JP2008258421A - Organic photoelectric conversion element, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an organic photoelectric conversion element wherein the orientation in a photoelectric conversion layer is highly controlled, and to provide an imaging element into which the organic photoelectric conversion element is integrated. <P>SOLUTION: In the method for manufacturing the organic photoelectric conversion element wherein a layer containing an organic compound having light conductivity is arranged between a pair of electrodes, vapor phase epitaxy is performed while controlling a part or all of the layer containing the organic compound having light conductivity at a substrate temperature of 60°C to 250°C, and the organic compound is a quinacridone-based colorant which improves the orientation of molecules. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic photoelectric conversion element, a method for producing the organic photoelectric conversion element, and an imaging element.

  In JP-A-6-326338, a method for improving the efficiency of photocharge generation and carrier mobility by spontaneously polarizing an organic material forming a photoelectric conversion layer using corona discharge and increasing the orientation of organic molecules. However, the effect is insufficient and the photoelectric conversion efficiency is only about 2%.

  In Japanese Patent Application Laid-Open No. 2005-235923, in an organic thin film transistor having a substrate and an organic semiconductor layer containing a fluorinated acene compound having a specific structure, the temperature of the substrate is controlled in a specific range according to a specific compound, A method is described for forming the organic semiconductor layer in which a compound is vacuum deposited on the substrate. As the fluorinated acene compound having a specific structure, tetradecafluoropentacene and dodecafluoronaphthacene are described. In the case of tetradecafluoropentacene, the temperature of the substrate is controlled to 30 ° C. or more and 65 ° C. or less, dodecafluoronaphthacene, In this case, it is described that an organic thin film transistor having high carrier mobility can be produced by controlling the temperature of the substrate to 24 ° C. or more and 60 ° C. or less, but there is no description about a photoelectric conversion element.

  In JP 2002-76027 A, when forming a photoelectric conversion layer of an organic photoelectric conversion element that can be used for a solar cell or the like, two kinds of organic materials, specifically metal-free phthalocyanine, are changed while changing the temperature of the substrate. And perylene pigment are co-evaporated, but there is no description of the relationship with carrier mobility.

The organic photoelectric conversion element has a drawback that the photoelectric conversion efficiency is lower than that of a silicon-based inorganic photoelectric conversion element. One of the reasons is that the carrier mobility is low, so that most of the carriers generated by charge separation following light absorption disappear by recombination before reaching the electrode, and the signal current Could not be read as. The technique for improving the carrier mobility is one of the important techniques for improving the performance of the organic photoelectric conversion element, and further improvement is required.
JP-A-6-326338 JP 2005-235923 A JP 2002-76027 A

  An object of the present invention is to provide a method for improving the carrier mobility of an organic film (layer) of an organic photoelectric conversion element, and to provide a method for producing an organic photoelectric conversion element in which the orientation of the photoelectric conversion layer is highly controlled. That is.

The above problems have been solved by the following means.
(1) In the method for manufacturing an organic photoelectric conversion element in which a layer containing a photoconductive organic compound is disposed between a pair of electrodes, a part of the layer containing the photoconductive organic compound, or A method for producing an organic photoelectric conversion element, characterized by performing vapor phase growth while controlling all of the substrate temperature at 60 ° C to 250 ° C.
(2) The method for producing an organic photoelectric conversion element according to (1), wherein the organic compound having photoconductivity is a quinacridone dye.
(3) In an organic photoelectric conversion element in which a layer containing a photoconductive organic compound is disposed between a pair of electrodes, a part or all of the layer containing the photoconductive organic compound is oriented. Organic photoelectric conversion element characterized by being made.
(4) The organic photoelectric conversion element according to (3), wherein the organic compound having photoconductivity is a quinacridone dye.
(5) When the layer containing the organic compound having photoconductivity is measured by X-ray diffraction with respect to the layer containing the organic compound, the diffraction angle 2θ is around 11 degrees, around 23 degrees, around 29 degrees. The organic photoelectric conversion device according to (3) or (4), which has a strong X-ray diffraction peak.

(6) A layer made of an organic compound or an inorganic substance that does not substantially absorb light is disposed between the layer containing the photoconductive organic compound and at least one of the pair of electrodes. The organic photoelectric conversion device according to any one of (3) to (5).
(7) The electric field applied to the organic photoelectric conversion element via the pair of electrodes is 1.0 × 10 ⁴ V / cm to 1.0 × 10 ⁷ V / cm (3) to (6) ) The organic photoelectric conversion element according to any one of the above.
(8) An imaging device comprising the organic photoelectric conversion device according to any one of (3) to (6).

  1st aspect of this invention contains the organic compound which has this photoconductivity in the manufacturing method of the organic photoelectric conversion element which has arrange | positioned the layer containing the organic compound which has photoconductivity between a pair of electrodes. It is a method for producing an organic photoelectric conversion element, characterized in that a part or all of a layer (organic layer) is vapor-phase grown while controlling the substrate temperature at 60 to 250 ° C.

According to a second aspect of the present invention, in an organic photoelectric conversion element in which a layer containing an organic compound having photoconductivity is disposed between a pair of electrodes, a layer containing an organic compound having photoconductivity (organic Part or all of the layer) is highly oriented, and is an organic photoelectric conversion element.
(Organic layer orientation control)
In the present invention, the orientation control described below can be applied.

  In the present invention, the orientation of the organic compound is preferably ordered as compared to a random state. If it is not random, the degree of order may be low or high, but high order is preferable.

  In a photoelectric conversion film having a p-type semiconductor layer, an n-type semiconductor layer (preferably a mixed / dispersed (bulk heterojunction structure) layer) between a pair of electrodes, at least one of the p-type semiconductor and the n-type semiconductor The case of a photoelectric conversion film containing an organic compound whose orientation is controlled in the direction is preferred, and the case where an organic compound whose orientation is controlled (possible) is contained in both the p-type semiconductor and the n-type semiconductor is more preferred.

  As the organic compound used in the organic layer of the photoelectric conversion element, those having π-conjugated electrons are preferably used, and the π-electron plane is oriented at a certain angle with respect to the substrate (electrode substrate). Is preferred. Since X-ray diffraction measurement is performed on the layer containing the organic compound, the quinacridone dye has strong X-ray diffraction peaks at diffraction angles 2θ of around 11 degrees, 23 degrees, and 29 degrees. Arise.

  As described above, the organic compound layer whose orientation is controlled may be partially included in the entire organic layer. Preferably, the proportion of the portion where the orientation is controlled with respect to the entire organic layer is 10% or more, more preferably 30% or more, more preferably 50% or more, further preferably 70% or more, and particularly preferably 90%. Above, most preferably 100%. Such a state compensates for the shortcoming of the short carrier diffusion length of the organic layer by controlling the orientation of the organic compound in the organic layer in the photoelectric conversion film, and improves the photoelectric conversion efficiency.

  The orientation of the organic compound can be controlled by selecting the substrate and adjusting the deposition conditions. In the present invention, the substrate temperature is highly oriented by a method for producing an organic photoelectric conversion layer that is vapor-phase grown while controlling the substrate temperature at 60 ° C. to 250 ° C., preferably 60 ° C. to 190 ° C., more preferably 80 ° C. to 180 ° C. The obtained organic photoelectric conversion layer is obtained.

As a result of vapor phase growth while controlling the substrate temperature to 60 ° C. to 250 ° C. when quinacridone is used as the organic compound, in the X-ray diffraction pattern, at 150 ° C., the diffraction angle 2θ is around 11 degrees and around 23 degrees. , And a strong X-ray diffraction peak appears around 29 degrees. This indicates that quinacridone is highly oriented with respect to the substrate. This phenomenon is also observed with quinacridone pigments other than quinacridone.
(Formation method of the organic layer of the present invention)
The layer containing the organic compound is formed by a vacuum deposition method.

