JP4945146B2 - Photoelectric conversion device and solid-state imaging device - Google Patents

Description

  The present invention provides a first electrode film, a second electrode film facing the first electrode film, a photoelectric conversion film containing a specific compound disposed between the first electrode film and the second electrode film, The present invention relates to a photoelectric conversion element having a photoelectric conversion unit including a solid-state imaging element in which a large number of photoelectric conversion elements are arranged in an array.

  A conventional optical sensor is generally an element formed by forming a photodiode (PD) in a semiconductor substrate such as silicon (Si). As a solid-state image sensor, a PD is two-dimensionally formed in a semiconductor substrate. 2. Description of the Related Art Planar solid-state image sensors that are arranged and read out signals by a CCD or CMOS circuit according to signal charges generated by photoelectric conversion in each PD are widely used. As a method for realizing a color solid-state imaging device, a structure in which a color filter that transmits only light of a specific wavelength for color separation is generally arranged on the light incident surface side of the flat-type solid-state imaging device. As a method widely used in digital cameras and the like at present, color filters that respectively transmit blue (B) light, green (G) light, and red (R) light are regularly arranged on the two-dimensionally arranged PDs. A single-plate type solid-state imaging device arranged in is well known.

  However, in the single-plate solid-state imaging device, the color filter transmits only light of a limited wavelength, so that the light that does not pass through the color filter is not used and the light use efficiency is poor. In addition, with the high integration of pixels, the size of the PD becomes about the same as the wavelength of light, and light is less likely to be guided to the PD. In addition, since blue light, green light, and red light are color-reproduced by detecting them with separate PDs that are close to each other, false colors may be generated. In order to avoid this false color An optical low-pass filter is required, and optical loss due to this filter also occurs.

  Conventionally, as a device for solving these drawbacks, three PDs are stacked in a silicon substrate by utilizing the wavelength dependence of the absorption coefficient of silicon, and color separation is performed by the difference in the depth of the pn junction surface of each PD. A color sensor that performs the above has been reported (see Patent Documents 1, 2, and 3). However, this method has a problem that the wavelength dependence of spectral sensitivity in the stacked PD is broad and color separation is insufficient. In particular, blue and green color separation is insufficient.

In order to solve this problem, a photoelectric conversion unit that detects green light and generates a signal charge corresponding to the detected green light is provided above the silicon substrate, and blue light and red light are emitted by two PDs stacked in the silicon substrate. A sensor for detection has been proposed (see Patent Document 4). The photoelectric conversion part provided above the silicon substrate is laminated on the first electrode film laminated on the silicon substrate, the photoelectric conversion film made of an organic material laminated on the first electrode film, and the photoelectric conversion film. The signal charge generated in the photoelectric conversion film is applied to the first electrode film and the second electrode film by applying a voltage to the first electrode film and the second electrode film. A signal corresponding to the signal charge that has moved and moved to one of the electrode films is read out by a CCD or CMOS circuit provided in the silicon substrate. However, this patent does not describe or suggest the compound represented by the general formula (I) or (II) used in the present invention.
Note that in this specification, the photoelectric conversion film refers to a film that absorbs light having a specific wavelength incident thereon and generates electrons and holes according to the absorbed light quantity.
US Pat. No. 5,965,875 US Pat. No. 6,632,701 Japanese Patent Laid-Open No. 7-38136 JP 2003-332551 A

  In the photoelectric conversion film made of an organic material, if light enters from above the second electrode film in the above-described configuration, a large number of electrons and holes generated by light absorption are generated in the vicinity of the second electrode film. In general, it does not occur so much in the vicinity of one electrode film. This is because most of the light in the vicinity of the absorption peak wavelength of this photoelectric conversion film is absorbed in the vicinity of the second electrode film, and the light absorption rate decreases as the distance from the vicinity of the second electrode film increases. is doing. For this reason, unless the electrons or holes generated in the vicinity of the second electrode film are efficiently transferred to the silicon substrate, the photoelectric conversion efficiency is lowered, resulting in a decrease in sensitivity of the element. In addition, since the signal due to the light wavelength strongly absorbed in the vicinity of the second electrode film decreases, as a result, the so-called broadening of the spectral sensitivity is caused.

  Further, in a photoelectric conversion film made of an organic material, the mobility of electrons is generally much smaller than the mobility of holes. Furthermore, it has been found that the mobility of electrons in a photoelectric conversion film made of an organic material is easily affected by oxygen, and that the mobility of electrons further decreases when the photoelectric conversion film is exposed to the atmosphere. For this reason, when moving electrons to the silicon substrate, if the moving distance of electrons generated in the vicinity of the second electrode film in the photoelectric conversion film is long, a part of the electrons is deactivated during the movement of the electrons. As a result, the sensitivity is lowered and the spectral sensitivity is broadened.

  In order to prevent the above-described sensitivity degradation and spectral sensitivity broadening, it is conceivable to make the photoelectric conversion film thin or use a material with high electron mobility, but it is necessary to obtain a sufficient amount of light absorption. There is a limit to reducing the film thickness of the photoelectric conversion film, and there is a demerit that the material is greatly restricted if the mobility requirement is satisfied. In order to assist the slow mobility of electrons, it is possible to apply an electric field to the photoelectric conversion film. However, when a sufficiently strong electric field is applied, the injectable leakage current from the two electrodes sandwiching the electric field increases. The S / N of the sensor may be reduced. For this reason, a technique for preventing a decrease in sensitivity and broadening of spectral sensitivity without adopting these methods is desired.

  In order to prevent lowering of sensitivity and broadening of spectral sensitivity, it is effective to efficiently move electrons or holes generated in the vicinity of the second electrode film to the charge accumulation / transfer / readout (silicon) substrate. In order to realize it, how to handle electrons or holes generated in the photoelectric conversion film becomes a problem.

  In addition, various dyes and pigments can usually be used for the organic photoelectric conversion film. However, it is necessary to increase the film thickness because the absorption intensity is low or the absorption waveform is broad, so that the spectral sensitivity is broad. In many cases, the photoelectric conversion efficiency is poor, and those satisfying all of these requirements are desired. In particular, what absorbs green light is desired.

  This invention is made | formed in view of the said situation, and it aims at providing the photoelectric conversion element which can prevent a sensitivity fall and the broadening of spectral sensitivity.

式中、環Ａは、

を表し、ｎ１、ｎ２は０または１を表す。但しｎ１及びｎ２が各々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。Ｒ ^１ 、Ｒ ^２ は各々独立に水素原子、アルキル基、アリール基、または複素環基を表す。Ｒ ^３ 、Ｒ ^４ 、Ｒ ^５ 、Ｒ ^６ は各々独立に置換基を表し、ｍ１、ｍ２、ｍ３、ｍ４は各々独立に０ないし４の整数を表す。ｍ１、ｍ２、ｍ３、ｍ４が２ないし４の整数の場合、複数のＲ ^３ 、Ｒ ^４ 、Ｒ ^５ 、Ｒ ^６ は連結して環を形成してもよい。
〔３〕 前記光電変換膜が、前記第一電極膜近傍よりも前記第二電極膜近傍の方が前記電子と前記正孔をより多く発生することを特徴とする上記〔１〕または〔２〕記載の固体撮像素子。
〔４〕 前記光電変換膜が、前記一般式（Ｉ）または一般式（ＩＩ）で表される化合物以外の有機材料を合わせて含んで構成されることを特徴とする上記〔２〕記載の固体撮像素子。
〔５〕 前記光電変換膜が有機ｐ型半導体及び有機ｎ型半導体の少なくとも一方を含むことを特徴とする上記〔４〕記載の固体撮像素子。
〔６〕 前記有機ｐ型半導体及び前記有機ｎ型半導体が、それぞれ、前記一般式（Ｉ）または一般式（ＩＩ）で表される化合物、ナフタレン誘導体、アントラセン誘導体、フェナントレン誘導体、テトラセン誘導体、ピレン誘導体、ペリレン誘導体、及びフルオランテン誘導体のいずれかを含むことを特徴とする上記〔５〕記載の固体撮像素子。
〔７〕 前記第一電極膜が、ＩＴＯ、ＩＺＯ、ＺｎＯ _２ 、ＳｎＯ _２ 、ＴｉＯ _２ 、ＦＴＯ、Ａｌ、Ａｇ、又はＡｕを含んで構成されるものであることを特徴とする上記〔１〕〜〔６〕のいずれか一項記載の固体撮像素子。
〔８〕 前記第二電極膜が、ＩＴＯ、ＩＺＯ、ＺｎＯ _２ 、ＳｎＯ _２ 、ＴｉＯ _２ 、ＦＴＯ、Ａｌ、Ａｇ、又はＡｕを含んで構成されるものであることを特徴とする上記〔１〕〜〔７〕のいずれか一項記載の固体撮像素子。
〔９〕 前記第二電極膜が、ＩＴＯ、ＩＺＯ、ＺｎＯ _２ 、ＳｎＯ _２ 、ＴｉＯ _２ 、又はＦＴＯを含んで構成されるものであり、前記光電変換部が、前記光電変換膜と前記第二電極膜との間に、仕事関数４．５ｅＶ以下の金属からなる膜を有することを特徴とする上記〔１〕〜〔８〕のいずれか一項記載の固体撮像素子。
〔１０〕 前記第二電極膜の可視光に対する透過率が６０％以上であることを特徴とする上記〔１〕〜〔９〕のいずれか一項記載の固体撮像素子。
〔１１〕 前記第一電極膜の可視光に対する透過率が６０％以上であることを特徴とする上記〔１〕〜〔１０〕のいずれか一項記載の固体撮像素子。
〔１２〕 前記光電変換部が、前記第一電極膜と前記光電変換膜との間に、有機高分子材料からなる膜を有することを特徴とする上記〔１〕〜〔１１〕のいずれか一項記載の固体撮像素子。
〔１３〕 前記光電変換膜下方の前記半導体基板内に、前記光電変換膜を透過した光を吸収し、該光に応じた電荷を発生してこれを蓄積する基板内光電変換部を備えることを特徴とする上記〔１〕〜〔１２〕のいずれか一項記載の固体撮像素子。
〔１４〕 前記基板内光電変換部が、前記半導体基板内に積層されたそれぞれ異なる色の光を吸収する複数のフォトダイオードであることを特徴とする上記〔１３〕記載の固体撮像素子。
〔１５〕 前記基板内光電変換部が、前記半導体基板内の前記入射光の入射方向に対して垂直な方向に配列されたそれぞれ異なる色の光を吸収する複数のフォトダイオードであることを特徴とする上記〔１３〕または〔１４〕記載の固体撮像素子。
〔１６〕 前記複数のフォトダイオードが、青色の光を吸収可能な位置にｐｎ接合面が形成された青色用フォトダイオードと、赤色の光を吸収可能な位置にｐｎ接合面が形成された赤色用フォトダイオードであり、前記光電変換膜が緑色の光を吸収するものであることを特徴とする上記〔１４〕または〔１５〕記載の固体撮像素子。
〔１７〕 前記複数のフォトダイオードが、青色の光を吸収する青色用フォトダイオードと、赤色の光を吸収する赤色用フォトダイオードであり、前記光電変換膜が緑色の光を吸収するものであることを特徴とする上記〔１５〕記載の固体撮像素子。
〔１８〕 前記半導体基板上方に、前記光電変換部が複数積層されており、前記複数の光電変換部毎に前記正孔蓄積部と前記接続部が設けられることを特徴とする上記〔１〕〜〔１７〕のいずれか一項記載の固体撮像素子。
〔１９〕 前記信号読み出し部がＭＯＳトランジスタで構成される上記〔１〕〜〔１８〕のいずれか一項記載の固体撮像素子。
本発明は、上記〔１〕〜〔１９〕項に関するものであるが、その他の事項についても参考のために記載した。
（１） 第一電極膜と、前記第一電極膜に対向する第二電極膜と、前記第一電極膜と前記第二電極膜の間に配置される光電変換膜とを含む光電変換部を有する光電変換素子であって、
前記第二電極膜上方から前記光電変換膜に光が入射されるものであり、
前記光電変換膜は、前記第二電極膜上方からの入射光に応じて電子と正孔を含む電荷を発生するものであり、
かつ、該光電変換膜がキナクリドン誘導体またはキナゾリン誘導体を含有し、
前記第一電極膜を前記正孔の取り出し用の電極としたことを特徴とする光電変換素子。
（２） （１）記載のキナクリドン誘導体またはキナゾリン誘導体が、下記の一般式（Ｉ）で表される化合物または一般式（ＩＩ）で表される化合物から選ばれることを特徴とする（１）記載の光電変換素子。 The above problems have been solved by the following means.
[1] A photoelectric conversion unit including a first electrode film, a second electrode film facing the first electrode film, and a photoelectric conversion film disposed between the first electrode film and the second electrode film. A solid-state imaging device in which a large number of photoelectric conversion devices having an array are arranged,
A semiconductor substrate provided below the first electrode film,
Light is incident on the photoelectric conversion film from above the second electrode film,
The photoelectric conversion film generates charges including electrons and holes in response to incident light from above the second electrode film,
And the photoelectric conversion film contains a quinacridone derivative or a quinazoline derivative,
In the first electrode film and the second electrode film, a voltage is applied so that the electrons move to the second electrode film and the holes move to the first electrode film,
In the semiconductor substrate, a hole accumulating part for accumulating the holes transferred to the first electrode film, and a connection part for electrically connecting the hole accumulating part and the first electrode film And
A signal readout unit that reads out a signal corresponding to the charge accumulated in the semiconductor substrate of each of the multiple photoelectric conversion elements;
The photoelectric conversion film and the second electrode film included in the photoelectric conversion element are shared by the entire number of photoelectric conversion elements,
The solid-state imaging device, wherein the first electrode film included in the photoelectric conversion device is separated for each of the plurality of photoelectric conversion devices.
[2] The above-mentioned [1], wherein the quinacridone derivative or quinazoline derivative according to claim 1 is selected from a compound represented by the following general formula (I) or a compound represented by the general formula (II): The solid-state imaging device described.

