JPH0542670B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photoconductive member that is sensitive to electromagnetic waves such as light (here, light in a broad sense includes ultraviolet light, visible light, infrared light, X-rays, gamma rays, etc.). As a photoconductive material for forming a photoconductive layer in a solid-state imaging device, an electrophotographic image forming member in the image forming field, or a document reading device, it is highly sensitive,
Must have a high signal-to-noise ratio [photocurrent (Ip)/dark current (Id)], have absorption spectral characteristics that match the spectral characteristics of the irradiated electromagnetic waves, have fast photoresponsiveness, and have the desired dark resistance value. At times, solid-state imaging devices are required to have characteristics such as being non-polluting to the human body and being able to easily process afterimages within a predetermined time.
Particularly in the case of an electrophotographic image forming member incorporated into an electrophotographic apparatus used in an office as a business machine, the above-mentioned non-polluting property during use is an important point. Based on these points, amorphous silicon (hereinafter referred to as a-Si) is a photoconductive material that has recently attracted attention. As a photographic image forming member, application to a photoelectric conversion reader is described in DE 2933411. However, conventional photoconductive members having photoconductive layers composed of a-Si have poor electrical, optical, and photoconductive properties such as dark resistance, photosensitivity, and photoresponsiveness, as well as moisture resistance. The reality is that there is a need to improve overall characteristics in terms of usage environment characteristics and stability over time, and there are areas that can be further improved. For example, when applied to an electrophotographic image forming member, when trying to achieve high photosensitivity and high dark resistance at the same time, in the past, it has often been observed that residual potential remains during use, and this type of When a conductive member is used repeatedly for a long period of time, fatigue accumulates due to repeated use, resulting in the so-called ghost phenomenon that causes an afterimage, or when used repeatedly at high speeds, the response gradually decreases, etc. This often occurred. Furthermore, a-Si has a relatively smaller absorption coefficient in the long wavelength region than in the short wavelength region of the visible light region, which makes it difficult to match with semiconductor lasers currently in practical use. However, when a commonly used halogen lamp or fluorescent lamp is used as a light source, there is still room for improvement in that the light on the longer wavelength side cannot be used effectively. In addition, if the irradiated light is not absorbed sufficiently in the photoconductive layer and the amount of light that reaches the support increases, the support itself will absorb the light that passes through the photoconductive layer. When the reflectance is high, interference due to multiple reflections occurs within the photoconductive layer, which is one of the causes of "blurring" of images. This effect becomes greater as the irradiation spot is made smaller in order to increase the resolution, and is a major problem especially when a semiconductor laser is used as the light source. Furthermore, when the photoconductive layer is composed of a-Si material, hydrogen atoms, halogen atoms such as fluorine atoms, chlorine atoms, etc., and electrically conductive type Boron atoms, phosphorus atoms, etc. are included for control purposes, and other atoms are included as constituent atoms in the photoconductive layer for the purpose of improving other properties. In this case, problems may arise in the electrical or photoconductive properties of the formed layer. That is, for example, the lifetime of photocarriers generated by light irradiation in the formed photoconductive layer is not sufficient, or the injection of charge from the support side is not sufficiently prevented in dark areas, etc. This often occurs. Therefore, while efforts are being made to improve the properties of the a-Si material itself, it is necessary to take measures to solve all of the above-mentioned problems when designing photoconductive members. The present invention has been made in view of the above points, and includes a
-As a result of intensive research and study on Si from the viewpoint of its applicability as a photoconductive member used in electrophotographic image forming members, solid-state imaging devices, reading devices, etc., we found that silicon atoms An amorphous material containing at least either a hydrogen atom (H) or a halogen atom (X), so-called hydrogenated amorphous silicon, halogenated amorphous silicon, or halogen-containing hydrogenated amorphous silicon [hereinafter referred to as "hydrogenated amorphous silicon"] ``a-Si(H,X)'' is used as a generic notation for The photoconductive materials designed and produced under this method not only exhibit extremely superior properties in practical use, but also exceed conventional photoconductive materials in every respect, especially when used in electrophotography. This is based on the discovery that it has extremely excellent properties as a photoconductive member and that it has excellent absorption spectrum properties on the long wavelength side. The present invention has stable electrical, optical, and photoconductive properties at all times, is suitable for all environments with almost no restrictions on usage environments, and has excellent photosensitivity on the long wavelength side and is extremely resistant to light fatigue. The main object of the present invention is to provide a photoconductive member that is durable, does not cause deterioration even after repeated use, and has no or almost no residual potential observed. Another object of the present invention is to provide a photoconductive member that has high photosensitivity in the entire visible light range, has excellent matching with semiconductor lasers in particular, and has fast photoresponse. Another object of the present invention is to maintain charge retention during charging processing for electrostatic image formation to such an extent that ordinary electrophotography can be applied very effectively when applied as an image forming member for electrophotography. It is an object of the present invention to provide a photoconductive member having sufficient performance. Still another object of the present invention is to provide a photoconductive member for electrophotography that can easily produce high-quality images with high density, clear halftones, and high resolution without image blur. It is to be. The photoconductive member of the present invention includes a support for the photoconductive member, a first layer region (G) made of an amorphous material containing germanium atoms, and a non-crystalline material containing silicon atoms on the support. The photoreceptive layer has a layered structure in which a second layer region (S) made of a crystalline material and exhibits photoconductivity is provided in order from the support side, and the photoreceptor layer has a conductivity. In the photoreceptive layer, the maximum value of the distribution concentration in the layer thickness direction is the second layer region (S) of the atom C belonging to Group 1 or Group 3 of the periodic table, which is the substance to be controlled. In the second layer region (S), the second layer region (S) is characterized in that it is contained in a state where it is distributed more toward the support side. The photoconductive member of the present invention designed to have the above-described layer structure can solve all of the problems described above, and has extremely excellent electrical, optical, and photoconductive properties. Indicates pressure resistance and usage environment characteristics. In particular, when applied as an image forming member for electrophotography, it is possible to sufficiently prevent interference even when using coherent light, and there is no influence of residual potential on image formation, and the electrical It has stable optical characteristics, high sensitivity, and high signal-to-noise ratio, and has good resistance to light fatigue and repeated use, and has high density, clear halftones, and high resolution. Images can be stably and repeatedly obtained. Furthermore, the photoconductive member of the present invention has high photosensitivity in the entire visible light range, is particularly excellent in matching with semiconductor lasers, and has fast optical response. Hereinafter, the photoconductive member of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a schematic structural diagram schematically shown to explain the layer structure of the photoconductive member of the present invention. The photoconductive member 100 shown in FIG.