  The vacuum deposition method is basically based on the heating method of the compound such as resistance heating deposition method and electron beam heating deposition method, the shape of the deposition source such as crucible and boat, vacuum degree, deposition temperature, substrate temperature, deposition rate, etc. It is a parameter. In order to make uniform deposition possible, it is preferable to perform deposition by rotating the substrate. It is preferable that all steps during the vapor deposition are performed in a vacuum, and basically the compound is not directly in contact with oxygen and moisture in the outside air. In the present invention, the degree of vacuum and the substrate temperature are important among the above parameters.

  Vapor phase growth is preferably performed while the substrate temperature is controlled in the range of 60 ° C. to 250 ° C., the substrate temperature is more preferably controlled in the range of 60 ° C. to 190 ° C., and the substrate temperature is controlled in the range of 80 ° C. to 180 ° C. More preferably, the substrate temperature is particularly preferably controlled in the range of 130 ° C to 170 ° C.

The degree of vacuum is preferably higher, and vacuum deposition is performed at 1.33 × 10 ⁻² Pa (10 ⁻⁴ Torr) or less, preferably 1.33 × 10 ⁻⁴ Pa (10 ⁻⁶ Torr) or less. The above-described conditions for vacuum deposition need to be strictly controlled because they affect the crystallinity, amorphousness, density, density, etc. of the organic film. It is preferable to use PI or PID control of the deposition rate using a film thickness monitor such as a quartz crystal resonator or an interferometer. When two or more kinds of compounds are vapor-deposited simultaneously, a co-evaporation method, a flash vapor deposition method, or the like can be preferably used.

  The substrate may be a transparent substrate, an opaque substrate, or a semi-transparent substrate, and transparent quartz glass, transparent crystallized glass, or the like is preferably used as the transparent substrate.

  It is preferable to use a quinacridone dye as the organic compound. Preferred quinacridone dyes are compounds represented by the following general formula (I).

式中、環Ａは、

Wherein ring A is

を表し、ｎ１は０または１を表す。但しｎ１が０の時、環Ａが表す部分はビニル基を表す。環Ａはさらに置換基を有してもよい。Ｒ¹、Ｒ²は各々独立に水素原子、アルキル基、アリール基、またはヘテロ環基を表す。Ｒ³、Ｒ⁴は各々独立に置換基を表し、ｍ１、ｍ２は各々独立に０ないし４の整数を表す。ｍ１、ｍ２が２ないし４の整数の場合、複数のＲ³、Ｒ⁴は同じでも異なっていてもよく、また互いに連結して環を形成してもよい。

N1 represents 0 or 1. However, when n1 is 0, the portion represented by ring A represents a vinyl group. Ring A may further have a substituent. R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. R ³ and R ⁴ each independently represent a substituent, and m1 and m2 each independently represents an integer of 0 to 4. When m1 and m2 are integers of 2 to 4, a plurality of R ³ and R ⁴ may be the same or different, and may be connected to each other to form a ring.

Examples of the substituent represented by R ³ and R ⁴ in formula (I) include an alkyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms). For example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 2 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 2 carbon atoms). 30, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include propargyl, 3-pentynyl and the like. ), An aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl, and anthranyl). An amino group (an amino group that can be substituted with an alkyl group, an aryl group, or a heterocyclic group, preferably 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 10 carbon atoms. , Methylamino, dimethylamino, diethylamino, dibenzylamino, diphenylamino, ditolylamino, etc.), an alkoxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 carbon atom). -10, for example, methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc. ), An aryloxy group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy and the like. And a heteroaryloxy group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy and the like. An acyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl). Alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferred) Ku is a 2 to 12 carbon atoms, such as methoxycarbonyl and ethoxycarbonyl. ), An aryloxycarbonyl group (preferably having a carbon number of 7 to 30, more preferably a carbon number of 7 to 20, particularly preferably a carbon number of 7 to 12, such as phenyloxycarbonyl), an acyloxy group (preferably Has 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetoxy and benzoyloxy.), An acylamino group (preferably 2 to 30 carbon atoms, More preferably, it has 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino, benzoylamino and the like, and an alkoxycarbonylamino group (preferably 2 to 30 carbon atoms, more preferably carbon atoms). 2 to 20, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino An aryloxycarbonylamino group (preferably having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino). A sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino and benzenesulfonylamino), a sulfamoyl group (Preferably having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 12 carbon atoms. Examples thereof include sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and phenylsulfamoyl. ), A carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably A prime number of 1-20, particularly preferably a carbon number of 1-12, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc., an alkylthio group (preferably having a carbon number of 1-30, more preferably a carbon number). 1 to 20, particularly preferably 1 to 12 carbon atoms, for example, methylthio, ethylthio, etc.), arylthio groups (preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably carbon atoms). And a heterocyclic group-substituted thio group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). For example, pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazoly Lucio etc. are mentioned. ), A sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms such as mesyl and tosyl), a sulfinyl group (preferably carbon). 1 to 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 30 carbon atoms, more Preferably it is C1-C20, Most preferably, it is C1-C12, for example, ureido, methylureido, phenylureido etc. are mentioned), phosphoric acid amide group (preferably C1-C30, more preferably It has 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms. Examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group Group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom, specifically, for example, imidazolyl, pyridyl and quinolyl. , Furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl group, azepinyl group, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms). Particularly preferably having 3 to 24 carbon atoms, such as trimethylsilyl, Such as Li triphenylsilyl and the like.) And the like. These substituents may be further substituted.

The substituent represented by R ¹ and R ² is an alkyl group, an aryl group, or a heterocyclic group, and more preferably, the alkyl described in the examples of the substituent represented by R ³ , R ⁴ , R ⁵ , and R ⁶ described above. Group, aryl group, and heterocyclic group. R ¹ and R ² are preferably a hydrogen atom, an alkyl group, or an aryl group, more preferably a hydrogen atom or an alkyl group, and particularly preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

Ring A is preferably a benzene ring, and n1 and n2 are preferably 1. The substituent represented by R ³ and R ⁴ is preferably a halogen atom, an alkyl group, an alkoxy group, an aryl group, or a heterocyclic group, and more preferably the substituent represented by the aforementioned R ³ , R ⁴ , R ⁵ , or R ^6. A halogen atom, an alkyl group, an alkoxy group, an aryl group, or a heterocyclic group described in the example of the group, and R ³ , R ⁴ , R ⁵ , and R ⁶ are preferably a halogen atom, an alkyl group, or an alkoxy group; More preferred is a halogen atom or an alkyl group, and particularly preferred is an alkyl group. Each of m1 and m2 is preferably 0 or 1.

  The compounds represented by formula (I) preferably used in the present invention are shown below, but the present invention is not limited to these.

［有機層］
本発明における光導電性を有する有機化合物を含む有機層（有機膜）について説明する。
本発明の有機層からなる電磁波吸収／光電変換部位は１対の電極に挟まれた有機層から成る。有機層は電磁波を吸収する部位、光電変換部位、電子輸送部位、正孔輸送部位、電子ブロッキング部位、正孔ブロッキング部位、結晶化防止部位、電極ならびに層間接触改良部位等の積み重ねもしくは混合から形成される。

[Organic layer]
The organic layer (organic film) containing the photoconductive organic compound in the present invention will be described.
The electromagnetic wave absorption / photoelectric conversion site comprising the organic layer of the present invention comprises an organic layer sandwiched between a pair of electrodes. The organic layer is formed by stacking or mixing parts that absorb electromagnetic waves, photoelectric conversion parts, electron transport parts, hole transport parts, electron blocking parts, hole blocking parts, crystallization prevention parts, electrodes and interlayer contact improvement parts, etc. The

  The organic layer preferably contains an organic p-type compound or an organic n-type compound.