Wherein ring A is

N1 and n2 represent 0 or 1. However, when n1 and n2 are each 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 , R ⁴ , R ⁵ , and R ⁶ each independently represent a substituent, and m1, m2, m3, and m4 each independently represent an integer of 0 to 4. When m1, m2, m3 and m4 are integers of 2 to 4, a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ may be linked to form a ring.
[3] The above [1] or [2], wherein the photoelectric conversion film generates more electrons and holes in the vicinity of the second electrode film than in the vicinity of the first electrode film. The solid-state imaging device described.
[4] The solid according to [2], wherein the photoelectric conversion film is configured to contain an organic material other than the compound represented by the general formula (I) or the general formula (II). Image sensor.
[5] The solid-state imaging device according to [4], wherein the photoelectric conversion film includes at least one of an organic p-type semiconductor and an organic n-type semiconductor.
[6] The organic p-type semiconductor and the organic n-type semiconductor are each a compound represented by the general formula (I) or the general formula (II), a naphthalene derivative, an anthracene derivative, a phenanthrene derivative, a tetracene derivative, or a pyrene derivative. , A perylene derivative, and a fluoranthene derivative. The solid-state imaging device as described in [5] above,
[7] The above-mentioned [1], wherein the first electrode film includes ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al, Ag, or Au. [6] The solid-state imaging device according to any one of [6].
[8] The above- mentioned [1] to [ 2], wherein the second electrode film comprises ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al, Ag, or Au. [7] The solid-state imaging device according to any one of [7].
[9] The second electrode film includes ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , or FTO, and the photoelectric conversion unit includes the photoelectric conversion film and the second electrode. The solid-state imaging device according to any one of [1] to [8], wherein a film made of a metal having a work function of 4.5 eV or less is provided between the film and the film.
[10] The solid-state imaging device as described in any one of [1] to [9], wherein the second electrode film has a transmittance for visible light of 60% or more.
[11] The solid-state imaging device according to any one of [1] to [10], wherein the first electrode film has a visible light transmittance of 60% or more.
[12] Any one of the above [1] to [11], wherein the photoelectric conversion unit includes a film made of an organic polymer material between the first electrode film and the photoelectric conversion film. The solid-state imaging device according to item.
[13] An in-substrate photoelectric conversion unit that absorbs light transmitted through the photoelectric conversion film, generates electric charge according to the light, and accumulates the light in the semiconductor substrate below the photoelectric conversion film. The solid-state imaging device as described in any one of [1] to [12] above.
[14] The solid-state imaging device according to [13], wherein the in-substrate photoelectric conversion unit is a plurality of photodiodes that are stacked in the semiconductor substrate and absorb light of different colors.
[15] The in-substrate photoelectric conversion unit is a plurality of photodiodes that absorb light of different colors arranged in a direction perpendicular to the incident direction of the incident light in the semiconductor substrate. The solid-state imaging device according to [13] or [14].
[16] A blue photodiode having a pn junction surface formed at a position where the plurality of photodiodes can absorb blue light, and a red photodiode having a pn junction surface formed at a position capable of absorbing red light. The solid-state imaging device according to [14] or [15], wherein the solid-state imaging device is a photodiode, and the photoelectric conversion film absorbs green light.
[17] The plurality of photodiodes are a blue photodiode that absorbs blue light and a red photodiode that absorbs red light, and the photoelectric conversion film absorbs green light. [15] The solid-state imaging device as described in [15] above.
[18] A plurality of the photoelectric conversion units are stacked above the semiconductor substrate, and the hole accumulation unit and the connection unit are provided for each of the plurality of photoelectric conversion units. [17] The solid-state imaging device according to any one of [17].
[19] The solid-state imaging device according to any one of [1] to [18], wherein the signal reading unit is configured by a MOS transistor.
The present invention relates to the items [1] to [19] above, but other matters are also described for reference.
(1) A photoelectric conversion unit including a first electrode film, a second electrode film facing the first electrode film, and a photoelectric conversion film disposed between the first electrode film and the second electrode film A photoelectric conversion element having
Light is incident on the photoelectric conversion film from above the second electrode film,
The photoelectric conversion film generates charges including electrons and holes in response to incident light from above the second electrode film,
And the photoelectric conversion film contains a quinacridone derivative or a quinazoline derivative,
A photoelectric conversion element, wherein the first electrode film is an electrode for extracting the holes.
(2) The description of (1), wherein the quinacridone derivative or quinazoline derivative according to (1) is selected from a compound represented by the following general formula (I) or a compound represented by the general formula (II): Photoelectric conversion element.

  Wherein ring A is

N1 and n2 represent 0 or 1. However, when n1 and n2 are each 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 , R ⁴ , R ⁵ , and R ⁶ each independently represent a substituent, and m1, m2, m3, and m4 each independently represent an integer of 0 to 4. When m1, m2, m3 and m4 are integers of 2 to 4, a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ may be linked to form a ring.
(3) (1) or (2), wherein the photoelectric conversion film generates more electrons and holes in the vicinity of the second electrode film than in the vicinity of the first electrode film. Photoelectric conversion element.
(4) The photoelectric conversion film is configured to include an organic material other than the compound represented by the general formula (I) or the general formula (II). (1) to (3) The photoelectric conversion element in any one of these.
(5) The photoelectric conversion element according to (4), wherein the photoelectric conversion film includes at least one of an organic p-type semiconductor and an organic n-type semiconductor.
(6) The organic p-type semiconductor and the organic n-type semiconductor are each a compound represented by the general formula (I) or the general formula (II), a naphthalene derivative, an anthracene derivative, a phenanthrene derivative, a tetracene derivative, or a pyrene derivative. , A perylene derivative, and a fluoranthene derivative, The photoelectric conversion element as described in (5) characterized by the above-mentioned.
(7) The first electrode film is made of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al, Ag,
Or it is comprised including Au, The photoelectric conversion element in any one of (1)-(6) characterized by the above-mentioned.
(8) The second electrode film is made of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al,
The photoelectric conversion element according to any one of (1) to (7), wherein the photoelectric conversion element is configured to contain Ag or Au.
(9) The second electrode film includes ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , or FTO, and the photoelectric conversion unit includes the photoelectric conversion film and the second electrode. The photoelectric conversion element according to any one of (1) to (8), wherein a film made of a metal having a work function of 4.5 eV or less is provided between the film and the film.
(10) The photoelectric conversion element according to any one of (1) to (9), wherein the transmittance of the second electrode film with respect to visible light is 60% or more.
(11) The photoelectric conversion element according to any one of (1) to (10), wherein the first electrode film has a visible light transmittance of 60% or more.
(12) In the first electrode film and the second electrode film, a voltage is applied so that the electrons move to the second electrode film and the holes move to the first electrode film. , A semiconductor substrate provided below the first electrode film, a hole accumulating unit formed in the semiconductor substrate for accumulating the holes transferred to the first electrode film, and the hole accumulating The photoelectric conversion element according to any one of (1) to (11), further comprising a connection portion that electrically connects the portion and the first electrode film.
(13) The photoelectric conversion unit may include a film made of an organic polymer material between the first electrode film and the photoelectric conversion film. Photoelectric conversion element.
(14) In the semiconductor substrate below the photoelectric conversion film, an in-substrate photoelectric conversion unit that absorbs light transmitted through the photoelectric conversion film, generates a charge according to the light, and accumulates the charge is provided. The photoelectric conversion element according to (12) or (13), which is characterized.
(15) The photoelectric conversion element according to (14), wherein the in-substrate photoelectric conversion unit is a plurality of photodiodes that are stacked in the semiconductor substrate and absorb light of different colors.
(16) The in-substrate photoelectric conversion unit is a plurality of photodiodes that absorb light of different colors arranged in a direction perpendicular to the incident direction of the incident light in the semiconductor substrate. The photoelectric conversion element according to (14) or (15).
(17) A blue photodiode in which the pn junction surface is formed at a position where the plurality of photodiodes can absorb blue light, and a red photodiode in which the pn junction surface is formed at a position where red light can be absorbed. The photoelectric conversion element according to (15) or (16), wherein the photoelectric conversion element is a photodiode, and the photoelectric conversion film absorbs green light.
(18) The plurality of photodiodes are a blue photodiode that absorbs blue light and a red photodiode that absorbs red light, and the photoelectric conversion film absorbs green light. The photoelectric conversion element as described in (16) characterized by these.
(19) A plurality of the photoelectric conversion units are stacked above the semiconductor substrate, and the hole accumulating unit and the connection unit are provided for each of the plurality of photoelectric conversion units. The photoelectric conversion element according to any one of 18).
(20) The light transmitted through the first electrode film is absorbed between the semiconductor substrate and the first electrode film in the immediate vicinity of the semiconductor substrate, and a charge corresponding to the light is generated and accumulated. The photoelectric conversion element according to any one of (12) to (19), further comprising an inorganic photoelectric conversion unit made of an inorganic material.
(21) A solid-state imaging device in which a large number of photoelectric conversion elements according to any one of (12) to (19) are arranged in an array, and the plurality of photoelectric conversion elements accumulated in the semiconductor substrate of each of the multiple photoelectric conversion elements A solid-state imaging device comprising a signal reading unit that reads a signal corresponding to an electric charge.
(22) A solid-state imaging device in which a large number of photoelectric conversion elements according to (20) are arranged in an array, and a signal corresponding to the charge accumulated in the semiconductor substrate of each of the multiple photoelectric conversion elements; A solid-state imaging device, comprising: a signal reading unit that reads a signal corresponding to the charge accumulated in the inorganic photoelectric conversion unit.
(23) The solid-state imaging device according to (21) or (22), wherein the signal readout unit is configured by a MOS transistor.
(24) The photoelectric conversion film and the second electrode film included in the photoelectric conversion element are shared by the plurality of photoelectric conversion elements, and the first electrode film included in the photoelectric conversion element is The solid-state imaging device according to any one of (21) to (23), wherein the plurality of photoelectric conversion devices are separated.

  ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion element which can prevent a sensitivity fall and broadening of spectral sensitivity can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The present applicant provides a first electrode film, a second electrode film facing the first electrode film, and a quinacridone derivative or a quinazoline derivative of the present invention disposed between the first electrode film and the second electrode film. In a photoelectric conversion element having a photoelectric conversion part including a photoelectric conversion film containing, when light is incident from above the second electrode film, holes generated in the photoelectric conversion film are moved to the first electrode film And the holes transferred to the first electrode film are accumulated in the charge accumulating portion formed in the semiconductor substrate, and a signal corresponding to the holes accumulated in the charge accumulating portion is stored in the CCD or the like formed on the semiconductor substrate. It has been found that by using a signal reading unit such as a CMOS circuit to read out to the outside, the photoelectric conversion efficiency can be improved and the sensitivity can be lowered and the spectral sensitivity can be prevented from being broadened.
The basis for this is that when the moving distance of the electron is long, a part of the electron is deactivated during the movement and is collected by the electrode film, so that the photoelectric conversion efficiency is lowered, whereas the hole is Even if the movement distance is long, the mobility is much larger than that of the electron, so there is almost no deactivation during movement, and the compound of the present invention is particularly excellent in absorption waveform, hole mobility, etc. It is mentioned. In addition, as described above, the mobility of electrons is much smaller than the mobility of holes and is further reduced by the influence of the atmosphere, but the mobility of holes is affected by the atmosphere. However, since the mobility is originally large, the influence is limited.

The quinacridone derivative or quinazoline derivative (hereinafter, these derivatives may be referred to as “the compound of the present invention”) used in the present invention will be described. Any derivative may be used. The derivatives are described in S. S. Labana, L. L. Labana, Chemical Review (Chem. Rev.) 67, 1 (1967), Satoru Ito. It is described in Shiro, the pigment dictionary (Asakura Shoten, 2000) and the like.
These compounds can be used as a p-type semiconductor or an n-type semiconductor, but are preferably used as a p-type semiconductor. In other words, it can be used as a hole transport material or an electron transport material, but is preferably used as a hole transport material. In this case, the compound of the present invention absorbs light and functions as a transport material.

The compound represented by the general formula (I) or (II), which is preferably used as the derivative, will be described in detail.
In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group. In addition, the substituent that can be used in the compound in the present invention may be any substituent.

When such a substituent is W, the substituent represented by W is not particularly limited, and examples thereof include halogen atoms, alkyl groups (cycloalkyl groups, bicycloalkyl groups, tricycloalkyl groups). ), Alkenyl groups (including cycloalkenyl groups and bicycloalkenyl groups), alkynyl groups, aryl groups, heterocyclic groups (also referred to as heterocyclic groups), cyano groups, hydroxyl groups, nitro groups, carboxyl groups, Alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (including anilino group), ammonio group, acylamino group, aminocarbonyl Amino group, alkoxycarbonylamino group, Oxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl Group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, aryl and heterocyclic azo group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono group, silyl group , Hydrazino group, ureido group, boronic acid group (—B (OH) ₂ ), phosphato group (—OPO (OH) ₂ ), sulfato group (—OSO ₃ H), and other known substituents. It is done.

  More specifically, W represents a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group [a linear, branched, or cyclic substituted or unsubstituted alkyl group. They are alkyl groups (preferably alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl). A cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably having 5 to 30 carbon atoms). A substituted or unsubstituted bicycloalkyl group, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), a tricyclo structure with more ring structures Domo is intended to cover. An alkyl group (for example, an alkyl group of an alkylthio group) in the substituent described below represents an alkyl group having such a concept, but further includes an alkenyl group and an alkynyl group. ], An alkenyl group [represents a linear, branched or cyclic substituted or unsubstituted alkenyl group. They are alkenyl groups (preferably substituted or unsubstituted alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, prenyl, geranyl, oleyl), cycloalkenyl groups (preferably substituted or substituted groups having 3 to 30 carbon atoms). An unsubstituted cycloalkenyl group, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), Bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond. For example, bicyclo [2,2,1] hept-2-en-1-yl, bicyclo 2,2,2] oct-2-en-4-yl). An alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl, trimethylsilylethynyl group), an aryl group (preferably a substituted or unsubstituted aryl having 6 to 30 carbon atoms) Groups such as phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl, ferrocenyl), heterocyclic groups (preferably 5- or 6-membered substituted or unsubstituted, aromatic or non-aromatic A monovalent group obtained by removing one hydrogen atom from a heterocyclic compound, and more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 2-furyl, 2- Thienyl, 2-pyrimidinyl, 2-benzothiazolyl, 1-methyl-2-pyridinio, 1-methyl-2-quinoli A cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as methoxy group) , Ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2-methoxyethoxy), an aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy, 2-methyl Phenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoylaminophenoxy), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, such as trimethylsilyloxy, t-butyldimethylsilyloxy) A heterocyclic oxy group (preferably having 2 to 3 carbon atoms) Substituted or unsubstituted heterocyclic oxy group, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyl having 2 to 30 carbon atoms) An oxy group, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy), carbamoyloxy group (preferably A substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N-di-n-octylaminocarbonyl Oxy, Nn-octylcarbamoyloxy), alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n -Octylcarbonyloxy), aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, pn-hexa Decyloxyphenoxycarbonyloxy), amino group (preferably amino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, substituted or unsubstituted arylamino group having 6 to 30 carbon atoms) For example, amino, methylamino, dimethylamino, anilino, N-methyl-anilino, diphenylamino), an ammonio group (preferably an ammonio group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, aryl, or heterocyclic ring is substituted. Ammonio groups such as trimethylammonio, triethylammonio, diphenylmethylammonio), acylamino groups (preferably formylamino groups, substituted or unsubstituted alkylcarbonylamino groups having 1 to 30 carbon atoms, 6 to 30 carbon atoms) Substituted or unsubstituted arylcarbonylamino groups such as formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino, 3,4,5-tri-n-octyloxyphenylcarbonylamino), aminocarbonylamino A group (preferably a substituted or unsubstituted aminocarbonylamino having 1 to 30 carbon atoms, such as carbamoylamino, N, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino), alkoxycarbonylamino Group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxycarbonylamino) An aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms such as phenoxycarbonylamino, p-chlorophenoxy Carbonylamino, mn-octyloxyphenoxycarbonylamino), sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms such as sulfamoylamino, N, N -Dimethylaminosulfonylamino, Nn-octylaminosulfonylamino), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino groups having 1 to 30 carbon atoms, substituted or unsubstituted groups having 6 to 30 carbon atoms) Substituted arylsulfonylamino groups such as methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino), mercapto groups, alkylthio groups (preferably Is a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms such as methylthio, ethylthio, n-hexadecylthio), an arylthio group (preferably a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms such as phenylthio, p -Chlorophenylthio, m-methoxyphenylthio), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio, 1-phenyltetrazole-5- Ylthio), sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl) N-acetylsulfamoyl, N-benzoyls Famoyl, N- (N′-phenylcarbamoyl) sulfamoyl), sulfo group, alkyl and arylsulfinyl group (preferably substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, substituted or unsubstituted group having 6 to 30 carbon atoms) Arylsulfinyl groups such as methylsulfinyl, ethylsulfinyl, phenylsulfinyl, p-methylphenylsulfinyl), alkyl and arylsulfonyl groups (preferably substituted or unsubstituted alkylsulfonyl groups having 1 to 30 carbon atoms, 6 to 30 A substituted or unsubstituted arylsulfonyl group such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl, p-methylphenylsulfonyl), an acyl group (preferably a formyl group, a substituted or unsubstituted group having 2 to 30 carbon atoms) An alkylcarbonyl group, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, a heterocyclic carbonyl group bonded to the carbonyl group by a substituted or unsubstituted carbon atom having 4 to 30 carbon atoms, such as acetyl, pivaloyl 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, 2-furylcarbonyl), an aryloxycarbonyl group (preferably a substituted or unsubstituted aryl having 7 to 30 carbon atoms) An oxycarbonyl group such as phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, pt-butylphenoxycarbonyl), an alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxy group having 2 to 30 carbon atoms) Bonyl group such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, n-octadecyloxycarbonyl), carbamoyl group (preferably substituted or unsubstituted carbamoyl having 1 to 30 carbon atoms such as carbamoyl, N-methylcarbamoyl) N, N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl, N- (methylsulfonyl) carbamoyl), aryl and heterocyclic azo group (preferably a substituted or unsubstituted arylazo group having 6 to 30 carbon atoms) A substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, such as phenylazo, p-chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo), an imide group (preferably N -Succinimide, N-phthalimide) A phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino, diphenylphosphino, methylphenoxyphosphino), a phosphinyl group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms) An unsubstituted phosphinyl group such as phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl), a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms such as , Diphenoxyphosphinyloxy, dioctyloxyphosphinyloxy), a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as dimethoxyphosphinylamino, Dimethylaminophosphinylamino), phosphor Group, silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, such as trimethylsilyl, triethylsilyl, triisopropylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl), hydrazino group (preferably carbon A substituted or unsubstituted hydrazino group of 0 to 30 or a ureido group (preferably a substituted or unsubstituted ureido group of 0 to 30 carbon atoms such as N, N-dimethylureido), Represent.

  In addition, two Ws can be combined to form a ring (aromatic or non-aromatic hydrocarbon ring or heterocyclic ring. These can be further combined to form a polycyclic fused ring. For example, a benzene ring or naphthalene. Ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, Indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring, Phenanthroline ring, thian Ren ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, or a phenazine ring.) May also be formed.

Among the above-described substituents W, those having a hydrogen atom may be substituted with the above groups by removing this. Examples of such substituents, -CONHSO ₂ - group (sulfonylcarbamoyl group, a carbonyl sulfamoyl group), - CONHCO- group (carbonylation carbamoyl _group), - SO ₂ NHSO 2 - group (sulfonylsulfamoyl group ).
More specifically, an alkylcarbonylaminosulfonyl group (eg, acetylaminosulfonyl), an arylcarbonylaminosulfonyl group (eg, benzoylaminosulfonyl group), an alkylsulfonylaminocarbonyl group (eg, methylsulfonylaminocarbonyl), or arylsulfonyl An aminocarbonyl group (for example, p-methylphenylsulfonylaminocarbonyl) is mentioned.