The photoreceptive layer 102 has a free surface 105 on one end surface. The light-receiving layer 102 is made of an amorphous material (hereinafter referred to as "a-Ge (Si, H , X)") and a second layer region (S) 104 composed of a-Si (H, It has a layered structure laminated in sequence. The photoreceptive layer 102 is a substance (C) that controls conduction properties.
In the photoreceptive layer 102, the substance (C) has a maximum distribution concentration in the layer thickness direction in the second layer region (S) and ), it is contained in a state where it is distributed in a larger amount toward the support 101 side. In the in-plane direction parallel to the surface of the support, the germanium atoms in the first layer region (G) are
Although it is contained in a uniform state, it may be uniform or non-uniform in the layer thickness direction. In addition, if the distribution state of germanium atoms in the first layer region (G) is non-uniform in the layer thickness direction, the distribution concentration C in the layer thickness direction may be changed to the support side or the second layer region. It is desirable to change it gradually, stepwise, or linearly toward the (S) side. In particular, the distribution state of germanium atoms in the first layer region (G) is such that germanium atoms are continuously distributed in the entire layer region, and the distribution concentration C (G) of germanium atoms in the layer thickness direction is supported. If a change is given that decreases from the body side toward the second layer region (S),
It has excellent affinity between the first layer region (G) and the second layer region (S), and has an extremely large distribution concentration C of germanium atoms at the support side edge, as described later. By doing so, when a semiconductor laser or the like is used, light on the long wavelength side that is almost completely absorbed by the second layer region (S) is effectively absorbed in the first layer region (G). It is possible to completely absorb it, prevent interference due to reflection from the support surface, and sufficiently suppress reflection at the interface between layer region (G) and layer region (S). Further, in the photoconductive member of the present invention, each of the amorphous materials constituting the first layer region (G) and the second layer region (S) has a common constituent element of silicon atoms. Therefore, chemical stability is sufficiently ensured at the laminated interface. 2 to 10 show typical examples of the distribution state of germanium atoms contained in the first layer region (G) of the photoconductive member of the present invention in the layer thickness direction. In FIGS. 2 to 10, the horizontal axis represents the distribution concentration C of germanium atoms, and the vertical axis represents the first layer region.
(G) indicates the layer thickness, and t _B is the first layer region (G) on the support side.
The position of the end face of t _T is the first position opposite to the support side.
The position of the end face of the layer region (G) is shown. That is, the first layer region (G) containing germanium atoms is t _T from the t _B side.
Layering takes place towards the sides. FIG. 2 shows a first typical example of the distribution state of germanium atoms contained in the first layer region (G) in the layer thickness direction. In the example shown in FIG. 2, from the interface position _tB where the surface where the first layer region (G) containing germanium atoms is formed and the surface of the first layer region (G) are in contact with each other,
Up to the position t ₁ , the distribution concentration C of germanium atoms
While (G) takes a constant value of C ₁ , germanium atoms are contained in the first layer region (G) where they are formed, and the position
From t ₁ onward, the concentration C ₂ is gradually and continuously reduced up to the interface position t _T . At the interface position _tT , the distribution concentration C of germanium atoms is _C3 . In the example shown in FIG. 3, the distribution concentration C of the germanium atoms contained is from the position t _B to the position t _T
A distribution state is formed in which the concentration gradually and continuously decreases from C ₄ until reaching C ₅ at position t _T . In the case of Fig. 4, the distribution concentration C of germanium atoms is constant at a concentration _C6 from position t _B to position t ₂ , and gradually and continuously between position t ₂ and position t _T. reduced, and at position t _T , the distribution concentration C
is substantially zero (substantially zero here means less than the detection limit amount). In the case of Fig. 5, the distribution concentration C of germanium atoms is gradually decreased continuously from the concentration C ₈ from position t _B to position t _T , and becomes substantially zero at position t _T. . In the example shown in FIG. 6, the distribution concentration C of germanium atoms between position t _B and position t ₃ is as follows:
The concentration C is a constant value of ₉ , and at the position t _T the concentration
C ₁₀ will be done. Between the position t ₃ and the position t _T , the distribution concentration C is linearly decreased from the position t ₃ to the position t _T . In the example shown in FIG. 7, the distribution concentration C takes a constant value of concentration C ₁₁ from position t _B to position t ₄ ,
From position _t4 to position _tT , the distribution state is such that the concentration decreases linearly from _C12 to _C13 . In the example shown in FIG. 8, from position t _B to position t _T
Up to , the distribution concentration C of germanium atoms decreases linearly from the concentration C ₁₄ to substantially zero. In FIG. 9, the distribution concentration C of germanium atoms from position t _B to position t ₅ is the concentration C ₁₅
The concentration C is linearly decreased to ₁₆ , and the position t ₅
An example is shown in which the concentration C ₁₆ is kept at a constant value between and the position t _T . In the example shown in FIG. 10, the distribution concentration C of germanium atoms is a concentration C ₁₇ at position t _B , and is gradually decreased from this concentration C ₁₇ until reaching position t ₆ , and then decreases from this concentration C 17 at t ₅ . Near the position, the concentration decreases rapidly to a concentration _C18 at position _t6 . Between position t ₆ and position t ₇ , the concentration is decreased rapidly at first, then slowly and gradually decreased to reach C ₁₉ at position t ₇ , and then between position t ₇ and position t ₈ Then, it is gradually decreased very slowly to reach the concentration C ₂₀ at position t ₈ . Between position _t8 and position _tT , the concentration is reduced from _C20 to substantially zero according to a curve shaped as shown in the figure. As described above with reference to FIGS. 2 to 10, some typical examples of the distribution state of germanium atoms contained in the first layer region (G) in the layer thickness direction, in the present invention, On the support side, there is a part where the distribution concentration C of germanium atoms is high, and on the interface _tT side, the distribution state of germanium atoms has a part where the distribution concentration C is considerably lower than that on the support side. is provided in the layer area (G). The first layer region (G) constituting the photoreceptive layer constituting the photoconductive member in the present invention is preferably a layer region (G) containing germanium atoms at a relatively high concentration on the support side, as described above. It is desirable to have a location area (A). In the present invention, the localized region (A) can be explained using the symbols shown in FIGS. 2 to 10, and can be defined as the interface position.
