JPH08250696A - Solid-state image sensor and manufacture thereof - Google Patents

Abstract

PURPOSE: To balance the reduction in the number of gap levels and hole injection preventing characteristics and to reduce the after-image by providing a hole injection preventing layer in a region between a photosensitive layer and a positive electrode and a wide band gap layer having a larger band gap than that of the photosensitive layer. CONSTITUTION: A charge transfer region B is formed on a semiconductor substrate 17, and the charge generated by photoelectric conversion is stored and transferred. A charge generating region A is laminated on the region B, and the charge is generated by the photoelectric conversion of the incident light. The region A is formed of a positive electrode 11, a hole injection preventing layer 12, a photosensitive layer 14, an electron injection preventing layer 15 and a negative electrode 16 sequentially formed on the region B. The layer 12 and a wide band gap layer 13 having a larger band gap than that of the layer 14 are provided in the region between the layer 14 and the electrode 11. Thus, the hole can be simultaneously injected without increasing the gap level density, and low after-image can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device using an amorphous semiconductor and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, amorphous semiconductors have attracted attention in the development of semiconductor materials. A typical example of this amorphous semiconductor is amorphous silicon. Amorphous silicon has a feature that a large-area film can be obtained at low cost, and thus has been widely tried to be applied to devices such as solar cells, thin film transistors, photosensitive drums, and solid-state imaging devices.

As an example of the above-mentioned devices, a typical element structure of a solid-state image pickup device (vertical CCD) using amorphous silicon is shown in FIG. This solid-state imaging device
It is mainly composed of a charge generation region and a charge transfer region. The charge generation region A includes the Ti pixel electrode 101 and the a-SiC: H (i) layer 10 provided on the charge transfer region B.
2, a-Si: H (i) layer 103, a-SiC: H
The (p) layer 104 and the ITO transparent electrode 105 constitute a photoelectric conversion diode. a-SiC:
The H (i) layer 102 is a carrier (hole) from the external electrode.
Block the injection of. In addition, the a-SiC: H (p) layer 10
4 serves as a window for allowing light to enter from the outside, and blocks injection of electrons from the external electrode. In general, amorphous silicon is called hydrogenated amorphous silicon because its dangling bond is terminated with hydrogen, and is referred to as a-Si: H. Further, (i) indicates an intrinsic semiconductor, and (p) indicates a p-type semiconductor by introducing impurities.

The charge transfer region B is a channel block region 10.
6a, depletion region 106b, and storage diode 106
p-type silicon substrate 106 in which c is formed, and depletion region 1
06b and a polysilicon transfer electrode 107 formed via a silicon oxide film 108, and a polysilicon transfer electrode 10
Mainly composed of a MoSi pixel wiring electrode 109 formed over the silicon oxide film 108 and electrically connected to the storage diode 106c, and a BPSG flattening insulating film 110 formed on the MoSi pixel wiring electrode 109. Is configured. The Ti pixel electrode 10 in the charge generation region A
1 and the MoSi pixel wiring electrode 109 are partially electrically connected.

In the solid-state image pickup device having the above structure, the incident light is photoelectrically converted by the a-Si: H (i) layer 103, and the electrons generated there are accumulated in the storage diode 106c.
And the image signal is obtained by transferring electrons from the storage diode 106c by adjusting the potential of the polysilicon gate electrode 107. As described above, in the solid-state imaging device using amorphous silicon, the charge generation region A can be arranged above the charge transfer region B, as shown in FIG.
Further, it has a feature that light does not directly enter the charge transfer region B, and as a result, the sensitivity is high and the optical smear is low.

[0006]

As described above, in the case of a laminated solid-state image pickup device using amorphous silicon, excellent element characteristics can be realized, but the amorphous material has a band gap (in the band structure). Since a high density level (gap level) exists in the forbidden band, this becomes a problem in device characteristics. That is, the gap level acts as a carrier trap level when the free carrier density is increased by an external stimulus such as light, and the trapped carrier is removed when the external stimulus is removed. Acts as a conduction carrier by thermal excitation. This means that the relaxation time constant of the current is large with respect to the external stimulus. This phenomenon appears as a problem of afterimage in the solid-state imaging device.