The substituents represented by R ³ , R ⁴ , R ⁵ , and R ⁶ in general formula (I) and general formula (II) may be any substituent, and examples thereof include the aforementioned W.

The substituent represented by R ¹ and R ² is an alkyl group, an aryl group, or a heterocyclic group, and more preferably an alkyl group, an aryl group, or a heterocyclic group described in the above example of W. 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 , R ⁴ , R ⁵ , R ⁶ is preferably a halogen atom, an alkyl group, an alkoxy group, an aryl group, or a heterocyclic group, and more preferably the aforementioned R ³ , R ⁴ , R ^5. , R ⁶ represents a halogen atom, an alkyl group, an alkoxy group, an aryl group, or a heterocyclic group described in the example of the substituent (substituent W), and R ³ , R ⁴ , R ⁵ , and R ⁶ are preferably A halogen atom, an alkyl group, or an alkoxy group, more preferably a halogen atom or an alkyl group, and particularly preferably an alkyl group. m1, m2, m3 and m4 are preferably 0 or 1.

  Among the compounds represented by general formula (I) to general formula (II), those more preferably used in the present invention are compounds represented by general formula (I).

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

The compounds shown in the above specific examples are S. S. Labana, L. L. Labana, Chemical Review (Chem. Rev.) 67, 1 ( 1967), edited by Seijiro Ito, dictionary of pigments (Asakura Shoten, 2000) and the like.
In addition, compounds belonging to the present invention described in these documents can be used in the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, a configuration example will be described which can be cited as a sensor having a configuration in which the photoelectric conversion units as described above are stacked above a semiconductor substrate.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of one pixel of a solid-state imaging device for explaining the first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the photoelectric conversion layer shown in FIG. This solid-state imaging device has a large number of one pixel shown in FIG. 1 arranged in an array on the same plane, and one pixel data of image data can be generated by a signal obtained from the one pixel.
One pixel of the solid-state imaging device shown in FIG. 1 includes an n-type silicon substrate 1, a transparent insulating film 7 formed on the n-type silicon substrate 1, a first electrode film 11 formed on the insulating film 7, A photoelectric conversion layer 12 formed on the first electrode film 11, and a photoelectric conversion unit including the second electrode film 13 formed on the photoelectric conversion layer 12. The provided light shielding film 14 is formed, and the light receiving region of the photoelectric conversion layer 12 is limited by the light shielding film 14. A transparent insulating film 15 is formed on the light shielding film 14 and the second electrode film 13.

  As shown in FIG. 2, the photoelectric conversion layer 12 includes an undercoat film 121, an electron blocking film 122, a photoelectric conversion film 123, a hole blocking film 124, and a hole blocking function on the first electrode film 11. A buffer film 125 and a work function adjusting film 126 are stacked in this order. The photoelectric conversion layer 12 should just contain the photoelectric conversion film 123 at least among these.

  The photoelectric conversion film 123 generates charges including electrons and holes in response to incident light from above the second electrode film 13, has a lower electron mobility than the hole mobility, and the first The vicinity of the second electrode film 13 includes a material having characteristics that generate more electrons and holes than the vicinity of the electrode film 11. A representative example of such a material for a photoelectric conversion film is an organic material containing the compound of the present invention. In the configuration of FIG. 1, the photoelectric conversion film 123 uses a material that absorbs green light and generates electrons and holes corresponding thereto. Since the photoelectric conversion film 123 can be used in common for all pixels, it may be a single-layer film and does not need to be separated for each pixel.

The organic material constituting the photoelectric conversion film 123 preferably contains at least one of an organic p-type semiconductor and an organic n-type semiconductor. The compound of the present invention may be any of these semiconductors, or may further contain the compound of the present invention in addition to these semiconductors.
As an organic p-type semiconductor and an organic n-type semiconductor, compounds represented by the above general formula (I) or general formula (II) (so-called quinacridone derivatives or quinazoline derivatives), naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, Any of a pyrene derivative, a perylene derivative, and a fluoranthene derivative can be particularly preferably used.

  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, o Metal complexes having as ligands such as saziazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds 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 p-type organic dye or n-type organic dye may be used, but preferably a cyanine dye, styryl dye, hemicyanine dye, merocyanine dye (including zero methine merocyanine (simple merocyanine)), three nucleus Merocyanine dye, tetranuclear merocyanine dye, rhodacyanine 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, triphenyl Methane dye, azo dye, azomethine dye, spiro compound, metallocene dye, fluorenone dye, fulgide dye, perylene dye, phenazine dye, phenothiazine dye, quinone dye, indigo Dye, diphenylmethane dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye, quinophthalone dye, phenoxazine dye, phthaloperylene dye, porphyrin dye, chlorophyll dye, phthalocyanine dye, metal complex dye, condensed aromatic carbocyclic dye (Naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives).

Next, the metal complex dye (compound) will be described. The metal complex dye (compound) is a metal complex having a ligand having at least one nitrogen atom, oxygen atom or sulfur atom coordinated to a metal, and the metal ion in the metal complex is not particularly limited, but preferably beryllium Ion, magnesium ion, aluminum ion, gallium ion, zinc ion, indium ion, or tin ion, more preferably beryllium ion, aluminum ion, gallium ion, or zinc ion, and still more preferably aluminum ion or zinc ion It is. There are various known ligands included in the metal complex. For example, “Photochemistry and Photophysics of Coordination Compounds” Springer-V
erlag H. Examples include the ligands described in Yersin's 1987 issue, “Organometallic Chemistry-Fundamentals and Applications”, Akebono Yamasha Akio's 1982 issue.
The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Or a bidentate or higher ligand, preferably a bidentate ligand such as a pyridine ligand, a bipyridyl ligand, a quinolinol ligand, a hydroxyphenylazole ligand (hydroxyphenyl) Benzimidazole, hydroxyphenylbenzoxazole ligand, hydroxyphenylimidazole ligand)), alkoxy ligand (preferably 1-30 carbon atoms, more preferably 1-20 carbon atoms, particularly preferably carbon 1-10, for example, methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), aryloxy ligands Preferably it has 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, 2,4,6-trimethylphenyl Oxy, 4-biphenyloxy, etc.), heteroaryloxy ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridyl. Oxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), alkylthio ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio, etc.), arylthio ligands (preferably having 6 to 30 carbon atoms, more preferred) Has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), a heterocyclic substituted thio ligand (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, or siloxy ligand (preferably Has 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group. More preferably a nitrogen-containing heterocyclic ligand, an aryloxy ligand, a heteroaryloxy group, or a siloxy ligand, Preferably, a nitrogen-containing heterocyclic ligand, an aryloxy ligand, or a siloxy ligand is used.

  The photoelectric conversion layer 12 includes a p-type semiconductor layer and an n-type semiconductor layer, at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and the p-type semiconductor layer is interposed between the semiconductor layers. It is preferable to include a photoelectric conversion film having a bulk heterojunction structure layer including a n-type semiconductor and an n-type semiconductor as an intermediate layer. In such a case, by including a bulk heterojunction structure in the photoelectric conversion layer 12, it is possible to compensate for the shortcoming that the carrier diffusion length of the photoelectric conversion layer 12 is short, and to improve the photoelectric conversion efficiency of the photoelectric conversion film. The bulk heterojunction structure is described in detail in JP-A-2005-303266.

  The photoelectric conversion layer 12 may contain a photoelectric conversion film having a structure having two or more repeating structures (tandem structures) of a pn junction layer formed of a p-type semiconductor layer and an n-type semiconductor layer. Preferably, more preferably, a thin layer of conductive material is inserted between the repetitive structures. The number of repeating structures (tandem structures) of the pn junction layer may be any number, but is preferably 2 to 50, more preferably 2 to 30, particularly preferably 2 or 10 in order to increase the photoelectric conversion efficiency. It is. Silver or gold is preferable as the conductive material, and silver is most preferable. The tandem structure is described in detail in Japanese Patent Application Laid-Open No. 2005-303266.

  The photoelectric conversion film included in the photoelectric conversion layer 12 includes a p-type semiconductor layer, an n-type semiconductor layer (preferably a mixed / dispersed (bulk heterojunction structure) layer), and includes a p-type semiconductor and an n-type semiconductor. It is preferable that at least one of them includes an organic compound whose orientation is controlled, and more preferably, it includes a (possible) organic compound whose alignment is controlled in both the p-type semiconductor and the n-type semiconductor. As this organic compound, those having π-conjugated electrons are preferably used, and it is more preferable that the π-electron plane is oriented at an angle close to parallel rather than perpendicular to the substrate (electrode substrate). As described above, the organic compound layer whose orientation is controlled may be partially included in the entire photoelectric conversion layer 12. Such a state compensates the shortcoming of the short carrier diffusion length of the photoelectric conversion layer 12 by controlling the orientation of the organic compound contained in the photoelectric conversion layer 12, and improves the photoelectric conversion efficiency of the photoelectric conversion film. is there.

  In the case where the orientation of the organic compound is controlled, it is more preferable that the heterojunction plane (for example, the pn junction plane) is not parallel to the substrate. It is more preferable that the heterojunction plane is oriented not at a parallel to the substrate (electrode substrate) but at an angle close to the vertical. The organic compound layer whose heterojunction surface is controlled as described above may be partially included in the entire photoelectric conversion layer 12. In such a case, the area of the heterojunction surface in the photoelectric conversion layer 12 increases, the amount of carriers of electrons, holes, electron-hole pairs, etc. generated at the interface increases, and the photoelectric conversion efficiency can be improved. In the above-described photoelectric conversion film in which the orientation of both the heterojunction plane and the π-electron plane of the organic compound is controlled, the photoelectric conversion efficiency can be particularly improved. These states are described in detail in Japanese Patent Application No. 2005-042357. In terms of light absorption, the thickness of the organic dye layer is preferably as large as possible, but considering the ratio that does not contribute to charge separation, the thickness of the organic dye layer is preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, Especially preferably, it is 80 nm or more and 200 nm or less.

  The photoelectric conversion layer 12 containing these organic compounds 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 where a polymer compound is used as at least one of the p-type semiconductor (compound) and the n-type semiconductor (compound), it is preferable to form the film by a wet film forming method that is easy to prepare. 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, 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 degree of vacuum is preferably higher, and vacuum deposition is performed at 10 ⁻⁴ Torr or less, preferably 10 ⁻⁶ Torr or less, particularly preferably 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.

  Since the solid-state imaging device 100 includes the photoelectric conversion film 123 having the above-described characteristics, as described above, holes are collected by the first electrode film 11 that is an electrode opposite to the light incident side electrode. By using this, the external quantum efficiency can be increased, and the sensitivity can be improved and the spectral sensitivity can be sharpened. Therefore, in the solid-state imaging device 100, the first electrode is formed such that electrons generated in the photoelectric conversion film 123 move to the second electrode film 13 and holes generated in the photoelectric conversion film 123 move to the first electrode film 11. A voltage is applied to the film 11 and the second electrode film 13.