It is desirable that it be provided within 5μ from _tB . In the present invention, the localized region (A) may be the entire layer region (L _T ) up to 5μ thick from the interface position t _B , or may be a part of the layer region (L _T ). In some cases, it may be done. Whether the localized region (A) is a part or all of the layer region (L _T ) is determined as appropriate depending on the characteristics required of the amorphous layer to be formed. The localized region (A) has a distribution state of germanium atoms contained therein in the layer thickness direction, and the maximum value Cmax of the distribution concentration of germanium atoms is preferably 1000 atomic ppm or more with respect to the sum with silicon atoms,
More preferably 5000 atomic ppm or more, optimally 1
It is desirable that the layer be formed in such a manner that a distribution state of 1.0 ⁴ atomic ppm or more can be obtained. That is, in the present invention, the layer region (G) containing germanium atoms has a layer thickness from the support side.
It is preferable to form the layer so that the maximum value Cmax of the distribution concentration exists within 5μ (layer region with a thickness of 5μ from t _B ). In the present invention, the content of germanium atoms contained in the first layer region (G) is appropriately determined as desired so as to effectively achieve the object of the present invention, but is preferably 1. ~10× ¹⁰⁵ atomic
ppm, more preferably 100-9.5× ¹⁰⁵ atomic
ppm, preferably 500 to 8×10 ⁵ atomic ppm. In the present invention, the first layer region (G) and the second layer region
The layer thickness with (S) is one of the important factors for effectively achieving the object of the present invention. due care must be taken in the design of the In the present invention, the layer thickness T _B of the first layer region (G) is
Preferably 30 Å to 50 μ, more preferably 40 Å
It is desirable that the thickness be ˜40 μ, optimally 50 Å to 30 μ. Further, the layer thickness T of the second layer region (S) is preferably
It is desirable that the thickness be 0.5 to 90μ, more preferably 1 to 80μ, and optimally 2 to 50μ. The sum (T _B +T) of the layer thickness T _B of the first layer region (G) and the layer thickness T of the second layer region (S) is based on the characteristics required for both layer regions and the overall photoreceptive layer. It is appropriately determined as desired when designing the layers of the photoconductive member, based on the organic relationship between the required properties. In the photoconductive member of the present invention, the above (T _B
The numerical range of +T) is preferably 1 to
100μ, more preferably 1-80μ, optimally 2-50μ
It is desirable that this is done. In a more preferred embodiment of the present invention,
The above layer thickness T _B and layer thickness T are preferably as follows:
When satisfying the relationship T _B /T≦1, it is desirable to select appropriate numerical values for each. In selecting the numerical values of the layer thickness T _B and the layer thickness T in the above case, it is more preferable that T _B /T≦0.9,
Optimally, it is desirable that the values of layer thickness T _B and layer thickness T be determined so that the relationship T _B /T≦0.8 is satisfied. In the present invention, the content of germanium atoms contained in the first layer region (G) is 1×10 ⁵ atomic
In the case of ppm or more, the layer thickness T _B of the first layer region (G)
It is desirable that the thickness be as thin as possible, preferably 30μ or less, more preferably 25μ or less, and optimally 20μ or less. In the present invention, the halogen atoms (X) contained as necessary in the first layer region (G) and/or second layer region (S) constituting the photoreceptive layer are specifically: Examples include fluorine, chlorine, bromine, and iodine, with fluorine and chlorine being particularly preferred. In the present invention, in order to form the first layer region (G) composed of a-Ge (Si, H, X), a discharge phenomenon such as a glow discharge method, a sputtering method, or an ion plating method is used. This is accomplished by using a vacuum deposition method. For example, to form the first layer region (G) composed of a-Ge (Si, H, X) by the glow discharge method, germanium atoms (Ge) can basically be supplied. Raw material gas for Ge supply and, if necessary, raw material gas for Si supply that can supply silicon atoms (Si) Raw material gas for hydrogen atom (H) introduction and/or raw material for halogen atom (X) introduction Gas is introduced at a desired gas pressure into a deposition chamber whose interior can be reduced in pressure, and a glow discharge is generated within the deposition chamber to form a layer on the surface of a predetermined support that has been placed at a predetermined position in advance. good. In order to non-uniformly distribute germanium atoms, a layer consisting of a-Ge (Si, H, good. In addition, when forming by sputtering method, for example, a target made of Si, or a target made of Si and Ge in an atmosphere of an inert gas such as Ar or He, or a mixed gas based on these gases. If necessary, use two of the prepared targets, or a mixed target of Si and Ge, and use the raw material gas for Ge supply diluted with a diluent gas such as He or Ar, or Si. The raw material gas for supply is converted into hydrogen atoms (H) or /
A gas for introducing halogen atoms (X) is introduced into the deposition chamber for sputtering to form a plasma atmosphere of the desired gas, and the gas flow rate of the raw material gas for Ge supply and/or the raw material gas for Si supply is introduced. It is sufficient to sputter the target while controlling the amount according to a desired rate of change curve. In the case of the ion plating method, for example, polycrystalline silicon or single crystal silicon and polycrystalline germanium or single crystal germanium are housed in a deposition boat as evaporation sources, and the evaporation sources are heated using a resistance heating method or an electron beam. Law (EB Law)
This can be carried out in the same manner as in the sputtering method, except that the evaporated material is heated and evaporated by a method such as the above method, and the flying evaporated material is passed through a desired gas plasma atmosphere. Substances that can be used as raw material gas for supplying Si used in the present invention include SiH ₄ , Si ₂ H ₆ ,
Silicon hydride (silanes) in a gaseous state or that can be gasified, such as Sis ₃ H ₈ and Si ₄ H ₁₀ , can be effectively used, especially for ease of handling during layer creation work and Si supply. SiH ₄ and Si ₂ H ₆ are preferred in terms of efficiency. Substances that can be used as raw material gas for Ge supply include:
_GeH4 , _{Ge2H6 , Ge3H8 , Ge4H10 , Ge5H12 ,}
Ge ₆ H ₁₄ , Ge ₇ H ₁₆ , Ge ₈ H ₁₈ Ge ₉ H ₂₀ and other germanium hydrides in a gaseous state or that can be gasified are mentioned as being effectively used, especially when handling during layer formation work. In terms of ease of use, good Ge supply efficiency, etc.