  The organic layer preferably contains an organic p-type semiconductor (compound) and an organic n-type semiconductor (compound), and any of these may be used. Further, it may or may not have absorption in the visible and infrared regions, but it is preferable to use at least one compound (organic dye) having absorption in the visible region. Further, a colorless p-type compound and an n-type compound may be used, and an organic dye may be added thereto.

  In the case of a three-layer structure of p-type layer / bulk heterojunction layer / n-type layer, the p-type or n-type semiconductor (compound) on the incident light side is preferably colorless.

  The organic p-type semiconductor (compound) is a donor-type organic semiconductor (compound), which is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. Not limited to this, as described above, any organic compound having an ionization potential smaller than that of the organic compound used as the n-type (acceptor property) compound may be used as the donor organic semiconductor.

  Organic n-type semiconductors (compounds) are acceptor organic semiconductors (compounds), which are mainly represented by electron-transporting organic compounds and refer to organic compounds that easily accept electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (E.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, Benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxa Azoles, imidazopyridines, pyralidines, pyrrolopyridines, thiadiazolopyridines, dibenzazepines, tribenzazepines, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds as ligands Etc. Note that the present invention is not limited thereto, and as described above, any organic compound having an electron affinity higher than that of the organic compound used as the donor organic compound may be used as the acceptor organic semiconductor.

  Any organic dye may be used for the organic layer, but a p-type organic dye or an n-type organic dye is preferred. Any organic dye may be used, but preferably a cyanine dye, styryl dye, hemicyanine dye, merocyanine dye (including zero methine merocyanine (simple merocyanine)), trinuclear merocyanine dye, tetranuclear merocyanine dye, Rhodocyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye, azamethine dye, coumarin dye, arylidene dye, anthraquinone dye, triphenylmethane dye, azo dye, azomethine dye , Spiro compounds, metallocene dyes, fluorenone dyes, fulgide dyes, perylene dyes, perinone dyes, phenazine dyes, phenothiazine dyes, quinone dyes, diphenylmeta Dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye (said quinacridone dye), quinophthalone dye, phenoxazine dye, phthaloperylene dye, diketopyrrolopyrrole dye, dioxane dye, porphyrin dye, chlorophyll dye, phthalocyanine dye , Metal complex dyes, or condensed aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, etc.).

The film formed by the organic dye preferably exhibits a strong X-ray diffraction peak at a specific angle with respect to the diffraction angle 2θ.
[Electron transporting materials]
In the photoelectric conversion film of the present invention, the organic material (n-type compound) having an electron transporting property preferably has an ionization potential larger than 6.0 eV, and more preferably represented by the following general formula (X).

Formula (X) L- (A) m
(In the formula, A represents a heterocyclic group in which two or more aromatic heterocycles are condensed, and the heterocyclic group represented by A may be the same or different. M is 2 or more (preferably 2 to 8). ) Represents an integer, and L represents a linking group.)
Details and preferred ranges of these organic materials having electron transport properties are described in detail in Japanese Patent Application No. 2004-082002.

When these electron transporting organic materials are used, the photoelectric conversion efficiency of the obtained photoelectric conversion film is remarkably increased.
(Formation method of organic layer other than the present invention)
The layer containing an organic compound other than the present invention is formed by a dry film formation method or a wet film formation method. Specific examples of the dry film forming method include a vacuum vapor deposition method, a sputtering method, an ion plating method, a physical vapor deposition method such as an MBE method, or a CVD method such as plasma polymerization. As the wet film forming method, a casting method, a spin coating method, a dipping method, an LB method, or the like is used.

  In the case of using a polymer compound as at least one of the p-type semiconductor (compound) or the n-type semiconductor (compound), it is preferable to form the film by a wet film forming method that is easy to create. When a dry film formation method such as vapor deposition is used, it is difficult to use a polymer because it may be decomposed, and an oligomer thereof can be preferably used instead.

On the other hand, in the present invention, when a low molecule is used, a dry film forming method is preferably used, and a vacuum deposition method is particularly preferably used. The vacuum deposition method is basically based on the method of heating compounds such as resistance heating deposition method and electron beam heating deposition method, shape of deposition source such as crucible and boat, degree of vacuum, deposition temperature, base temperature, deposition rate, etc. It is a parameter. In order to make uniform deposition possible, it is preferable to perform deposition by rotating the substrate. The higher the degree of vacuum is, preferably 1.33 × 10 ⁻² Pa (10 ⁻⁴ Torr) or less, preferably 1.33 × 10 ⁻⁴ Pa (10 ⁻⁶ Torr) or less, particularly preferably 1.33 × 10 ⁻ Vacuum deposition is performed at ⁶ Pa (10 ⁻⁸ Torr) or less. It is preferable that all steps during the vapor deposition are performed in a vacuum, and basically the compound is not directly in contact with oxygen and moisture in the outside air. The above-described conditions for vacuum deposition need to be strictly controlled because they affect the crystallinity, amorphousness, density, density, etc. of the organic film. It is preferable to use PI or PID control of the deposition rate using a film thickness monitor such as a quartz crystal resonator or an interferometer. When two or more kinds of compounds are vapor-deposited simultaneously, a co-evaporation method, a flash vapor deposition method, or the like can be preferably used.
[Organic dye layer thickness regulation]
When the photoelectric conversion film of the present invention is used as a color image sensor (image sensor), the light absorption rate of each of the organic dye layers of the B, G, and R layers is preferably 50% or more, more preferably 70% or more, and particularly preferably. Is preferably 90% (absorbance = 1) or more, most preferably 99% or more in order to improve the photoelectric conversion efficiency. Therefore, in terms of light absorption, the larger the thickness of the organic dye layer, the better. However, considering the ratio contributing to charge separation, the thickness of the organic dye layer in the present invention is preferably 30 nm or more and 300 nm or less, more preferably It is 50 nm or more and 250 nm or less, particularly preferably 60 nm or more and 200 nm or less, and most preferably 80 nm or more and 130 nm or less.
[Voltage application]
When a voltage is applied to the photoelectric conversion film of the present invention via a pair of electrodes, it is preferable in that the photoelectric conversion efficiency is improved. The applied voltage may be any voltage, but the required voltage varies depending on the film thickness of the photoelectric conversion film. That is, the photoelectric conversion efficiency improves as the electric field applied to the photoelectric conversion film increases, but the applied electric field increases as the film thickness of the photoelectric conversion film decreases even at the same applied voltage. Therefore, when the photoelectric conversion film is thin, the applied voltage may be relatively small. The electric field applied to the photoelectric conversion film is preferably 10 ⁻² V / cm or more, more preferably 10 V / cm or more, further preferably 1 × 10 ³ V / cm or more, and particularly preferably 1 × 10 ⁴ V / cm. As described above, it is most preferably 1 × 10 ⁵ V / cm or more. There is no particular upper limit, but if an electric field is applied too much, an electric current flows even in a dark place, which is not preferable. Therefore, it is preferably 1 × 10 ¹⁰ V / cm or less, and more preferably 1 × 10 ⁷ V / cm or less.
[General requirements]
In the present invention, it is preferable to use a structure in which at least two photoelectric conversion films are laminated, more preferably three or four layers, and particularly preferably three layers.

  In the present invention, these photoelectric conversion elements can be preferably used as imaging elements, particularly preferably as solid-state imaging elements. Moreover, in this invention, the case where a voltage is applied to these photoelectric conversion elements and an image pick-up element is preferable.

The photoelectric conversion element in the present invention is preferably a case where a p-type semiconductor layer and an n-type semiconductor layer have a photoelectric conversion film having a stacked structure between a pair of electrodes. Preferably, at least one of the p-type and n-type semiconductors contains an organic compound, and more preferably, both the p-type and n-type semiconductors contain an organic compound.
[Laminated structure]
As one preferable aspect of the present invention, when no voltage is applied to the photoelectric conversion film, it is preferable that at least two photoelectric conversion films are laminated. There are no particular limitations on the multilayer imaging device, and any of those used in this field can be applied. However, a BGR three-layer structure is preferable, and a preferred example of the BGR multilayer structure is shown in FIG.