The undercoat film 121 is for reducing unevenness on the first electrode film 11. When the first electrode film 11 has irregularities, or when dust adheres to the first electrode film 11, a low molecular organic material is deposited thereon to form the photoelectric conversion film 123. It is easy to form a fine crack in the photoelectric conversion element 123, that is, a portion where the photoelectric conversion film 123 is formed only thin. At this time, if the second electrode film 13 is further formed thereon, the crack portion is covered by the second electrode film 13 and close to the first electrode film 11, so that a DC short circuit and an increase in leakage current are likely to occur. In particular, when TCO is used as the second electrode film 13, the tendency is remarkable. For this reason, the unevenness | corrugation can be relieve | moderated by providing the undercoat film | membrane 121 on the 1st electrode film | membrane 11 previously, and these can be suppressed.
Examples of the undercoat film 121 include organic polymer materials such as polyaniline, polythiophene, polypyrrole, polycarbazole, PTPDES, and PTPDK, and are preferably formed by a spin coating method.

  The electron blocking film 122 is provided in order to reduce dark current due to injection of electrons from the first electrode film 11, and the electrons from the first electrode film 11 are injected into the photoelectric conversion film 123. Stop.

  The hole blocking film 124 is provided to reduce dark current caused by holes injected from the second electrode film 13, and holes from the second electrode film 13 are injected into the photoelectric conversion film 123. To stop.

The hole blocking / buffer film 125 has a function of reducing the damage given to the photoelectric conversion film 123 when the second electrode film 13 is formed, in addition to the function of the hole blocking film 124.
When the second electrode film 13 is formed on the photoelectric conversion film 123, high-energy particles existing in an apparatus used for forming the second electrode film 13, such as sputtered particles and secondary electrons in the case of sputtering, When the Ar particles, oxygen negative ions, and the like collide with the photoelectric conversion film 123, the photoelectric conversion film 123 may be altered, and performance degradation such as increase in leakage current or reduction in sensitivity may occur. As one method for preventing this, it is preferable to provide the buffer film 125 on the photoelectric conversion film 123.
The material of the hole blocking / buffer film 125 is preferably an organic substance such as copper phthalocyanine, PTCDA, acetylacetonate complex, or BCP, an organic-metal compound, or an inorganic substance such as MgAg or MgO. Further, the hole blocking and buffer film 125 preferably has a high visible light transmittance so as not to prevent light absorption of the photoelectric conversion film 123, and a material that does not absorb in the visible region is selected. It is preferable to use an extremely thin film thickness. The film thickness of the hole blocking / buffer film 125 varies depending on the configuration of the photoelectric conversion film 123, the film thickness of the second electrode film 13, and the like, but it is particularly preferable to use a film thickness of 2 to 50 nm.

The work function adjustment film 126 is for adjusting the work function of the second electrode film 13 and suppressing dark current. When the second electrode film 13 is made of a material having a relatively large work function (for example, 4.5 eV or more) (for example, any one of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , and FTO), the work As a material of the function adjusting film 126, a dark current can be effectively suppressed by using a material containing a metal having a work function of 4.5 eV or less (for example, In). The description of the advantages and the like by providing such a work function adjusting film 126 will be described later.

  Returning to FIG. 1, in the n-type silicon substrate 1, a p-type semiconductor region (hereinafter abbreviated as p region) 4, an n-type semiconductor region (hereinafter abbreviated as n region) 3, and a p region from the shallower side. 2 are formed in this order. A high-concentration p region (referred to as a p + region) 6 is formed on the surface portion of the p region 4 that is shielded by the light shielding film 14, and the p + region 6 is surrounded by the n region 5.

  The depth of the pn junction surface between the p region 4 and the n region 3 from the surface of the n-type silicon substrate 1 is a depth that absorbs blue light (about 0.2 μm). Therefore, the p region 4 and the n region 3 absorb blue light, generate holes corresponding thereto, and form a photodiode (B photodiode) that accumulates the holes. Holes generated in the B photodiode are accumulated in the p region 4.

  The depth of the pn junction surface between the p region 2 and the n-type silicon substrate 1 from the surface of the n-type silicon substrate 1 is a depth that absorbs red light (about 2 μm). Therefore, the p region 2 and the n-type silicon substrate 1 absorb red light, generate holes corresponding to the red light, and form a photodiode (R photodiode) that accumulates the holes. Holes generated in the R photodiode are accumulated in the p region 2.

  The p + region 6 is electrically connected to the first electrode film 11 via a connection portion 9 formed in an opening opened in the insulating film 7, and is connected to the first electrode film 11 via the connection portion 9. Accumulate the collected holes. The connection portion 9 is electrically insulated by the insulating film 8 except for the first electrode film 11 and the p + region 6.

  The holes accumulated in the p region 2 are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) made of a p-channel MOS transistor formed in the n-type silicon substrate 1 and accumulated in the p region 4. The generated holes are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n region 3, and the electrons accumulated in the p + region 6 5 is converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in 5 and output to the outside of the solid-state imaging device 100. These MOS circuits constitute the signal readout section in the claims. Each MOS circuit is connected to a signal readout pad (not shown) by wiring 10. If extraction electrodes are provided in the p region 2 and the p region 4 and a predetermined reset potential is applied, each region is depleted, and the capacitance of each pn junction becomes an infinitely small value. Thereby, the capacity | capacitance produced in a joint surface can be made very small.

  With such a configuration, G light can be photoelectrically converted by the photoelectric conversion film 123, and B light and R light can be photoelectrically converted by the B photodiode and the R photodiode in the n-type silicon substrate 1. In addition, since G light is first absorbed at the top, color separation between BG and between GR is excellent. This is a great advantage over a solid-state imaging device in which three PDs are stacked in a silicon substrate and all BGR light is separated in the silicon substrate. In the following description, the part (B photodiode and R photodiode) that performs photoelectric conversion made of an inorganic material formed in the n-type silicon substrate 1 of the solid-state imaging device 100 is also referred to as an inorganic layer.

  In addition, light that has passed through the photoelectric conversion film 123 is absorbed between the n-type silicon substrate 1 and the first electrode film 11 (for example, between the insulating film 7 and the n-type silicon substrate 1), and in response to the light. It is also possible to form an inorganic photoelectric conversion portion made of an inorganic material that generates and accumulates the charges. In this case, a MOS circuit for reading a signal corresponding to the charge accumulated in the charge accumulation region of the inorganic photoelectric conversion unit is provided in the n-type silicon substrate 1, and the wiring 10 is also connected to this MOS circuit. It ’s fine.

The first electrode film 11 plays a role of collecting holes generated and moved in the photoelectric conversion film 123. The first electrode film 11 is separated for each pixel, whereby image data can be generated. In the configuration shown in FIG. 1, since photoelectric conversion is also performed on the n-type silicon substrate 1, the first electrode film 11 preferably has a visible light transmittance of 60% or more, more preferably 90%. preferable. In the case where the photoelectric conversion region does not exist below the first electrode film 11, the first electrode film 11 may be low in transparency. As a material, any of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al, Ag, and Au can be most preferably used. Details of the first electrode film 11 will be described later.

The second electrode film 13 has a function of discharging electrons generated and moved in the photoelectric conversion film 123. The second electrode film 13 can be used in common for all pixels. For this reason, in the solid-state imaging device 100, the second electrode film 13 is a single-layer film common to all pixels. Since the second electrode film 13 needs to make light incident on the photoelectric conversion film 123, it is necessary to use a material having high transparency to visible light. The second electrode film 13 preferably has a visible light transmittance of 60% or more, and more preferably 90%. As a material, any of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , FTO, Al, Ag, and Au can be most preferably used.
Details of the second electrode film 13 will be described later.

  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. 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 significantly improved by using the photoelectric conversion layer 12 as an upper layer as shown in FIG. 1, that is, by detecting light transmitted through the photoelectric conversion layer 12 in the depth direction of silicon. In particular, as shown in FIG. 1, when G light is detected by the photoelectric conversion layer 12, light transmitted through the photoelectric conversion layer 12 becomes B light and R light. Therefore, the separation of light in the depth direction in silicon is BR. Only light is used and color separation is improved. Even when the photoelectric conversion layer 12 detects B light or R light, color separation is remarkably improved by appropriately selecting the depth of the pn junction surface of silicon.

  The structure of the inorganic layer 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.

  Although FIG. 1 shows a configuration in which one photoelectric conversion unit is stacked above the n-type silicon substrate 1, a configuration in which a plurality of photoelectric conversion units are stacked above the n-type silicon substrate 1 is also possible. is there. A configuration in which a plurality of photoelectric conversion units are stacked will be described later in a third embodiment. In this case, the light detected by the inorganic layer may be one color, and preferable color separation can be achieved. Further, when detecting four colors of light with one pixel of the solid-state imaging device 100, for example, a configuration in which one color is detected with one photoelectric conversion unit and three colors are detected with an inorganic layer, A structure in which two photoelectric conversion units are stacked to detect two colors and two colors are detected in the inorganic layer, three photoelectric conversion units are stacked to detect three colors, and one color is detected in the inorganic layer Configuration etc. can be considered. The solid-state imaging device 100 may be configured to detect only one color with one pixel. In this case, the p region 2, the n region 3, and the p region 4 are eliminated in FIG.

  The inorganic layer will be described in more detail. As a preferable configuration of the inorganic layer, a photoconductive type, a pn junction type, a Schottky junction type, a PIN junction type, an MSM (metal-semiconductor-metal) type light receiving element or a phototransistor type light receiving element can be given. In particular, as shown in FIG. 1, a plurality of first conductivity type regions and second conductivity type regions that are opposite to the first conductivity type are alternately stacked in a single semiconductor substrate. It is preferable to use an inorganic layer formed by forming each bonding surface of the first conductivity type region and the second conductivity type region to a depth suitable for mainly photoelectrically converting light in a plurality of different wavelength bands. . As the single semiconductor substrate, single crystal silicon is preferable, and color separation can be performed using absorption wavelength characteristics depending on the depth direction of the silicon substrate.

As the inorganic semiconductor, an InGaN-based, InAlN-based, InAlP-based, or InGaAlP-based inorganic semiconductor can also be used. The nGaN-based inorganic semiconductor is adjusted so as to have a maximum absorption value in the blue wavelength range by appropriately changing the composition of In. That is, the composition is In _x Ga _1-x N (0 ≦ X <1). Such a compound semiconductor is manufactured using a metal organic chemical vapor deposition method (MOCVD method). A nitride semiconductor InAlN system using Al, which is the same group 13 raw material as Ga, can also be used as a short wavelength light receiving section in the same manner as the InGaN system. It is also possible to use InAlP or InGaAlP lattice-matched to the GaAs substrate.

  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.

  As the material of the first electrode film 11 and the second electrode film 13, a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used. As metal materials, Li, Na, Mg, K, Ca, Rb, Sr, Cs, Ba, Fr, Ra, Sc, Ti, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn , Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P , As, Sb, Bi, Se, Te, Po, Br, I, At, B, C, N, F, O, S, and N may be mentioned, but particularly preferred Are Al, Pt, W, Au, Ag, Ta, Cu, Cr, Mo, Ti, Ni, Pd, and Zn.