Preferred examples include GeH ₄ , Ge ₂ H ₆ and Ge ₃ H ₆ . Effective raw material gases for introducing halogen atoms used in the present invention include many halogen compounds, such as halogen gases, halides, interhalogen compounds, halogen-substituted silane derivatives, etc. Preferred examples include halogen compounds that can be converted into Further, a silicon hydride compound containing a halogen atom, which is in a gaseous state or can be gasified and whose constituent elements are a silicon atom and a halogen atom, can also be mentioned as an effective compound in the present invention. Specifically, halogen compounds that can be suitably used in the present invention include fluorine, chlorine, bromine,
Iodine halogen gas, BrF, ClF, ClF ₃ ,
Examples include interhalogen compounds such as BrF ₅ , BrF ₃ , IF ₃ , IF ₇ , ICl, and IBr. Preferred examples of silicon compounds containing halogen atoms, so-called silane derivatives substituted with halogen atoms, include silicon halides such as SiF ₄ , Si ₂ F ₆ , SiCl ₄ , and SiBr ₄ . I can do it. When forming the characteristic photoconductive member of the present invention using a glow discharge method using such a silicon compound containing a halogen atom, the material gas that can supply Si together with the material gas for supplying Ge is used. The first layer region (G) made of a-SiGe containing halogen atoms can be formed on a desired support without using silicon hydride gas. When creating the first layer region (G) containing halogen atoms according to the glow discharge method, basically, for example, silicon halide, which is the raw material gas for supplying Si, and
Germanium hydride, which is the source gas for supplying Ge, and gases such as Ar, H ₂ , He, etc. are introduced into the deposition chamber to form the first layer region (G) at a predetermined mixing ratio and gas flow rate. The first layer region (G) can be formed on the desired support by generating a glow discharge and forming a plasma atmosphere of these gases, but the introduction of hydrogen atoms In order to more easily control the ratio, a desired amount of hydrogen gas or a silicon compound gas containing hydrogen atoms may be mixed with these gases to form a layer. Moreover, each gas may be used not only as a single species but also as a mixture of multiple species at a predetermined mixing ratio. In order to introduce halogen atoms into the layer formed by either the sputtering method or the ion plating method, a gas of the above-mentioned halogen compound or a silicon compound containing the above-mentioned halogen atoms is introduced into the deposition chamber. It is sufficient to form a plasma atmosphere of the gas. In addition, when introducing hydrogen atoms, a raw material gas for introducing hydrogen atoms, for example, H ₂ or gases such as the above-mentioned silanes and/or germanium hydride, is introduced into the deposition chamber for sputtering. It is sufficient to form a plasma atmosphere of the gases. In the present invention, the above-mentioned halogen compounds or halogen-containing silicon compounds are effectively used as raw material gases for introducing halogen atoms, but in addition, HF, HCl,
Hydrogen halides such as HBr and HI, SiH ₂ F ₂ ,
Halogen-substituted silicon hydrides such as SiH ₂ I ₂ , SiH ₂ Cl ₂ , SiHCl ₃ , SiH ₂ Br ₂ , SiHBr ₃ , and GeHF ₃ ,
_GeH2F2 , _{GeH3F1 , GeHCl3 , GeH2Cl2 ,
GeH3Cl} , _GeHBr3 , _GeH2Br2 , _{GeH3Br ,}
GeHI ₃ , GeH ₂ I ₂ , GeH ₃ I and other hydrogenated germanium halides, halides containing a hydrogen atom as one of their constituent elements, GeF ₄ , GeCl ₄ , GeBr ₄ ,
Germanium halides such as GeI ₄ , GeF ₂ , GeCl ₂ , GeBr ₂ , GeI ₂ and other gaseous or gasifiable substances may also be mentioned as useful starting materials for forming the first layer region (G). I can do it. The halides containing hydrogen atoms in these substances introduce halogen atoms into the layer when forming the first layer region (G), and at the same time introduce hydrogen atoms, which are extremely effective in controlling electrical or photoelectric properties. Therefore, in the present invention, it is used as a suitable raw material for introducing halogen. In order to structurally introduce hydrogen atoms into the first layer region (G), in addition to the above, H ₂ , SiH ₄ , Si ₂ H ₆ ,
Silicon hydride such as Si ₃ H ₈ , Si ₄ H ₁₀ with germanium or germanium compound for supplying Ge, or GeH ₄ , Ge ₂ H ₆ , Ge ₃ H ₈ , Ge ₄ H ₁₀ , Ge ₅ H ₁₂ ,
Generating a discharge by coexisting germanium hydride such as Ge ₆ H ₁₄ , Ge ₇ H ₁₆ , Ge ₈ H ₁₈ , Ge ₂ H ₂₀ and silicon or a silicon compound for supplying Si in a deposition chamber. But it can be done. In a preferred example of the present invention, hydrogen atoms contained in the first layer region (G) of the photoconductive member to be formed
The amount of (H) or the amount of halogen atom (X) or the sum of the amounts of hydrogen atom and halogen atom (H+X) is preferably 0.01
~40atomic%, more preferably 0.05-30atomic%,
The optimum range is preferably 0.1 to 25 atomic%. In order to control the amount of hydrogen atoms (H) and/or halogen atoms (X) contained in the first layer region (G), for example, the support temperature or/and the amount of hydrogen atoms (H) or halogen atoms can be controlled. The amount of the starting material used to contain (X) introduced into the deposition system, the discharge force, etc. may be controlled. In the photoconductive member of the present invention, the second layer region (S) does not contain germanium atoms, and the first layer region (G) contains germanium atoms as necessary.