  Next, the solid-state imaging device according to the present invention has, for example, a photoelectric conversion film as shown in this embodiment. In the solid-state imaging device as shown in FIG. 3, a stacked photoelectric conversion film is provided on the scanning circuit unit. The scanning circuit unit can appropriately adopt a configuration in which a MOS transistor is formed on a semiconductor substrate for each pixel unit, or a configuration having a CCD as an image sensor.

  For example, in the case of a solid-state imaging device using a MOS transistor, charges are generated in the photoelectric conversion film by incident light transmitted through the electrodes, and the charges are generated by an electric field generated between the electrodes by applying a voltage to the electrodes. It travels to the electrode through the photoelectric conversion film, and further moves to the charge storage part of the MOS transistor, and charges are stored in the charge storage part. The charge accumulated in the charge accumulation unit moves to the charge readout unit by switching of the MOS transistor, and is further output as an electric signal. Thereby, a full-color image signal is input to the solid-state imaging device including the signal processing unit.

  As these laminated image pickup devices, solid color image pickup devices represented by FIG. 2 of JP-A-58-103165, FIG. 2 of JP-A-58-103166, and the like can also be applied.

The method described in JP-A-2002-83946 (see FIGS. 7 to 23 and paragraph numbers 0026 to 0038 of the same publication) can be applied to the manufacturing process of the above-described multilayer image sensor, preferably a three-layer image sensor.
(Photoelectric conversion element)
The photoelectric conversion element of the preferable aspect of this invention is demonstrated below.

  The photoelectric conversion element of the present invention comprises an electromagnetic wave absorption / photoelectric conversion site and a charge accumulation / transfer / readout site for charges generated by photoelectric conversion.

  In the present invention, the electromagnetic wave absorption / photoelectric conversion site has a laminated structure of at least two layers capable of absorbing and photoelectrically converting at least blue light, green light, and red light. The blue light absorbing layer (B) can absorb light of at least 400 nm to 500 nm. The green light absorbing layer (G) can absorb light of at least 500 nm and 600 nm. The red light absorbing layer (R) can absorb light of at least 600 nm and 700 nm. The order of these layers may be any order, and in the case of a three-layer stacked structure, the order of BGR, BRG, GBR, GRB, RBG, and RGB is possible from the upper layer (light incident side). Preferably, the uppermost layer is G. In the case of a two-layer structure, when the upper layer is the R layer, the lower layer is the same BG layer, when the upper layer is the B layer, the lower layer is the same planar GR layer, and when the upper layer is the G layer, the lower layer is the same A BR layer is formed in a planar shape. Preferably, the upper layer is a G layer and the lower layer is a BR layer in the same plane.

  In the present invention, the charge accumulation / transfer / readout part is provided under the electromagnetic wave absorption / photoelectric conversion part. It is preferable that the electromagnetic wave absorption / photoelectric conversion site in the lower layer also serves as a charge storage / transfer / readout site.

  In the present invention, the electromagnetic wave absorption / photoelectric conversion site is composed of an organic layer, an inorganic layer, or a mixture of an organic layer and an inorganic layer. The organic layer may form a B / G / R layer, or the inorganic layer may form a B / G / R layer. A mixture of an organic layer and an inorganic layer is preferred. In this case, basically, when the organic layer is one layer, the inorganic layer is one or two layers, and when the organic layer is two layers, the inorganic layer is one layer. When the organic layer and the inorganic layer are one layer, the inorganic layer forms electromagnetic wave absorption / photoelectric conversion sites of two or more colors on the same plane. Preferably, the upper layer is an organic layer and is a G layer, and the lower layer is an inorganic layer and is an order of B layer and R layer from the top. In the case where the organic layer forms a B / G / R layer, a charge accumulation / transfer / readout portion is provided thereunder. When an inorganic layer is used as the electromagnetic wave absorption / photoelectric conversion site, this inorganic layer also serves as a charge accumulation / transfer / readout site.

  In the present invention, one particularly preferable aspect among the elements described above is as follows.

  This is a case where at least two electromagnetic wave absorption / photoelectric conversion sites are included, and at least one of these sites is the photoelectric conversion element (preferably an image sensor) of the present invention.

  Furthermore, it is preferable that the element has a laminated structure in which at least two electromagnetic wave absorption / photoelectric conversion sites have at least two layers. Furthermore, it is preferable that the upper layer is an element composed of a part capable of absorbing green light and performing photoelectric conversion.

  Particularly preferably, it has at least three electromagnetic wave absorption / photoelectric conversion sites, and at least one of them is the photoelectric conversion element (preferably an image sensor) of the present invention.

Furthermore, it is preferable that the upper layer is an element composed of a part capable of absorbing green light and performing photoelectric conversion. Further, at least two of the three electromagnetic wave absorption / photoelectric conversion sites are inorganic layers (preferably formed in a silicon substrate).
(electrode)
The electromagnetic wave absorption / photoelectric conversion site made of the organic layer of the present invention is sandwiched between a pair of electrodes, each of which forms a pixel electrode and a counter electrode. The lower layer is preferably a pixel electrode.

  The counter electrode is preferably a material that can take out holes from the hole transport photoelectric conversion film or the hole transport layer, and can use a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof. . The pixel electrode preferably takes out electrons from the electron-transporting photoelectric conversion layer or the electron-transporting layer. Selected in consideration of Specific examples of these include conductive metal oxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide (ITO), or metals such as gold, silver, chromium and nickel, and these metals and conductive metal oxides. Inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene and polypyrrole, silicon compounds and laminates of these with ITO, etc. In particular, ITO and IZO are preferable from the viewpoints of productivity, high conductivity, transparency, and the like. Although the film thickness can be appropriately selected depending on the material, it is usually preferably in the range of 10 nm to 1 μm, more preferably 30 nm to 500 nm, and still more preferably 50 nm to 300 nm.

  Various methods are used for manufacturing the pixel electrode and the counter electrode depending on the material. For example, in the case of ITO, electron beam method, sputtering method, resistance heating vapor deposition method, chemical reaction method (sol-gel method, etc.), dispersion of indium tin oxide A film is formed by a method such as application of an object. In the case of ITO, UV-ozone treatment, plasma treatment, etc. can be performed.

  In the present invention, it is preferable to produce the transparent electrode film free of plasma. By creating a transparent electrode film free from plasma, the influence of plasma on the substrate can be reduced, and the photoelectric conversion characteristics can be improved. Here, plasma free means that no plasma is generated during the formation of the transparent electrode film, or the distance from the plasma generation source to the substrate is 2 cm or more, preferably 10 cm or more, more preferably 20 cm or more. It means a state in which the plasma that reaches is reduced.

  Examples of an apparatus that does not generate plasma during the formation of the transparent electrode film include an electron beam vapor deposition apparatus (EB vapor deposition apparatus) and a pulse laser vapor deposition apparatus. Regarding EB deposition equipment or pulse laser deposition equipment, “Surveillance of Transparent Conductive Films” supervised by Yutaka Sawada (published by CMC, 1999), “New Development of Transparent Conductive Films II” supervised by Yutaka Sawada (published by CMC, 2002) ), "Transparent conductive film technology" by the Japan Society for the Promotion of Science (Ohm Co., 1999), and the references attached thereto, etc. can be used. Hereinafter, a method of forming a transparent electrode film using an EB vapor deposition apparatus is referred to as an EB vapor deposition method, and a method of forming a transparent electrode film using a pulse laser vapor deposition apparatus is referred to as a pulse laser vapor deposition method.