  The first electrode film 11 takes out holes from the hole-transporting photoelectric conversion film or hole-transporting film contained in the photoelectric conversion layer 12 and collects them, so that the hole-transporting photoelectric conversion film, hole It is selected in consideration of adhesion to an adjacent film such as a transport film, electron affinity, ionization potential, and stability. The second electrode film 13 takes out electrons from the electron transport photoelectric conversion film or electron transport film included in the photoelectric conversion layer 12 and discharges them, so that adjacent films such as an electron transport photoelectric conversion film and an electron transport film are used. Is selected in consideration of adhesiveness, electron affinity, ionization potential, stability, and the like. 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.

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

  The conditions for forming a transparent electrode film (transparent electrode film) will be described. The silicon substrate temperature at the time of forming the transparent electrode film is preferably 500 ° C. or lower, more preferably 300 ° C. or lower, further preferably 200 ° C. or lower, and further preferably 150 ° C. or lower. Further, a gas may be introduced during the formation of the transparent electrode film, and basically the gas species is not limited, but Ar, He, oxygen, nitrogen and the like can be used. Further, a mixed gas of these gases may be used. In particular, in the case of an oxide material, oxygen defects are often introduced, so that oxygen is preferably used.

  Further, the preferable range of the surface resistance of the transparent electrode film differs depending on whether it is the first electrode film 11 or the second electrode film 13. When the signal readout part has a CMOS structure, the surface resistance of the transparent conductive film is preferably 10000Ω / □ or less, more preferably 1000Ω / □ or less. If the signal reading unit has a CCD structure, the surface resistance is preferably 1000Ω / □ or less, and more preferably 100Ω / □ or less. When used for the second electrode film 13, it is preferably 1000000 Ω / □ or less, more preferably 100000 Ω / □ or less.

Particularly preferable as the material 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 90% or more, at the absorption peak wavelength of the photoelectric conversion film included in the photoelectric conversion part including the transparent electrode film. More preferably, it is 95% or more.

  In addition, when a plurality of photoelectric conversion layers 12 are stacked, the first electrode film 11 and the second electrode film 13 are respectively connected from the photoelectric conversion film located closest to the light incident side to the photoelectric conversion film located farthest. It is necessary to transmit light having a wavelength other than the light detected by the photoelectric conversion film, and it is preferable to use a material that transmits light of 90%, more preferably 95% or more with respect to visible light.

  The second electrode film 13 is preferably made plasma-free. By creating the second electrode film 13 free of 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 second electrode film 13, 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 reaching the substrate is reduced.

  Examples of apparatuses that do not generate plasma during the formation of the second electrode film 13 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. can be 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.

  When a transparent conductive film such as TCO is used as the second electrode film 13, a DC short circuit or an increase in leakage current may occur. One reason for this is thought to be that fine cracks introduced into the photoelectric conversion film 123 are covered by a dense film such as TCO, and conduction between the first electrode film 11 on the opposite side is increased. For this reason, in the case of an electrode having a poor film quality such as Al, an increase in leakage current hardly occurs. By controlling the film thickness of the second electrode film 13 with respect to the film thickness of the photoelectric conversion film 123 (that is, the depth of cracks), an increase in leakage current can be largely suppressed. The thickness of the second electrode film 13 is desirably 1/5 or less of the thickness of the photoelectric conversion film 123, preferably 1/10 or less.

  Usually, when the conductive film is made thinner than a certain range, the resistance value is rapidly increased. However, in the solid-state imaging device 100 of the present embodiment, the sheet resistance is preferably 100 to 10,000 Ω / □, and can be thinned. The degree of freedom in the thickness range is large. Further, the thinner the transparent conductive thin film is, the less light is absorbed, and the light transmittance is generally increased. An increase in light transmittance is very preferable because it increases the light absorption in the photoelectric conversion film 123 and increases the photoelectric conversion ability. Considering the suppression of leakage current, the increase in the resistance value of the thin film, and the increase in transmittance due to the thinning, the thickness of the transparent conductive thin film is preferably 5 to 100 nm, more preferably 5 to 20 nm. Something is desirable.

  The material of the transparent electrode film 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.

  The advantages and technical contents of providing the work function adjusting film 126 are described in detail in Japanese Patent Application No. 2005-251745.

(Second embodiment)
In the present embodiment, the inorganic layer having the configuration shown in FIG. 1 described in the first embodiment is not laminated with two photodiodes in an n-type silicon substrate, but in a direction perpendicular to the incident direction of incident light. Two photodiodes are arranged to detect two colors of light in the n-type silicon substrate.

FIG. 3 is a schematic cross-sectional view of one pixel of a solid-state image sensor for explaining the second embodiment of the present invention.
One pixel of the solid-state imaging device 200 shown in FIG. 3 includes an n-type silicon substrate 17, a first electrode film 30 formed above the n-type silicon substrate 17, and a photoelectric conversion layer 31 formed on the first electrode film 30. And a photoelectric conversion part composed of the second electrode film 32 formed on the photoelectric conversion layer 31, and a light shielding film 34 having an opening is formed on the photoelectric conversion part. The light receiving region of the photoelectric conversion layer 31 is limited by the film 34. A transparent insulating film 33 is formed on the light shielding film 34.

  The first electrode film 30, the photoelectric conversion layer 31, and the second electrode film 32 have the same configuration as the first electrode film 11, the photoelectric conversion layer 12, and the second electrode film 13.

  On the surface of the n-type silicon substrate 17 below the opening of the light shielding film 34, a photodiode composed of the n region 19 and the p region 18 and a photodiode composed of the n region 21 and the p region 20 are formed on the surface of the n-type silicon substrate 17. It is formed side by side. An arbitrary direction on the surface of the n-type silicon substrate 17 is a direction perpendicular to the incident direction of incident light.

  Above the photodiode composed of the n region 19 and the p region 18, a color filter 28 that transmits B light through a transparent insulating film 24 is formed, and a first electrode film 30 is formed thereon. A color filter 29 that transmits R light through a transparent insulating film 24 is formed above the photodiode composed of the n region 21 and the p region 20, and a first electrode film 30 is formed thereon. The periphery of the color filters 28 and 29 is covered with a transparent insulating film 25.

  The photodiode composed of the n region 19 and the p region 18 absorbs the B light transmitted through the color filter 28 and generates holes corresponding thereto, and accumulates the generated holes in the p region 18. The photodiode composed of the n region 21 and the p region 20 absorbs the R light transmitted through the color filter 29 and generates holes corresponding thereto, and accumulates the generated holes in the p region 20.

  A p + region 23 is formed on the surface of the p-type silicon substrate 17 that is shielded by the light shielding film 34, and the p + region 23 is surrounded by the n region 22.

  The p + region 23 is electrically connected to the first electrode film 30 via a connection portion 27 formed in an opening formed in the insulating films 24 and 25, and the first electrode film is connected via the connection portion 27. The holes collected at 30 are accumulated. The connecting portion 27 is electrically insulated by the insulating film 26 except for the first electrode film 30 and the p + region 23.

The holes accumulated in the p region 18 are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n-type silicon substrate 17 and accumulated in the p region 20. The generated holes are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n-type silicon substrate 17, and the holes accumulated in the p + region 23 are The signal is converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n region 22 and output to the outside of the solid-state imaging device 200. These MOS circuits constitute the signal readout section in the claims. Each MOS circuit is connected to a signal readout pad (not shown) by wiring 35.
The signal reading unit may be constituted by a CCD and an amplifier instead of the MOS circuit. That is, the holes accumulated in the p region 18, the p region 20, and the p + region 23 are read out to the CCD formed in the n-type silicon substrate 17, transferred to the amplifier by the CCD, and transferred from the amplifier to the holes. A signal reading unit that outputs a corresponding signal may be used.

As described above, the signal reading unit includes a CCD and a CMOS structure, but CMOS is preferable from the viewpoint of power consumption, high-speed reading, pixel addition, partial reading, and the like.

  In FIG. 3, the color filters 28 and 29 perform color separation of the R light and the B light. However, the color filters 28 and 29 are not provided, and the depths of the pn junction surfaces of the p region 20 and the n region 21 are as follows. The depths of the pn junction surfaces of the p region 18 and the n region 19 may be adjusted to absorb the R light and the B light with the respective photodiodes. In this case, the light transmitted through the photoelectric conversion layer 31 is absorbed between the n-type silicon substrate 17 and the first electrode film 30 (for example, between the insulating film 24 and the n-type silicon substrate 17), and the light is absorbed. It is also possible to form an inorganic photoelectric conversion portion made of an inorganic material that generates and accumulates a corresponding charge. In this case, a MOS circuit for reading a signal corresponding to the charge accumulated in the charge accumulation region of the inorganic photoelectric conversion unit is provided in the n-type silicon substrate 17, and the wiring 35 is also connected to this MOS circuit. It ’s fine.

  Alternatively, a single photodiode provided in the n-type silicon substrate 17 may be used, and a plurality of photoelectric conversion units may be stacked above the n-type silicon substrate 17. Further, a plurality of photodiodes provided in the n-type silicon substrate 17 may be provided, and a plurality of photoelectric conversion units may be stacked above the n-type silicon substrate 17. If there is no need to produce a color image, a single photodiode provided in the n-type silicon substrate 17 and only one photoelectric conversion unit may be stacked.

(Third embodiment)
The solid-state imaging device of this embodiment has a configuration in which a plurality of (here, three) photoelectric conversion layers are stacked above a silicon substrate without providing the inorganic layer having the configuration shown in FIG. 1 described in the first embodiment.
FIG. 4 is a schematic cross-sectional view of one pixel of a solid-state image sensor for explaining the third embodiment of the present invention.
A solid-state imaging device 300 illustrated in FIG. 4 includes a first electrode film 56, a photoelectric conversion layer 57 stacked on the first electrode film 56, and a second electrode stacked on the photoelectric conversion layer 57 above the silicon substrate 41. B photoelectric including an R photoelectric conversion portion including a film 58, a first electrode film 60, a photoelectric conversion layer 61 stacked on the first electrode film 60, and a second electrode film 62 stacked on the photoelectric conversion layer 61. The conversion unit, the G photoelectric conversion unit including the first electrode film 64, the photoelectric conversion layer 65 stacked on the first electrode film 64, and the second electrode film 66 stacked on the photoelectric conversion layer 65, respectively. In this state, the first electrode film included in the structure is laminated in this order with the first electrode film facing the silicon substrate 41 side.

  A transparent insulating film 48 is formed on the silicon substrate 41, an R photoelectric conversion portion is formed thereon, a transparent insulating film 59 is formed thereon, a B photoelectric conversion portion is formed thereon, and A transparent insulating film 63 is formed thereon, a G photoelectric conversion portion is formed thereon, a light shielding film 68 having an opening is formed thereon, and a transparent insulating film 67 is formed thereon. .

  The first electrode film 64, the photoelectric conversion layer 65, and the second electrode film 66 included in the G photoelectric conversion unit have the same configuration as the first electrode film 11, the photoelectric conversion layer 12, and the second electrode film 13 illustrated in FIG. It is.

  The first electrode film 60, the photoelectric conversion layer 61, and the second electrode film 62 included in the B photoelectric conversion unit have the same configuration as the first electrode film 11, the photoelectric conversion layer 12, and the second electrode film 13 illustrated in FIG. It is. However, the photoelectric conversion film included in the photoelectric conversion film 61 uses a material that absorbs blue light and generates electrons and holes according to the blue light.

