a chemically adsorbed monomolecular film 25 containing fluorine is formed in a state of being chemically bonded to the lower siloxane monomolecular film 24,
The insulating layer 23 has a thickness of about 20 over the entire surface of the lower electrode 12.
Angstrom film thickness was formed.

[0031]

Embedded image

The insulating layer 23 did not peel off at all even when a peeling test was performed. Further, in the specific example 1, the case of one monomolecular film was shown, and in the specific example 2, the case of accumulating a fluorine-containing silane-based surfactant layer after the siloxane monomolecular film was shown. The effect is not changed even if the chemisorption monomolecular film of the invention is accumulated not only in one layer but also in multiple layers.

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

The fluorocarbon surfactants described above
Other than CF_ThreeCH_TwoO (CH_Two)_FifteenSiC
l_Three, CF_Three(CH_Two)_TwoSi (CH_Three)_Two(CH_Two)
_FifteenSiCl_Three, F (CF_Two)_Four(CH_Two)_TwoSi (CH
_Three)_Two(CH_Two)₉SiCl_Three, CF_ThreeCOO (C
H_Two)_FifteenSiCl_Three, CF_Three(CF_Two)_Five(CH_Two)_Two
SiCl_ThreeStarting with trichlorosilane surfactants such as
For example, CF_ThreeCH_TwoO (CH_Two)_FifteenSi (CH_Three)_TwoC
1, CF_Three(CH_Two)_TwoSi (CH_Three)_Two(CH_Two)_Fifteen
Si (CH_Three)_TwoCl, CF_ThreeCH_TwoO (CH_Two)_FifteenS
i (CH_Three) Cl_Two, CF_ThreeCOO (CH_Two)_FifteenSi
(CH_Three)_TwoUses chlorosilane surfactants such as Cl
did it. Also CF_Three(CF_Two)₇(CH_Two)_TwoSi (OC
H_Three)_Three, CF_ThreeCH_TwoO (CH_Two)_FifteenSi (OC
H_Three)_ThreeAlkoxysilane-based surfactants such as
A similar effect was obtained by heating the solution.
CH_Three(CH_Two) ₉SiCl_Three, CH_Three(CH_Two)_FifteenS
iCl_Three, CH_ThreeCH_TwoO (CH_Two)_FifteenSiCl_Three, C
H_Three(CH_Two)_TwoSi (CH_Three)_Two(CH_Two)_FifteenSiC
l_ThreeChlorosilane-based surfactants containing hydrocarbon groups such as
However, a chemically adsorbed monolayer is formed at room temperature
A simple insulating layer can be formed.

Next, a method of 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 device, evacuated, and then, in a helium atmosphere with a degree of vacuum of about 100 Torr, an electric current is caused to flow between two graphite rods to cause arc discharge. Then, an upper electrode 4 made of a graphite thin film is formed on the insulating layer 3. This is fine, but A
The upper electrode may be formed by stacking thin films and vacuum depositing them. When the graphite thin film is formed in this manner, the leak current density is reduced by about one digit or more compared to a capacitor in which a metal thin film such as Al is directly deposited on the insulating layer 3 and is 2 × 10 ⁻¹¹ A / m 2.
values less than m ² were obtained. The withstand voltage was about 4 V, about 1 V higher than that of the capacitor in which the Al upper electrode was formed by the vacuum evaporation method. This is because the conductive molecules 34 having a cyclic carbon structure, such as graphite, cannot easily enter the molecular order pinholes 35 of the chemically adsorbed monomolecular film due to their large molecular size, and short-circuits at the pinholes It is considered that the leak current was effectively reduced.
Further, in the graphite film formed as described above, there are fullerenes such as C ₆₀ and C _70, which are, in sizes of ten Angstroms, more steric hindrance increases, the molecular pinholes It is considered difficult to enter and is desirable as the upper electrode of the capacitor.

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

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

Further, when polypyrrole or polyaniline is used as the conductive molecule having a cyclic carbon structure of the upper electrode material, a diluted aqueous solution obtained by mixing 30% by weight of FeCl ₃ as an oxidizing agent with polyvinyl alcohol (PVA) is chemically adsorbed. After thinly coating and drying the insulating layer 3 made of a monomolecular film, a pyrrole vapor or an aniline vapor is brought into contact, and the monomer vapor is polymerized to form an upper electrode as a polymer. In this case, it is desirable that the terminal of the insulating layer 3 on the upper electrode side of the chemically adsorbed monomolecular film has a hydroxyl group and a hydrophilic surface. In this case, PV
Since the A- FeCl ₃ thin film is a high-resistance layer, characteristics of the layer vary, so that it is preferable to be as thin as possible. Although the leakage current and insulation withstand voltage of the capacitor thus produced varied slightly, they were almost the same as those using the graphite thin film for the upper electrode.

[0039]

As described above, in the capacitor of the present invention, the chemically adsorbed monomolecular film chemically bonded to the lower electrode is used for the insulating layer, so that the capacitor is mechanically stable and strong. Further, since the thickness of the chemisorption monomolecular film is uniform in the molecular order, a small and lightweight capacitor with little characteristic variation can be realized. Furthermore, since the upper electrode is made of a conductive molecule containing a cyclic carbon structure having a molecular size larger than that of the chemisorbed monomolecule, the leakage current density of the capacitor is reduced, the dielectric strength is increased, and the insulating layer made of a chemisorbed monomolecular film is used. Capacitors utilizing the above characteristics can be manufactured easily and with high yield.

[Brief description of the drawings]

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

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

FIG. 3 is a conceptual view of a sectional process 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 symbols]

 DESCRIPTION OF SYMBOLS 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 monomolecular film 25 Fluorine Includes chemisorbed monolayer 34 Conductive molecule containing cyclic carbon structure 35 Pinhole

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 4/00-4/40

Claims (5)

(57) [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 is a hydrocarbon.
A chemically adsorbed film made of a substance having a water-repellent group or a fluorocarbon group and silicon in the molecule, wherein the chemisorbed film is directly or indirectly fixed to the surface of the lower electrode by a covalent bond. A capacitor comprising: an upper electrode formed on the insulating layer by using a conductive organic molecule. 2. The capacitor according to claim 1, wherein the covalent bond is a siloxane bond. 3. The capacitor according to claim 2, wherein the chemical adsorption film is chemically bonded to the lower electrode surface via at least a siloxane-based monomolecular film. 4. The capacitor according to claim 1, wherein the conductive organic molecule is a molecule containing a cyclic carbon structure. 5. The conductive organic molecule containing a cyclic carbon structure,
The capacitor according to claim 4 , comprising at least one of an alkyl-substituted oligothiophene, polypyrrole, and polyaniline.