By containing a substance (C) that controls the conduction characteristics in the layer region (S) and the layer region (G), the conduction characteristics of the layer region (S) and the layer region (G) can be arbitrarily controlled as desired. At this time, the substance contained in the second layer region (S)
(C) may be contained in the entire layer region (G) or a part of the layer region, but in either case, it needs to be contained in a state where it is distributed more toward the support side. That is, the layer region (SPN) containing the substance (C) provided in the second layer region (S) is provided as the entire layer region of the second layer region (S), or the layer region (SPN) containing the substance (C) is provided as the entire layer region of the second layer region (S), or region
(S) is provided as a support side end region (SE). In the former case where it is provided as a full layer area, it is provided in a line where the distribution concentration C(S) increases linearly, stepwise, or curved toward the support side. When the distribution concentration C(S) increases in a curved manner, it is desirable to provide a substance (C) that controls conductivity in the layer region (S) so that it monotonically increases toward the support side. . When the layer region (SPN) is provided as a part of the second layer region (S), the distribution state of the substance (C) in the layer region (SPN) is parallel to the surface of the support. Although it is assumed to be uniform in the in-plane direction, it may be uniform or non-uniform in the layer thickness direction. In this case, in order to provide the substance (C) so that it is distributed non-uniformly in the layer thickness direction in the layer region (SPN), it is necessary to provide the substance (C) in the entire layer region of the first layer region (S). It is desirable to provide the same distribution concentration line. The first layer region (G) contains a substance (C) that controls conductivity to form a layer region (GPN) containing the substance (C).
Also when providing a layer area (SPN) in the second layer area (S)
This can be done in the same way as when providing . In the present invention, a substance (C) that controls conduction properties is added to both the first layer region (G) and the second layer region (S).
When containing, the substance (C) contained in both layer regions
may be the same species or mutually different species. However, when both layer regions contain the same type of substance (C) that controls conductivity, the maximum distribution concentration of the substance (C) in the layer thickness direction is equal to that in the second layer region (S). It is in,
That is, inside the second layer region (S) or the first layer region
It is preferable to provide it at the interface with (G). In particular, it is desirable that the maximum distribution concentration is provided at or near the contact interface with the first layer region (G). In the present invention, as described above, the substance (C) that controls conduction properties is contained in the photoreceptive layer, and the layer region (PN) containing the substance (C) is replaced by the second layer region (PN). Preferably, the support side end layer region (SE) of the second layer region (S) occupies at least a part of the layer region of the second layer region (S).
Established as When the layer region (PN) is provided so as to span both the first layer region (S) and the second layer region (G), the layer region (GPN) of the substance (C) that controls conduction properties There is C(G) _{nax between the maximum distribution concentration C(G) nax} in the layer region (SPN) and the maximum distribution concentration C(S) _nax in the layer region (SPN) _.
The substance (C) is contained in the photoreceptive layer so that the relational expression <C(S) _nax is established. The substance (C) that controls conductivity contained in the layer region (PN) can include so-called impurities in the semiconductor field, and in the present invention, Si
Alternatively, for Ge, a P-type impurity that gives P-type conductivity characteristics and an n-type impurity that gives N-type conductivity characteristics can be mentioned. Specifically, P-type impurities include atoms belonging to the group of the periodic table (group atoms), such as B (boron), Al (aluminum), Ga (gallium), In (indium), and Tl (thallium). Among them, B and Ga are particularly preferably used. Examples of n-type impurities include atoms belonging to the group of the periodic table (group atoms), such as P (phosphorus), As (arsenic), Sb (antimony), Bi (bismuth), etc.
In particular, P and As are preferably used. In the present invention, a substance controlling conduction properties contained in a layer region (PN) provided in a photoreceptive layer
The content of (C) depends on the conductive properties required for the layer region (PN), or the properties at the contact interface with the support or other layer region that the layer region (PN) is provided in direct contact with. It can be selected as appropriate based on the organic relationship, such as the relationship between Also, the characteristics of other layer regions provided in direct contact with the layer region,
The content of the substance (C) that controls conduction properties is appropriately selected, taking into consideration the relationship with the properties at the contact interface with the other layer regions. In the present invention, the content of the substance (C) that controls conduction properties contained in the layer region (PN) is as follows:
Preferably 0.01 to 5×10 ⁴ atomic ppm, more preferably 0.5 to 1×10 ⁴ atomic ppm, optimally 1 to 5
It is desirable to set it to ×10 ³ atomic ppm. In the present invention, the layer region (PN) containing the substance (C) that controls the conduction properties is placed in contact with the contact interface between the first layer region (S) and the second layer region (G), or the layer region (PN) occupies at least a part of the first layer region (G), and the content of the substance (C) in the layer region (PN) is preferably 30 atomic ppm.