In the charge generation region A of the solid-state image pickup device shown in FIG. 10, the region where the afterimage is generated is mainly a-Si: H (i) layer 103 and a-SiC: H in view of the above-mentioned mechanism of the afterimage generation. The bulk region of the (i) layer 102 and the a-Si: H (i) layer 103 and a-SiC: H (i).
It is believed to be the interface with layer 102. in this case,
Considering the mechanism of the afterimage, reducing the gap level density in the bulk region and the interface leads to the reduction of the afterimage.

A-Si: H (i) layer 103 and a-S
There are several known means for reducing the gap level density in the bulk region of the iC: H (i) layer 102.
One of them is a method of using a source gas diluted with hydrogen when forming these layers. This method controls the surface reaction in the film growth process to reduce the surface defect density, and consequently the bulk gap level density. Specifically, plasma CV
When the a-Si: H (i) layer 103 is formed by D, when the hydrogen dilution degree is defined as Z = [H ₂ ] / [SiH ₄ ] ([] indicates the gas flow rate), Z = 5 to 5 SiH ₄ gas diluted with hydrogen of 10 is used.

As another method, by controlling the reaction in the gas phase to suppress the formation of highly reactive radicals, film growth is carried out while the structural relaxation is sufficiently promoted. A method of increasing the flow rate to reduce the density can be mentioned. This method suppresses the reaction in the gas phase by increasing the flow rate of the introduced gas and decreasing the residence time in the reaction furnace. Further, although the density of the gap level is constant, it is considered that reducing the total level by reducing the film thickness is also effective.

On the other hand, the a-Si: H (i) layer and the a-Si
As a typical method for reducing the gap level density of the interface with the C: H (i) layer, in order to prevent the generation of the interface level due to contact of different materials at the interface, The method of providing a composition modulation layer is mentioned. Specifically, the a-Si: H (i) layer and the a-SiC: H (i) layer.
A composition modulation layer in which the carbon composition is gradually changed is provided at the interface between the layers.

As described above, in the stacked solid-state image pickup device using the amorphous semiconductor in the charge generation region, the afterimage can be reduced to a certain extent by the reduction of the gap level density and the interface state density as described above. it can. However, the above method does not sufficiently reduce the afterimage,
Further, there is a demand for a solid-state image pickup device with less afterimage.

The a-SiC: H (p) layer 104, a
-Si: H (i) layer 103, and a-SiC: H
(I) The thickness of the layer 102 is 10 nm and 1000 n, respectively.
m and 10 nm, and after applying a reverse bias of 8 V, an afterimage was obtained from the transient photocurrent after a steady photocurrent of 1 × 10 ⁻⁷ A / cm ² was obtained, and 2/60 to 3 / When expressed by the value of the average value of the current value for 60 seconds (3-Field) with respect to the stationary photocurrent value, the afterimage value when the solid electrode is used without partitioning the Ti electrode into each pixel is 0.1%, The Ti pixel electrode has a pixel shape as shown in FIG. 10, for example, 7 μm × 7 μ
When the m size (thickness is 50 nm) and the gap between pixel electrodes is 1 μm, the afterimage value is 0.4%. In general, the afterimage value is preferably 0.2% or less in consideration of the afterimage of human eyes and the afterimage of a monitor. Therefore, there is a problem that the afterimage value is too large when the structure of an actual solid-state imaging device is used. The present invention has been made in view of the above points, and an object of the present invention is to provide a stacked solid-state imaging device having a very small afterimage and a manufacturing method thereof.

[0013]

Means and Actions for Solving the Problems First of the Invention
In the invention, a charge transfer region which is formed on a semiconductor substrate and accumulates and transfers charges generated by photoelectric conversion, and a charge which is stacked on the charge transfer region and generates charges by photoelectric conversion from incident light. And a generation area,
The charge generation region is composed of a positive electrode, a hole injection blocking layer, a photosensitive layer, an electron injection blocking layer, and a negative electrode, which are sequentially formed on the charge transfer region, and the photosensitive layer and the positive electrode are formed. A hole-injection blocking layer and a wide bandgap layer having a bandgap larger than that of the photosensitive layer are provided in a region between the solid-state imaging devices.