  For an apparatus that can realize a state in which the distance from the plasma generation source to the substrate is 2 cm or more and the arrival of plasma to the substrate is reduced (hereinafter referred to as a plasma-free film forming apparatus), for example, an opposed target sputtering Equipment, arc plasma deposition, etc. are considered, and these are supervised by Yutaka Sawada "New development of transparent conductive film" (published by CMC, 1999), and supervised by Yutaka Sawada "New development of transparent conductive film II" (published by CMC) 2002), “Transparent conductive film technology” (Ohm Co., 1999) by the Japan Society for the Promotion of Science, and references and the like attached thereto can be used.

  The electrode of the organic electromagnetic wave absorption / photoelectric conversion site of the present invention will be described in more detail. The photoelectric conversion film (layer) of the organic layer is sandwiched between the pixel electrode film and the counter electrode film, and can include an interelectrode material or the like. The pixel electrode film is an electrode film formed above the substrate on which the charge accumulation / transfer / read-out site is formed, and is usually divided for each pixel. This is to obtain an image by reading out the signal charges converted by the photoelectric conversion film on a charge storage / transfer / signal readout circuit substrate for each pixel.

  The counter electrode film has a function of discharging a signal charge having a polarity opposite to that of the signal charge by sandwiching the photoelectric conversion film (layer) together with the pixel electrode film. Since the discharge of the signal charge does not need to be divided between the pixels, the counter electrode film can be commonly used between the pixels. Therefore, it may be called a common electrode film (common electrode film).

  The photoelectric conversion film (layer) is located between the pixel electrode film and the counter electrode film. The photoelectric conversion function functions by the photoelectric conversion film, the pixel electrode film, and the counter electrode film.

  As an example of the configuration of the photoelectric conversion film stack, first, when there is one organic layer stacked on the substrate, the pixel electrode film (basically a transparent electrode film), the photoelectric conversion film (layer), the counter electrode film ( Although the structure which laminated | stacked the transparent electrode film | membrane in order is mentioned, it is not limited to this.

  Furthermore, when there are two organic layers stacked on the substrate, for example, from the substrate to the pixel electrode film (basically a transparent electrode film), a photoelectric conversion film (layer), a counter electrode film (transparent electrode film), an interlayer insulating film , A configuration in which a pixel electrode film (basically a transparent electrode film), a photoelectric conversion film (layer), and a counter electrode film (transparent electrode film) are sequentially stacked.

  The material of the transparent electrode film constituting the photoelectric conversion site of the present invention is preferably one that can be formed by a plasma-free film forming apparatus, an EB vapor deposition apparatus, and a pulse laser vapor deposition apparatus. For example, a metal, an alloy, a metal oxide, a metal nitride, a metal boride, an organic conductive compound, a mixture thereof, and the like are preferable. Specific examples include tin oxide, zinc oxide, indium oxide, and indium zinc oxide. (IZO), indium tin oxide (ITO), conductive metal oxides such as indium tungsten oxide (IWO), metal nitrides such as titanium nitride, metals such as gold, platinum, silver, chromium, nickel, aluminum, and these A mixture or laminate of a metal and a conductive metal oxide, an inorganic conductive material such as copper iodide or copper sulfide, an organic conductive material such as polyaniline, polythiophene or polypyrrole, a laminate of these and ITO, Etc. Also, supervised by Yutaka Sawada “New Development of Transparent Conductive Film” (published by CMC, 1999), supervised by Yutaka Sawada “New Development of Transparent Conductive Film II” (published by CMC, 2002), “Transparency by Japan Society for the Promotion of Science” Those described in detail in “Technology of Conductive Film” (Ohm Co., 1999) may be used.

Particularly preferable materials for the transparent electrode film are ITO, IZO, SnO ₂ , ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO ₂ , FTO (fluorine). Doped tin oxide).

The light transmittance of the transparent electrode film is preferably 60% or more, more preferably 80% or more, more preferably, in the photoelectric conversion light absorption peak wavelength of the photoelectric conversion film included in the photoelectric conversion element including the transparent electrode film. It is 90% or more, more preferably 95% or more. The preferred range of the surface resistance of the transparent electrode film varies depending on whether it is a pixel electrode or a counter electrode, and whether the charge storage / transfer / read-out site is a CCD structure or a CMOS structure. When it is used for the counter electrode and the charge storage / transfer / readout part has a CMOS structure, it is preferably 10000Ω / □ or less, more preferably 1000Ω / □ or less. When it is used for the counter electrode and the charge storage / transfer / readout part has a CCD structure, it is preferably 1000Ω / □ or less, more preferably 100Ω / □ or less. When used for a pixel electrode, it is preferably 1000000 Ω / □ or less, more preferably 100000 Ω / □ or less.
(Inorganic layer)
The inorganic layer as the electromagnetic wave absorption / photoelectric conversion site will be described. In this case, light passing through the upper organic layer is photoelectrically converted by the inorganic layer. As the inorganic layer, a pn junction or a pin junction of a compound semiconductor such as crystalline silicon, amorphous silicon, or GaAs is generally used. The method disclosed in US Pat. No. 5,965,875 can be adopted as the laminated structure. In other words, a stacked light receiving portion is formed using the wavelength dependence of the absorption coefficient of silicon, and color separation is performed in the depth direction. In this case, since color separation is performed based on the light penetration depth of silicon, the spectral range detected by each stacked light receiving unit is broad. However, color separation is remarkably improved by using the above-described organic layer as an upper layer, that is, by detecting light transmitted through the organic layer in the depth direction of silicon. In particular, when the G layer is disposed in the organic layer, the light transmitted through the organic layer becomes B light and R light, so that the separation of light in the depth direction in silicon becomes only BR light, and color separation is improved. Even when the organic layer is a B layer or an R layer, color separation is remarkably improved by appropriately selecting the electromagnetic wave absorption / photoelectric conversion site of silicon in the depth direction. When the organic layer has two layers, the function as an electromagnetic wave absorption / photoelectric conversion site in silicon may be basically one color, and preferable color separation can be achieved.

As the inorganic semiconductor, an InGaN-based, InAlN-based, InAlP-based, or InGaAlP-based inorganic semiconductor can also be used. The InGaN-based inorganic semiconductor is adjusted so as to have a maximum absorption value in a blue wavelength range by appropriately changing the In-containing composition. _That, In _x Ga ₁ - a composition of x N (0 <X <1 ).

  Such a compound semiconductor is manufactured using a metal organic chemical vapor deposition method (MOCVD method).

  The inorganic semiconductor may have a buried structure. The embedded structure means a structure in which both ends of the short wavelength light receiving part are covered with a semiconductor different from the short wavelength light receiving part. The semiconductor covering both ends is preferably a semiconductor having a band gap wavelength shorter than or equivalent to the band gap wavelength of the short wavelength light receiving part.

  The organic layer and the inorganic layer may be combined in any form. In addition, it is preferable to provide an insulating layer between the organic layer and the inorganic layer in order to electrically insulate.

  The junction is preferably npn or pnpn from the light incident side. In particular, by providing a p layer on the surface and increasing the surface potential, holes generated in the vicinity of the surface and dark current can be trapped and dark current can be reduced. preferable.

  In such a photodiode, an n-type layer, a p-type layer, an n-type layer, and a p-type layer that are sequentially diffused from the surface of the p-type silicon substrate are formed deeply in this order, so that the pn junction diode has a silicon depth. Four layers of pnpn are formed in the direction. The light incident on the diode from the surface side penetrates deeper as the wavelength is longer, and the incident wavelength and attenuation coefficient show values specific to silicon, so that the depth of the pn junction surface covers each wavelength band of visible light. design. Similarly, an n-type layer, a p-type layer, and an n-type layer are formed in this order to obtain a npn three-layer junction diode. Here, an optical signal is taken out from the n-type layer, and the p-type layer is connected to the ground.