As described above, by more preferably 50 atomic ppm or more, optimally 100 atomic ppm or more, for example, when the substance to be contained is the above-mentioned P-type impurity, the free surface of the photoreceptive layer is charged to be polar. The transfer of electrons injected from the support side into the second layer region (G) when received can be effectively prevented,
Further, when the substance to be included is the n-type impurity, it is injected from the support side into the second layer region (G) when the free surface of the photoreceptive layer is subjected to polar charging treatment. The movement of holes can be effectively prevented. In the above case, under the above-mentioned basic structure of the present invention, the layer region (Z) excluding the layer region (PN) has a layer region (Z) that controls the conductive properties contained in the layer region (PN). It is also possible to contain a substance that controls conduction properties of a polarity different from that of the substance to be used, or a substance that controls conduction properties of the same polarity may be contained in a smaller amount than the actual amount contained in the layer region (PN). It may also be contained in a much smaller amount. In such a case, the content of the substance controlling the conduction characteristics contained in the layer region (Z) may be determined as desired depending on the polarity and content of the substance contained in the layer region (PN). Therefore, it is determined as appropriate, but preferably 0.001 to 1000 atomic ppm, more preferably 0.05 to 500 atomic ppm, and optimally 0.1
It is desirable to set it to ~200 atomic ppm. In the present invention, a layer region (PN) and a layer region (Z)
When containing a substance that controls the same type of conductivity, the content in the layer region (Z) is preferably 30 atomic ppm or less. In addition to the above-mentioned cases, in the present invention, the photoreceptive layer contains a layer region containing a substance controlling conductivity having one polarity and a substance controlling conductivity having the other polarity. It is also possible to provide a so-called depletion layer in the contact region by providing the layer region in direct contact with the contact region. That is, for example, the layer region containing the p-type impurity and the layer region containing the n-type impurity are provided in the photoreceptive layer so as to be in direct contact with each other to form a so-called P-n junction. A depletion layer can be provided. FIGS. 11 to 24 show typical examples of the distribution state of the substance (C) in the layer thickness direction, which is contained in the photoreceptive layer and controls the conduction characteristics. In these figures, the horizontal axis shows the distribution concentration C _(PN) of the substance (C) in the layer thickness direction, and the vertical axis shows the layer thickness t from the support side of the photoreceptive layer. t ₀ indicates the position of the contact interface between the layer region (G) and the layer region (S). Further, the symbols used on the horizontal and vertical axes have the same meanings as those used in FIGS. 2 to 10, unless otherwise specified. Figure 11 shows the first distribution state of the substance (C) in the layer thickness direction that controls the conduction properties contained in the photoreceptive layer.
A typical example is shown. In the example shown in FIG. 11, the material (C) is in the layer region
Not contained in (G), concentrated only in layer region (S)
It is contained in a uniformly distributed concentration of _C1 . When clogging, the layer region (S) has a substance (C) in the end layer region between t ₀ and t ₁ at a concentration C ₁
It is contained in a certain distributed concentration of. In the example of FIG. 12, the layer region (G) contains the substance (C) evenly, but the layer region (S) does not contain the substance (C). The substance (C) is contained in the layer region between t ₀ and t ₂ at a constant distribution concentration of C ₂ , and in the layer region between t ₂ and t _T , the distribution concentration is much lower than C ₂ Contained at a constant concentration of _C3 . By incorporating the substance (C) in the layer region (S) constituting the photoreceptive layer with such a distributed concentration C _(PN) , the surface of the charge injected from the layer region (G) into the layer region (S) It is possible to effectively prevent movement in this direction, and at the same time, it is possible to improve light sensitivity and dark resistance. In the example shown in Fig. 13, the substance (C) is uniformly contained in the layer region (G), but the concentration monotonically decreases toward the upper surface from the concentration _C4 at _t0 until _tT. When the distribution concentration C _(PN) changes so that the concentration becomes 0,
Contains (C). The layer region (G) does not contain the substance (C). In the examples shown in FIGS. 14 and 15, the substance (C) is unevenly contained in the lower end layer region of the layer region (S). That is, in the case of the examples shown in FIGS. 14 and 15, the layer region (S) is divided into a layer region containing the substance (C) and a layer region not containing the substance (C). It has a layered structure in which the layers are stacked in order from the support side. The difference between the examples in Fig. 14 and Fig. 15 is that in the case of Fig. 14, the distribution concentration C _(PN) is greater than the concentration C ₅ at position t ₀ between t ₀ and t ₃ . The concentration decreases monotonically to 0 at the position of t ₃ , while the concentration at the first
In the case of FIG. 5, between t ₀ and t ₄ , the concentration decreases linearly and continuously from the concentration C ₆ at the t ₀ position to the concentration 0 at the t ₄ position. Figure 14 and 1
In the case of the example shown in FIG. 5 as well, the layer region (G) does not contain the substance (C). In the examples of FIGS. 17 to 24, the layer region
Material (C) that controls conductivity in both (G) and layer region (S)
Indicates the case where . In the case of the examples shown in FIGS. 17 to 22, the layer region (S)
Commonly, these have a two-layer structure in which a layer region containing substance (C) and a layer region not containing substance (C) are laminated in this order from the support side. . In the examples shown in FIGS. 17 to 21, the distribution state of the substance (C) in the layer region (G) is the interface position t ₀ with the second layer region (S). This means that the distribution concentration C _(PN) decreases closer to the support. In the examples shown in FIGS. 23 and 24, the substance (C) is evenly contained in the layer thickness direction over the entire layer region of the photoreceptive layer. In addition, in the case of Fig. 23, in the layer region (G), the concentration increases linearly from _{t B} toward t ₀ from the concentration C ₂₃ at t 0 to the concentration C ₂₂ at t ₀ . , in the layer region (S), the concentration monotonically and continuously decreases from t ₀ to t _T from the concentration C ₂₂ at t 0 to ₀ at t _T . In the case of Fig. 24, the layer region between t _B and t ₁₃ contains the substance (C) at a constant distribution concentration of C ₂₄ , and the layer region between t ₁₃ and t _T contains the substance (C). It decreases linearly from the concentration C ₂₅ and reaches 0 at t _T . In the above figures 11 to 24, the distribution concentration of the substance (C) that controls conductivity in the photoreceptive layer
As explained in the typical cases of changes in C _(PN) , in all examples, the substance (C) is ) is contained in the photoreceptive layer. In the present invention, in order to form the second layer region (S) composed of a-Si (H, The first layer region (G) is formed using the starting material [starting material for forming the second layer region (S) ()] excluding the starting material that becomes the raw material gas for supplying G. It can be carried out according to the same method and conditions as in the case. That is, in the present invention, in order to form the second layer region (S) composed of a-Si (H, It is made by a vacuum deposition method using . For example, in order to form the second layer region (S) composed of a-Si (H, Along with the raw material gas for supplying Si, a raw material gas for introducing hydrogen atoms (H) and/or halogen atoms (X) as needed is introduced into a deposition chamber whose interior can be reduced in pressure. What is necessary is to generate a glow discharge to form a layer made of a-Si(H,X) on a predetermined support surface set in advance at a predetermined position. In addition, when forming by sputtering, for example, when sputtering a target composed of Si in an atmosphere of an inert gas such as Ar or He or a mixed gas based on these gases, hydrogen atoms (H ) or/and a gas for introducing halogen atoms (X) may be introduced into the deposition chamber for sputtering. In the present invention, the amount of hydrogen atoms (H) or the amount of halogen atoms (X) or hydrogen atoms and halogen atoms contained in the second layer region (S) constituting the amorphous layer to be formed The sum of the amounts (H+X) is preferably 1 to
It is desirable that the content be 40 atomic %, more preferably 5 to 30 atomic %, most preferably 5 to 25 atomic %. A substance (C) that controls conduction properties, for example, a group group atom or a group atom, is structurally introduced into the layer region constituting the photoreceptive layer to form a layer region containing the substance (C) (PN ), during layer formation,
The starting material for introducing the group atom or the starting material for introducing the group atom may be introduced in a gaseous state into the deposition chamber together with other starting materials for forming the photoreceptive layer. As a starting material for introducing such group atoms, it is desirable to employ a material that is gaseous at room temperature and pressure, or that can be easily gasified at least under layer-forming conditions. Specifically, starting materials for introducing such group atom include B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ ,
Boron hydride _{such as B5H11} , _B6H10 , _{B6H12 , B6H14 ,} etc.