Further, in the first invention, a step of forming a charge transfer region for accumulating and transferring charges generated by photoelectric conversion on a semiconductor substrate, and a positive electrode and a hole are sequentially formed on the charge transfer region. A step of forming an injection blocking layer, a photosensitive layer, a hole injection blocking layer, and a negative electrode; a hole injection blocking layer in a region between the photosensitive layer and the positive electrode; And a step of providing a wide bandgap layer having a large gap.

The first aspect of the present invention is to accumulate and store charges generated by photoelectric conversion on a semiconductor substrate.
A charge transfer region for transferring and a charge generation region stacked on the charge transfer region for generating charges by photoelectric conversion from incident light are provided, and the charge generation region is sequentially formed on the charge transfer region. A positive electrode, a hole injection blocking layer, a photosensitive layer, an electron injection blocking layer, and a negative electrode. The hole injection blocking layer and the n-type semiconductor are formed in a region between the photosensitive layer and the positive electrode. A solid-state imaging device, comprising: a layer.

According to a second aspect of the present invention, a charge transfer region formed on a semiconductor substrate for accumulating and transferring charges generated by photoelectric conversion, and a charge transfer region stacked on the charge transfer region, are formed from incident light. A charge generation region for generating charges by photoelectric conversion, wherein the charge generation region is a positive electrode sequentially formed on the charge transfer region, a hole injection blocking layer,
The positive electrode is composed of a photosensitive layer, an electron injection blocking layer, and a negative electrode, and the positive electrode is partitioned at intervals for each pixel, and the hole injection blocking layer is provided only on the partitioned positive electrode. There is provided a solid-state imaging device characterized by the above. In this case, it is preferable that the photosensitive layer is provided on the end of the positive electrode in the space.

Further, in the second invention, a step of forming a charge transfer region for storing and transferring charges generated by photoelectric conversion on a semiconductor substrate, and a positive electrode having a step portion on the charge transfer region. A step of forming a hole injection blocking layer only on the positive electrode, a step of forming a photosensitive layer on the end face of the step and the hole injection blocking layer, and a step of forming a photosensitive layer on the photosensitive layer. And a step of forming a negative electrode via an electron injection blocking layer.

In the first and second inventions, Ti, W, p-Si or the like can be used as the material of the positive electrode. The material for the hole injection blocking layer may be any material that can block the injection of holes, and may be a-SiC.
(I), a-SiN, a-SiC (n), a-SiO
(I, p) etc. can be mentioned. The material of the photosensitive layer is a-Si (i), a-Ge, a-Se, a-Si.
Ge or the like can be used. The material for the electron injection blocking layer may be any material that can block the injection of electrons, such as a-SiC (p), a-SiN (p), and a-S.
iO (p) etc. can be mentioned. As a material for the negative electrode, a transparent conductive film such as ITO or Sn ₂ O ₃ can be used.

In the first invention, a-SiH (i)
Layer and the bulk region of the a-SiC: H (i) layer and the afterimage component generated at the interface between the a-SiH (i) layer and the a-SiC: H (i) layer, and the afterimage component Is reduced, a solid-state imaging device with less afterimage is obtained.

When reducing the afterimage component in the above-mentioned region and interface, the gap level density is reduced, and the a-SiH (i) layer or a-SiC: H (i) is reduced.
It is conceivable to reduce the layer thickness. However,
For example, when the afterimage component is reduced as described above for the a-SiC: H (i) layer, the hole injection blocking layer a-
The injection of holes into the SiC: H (i) layer is promoted, the leak current of the photoelectric conversion diode increases, and this causes noise in terms of images. In addition, an afterimage component is generated due to carrier recombination due to carriers injected from the outside,
On the contrary, the afterimage increases. Therefore, it is necessary to maintain the hole injection blocking performance without increasing the gap level density.

In view of the above points, the present inventors, as a first aspect of the first invention, use the wide band gap layer as a hole barrier to simultaneously increase the gap level density without increasing the gap level density. It was found to block hole injection.