  The first electrode film 56, the photoelectric conversion layer 57, and the second electrode film 58 included in the R photoelectric conversion unit have the same configuration as the first electrode film 11, the photoelectric conversion layer 12, and the second electrode film 13 illustrated in FIG. It is. However, the photoelectric conversion film included in the photoelectric conversion film 57 uses a material that absorbs red light and generates electrons and holes corresponding thereto.

  P + regions 43, 45, and 47 are formed in the portion of the silicon substrate 41 that is shielded by the light-shielding film 68, and each region is surrounded by n regions 42, 44, and 46.

  The p + region 43 is electrically connected to the first electrode film 56 via a connection portion 54 formed in an opening opened in the insulating film 48, and is connected to the first electrode film 56 via the connection portion 54. Accumulate the collected holes. The connecting portion 54 is electrically insulated by the insulating film 51 except for the first electrode film 56 and the p + region 43.

  The p + region 45 is electrically connected to the first electrode film 60 through a connection portion 53 formed in an opening formed in the insulating film 48, the R photoelectric conversion portion, and the insulating film 59. Then, holes collected by the first electrode film 60 are accumulated. The connection portion 53 is electrically insulated by the insulating film 50 except for the first electrode film 60 and the p + region 45.

  The p + region 47 is electrically connected to the first electrode film 64 through the insulating film 48, the R photoelectric conversion portion, the insulating film 59, the B photoelectric conversion portion, and the connection portion 52 formed in the opening opened in the insulating film 63. And the holes collected by the first electrode film 64 are accumulated through the connection portion 52. The connecting portion 52 is electrically insulated by the insulating film 49 except for the first electrode film 64 and the p + region 47.

  The holes accumulated in the p + region 43 are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n region 42 and accumulated in the p + region 45. The holes are converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed in the n region 44, and the holes accumulated in the p + region 47 are converted into the n region 46. The signal is converted into a signal corresponding to the amount of charge by a MOS circuit (not shown) formed of a p-channel MOS transistor formed therein and output to the outside of the solid-state imaging device 300. These MOS circuits constitute the signal readout section in the claims. Each MOS circuit is connected to a signal readout pad (not shown) by wiring 55. The signal reading unit may be constituted by a CCD and an amplifier instead of the MOS circuit. That is, the holes accumulated in the p + regions 43, 45, and 47 are read out to the CCD formed in the silicon substrate 41 and transferred to the amplifier by the CCD so that a signal corresponding to the holes is output from the amplifier. A simple signal reading unit may be used.

  In addition, between the silicon substrate 41 and the first electrode film 56 (for example, between the insulating film 48 and the silicon substrate 41), light transmitted through the photoelectric conversion layers 57, 61, and 65 is received, and the light is received. It is also possible to form an inorganic photoelectric conversion portion made of an inorganic material that generates and accumulates a corresponding charge. In this case, a MOS circuit for reading a signal corresponding to the charge accumulated in the charge accumulation region of the inorganic photoelectric conversion unit is provided in the silicon substrate 41, and the wiring 55 may be connected to this MOS circuit. .

  As described above, the configuration in which a plurality of photoelectric conversion layers are stacked on the silicon substrate described in the first embodiment and the second embodiment can be realized by the configuration shown in FIG.

  In the above description, the photoelectric conversion film that absorbs B light can absorb light of at least 400 to 500 nm, and preferably has a peak wavelength absorptance of 50% or more in that wavelength region. Means. The photoelectric conversion film that absorbs G light means that it can absorb light of at least 500 to 600 nm, and preferably has a peak wavelength absorptance of 50% or more in that wavelength region. The photoelectric conversion film that absorbs R light means that it can absorb at least light of 600 to 700 nm, and preferably has an absorption factor of a peak wavelength in the wavelength region of 50% or more.

  In the case of the configuration of the first embodiment or the third embodiment, a pattern for detecting colors in the order of BGR, BRG, GBR, GRB, RBG, and RGB from the upper layer is conceivable. Preferably, the uppermost layer is G. In the case of the configuration as in the second embodiment, when the upper layer is the R layer, the lower layer is the same BG layer, and when the upper layer is the B layer, the lower layer is the same plane and the upper layer is the G layer. In the case of (2), a combination in which the lower layer is the same plane and the BR layer is possible. Preferably, the upper layer is the G layer and the lower layer is the same plane as shown in FIG.

(Fourth embodiment)
FIG. 5 is a schematic cross-sectional view of a solid-state imaging device for explaining a fourth embodiment of the present invention. In FIG. 5, a cross section of two pixels in a pixel portion, which is a portion that detects light and accumulates charges, wiring connected to an electrode in the pixel portion, bonding PAD connected to the wiring, and the like are formed. The cross section with the peripheral circuit part which is a part to be performed is also shown.

  In the n-type silicon substrate 213 of the pixel portion, a p region 221 is formed on the surface portion, an n region 222 is formed on the surface portion of the p region 221, and a p region 223 is formed on the surface portion of the n region 222. N region 224 is formed on the surface of p region 223.

  The p region 221 accumulates red (R) component holes photoelectrically converted by a pn junction with the n-type silicon substrate 213. The potential change in the p region 221 due to the accumulation of R component holes is read out from the MOS transistor 226 formed in the n-type silicon substrate 213 to the signal readout PAD 227 via the metal wiring 219 connected thereto. .

  The p region 223 accumulates blue (B) component holes photoelectrically converted by the pn junction with the n region 222. The potential change in the p region 223 due to the accumulation of the B component holes is read out from the MOS transistor 226 ′ formed in the n region 222 to the signal readout PAD 227 through the metal wiring 219 connected thereto.

  In the n region 224, a hole accumulation region 225 made of a p region for accumulating green (G) component holes generated in the photoelectric conversion film 123 stacked above the n-type silicon substrate 213 is formed. The potential change in the hole accumulation region 225 due to the accumulation of the G component holes is caused by the signal readout PAD 227 from the MOS transistor 226 ″ formed in the n region 224 through the metal wiring 219 connected thereto. Is read out. Normally, the signal readout PAD 227 is provided separately for each transistor from which each color component is read out.

  Here, the p region, the n region, the transistor, the metal wiring, and the like are schematically shown. However, the structure of each is not limited to this, and an optimal one is appropriately selected. Since the B light and R light are separated according to the depth of the silicon substrate, it is important to select the depth from the surface of the silicon substrate such as a pn junction and the doping concentration of each impurity. The technology used in a normal CMOS image sensor can be applied to the CMOS circuit serving as the signal readout unit. A circuit configuration that reduces the number of transistors in the pixel portion, such as a low noise readout column amplifier or a CDS circuit, can be applied.

  A transparent insulating film 212 mainly composed of silicon oxide, silicon nitride, or the like is formed on the n-type silicon substrate 213, and a transparent insulating film mainly composed of silicon oxide, silicon nitride, or the like is formed on the insulating film 212. 211 is formed. The thickness of the insulating film 212 is preferably as small as possible, and is 5 μm or less, preferably 3 μm or less, more preferably 2 μm or less, and further preferably 1 μm or less.

  In the insulating films 211 and 212, a plug 215 mainly composed of tungsten for electrically connecting the first electrode film 214 and the p region 225 as a hole accumulation region is formed. The plug 215 is insulated. The film 211 and the insulating film 212 are relay-connected by a pad 216. The pad 216 is preferably made mainly of aluminum. In the insulating film 212, the metal wiring 219 and the gate electrodes of the transistors 226, 226 ', and 226' 'are formed. It is preferable that a barrier layer including a metal wiring is provided. The plug 215 is provided for each pixel.

  A light shielding film 217 is provided in the insulating film 211 in order to prevent noise caused by the generation of charges due to the pn junction of the n region 224 and the p region 225. As the light shielding film 217, a film mainly composed of tungsten, aluminum, or the like is usually used. A bonding PAD 220 (PAD for supplying power from outside) and a signal readout PAD 227 are formed in the insulating film 211, and a metal wiring for electrically connecting the bonding PAD 220 and a first electrode film 214 described later. (Not shown) is also formed.

  A transparent first electrode film 214 is formed on the plug 215 of each pixel in the insulating film 211. The first electrode film 214 is divided for each pixel, and the light receiving area is determined by this size. A bias is applied to the first electrode film 214 through the wiring from the bonding PAD 220. A structure in which holes can be accumulated in the hole accumulation region 225 by applying a negative bias to the first electrode film 214 with respect to a second electrode film 205 described later is preferable.

  The photoelectric conversion layer 12 having the same structure as that shown in FIG. 2 is formed on the first electrode film 214, and the second electrode film 205 is formed thereon.

  A protective film 204 mainly composed of silicon nitride or the like having a function of protecting the photoelectric conversion layer 12 is formed on the second electrode film 205. An opening is formed in the protective film 204 at a position that does not overlap with the first electrode film 214 in the pixel portion, and an opening is formed in a part on the bonding PAD 220 in the insulating film 211 and the protective film 204. A wiring 218 made of aluminum or the like for electrically connecting the second electrode film 205 exposed by the two openings and the bonding PAD 220 to apply a potential to the second electrode film 205 is formed inside the opening and the protective film. 204 is formed. As a material of the wiring 218, an alloy containing aluminum such as Al—Si or Al—Cu alloy can be used.

  A protective film 203 mainly composed of silicon nitride or the like for protecting the wiring 218 is formed on the wiring 218. An infrared cut dielectric multilayer film 202 is formed on the protective film 203, and an infrared cut dielectric. An antireflection film 201 is formed on the body multilayer film 202.

  The first electrode film 214 performs the same function as the first electrode film 11 shown in FIG. The second electrode film 205 performs the same function as the second electrode film 13 shown in FIG.

  With the above configuration, it is possible to perform color imaging by detecting light of BGR three colors with one pixel. In the configuration of FIG. 5, R and B are used as common values in two pixels, and only the G value is used separately. However, since the sensitivity of G is important when generating an image, such a configuration is used. Even so, it is possible to generate a good color image.

  The solid-state imaging device described above can be applied to imaging devices such as digital cameras, video cameras, facsimile machines, scanners, and copying machines. It can also be used as an optical sensor such as a bio or chemical sensor.

In addition, the materials mentioned as the insulating film described in the above embodiment are SiOx, SiNx, BSG, PSG, BPSG, Al ₂ O ₃ , MgO, GeO, NiO, CaO, BaO, Fe ₂ O ₃ , Y ₂ O. ₃ , metal oxides such as TiO ₂ , metal fluorides such as MgF ₂ , LiF, AlF ₃ , and CaF _{2. The} most preferred materials are SiOx, SiNx, BSG, PSG, and BPSG.

  In addition, in 1st embodiment-4th embodiment, reading of the signal from photoelectric conversion parts other than the photoelectric converting film of this invention may use either a hole or an electron. That is, as described above, holes are accumulated in the inorganic photoelectric conversion unit provided between the semiconductor substrate and the photoelectric conversion unit stacked on the semiconductor substrate, or in the photodiode formed in the semiconductor substrate. It is good also as a structure which reads the signal according to a hole with a signal read-out part, accumulate | stores an electron with an inorganic photoelectric conversion part or the photodiode formed in a semiconductor substrate, and the signal according to this electron is read with a signal read-out part. It is good also as a structure to read.

[Example]
Examples are shown below, but the present invention is not limited thereto.