Examples include boron halides such as BF ₃ , BCl ₃ and BBr ₃ . In addition, AlCl ₃ , GaCl ₃ , Ga(CH ₃ ) ₃ ,
InCl ₃ , TlCl ₃ and the like can also be mentioned. Effective starting materials for the introduction of Group V atoms in the present invention include hydrogenated phosphorus such as PH ₃ and P ₂ H ₄ , PH ₄ I, PF ₃ ,
Examples include phosphorus halides such as PF ₅ , PCl ₃ , PCl ₅ , PBr ₃ , PIr ₅ and PI ₃ . In addition, AsH ₃ , AsF ₃ ,
AsCl ₃ , AsBr ₃ , AsF ₅ , SbH ₃ , SbF ₃ , SbF ₅ ,
SbCl ₃ , SbCl ₅ , BiH ₃ , BiCl ₃ , BiBr ₃ and the like can also be mentioned as effective starting materials for the introduction of group atoms. The support used in the present invention may be electrically conductive or electrically insulating. Examples of the conductive support include NiCr, stainless steel, Al,
Examples include metals such as Cr, Mo, Au, Nb, Ta, V, Ti, Pt, and Pd, and alloys thereof. As the electrically insulating support, films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, glass, ceramic, paper, etc. are usually used. . Preferably, at least one surface of these electrically insulating supports is conductively treated, and another layer is preferably provided on the conductively treated surface side. For example, if it is glass, NiCr,
Al, Cr, Mo, Au, Ir, Nb, Ta, V, Ti, Pt,
Conductivity can be imparted by providing a thin film made of Pd, In ₂ O ₃ , SnO ₂ , ITO (In ₂ O ₃ +SnO ₂ ), etc., or if it is a synthetic resin film such as polyester film, NiCr, Al , Ag, Pb, Zn, Ni,
A thin film of metal such as Au, Cr, Mo, Ir, Nb, Ta, V, Ti, Pt, etc. is provided on the surface by vacuum evaporation, electron beam evaporation, sputtering, etc., or the surface is laminated with the metal, Conductivity is imparted to the surface. The shape of the support may be any shape such as a cylinder, a belt, or a plate, and the shape is determined as desired. For example, the photoconductive member 100 in FIG. If it is used as a forming member, it is preferably in the form of an endless belt or a cylinder in the case of continuous high-speed copying. The thickness of the support is determined appropriately so that the desired photoconductive member is formed, but if flexibility is required as a photoconductive member, the support can sufficiently function as a support. It is made as thin as possible within this range. However, in such cases, the thickness is usually 10μ or more in view of manufacturing and handling of the support, mechanical strength, etc. Next, an outline of an example of the method for manufacturing a photoconductive member of the present invention will be explained. FIG. 25 shows an example of a photoconductive member manufacturing apparatus. In the gas cylinders 202 to 206 in the figure, raw material gas for forming the photoconductive member of the present invention is sealed.
_SiH4 gas diluted with He (purity 99.999% or less)
Abbreviated as SiH ₄ /He. ) cylinder, 203 is GeH ₄ gas diluted with He (99.999% purity, hereinafter GeH ₄ /
Abbreviated as He. ) cylinder, 204 diluted with He
SiF ₄ gas (99.99% purity, hereinafter abbreviated as SiF ₄ /He)
cylinder, 205 is a B ₂ H ₆ gas diluted with He (purity 99.999%, hereinafter abbreviated as B ₂ H ₆ /he);
206 is a H ₂ gas (purity 99.999%) cylinder. In order to flow these gases into the reaction chamber 201, the valves 222-22 of the gas cylinders 206-206 are used.
6. Check that the leak valve 235 is closed, and also check the inflow valves 212 to 216, the outflow valves 217 to 221, and the auxiliary valves 232 and 233.
After confirming that the main valve 234 is opened, the reaction chamber 201 and each gas pipe are evacuated by opening the main valve 234. Next, the reading on the vacuum gauge 236 is approximately 5×
When the temperature reaches 10 ^-6 torr, the auxiliary valves 232 and 23
3. Close the outflow valves 217-221. Next, to give an example of forming a light-receiving layer on the cylindrical substrate 237, the gas cylinder 202
From SiH ₄ /He gas, gas cylinder 203
Open the valves 222, 223 and increase the pressure of the outlet pressure gauges 227 _, 228 to 1 kg/He gas.
cm ² and gradually open the inflow valves 212 and 213 to flow into the mass flow controllers 207 and 208, respectively. Subsequently, the outflow valve 21
7, 218, the auxiliary valve 232 is gradually opened to allow each gas to flow into the reaction chamber 201. At this time, _the outflow valve 217 _,
218 and the opening of the main valve 234 while checking the reading on the vacuum gauge 236 so that the pressure inside the reaction chamber 201 reaches the desired value. Then, the temperature of the base 237 is raised to 50°C by the heating heater 238.