The bandgap of this wide bandgap layer is wider than the bandgap of the a-Si: H (i) layer as a photosensitive layer, which is 1.75 to 1.8 eV (determined by sensitivity, dark current, etc.). It is preferably about 1.8 to 2.1 eV. Further, as the material of the wide band gap layer, those having a low defect density are preferable, and a-Si: H (i) in which defects are terminated by hydrogen atoms is preferable.

This wide band gap layer has a gap level density of about 2 to 3 × 10 ¹⁶ cm ^-3 as measured by a neutral defect density by an electron spin resonance method (ESR method),
It is about the same as the a-Si: H (i) layer as the photosensitive layer.

A-Si: H as a wide gap layer
When the (i) layer is used, it may be formed by a plasma CVD method under a high hydrogen dilution condition of about 30 or more of hydrogen dilution (flow rate of hydrogen gas relative to flow rate of source gas such as SiH ₄ introduced into the processing chamber). it can. The hydrogen concentration of the a-Si: H (i) layer, which is the wide band gap layer thus formed, is 20 to 30% when the concentration of hydrogen bonding to silicon is determined from the infrared absorption spectrum. Is higher than the concentration of the a-Si: H (i) layer of 10 to 20%. The defect density of the a-Si: H (i) layer as the wide band gap layer is as small as that of the a-Si: H (i) layer as the photosensitive layer.

Further, a as a wide band gap layer
The fact that the hydrogen concentration of the —Si: H (i) layer is high is obtained from the peak appearing in the vicinity of 2000 to 2100 cm ⁻¹ in the infrared absorption spectrum (Si—H ₂ ) / [(Si−
_{H) + (Si-H 2} )] can be seen from the coupling ratio. That is, the a-Si: H (i) layer as the photosensitive layer had a value such that the above-mentioned coupling ratio did not exceed 20%, whereas the a-Si: H (i) layer as the wide band gap layer. Has a large value of the above-mentioned coupling ratio of about 20 to 30%. As described above, by using the a-Si: H (i) layer having a high hydrogen concentration as the wide band gap layer, a hole barrier can be obtained.

By providing the wide band gap layer, even if the afterimage is reduced by reducing the thickness of the a-Si: H (i) layer as the hole injection blocking layer, the hole injection blocking layer and the wide band gap blocking layer can be reduced. The band gap layer can exert a hole injection blocking effect. In addition, since the wide band gap layer has a relatively low gap level density, the increase in the afterimage component due to the provision of the wide bandgap layer is small, and as a result, a low afterimage as a solid-state imaging device can be realized.

This wide band gap layer is provided in the region between the photosensitive layer and the positive electrode. This is to suppress the injection of holes into the photosensitive layer. Therefore, the layer structure may be photosensitive layer / wide gap layer / hole injection blocking layer / positive electrode, or photosensitive layer / hole injection blocking layer / wide gap layer / positive electrode. In particular, the wide band gap layer is preferably provided at the interface between the hole injection blocking layer and the photosensitive layer. This is a hole injection blocking layer a-SiC: H
This is because the layer (i) has excellent adhesiveness to the positive electrode. In addition, a-Si: H which is a wide band gap layer
This is because the layer (i) plays a role of blocking hole injection, and thus it is preferable that the layer (i) is mainly present on the positive electrode side rather than the region where photoelectric conversion is performed. The wide band gap layer may be located in the photosensitive layer. In this case, it is effective in the photoelectric conversion region on the light incident side of the wide band gap layer with respect to the photosensitive layer having a certain film thickness.

Further, the wide band gap layer a-
Since the Si: H (i) layer plays a role of blocking hole injection,
A hole injection blocking layer may be used in combination with the —SiC: H (i) layer and is a wide bandgap layer of a-Si: H.
The layer (i) may also serve as the hole injection blocking layer.