As a photoelectric conversion unit, the one having the configuration shown in FIG. 2 is prepared as follows to make a sample 1, light is incident from above the second electrode film 13, and holes are collected by the first electrode film 11, A signal corresponding to the collected holes was read out by the MOS circuit. Note that a voltage was applied between the first electrode and the second electrode so that the second electrode was positive (bias) so that the voltage was 20 V at the start of exposure.
And from this signal, the relative sensitivity which made the maximum sensitivity in the wavelength range of 500-600 nm 100, and the normalized relative sensitivity which made the maximum sensitivity 100 in the wavelength region of 500-600 nm were calculated | required.

As the first electrode film 11, ITO having a thickness of 100 nm is formed on a glass substrate by sputtering. On top of this, PEDOT doped with PSS is spin-coated as a polymer undercoat film 121 having electrical conductivity, and then 40 nm is formed by vacuum heating. On top of that, m-MTDATA is deposited as an electron blocking film 122 to a thickness of 50 nm by vacuum deposition. On top of that, (S-8) of the present invention is formed as a photoelectric conversion film 123 that absorbs green light to a thickness of 100 nm by a vacuum deposition method, and Alq ₃ is deposited as a hole blocking film 124 by a thickness of 50 nm by a vacuum deposition method. Similarly, 20 nm of BCP is formed as a hole blocking / buffer film 125 by vacuum deposition. On top of that, in order to suitably adjust the work function of the second electrode film 13 as an electron collecting electrode, a 5 nm film of In is formed by vacuum deposition. Furthermore, as the second electrode film 13, ITO is deposited to a thickness of 10 nm by sputtering under plasma-free conditions.
The film formation from the m-MTDATA to the sputtering film formation of ITO as the second electrode film 13 are performed in a consistent vacuum without being exposed to the atmosphere. The chemical formulas of the materials used here are listed below.

(Comparative example)
As a photoelectric conversion part, the one having the configuration shown in FIG. 6 is prepared as follows to make a comparative sample 2, light is incident from above the second electrode film 13, and electrons are collected by the first electrode film 11, A signal corresponding to the collected electrons was read out by the MOS circuit. In addition, a voltage was applied between the first electrode and the second electrode so that the second electrode was negative (bias) so that the voltage was 20 V at the start of exposure.
And from this signal, the relative sensitivity which set the maximum sensitivity in the 500-600 nm wavelength range of sample 1 as 100, and the standardized relative sensitivity which set the maximum sensitivity in the wavelength range of 500-600 nm as 100 was calculated | required.

As the first electrode film 11, ITO having a thickness of 100 nm is formed on a glass substrate by sputtering. On top of this, PEDOT doped with PSS is spin-coated as an undercoat film 321 of a conductive polymer, and a film of 40 nm is formed by vacuum heating. On top of this, 2 nm of In is deposited by vacuum deposition as a work function adjusting film 322 for suitably adjusting the work function of the first electrode film 11 as an electron collecting electrode. On top of that, BCP is deposited as a hole blocking film 333 by 20 nm by vacuum deposition. Further, Alq ₃ is deposited to a thickness of 50 nm by a vacuum evaporation method as an electron transporting photoelectric conversion film 334 that absorbs green light. Further, (S-8) is deposited to a thickness of 100 nm as a hole-transporting photoelectric conversion film 335 that absorbs green light by a vacuum deposition method. On top of that, m-MTDATA is deposited to a thickness of 50 nm as an electron blocking film 336 by vacuum deposition. On top of that, as the second electrode film 13, ITO is deposited to a thickness of 10 nm by sputtering under plasma-free conditions. The process from the In film formation to the ITO film formation of the second electrode film 13 is performed in a consistent vacuum without exposure to the atmosphere.

The relative sensitivity of Sample 1 of the present invention and Comparative Sample 2 is shown in FIG. 7, and the normalized relative sensitivity is shown in FIG.
As shown in FIG. 7, the absolute sensitivity of the sample 1 of the present invention was about twice that of the comparative sample 2. Further, as shown in FIG. 8, the spectral characteristics were also sharper in the example. Based on the above results, high sensitivity and sharpening of spectral sensitivity can be realized by collecting holes with the electrode opposite to the light incident side electrode and reading the signal according to the holes. all right.

  The same sample 3 and comparative sample 4 of the present invention were prepared except that the photoelectric conversion films used in the sample 1 and the comparative sample 2 described above were changed as follows. When similarly evaluated, the results of FIGS. 9 and 10 were obtained. Based on the above results, as in the first embodiment, holes are collected by the electrode opposite to the electrode on the light incident side, and a signal corresponding to the holes is read out, thereby increasing sensitivity and sharpening spectral sensitivity. It has been found that realization is realized.

Photoelectric conversion film of Sample 3 of the present invention:
ITO (100 nm: first electrode) / (S-9) (100 nm) / Alq3 (50 nm) / ITO (10 nm: second electrode)
Photoelectric conversion film of Comparative Sample 4:
ITO (100 nm: first electrode) / Alq3 (50 nm) / (S-9) (100 nm) / ITO (10 nm: second electrode)

  Instead of the above (S-9), (S-13), (S-15), (S-28), (S-29), (S-30), (S-31), Except for using (S-32), (S-33), (S-34), (S-35), (S-36), (S-37), (S-38), it is exactly the same. Similar results are obtained even when a photoelectric conversion unit is created.

1 is a schematic cross-sectional view of one pixel of a solid-state image sensor for explaining a first embodiment of the present invention. Schematic cross-sectional view of the photoelectric conversion layer shown in FIG. Sectional schematic diagram for 1 pixel of the solid-state image sensor for demonstrating 2nd embodiment of this invention Sectional schematic diagram for 1 pixel of the solid-state image sensor for demonstrating 3rd embodiment of this invention Sectional schematic diagram of the solid-state image sensor for demonstrating 4th embodiment of this invention Schematic cross-sectional view of a photoelectric conversion part created in an embodiment of the present invention The figure which shows the result of the Example of this invention The figure which shows the result of the Example of this invention The figure which shows the result of the Example of this invention The figure which shows the result of the Example of this invention

Explanation of symbols

1 p-type silicon substrate (semiconductor substrate)
2, 4 n-type semiconductor region 6 High-concentration n-type semiconductor region (electron storage part)
3, 5 p-type semiconductor regions 7, 8, 15 Insulating film 9 Connection portion 10 Wiring 11 First electrode film 12 Photoelectric conversion layer 13 Second electrode film 14 Light shielding film

Claims (19)

Photoelectric conversion having a photoelectric conversion part including a first electrode film, a second electrode film facing the first electrode film, and a photoelectric conversion film disposed between the first electrode film and the second electrode film A solid-state imaging device in which a large number of elements are arranged in an array,
A semiconductor substrate provided below the first electrode film,
Light is incident on the photoelectric conversion film from above the second electrode film,
The photoelectric conversion film generates charges including electrons and holes in response to incident light from above the second electrode film,
And the photoelectric conversion film contains a quinacridone derivative or a quinazoline derivative,
In the first electrode film and the second electrode film, a voltage is applied so that the electrons move to the second electrode film and the holes move to the first electrode film,
In the semiconductor substrate, a hole accumulating part for accumulating the holes transferred to the first electrode film, and a connection part for electrically connecting the hole accumulating part and the first electrode film And
A signal readout unit that reads out a signal corresponding to the charge accumulated in the semiconductor substrate of each of the multiple photoelectric conversion elements;
The photoelectric conversion film and the second electrode film included in the photoelectric conversion element are shared by the entire number of photoelectric conversion elements,
The solid-state imaging device, wherein the first electrode film included in the photoelectric conversion device is separated for each of the plurality of photoelectric conversion devices. The solid-state imaging according to claim 1, wherein the quinacridone derivative or quinazoline derivative according to claim 1 is selected from a compound represented by the following general formula (I) or a compound represented by the general formula (II): Element .

Wherein ring A is

N1 and n2 represent 0 or 1. However, when n1 and n2 are each 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 , R ⁴ , R ⁵ , and R ⁶ each independently represent a substituent, and m1, m2, m3, and m4 each independently represent an integer of 0 to 4. When m1, m2, m3 and m4 are integers of 2 to 4, a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ may be linked to form a ring. 3. The solid-state imaging device according to claim 1, wherein the photoelectric conversion film generates more electrons and holes in the vicinity of the second electrode film than in the vicinity of the first electrode film. The solid-state imaging device according to claim 2 , wherein the photoelectric conversion film is configured to include an organic material other than the compound represented by the general formula (I) or the general formula (II). The solid-state imaging device according to claim 4, wherein the photoelectric conversion film includes at least one of an organic p-type semiconductor and an organic n-type semiconductor. The organic p-type semiconductor and the organic n-type semiconductor are compounds represented by the general formula (I) or the general formula (II), naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, respectively. And a fluoranthene derivative. The solid-state imaging device according to claim 5. The first electrode _{film, ITO,} IZO, any one of the preceding claims, characterized in that the _{ZnO 2, SnO 2, TiO 2} , FTO, those Al, which is configured to include Ag, or Au The solid-state imaging device according to one item . The second electrode _{film, ITO,} IZO, or the _{ZnO 2, SnO 2, TiO 2} , FTO, Al, claims 1 to 7, characterized in that is configured to include Ag, or Au The solid-state imaging device according to one item . The second electrode film includes ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , or FTO, and the photoelectric conversion unit includes the photoelectric conversion film and the second electrode film. during the solid-state imaging device of any one of claims 1-8, characterized in that it comprises a film made of a work function 4.5eV following metals. The second electrode film solid-state imaging device of any one of claims 1 to 9, the transmittance for visible light, characterized in that at least 60%. The first electrode film solid-state imaging device of any one of claims 1 to 10 in which the transmittance for visible light, characterized in that at least 60%. The photoelectric conversion portion, wherein between the first electrode film and the photoelectric conversion layer, the solid-state imaging device of any one of claims 1 to 11, characterized in that it comprises a film made of an organic polymer material . The semiconductor substrate under the photoelectric conversion film includes an in-substrate photoelectric conversion unit that absorbs light transmitted through the photoelectric conversion film, generates a charge corresponding to the light, and accumulates the charge. The solid-state image sensor as described in any one of Claims 1-12 . The solid-state imaging device according to claim 13, wherein the in-substrate photoelectric conversion unit is a plurality of photodiodes that absorb light of different colors stacked in the semiconductor substrate. The in-substrate photoelectric conversion unit is a plurality of photodiodes that absorb light of different colors arranged in a direction perpendicular to an incident direction of the incident light in the semiconductor substrate. The solid-state image sensor according to 13 or 14 . The plurality of photodiodes are a blue photodiode having a pn junction surface formed at a position capable of absorbing blue light, and a red photodiode having a pn junction surface formed at a position capable of absorbing red light. There, the solid-state imaging device according to claim 14 or 15, wherein said photoelectric conversion film and absorbs green light. The plurality of photodiodes are a blue photodiode that absorbs blue light and a red photodiode that absorbs red light, and the photoelectric conversion film absorbs green light. The solid-state imaging device according to claim 15 . Above the semiconductor substrate, the photoelectric conversion unit are stacked, any one of claims 1 to 17, wherein the said connecting portion and hole accumulation portion is provided for each of the plurality of photoelectric conversion unit The solid-state imaging device according to one item . The solid-state imaging device of any one of claims 1 to 18 configured wherein the signal reading section is a MOS transistor.

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