Further, when an extraction electrode is provided in each region and a predetermined reset potential is applied, each region is depleted, and the capacitance of each junction becomes an extremely small value. Thereby, the capacity | capacitance produced in a joint surface can be made very small.
(Auxiliary layer)
In the present invention, an ultraviolet absorption layer and / or an infrared absorption layer are preferably provided on the uppermost layer of the electromagnetic wave absorption / photoelectric conversion site. The ultraviolet absorbing layer can absorb or reflect at least light of 400 nm or less, and preferably has an absorptance of 50% or more in a wavelength region of 400 nm or less. The infrared absorbing layer can absorb or reflect light of at least 700 nm or more, and preferably has an absorptance of 50% or more in a wavelength region of 700 nm or more.

  These ultraviolet absorbing layer and infrared absorbing layer can be formed by a conventionally known method. For example, a method of forming a colored layer by providing a mordanting layer made of a hydrophilic polymer material such as gelatin, casein, mulled or polyvinyl alcohol on a substrate and adding or dyeing a dye having a desired absorption wavelength to the mordanting layer. Are known. Furthermore, a method using a colored resin in which a certain kind of coloring material is dispersed in a transparent resin is known. For example, JP-A-58-46325, JP-A-60-78401, JP-A-60-184202, JP-A-60-184203, JP-A-60-184204, JP-A-60-184204 As shown in Japanese Patent Application Laid-Open No. 60-184205 and the like, a colored resin film obtained by mixing a colorant with a polyamino resin can be used. A colorant using a polyimide resin having photosensitivity is also possible.

  Dispersing a coloring material in an aromatic polyamide resin having a photosensitivity group described in JP-B-7-113685 in the molecule and capable of obtaining a cured film at 200 ° C. or lower, JP-B-7-69486 It is also possible to use dispersed colored resins with the stated content.

  In the present invention, a dielectric multilayer film is preferably used. The dielectric multilayer film is preferably used because the wavelength dependency of light transmission is sharp.

  Each electromagnetic wave absorption / photoelectric conversion site is preferably separated by an insulating layer. The insulating layer can be formed using a transparent insulating material such as glass, polyethylene, polyethylene terephthalate, polyethersulfone, and polypropylene. Silicon nitride, silicon oxide and the like are also preferably used. Silicon nitride formed by plasma CVD is preferably used in the present invention because it has high density and good transparency.

  A protective layer or a sealing layer can be provided for the purpose of preventing contact with oxygen or moisture.

  Examples of protective layers include diamond thin films, inorganic material films such as metal oxides and metal nitrides, polymer films such as fluororesins, polyparaxylene, polyethylene, silicon resins, and polystyrene resins, and photocurable resins. Can be mentioned. Further, the element portion can be covered with glass, gas-impermeable plastic, metal, etc., and the element itself can be packaged with an appropriate sealing resin. In this case, a substance having high water absorption can be present in the packaging.

Furthermore, since the light collection efficiency can be improved by forming the microlens array on the light receiving element, such an embodiment is also preferable.
(Charge accumulation / transfer / readout part)
Regarding the charge transfer / readout part, reference can be made to JP-A-58-103166, JP-A-58-103165, JP-A-2003-332551 and the like. A configuration in which a MOS transistor is formed in each pixel unit on a semiconductor substrate or a configuration having a CCD as an element can be appropriately employed. For example, in the case of a photoelectric conversion element using a MOS transistor, charges are generated in the photoconductive film by incident light transmitted through the electrodes, and the charges are generated by an electric field generated between the electrodes by applying a voltage to the electrodes. It travels to the electrode through the photoconductive film, and further moves to the charge storage part of the MOS transistor, and charges are stored in the charge storage part. The charge accumulated in the charge accumulation unit moves to the charge readout unit by switching of the MOS transistor, and is further output as an electric signal. Thereby, a full-color image signal is input to the solid-state imaging device including the signal processing unit.

  It is possible to inject a certain amount of bias charge into the storage diode (refresh mode) and store the constant charge (photoelectric conversion mode), and then read out the signal charge. The light receiving element itself can be used as a storage diode, or a storage diode can be additionally provided.

  The signal readout will be described in more detail. An ordinary color readout circuit can be used for signal readout. The signal charge or signal current optically / electrically converted by the light receiving unit is stored in the light receiving unit itself or an attached capacitor. The stored charge is read out together with the selection of the pixel position by a technique of a MOS type image pickup device (so-called CMOS sensor) using an XY address method. In addition, as an address selection method, there is a method in which each pixel is sequentially selected by a multiplexer switch and a digital shift register and read as a signal voltage (or charge) to a common output line. An image sensor for XY address operation that is two-dimensionally arrayed is known as a CMOS sensor. This is because a switch connected to a pixel connected to the intersection of XY is connected to a vertical shift register, and when a switch is turned on by a voltage from the vertical scanning shift register, it is read from a pixel placed in the same row. The signal is read out to the output line in the column direction. This signal is sequentially read from the output through a switch driven by a horizontal scanning shift register.

  For reading out the output signal, a floating diffusion detector or a floating gate detector can be used. Further, the S / N can be improved by providing a signal amplification circuit in the pixel portion or a correlated double sampling technique.

  For signal processing, gamma correction by an ADC circuit, digitization by an AD converter, luminance signal processing, and color signal signal processing can be performed. Examples of the color signal processing include white balance processing, color separation processing, and color matrix processing. When used for NTSC signals, RGB signals can be converted to YIQ signals.

The charge transfer / readout site needs to have a charge mobility of 100 cm ² / volt · sec or more, and this mobility is selected from a group IV, III-V, or II-VI group semiconductor. Can be obtained. Of these, silicon semiconductors (also referred to as Si semiconductors) are preferable because miniaturization technology is advanced and the cost is low. Many methods of charge transfer and charge reading have been proposed, but any method may be used. A particularly preferred method is a CMOS type or CCD type device. Furthermore, in the case of the present invention, the CMOS type is often preferable in terms of high-speed readout, pixel addition, partial readout, power consumption, and the like.
(Connection)
A plurality of contact parts for connecting the electromagnetic wave absorption / photoelectric conversion part and the charge transfer / reading part may be connected by any metal, but preferably selected from copper, aluminum, silver, gold, chromium, and tungsten. In particular, copper is preferred. In accordance with a plurality of electromagnetic wave absorption / photoelectric conversion parts, it is necessary to install each contact part between the charge transfer / readout part. When a laminated structure of a plurality of photosensitive units of blue, green, and red light is adopted, between the blue light extraction electrode and the charge transfer / readout portion, between the green light extraction electrode and the charge transfer / readout portion, and the red light extraction electrode; It is necessary to connect between the charge transfer / readout portions.
(process)
The laminated photoelectric conversion device of the present invention can be manufactured according to a so-called microfabrication process used for manufacturing a known integrated circuit or the like. Basically, this method uses pattern exposure by active light or electron beam (mercury i, g emission line, excimer laser, X-ray, electron beam), pattern formation by development and / or burning, element formation material By repeated operation of arrangement (coating, vapor deposition, sputtering, CV, etc.) and removal of non-patterned material (heat treatment, dissolution treatment, etc.).
(Use)
The photoelectric conversion element (preferably imaging element) of the present invention can be used for a digital still camera. It is also preferable to use it for a TV camera. Other applications include digital video cameras, surveillance cameras for the following applications (office buildings, parking lots, financial institutions and unmanned contractors, shopping centers, convenience stores, outlet malls, department stores, pachinko halls, karaoke boxes, game centers, Hospital), various other sensors (TV door phone, personal authentication sensor, factory automation sensor, home robot, industrial robot, piping inspection system), medical sensor (endoscope, fundus camera), video conference system, It can be used for applications such as videophones, mobile phones with cameras, safe driving systems for vehicles (back guide monitors, collision prediction, lane keeping systems), and video game sensors.