After confirming that the temperature is set in the range of ~400°C, the power supply 240 is set to the desired power to generate glow discharge in the reaction chamber 201 to perform the basic 2
A first layer region (G) is formed on the layer 37. At the time when the first layer region (G) is formed to a desired layer thickness, the outflow valve 218 is completely closed and B ₂ H ₆ /He gas is supplied from the gas cylinder 205 in the same manner as the SiH ₄ /He gas described above. Following the same conditions and procedures, except that the mass flow controller 210 is controlled according to the desired doping curve by introducing it into the reaction chamber 201 by operating the valve, and changing the discharge conditions as necessary. By maintaining the glow discharge for a desired period of time, a second layer region (S) substantially free of germanium atoms can be formed on the first layer region (G). In this way, the first layer region (G) and the second layer region
(S) is formed on the substrate 237. During layer formation, it is desirable that the base body 237 be rotated at a constant speed by a motor 239 in order to ensure uniform layer formation. Examples will be described below. Example 1 Using the manufacturing apparatus shown in FIG. 25, each sample as an electrophotographic image forming member was formed on a cylindrical Al substrate under the conditions shown in Table 1 (see Table 2). When _forming the layer region (S), the distribution concentrations _shown in _FIG . A sample was formed.

[Table] Each sample thus obtained was placed in a charging exposure experimental device and corona charged at 5.0 kV for 0.3 seconds.
A light image was immediately irradiated. The optical image was generated using a tungsten lamp light source, and a light intensity of 2 lux·sec was irradiated through a transmission type test chart. Immediately thereafter, a good toner image was obtained on the photoreceptive layer surface by cascading a charged developer (including toner and carrier) over the photoreceptive layer surface of each sample. When the toner image on the photoreceptive layer was transferred onto transfer paper using 5.0 kV corona charging, each sample had excellent resolution and a clear, high-density image with good gradation reproducibility was obtained. A toner transfer image was obtained for each sample in the same manner as above, except that an 810 nm GaAs semiconductor laser (10 mW) was used as the light source instead of a tungsten lamp, and an electrostatic image was formed. When we evaluated the image quality of each sample, we found that each sample had excellent resolution.
A clear, high-quality image with good gradation reproducibility was obtained. Example 2 Using the manufacturing apparatus shown in FIG. 25, each sample as an electrophotographic image forming member was formed on a cylindrical Al substrate under the conditions shown in Table 3 (see Table 4). By changing the flow rate ratio of B ₂ H ₆ gas and PH ₃ gas according to a pre-designed change rate line during formation of layer region (G) and layer region (S), the result shown in FIG. 27 is obtained. The distribution concentrations shown were formed for each sample, respectively. When each of these samples was subjected to the same image evaluation test as in Example 1, all of the samples provided high quality toner transfer images. Furthermore, when each sample was tested for repeated use 200,000 times in an environment of 38°C and 80% RH, no deterioration in image quality was observed in any of the samples.

[Table] Example 3 Samples (sample Nos. 31-1 to 37-
12) respectively (Table 6). The concentration distribution of germanium atoms in each sample is shown in FIG. 28, and the distribution concentration of impurity atoms in each sample is shown in FIGS. 26 and 27. When each of these samples was subjected to the same image evaluation test as in Example 1, all of the samples provided high quality toner transfer images. Furthermore, when each sample was tested for repeated use 200,000 times in an environment of 38°C and 80% RH, no deterioration in image quality was observed in any of the samples.

【table】

【table】

【table】

[Table] Common layer forming conditions in the above embodiments of the present invention are shown below. Substrate temperature: Germanium atom (Ge) containing layer…approx.
200℃ Germanium atom (Ge)-free layer...approx. 250℃ Discharge frequency: 13.56MHz Reaction chamber pressure during reaction: 0.3Torr

[Brief explanation of the drawing]

FIG. 1 is a schematic layer structure diagram for explaining the layer structure of the photoconductive member of the present invention, and FIGS. 2 to 10 are for explaining the distribution state of germanium atoms in the layer region (G), respectively. The explanatory diagrams of FIGS. 11 to 24 are
FIG. 25 is a schematic explanatory diagram of the device used in the present invention, and FIGS. 26 to 28 are explanatory diagrams for explaining the distribution state of impurity atoms in the photoreceptive layer, respectively. It is an explanatory view showing the distribution state of each atom in an example. 100...Photoconductive member, 101...Support, 1
02...Photoreceptive layer.

Claims (1)

[Scope of Claims] 1. A support for a photoconductive member, a first layer region (G) made of an amorphous material containing germanium atoms on the support, and an amorphous material containing silicon atoms. The photoreceptive layer has a layer structure in which a second layer region (S) is made of a transparent material and exhibits photoconductivity and is provided in order from the support side, and the photoreceptor layer has a layer structure according to the periodic table. In the photoreceptive layer, the maximum value of the distribution concentration in the layer thickness direction is in the second layer region (S), and the atom C belonging to at least one of the atoms belonging to the group or the group A photoconductive member characterized in that, in the second layer region (S), the content is distributed more toward the support side. 2. The photoconductive member according to claim 1, wherein the first layer region (G) contains silicon atoms. 3. The photoconductive member according to claim 1, wherein the distribution state of germanium atoms in the first layer region (G) is non-uniform in the layer thickness direction. 4. The photoconductive member according to claim 1, wherein the distribution state of germanium atoms in the first layer region (G) is uniform in the layer thickness direction. 5. The photoconductive member according to claim 1, wherein at least one of the first layer region (G) and the second layer region (S) contains hydrogen atoms. 6. The photoconductive member according to claim 1 or 5, wherein at least one of the first layer region (G) and the second layer region (S) contains a halogen atom. 7. The photoconductive member according to claim 2, wherein germanium atoms in the first layer region (G) are distributed more toward the support side.