  Among these, the photoelectric conversion element (preferably the image pickup element) of the present invention is suitable for use as a television camera. This is because a television camera can be reduced in size and weight because no color separation optical system is required. Further, since it has high sensitivity and high resolution, it is particularly preferable for a television camera for high-definition broadcasting. In this case, the high-definition broadcast television camera includes a digital high-definition broadcast camera.

  Furthermore, the photoelectric conversion element of the present invention is preferable in that an optical low-pass filter can be omitted, and higher sensitivity and higher resolution can be expected.

  Furthermore, in the photoelectric conversion element of the present invention, it is possible to reduce the thickness and eliminate the need for a color separation optical system, so that "an environment with different brightness such as daytime and nighttime" For shooting scenes that require different sensitivities, such as `` subjects that are moving and subjects that are moving, '' and other shooting scenes that require different spectral sensitivity and color reproducibility, replace the photoelectric conversion element of the present invention and shoot. A single camera can meet a variety of shooting needs, and it is not necessary to carry multiple cameras at the same time, reducing the burden on the photographer. As the photoelectric conversion element to be exchanged, an exchange photoelectric conversion element can be prepared for infrared light photography, black-and-white photography, and dynamic range change in addition to the above.

  The TV camera of the present invention can be obtained by referring to the description in Chapter 2 of the TV Information Technology Society, Television Camera Design Technology (August 20, 1999, Corona, ISBN 4-339-00714-5). Fig. 2.1 The television camera can be manufactured by replacing the part of the color separation optical system and the imaging device in the basic configuration with the photoelectric conversion element of the present invention.

The above-described stacked light receiving elements can be used not only as an image pickup element by arranging them but also as a light sensor such as a biosensor or a chemical sensor or a color light receiving element as a single unit.
(Preferred photoelectric conversion element of the present invention)
A preferred photoelectric conversion element of the present invention will be described with reference to FIG. Reference numeral 13 denotes a silicon single crystal substrate, which serves as an electromagnetic wave absorption / photoelectric conversion site for B light and R light and a charge accumulation / transfer / readout site for charges generated by photoelectric conversion. Usually, a p-type silicon substrate is used. Reference numerals 21, 22, and 23 denote an n layer, a p layer, and an n layer provided in the silicon substrate, respectively. The n layer 21 is an R light signal charge accumulating unit for accumulating the R light signal charge photoelectrically converted by the pn junction. The accumulated charges are connected to 27 signal readout pads through 19 transistors through 19 transistors. The n layer 23 is a B light signal charge accumulating unit for accumulating B light signal charges photoelectrically converted by a pn junction. The accumulated electric charge is connected to 27 signal readout pads through 19 metal wires through transistors similar to 26. Here, the p layer, the n layer, the transistor, the metal wiring, and the like are schematically shown. However, as described in detail in the previous discussion, an optimal structure is appropriately selected. Since B light and R light are separated according to the depth of the silicon substrate, selection of the depth from the silicon substrate such as a pn junction and the doping concentration is important. Reference numeral 12 denotes a layer containing metal wiring, which is mainly composed of silicon oxide, silicon nitride, or the like. The thickness of the layer 12 is preferably as thin as possible, and is 5 μm or less, preferably 3 μm or less, and more preferably 2 μm or less. Similarly, 11 is a layer mainly composed of silicon oxide, silicon nitride or the like. The layers 11 and 12 are provided with plugs for sending the signal charges of G light to the silicon substrate. The plug is connected by 16 pads between the 11 and 12 layers. The plug is preferably made mainly of tungsten. A pad mainly composed of aluminum is preferably used. It is preferable that a barrier layer is provided including the metal wiring described above. The signal charges of G light transmitted through the 15 plugs are accumulated in the n layer indicated by 25 in the silicon substrate. The n layer shown in 25 is separated by the p layer shown in 24. The accumulated electric charge is connected to 27 signal readout pads through 19 metal wires through transistors similar to 26. Since photoelectric conversion by the pn junctions 24 and 25 causes noise, the light shielding film shown in 17 is provided in 11 layers. As the light shielding film, a film mainly composed of tungsten, aluminum or the like is usually used. The thickness of the layer 12 is preferably as small as possible, but is 3 μm or less, preferably 2 μm or less, and more preferably 1 μm or less. 27 signal readout pads are preferably provided for each of the B, G, and R signals. The above process can be prepared by a conventionally known process, a so-called CMOS process.

The electromagnetic wave absorption / photoelectric conversion site of G light is indicated by 6, 7, 8, 9, 10, and 14. Reference numerals 6 and 14 denote transparent electrodes, which correspond to a counter electrode and a pixel electrode, respectively. Although the pixel electrode 14 is a transparent electrode, a part such as aluminum or molybdenum is often required for the connection portion in order to improve electrical connection with the 15 plugs. A bias is applied between these transparent electrodes through wiring from 18 connection electrodes and 20 counter electrode pads. A structure in which electrons can be stored in 25 by applying a positive bias to the pixel electrode 14 with respect to the transparent counter electrode 6 is preferable. In this case, 7 is an electron blocking layer, 8 is a p layer, 9 is an n layer, and 10 is a hole blocking layer, showing a typical organic layer structure. The total thickness of the organic layer composed of 7, 8, 9, 10 is preferably 0.5 μm or less, more preferably 0.4 μm or less, and particularly preferably 0.3 μm or less. The thicknesses of the transparent counter electrode 6 and the transparent pixel electrode 14 are particularly preferably 0.2 μm or less. Reference numerals 3, 4, and 5 are protective films mainly composed of silicon nitride or the like. These protective films facilitate the manufacturing process of the layer including the organic layer. In particular, these layers can reduce damage to the organic layer at the time of forming a resist pattern at the time of forming connection electrodes such as 18 and etching. Further, in order to avoid the formation of a resist pattern, etching, etc., it is possible to manufacture with a mask. The thicknesses of the protective films 3, 4, and 5 are preferably 0.5 μm or less as long as the above-described conditions are satisfied. 3 is a protective film of 18 connection electrodes. Reference numeral 2 denotes an infrared cut dielectric multilayer film. Reference numeral 1 denotes an antireflection film. The total thickness of the layers 1, 2, and 3 is preferably 1 μm or less.
[Example]
Examples and embodiment examples of the present invention will be described below, but the present invention is not limited thereto.

A 25 mm square glass substrate with ITO was ultrasonically cleaned with acetone, semi-coclean (trade name of Furuuchi Chemical), and isopropyl alcohol (IPA) for 15 minutes.
The substrate was moved to the organic vapor deposition chamber, and the pressure in the chamber was reduced to 1 × 10 ⁻⁴ Pa or less. Then, quinacridone (manufactured by DOJINDO) purified by sublimation three times or more with a lamp heating so that the substrate temperature is kept at 100 ° C. by a resistance heating method to a thickness of 1000 mm at a deposition rate of 0.5 to 1 mm / sec. Vapor deposited.

Next, the board | substrate which vapor-deposited organic material was conveyed in the metal vapor deposition chamber in the vacuum. After that, while keeping the room at 1 × 10 ⁻⁴ Pa or less, Al was vapor-deposited so as to have a thickness of 800 mm as a counter electrode while keeping the substrate temperature at room temperature. The area of the photoelectric conversion region formed by ITO serving as the pixel electrode and Al serving as the counter electrode was set to 2 mm × 2 mm.

  Without exposing this board | substrate to air | atmosphere, it conveyed to the glove box which kept the water | moisture content and oxygen each 1 ppm or less, and sealed with the stainless steel sealing can which stretched | stretched the moisture absorption agent using UV curable resin.

This element flows when light is not irradiated when an external electric field of 6.0 × 10 ⁵ V / cm is applied to the element by using an optical constant energy efficiency measurement device (source meter uses Keithley 6430). The dark current value and the photocurrent value flowing during light irradiation were measured. For IPCE, the quantum efficiency was calculated using the signal current value obtained by subtracting the dark current value from the photocurrent value. The amount of light irradiated was 50 μW / cm ² .

  Regarding the carrier mobility, an element having a quinacridone film thickness of 2 μm formed at a substrate temperature of 100 ° C. under the same conditions as described above was prepared, and the electron carrier mobility was measured with an Optel TOF measuring device. It was.

With respect to the substrate with ITO washed in the same manner as in Example 1, quinacridone (manufactured by DOJINDO) purified by sublimation three times or more with the substrate temperature kept at 150 ° C. by lamp irradiation was deposited at a deposition rate of 0 by the resistance heating method. Vapor deposition was carried out at a thickness of 1000 Å at 5 to 1 Å / sec.
Next, in the same manner as in Example 1, this substrate was transported to a metal vapor deposition chamber, Al was vapor deposited while the substrate temperature was at room temperature, and after further sealing, photocurrent, dark current, and IPCE were measured. It was.

Regarding the carrier mobility, an element having a quinacridone film thickness of 2 μm formed at a substrate temperature of 150 ° C. under the same conditions as described above was prepared, and the electron carrier mobility was measured with an Optel TOF measurement device. It was.
[Comparative Example 1]
As in Example 1, quinacridone (manufactured by DOJINDO) purified by sublimation three or more times with the substrate temperature kept at room temperature (about 25 ° C.) with respect to the washed ITO-attached substrate was deposited by a resistance heating method. It vapor-deposited so that it might become a thickness of 1000 で at 0.5-1 liter / sec.

  Next, in the same manner as in Example 1, this substrate was transported to a metal vapor deposition chamber, Al was vapor deposited while the substrate temperature was at room temperature, and after further sealing, photocurrent, dark current, and IPCE were measured. It was.

Regarding the carrier mobility, an element in which the film thickness of quinacridone formed at a substrate temperature of room temperature was set to 2 μm under the same conditions as described above was prepared, and the electron carrier mobility was measured with an Optel TOF measuring device. .
[Comparative Example 2]
Similarly to Example 1, quinacridone (manufactured by DOJINDO) purified by sublimation three times or more with the substrate temperature kept at 50 ° C. by lamp irradiation on the cleaned ITO-attached substrate was deposited by a resistance heating method. It vapor-deposited so that it might become a thickness of 1000 で at 0.5-1 liter / sec.
Next, in the same manner as in Example 1, this substrate was transported to a metal vapor deposition chamber, Al was vapor deposited while the substrate temperature was at room temperature, and after further sealing, photocurrent, dark current, and IPCE were measured. It was.

Regarding the carrier mobility, an element having a quinacridone film thickness of 2 μm formed at a substrate temperature of 50 ° C. under the same conditions as described above was prepared, and the electron carrier mobility was measured with an Optel TOF measuring device. It was.
[Comparative Example 3]
In the same manner as in Example 1, quinacridone (manufactured by DOJINDO) purified by sublimation three times or more with the substrate temperature kept at 300 ° C. by lamp irradiation on the cleaned ITO-attached substrate was deposited by a resistance heating method. An attempt was made to deposit at 0.5 to 1 liter / sec. However, since the substrate surface temperature was too high, re-sublimation of quinacridone adhering to the substrate occurred and no film could be formed.

  The X-ray used for the measurement of the X-ray diffraction pattern was a Cu-Kα ray having a wavelength of 5.14Å.

FIG. 1 shows the results of an X-ray diffraction pattern performed on quinacridone in Comparative Example 1 and FIG.
The results are shown in the table below.

基板温度を室温や５０℃でキナクリドン成膜した比較例１、２と比べて、基板温度１００℃や１５０℃でキナクリドンを成膜した実施例１、２では、電子キャリア移動度が高くなると共に光電変換効率の向上が見られた。また、基板温度３００℃という高温でキナクリドンを成膜しようとした比較例３では、温度が高すぎて成膜することができなかった。

Compared with Comparative Examples 1 and 2 where the quinacridone film was formed at room temperature or 50 ° C., in Examples 1 and 2 where quinacridone was formed at a substrate temperature of 100 ° C. or 150 ° C., the electron carrier mobility increased and The conversion efficiency was improved. In Comparative Example 3 in which quinacridone was formed at a substrate temperature of 300 ° C., the temperature was too high to form a film.

  In addition, in the X-ray diffraction pattern of quinacridone of Example 2 formed at a substrate temperature of 150 ° C., strong X-ray diffraction peaks were observed at diffraction angles 2θ of around 11 degrees, 23 degrees, and 29 degrees as shown in FIG. It can be seen that quinacridone is oriented. Similarly, the X-ray diffraction pattern for quinacridone of Example 1 deposited at a substrate temperature of 100 ° C. also showed a strong peak at the same diffraction angle as in FIG.

  On the other hand, the X-ray diffraction pattern for quinacridone of Comparative Example 1 formed at room temperature is a broad pattern as shown in FIG.

FIG. 4 is a diagram showing an X-ray diffraction pattern in Comparative Example 1. These are the figures which show the X-ray-diffraction pattern in Example 2. FIG. These are the cross-sectional schematic diagrams for 1 pixel of the photoelectric conversion film laminated | stacked image pick-up element of BGR 3 layer lamination by this invention. FIG. 2 is a schematic cross-sectional view of a preferred image sensor according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antireflection film 2 Infrared cut dielectric multilayer film 3, 4, 5 Protective film 6 Transparent counter electrode 7 Electron blocking layer 8 P layer 9 N layer 10 Hole blocking layer 11, 12 Layer including metal wiring 13 Silicon single crystal Base 14 Transparent pixel electrode 15 Plug 16 Pad 17 Light shielding film 18 Connection electrode 19 Metal wiring 20 Counter electrode pad 21 n layer 22 p layer 23 n layer 24 p layer 25 n layer 26 Transistor 27 Signal readout pad 101 P well layers 102, 104 , 106 High-concentration impurity regions 103, 105, 107 MOS circuit 108 Gate insulating film 109, 110 Insulating film 111, 114, 116, 119, 121, 124, transparent electrode film 112, 117, 122, electrode 113, 118, 123 photoelectric Conversion film 110, 115, 120, 125 Transparent insulating film 126 Light shielding film 150 Semiconductor Substrate

Claims (8)

  In the method of manufacturing an organic photoelectric conversion element in which a layer containing a photoconductive organic compound is disposed between a pair of electrodes, a part or all of the layer containing the photoconductive organic compound is a substrate. A method for producing an organic photoelectric conversion element, wherein vapor phase growth is performed while controlling the temperature at 60 ° C to 250 ° C.   The method for producing an organic photoelectric conversion element according to claim 1, wherein the organic compound having photoconductivity is a quinacridone dye.   In the organic photoelectric conversion element in which a layer containing a photoconductive organic compound is disposed between a pair of electrodes, a part or all of the layer containing the photoconductive organic compound is oriented. The organic photoelectric conversion element characterized by the above-mentioned.   The organic photoelectric conversion element according to claim 3, wherein the organic compound having photoconductivity is a quinacridone dye.   When the layer containing the organic compound having photoconductivity is subjected to X-ray diffraction measurement with respect to the layer containing the organic compound, X is strong around 11 degrees, 23 degrees, and 29 degrees of the diffraction angle 2θ. The organic photoelectric conversion device according to claim 3, wherein the organic photoelectric conversion device has a line diffraction peak.   The layer made of an organic compound or an inorganic substance that does not substantially absorb light is disposed between the layer containing the organic compound having photoconductivity and at least one of the pair of electrodes. The organic photoelectric conversion element in any one of 3-5. The electric field applied to the organic photoelectric conversion element through the pair of electrodes is 1.0 × 10 ⁴ V / cm to 1.0 × 10 ⁷ V / cm. The organic photoelectric conversion element as described.   An image pickup device comprising the organic photoelectric conversion device according to any one of claims 3 to 6.

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