In forming this wide band gap layer, considering the influence of the interface state, the interface between the hole injection blocking layer and the wide band gap layer is formed so that the carbon composition gradually changes. It is desirable to do so (carbon composition modulation layer). Further, it is desirable that the interface between the wide band gap layer and the photosensitive layer is formed so that the hydrogen concentration gradually changes (hydrogen concentration modulation layer). The hydrogen concentration modulation layer and the carbon composition modulation layer are for suppressing the generation of interface states by not forming a clear interface.

In addition, as a second aspect of the first invention, the present inventors have proposed an n-type semiconductor layer such as an n-type aS.
i: H (n) layer (lightly doped a-Si: H (n)
It was found that the formation of the (layer) simultaneously blocks the hole injection without increasing the gap level density.

By inserting the n-type semiconductor between the photosensitive layer and the positive electrode, the Fermi level shifts to the conduction band side, and as a result, it becomes a hole barrier layer. If the impurity concentration for the n-type conductivity is increased, the Fermi level shift is increased and the barrier against holes is increased. However, as described above, the hole injection blocking property is improved without increasing the gap level density. Since it is necessary to maintain the impurity concentration, if the impurity concentration is made too high, the disorder of the lattice is caused by the impurity and the gap level density increases, which is not suitable.

The position where the n-type semiconductor layer is inserted is provided in the region between the photosensitive layer and the positive electrode, like the wide band gap layer. This is because the injection of holes into the photosensitive layer is blocked as described above. Therefore, an n-type semiconductor layer may be provided in the photosensitive layer. In particular, it is desirable that the n-type semiconductor layer is also provided at the interface between the hole injection blocking layer and the photosensitive layer. This is because the hole injection blocking layer in this structure exerts an effect of suppressing leakage between pixels. Also in this structure, in order to reduce the interface state density at the interface between the hole injection blocking layer and the n-type semiconductor layer and the interface between the n-type semiconductor layer and the photosensitive layer, hydrogen concentration modulation is performed. It is desirable to provide a layer or a carbon composition modulation layer.

In the first aspect of the present invention, a plasma CVD method, a photo CVD method, a sputtering method, or the like can be used as a method for forming a thin film of an amorphous material, particularly amorphous silicon. Among them, the photo-CVD method (when forming a thin film of amorphous silicon, a mercury-sensitized CVD method is generally used) has advantages such as selective generation of radical species and less ion damage. And is an effective method for forming a high quality thin film. Therefore, in the manufacture of the device according to the present invention, in order to reduce the bulk gap level density, a-Si: H (i)
It is effective to form the layer by a photo CVD method. However, if a carbon-based source gas and mercury are introduced into the same reaction furnace, organic mercury may be formed.
The method is not suitable for forming a-SiC: H (i) layer. Therefore, in the manufacture of the device of the present invention, a-SiC:
An H (i) layer is formed by a plasma CVD method, and a-Si: H
It is desirable to form the layer (i) by the photo-CVD method.

When laminating films obtained by different thin film forming methods as described above, the state of the interface between the films becomes more important. In this case, formation of a-Si: H (i) as a wide band gap layer has an important meaning. That is, if a-SiC: H (i)-> carbon composition modulation layer-> a-Si: H (i) (wide bandgap) is formed in this order by plasma CVD, then a-CVD:
By forming -Si: H (i), a-Si: H
A laminated structure of (i) / a-Si: H (i) is obtained, and the reduction of the interface state density can be promoted. Further, when the wide band gap layer is formed by the plasma CVD method according to the present invention, the hydrogen concentration of the wide band gap layer becomes high as described above. Light C from plasma CVD method
When shifting to the VD method, film formation is stopped in a state where the substrate temperature is high. However, even if hydrogen is desorbed from the surface of the wide band gap layer due to the high substrate temperature, the film in the wide band gap layer It is possible to prevent hydrogen from being replenished to generate new defects.

According to the second aspect of the present invention, attention is paid to the shape of the underlying electrode, that is, the afterimage component caused by the gap between the pixel electrodes, and the afterimage component is reduced to obtain a solid-state image pickup device with less afterimage.

The afterimage caused by the gap between the pixel electrodes is caused by the heat release of the carriers trapped in the gap level. That is, the afterimage carrier in the step portion increases the afterimage value of the entire solid-state imaging device. It is necessary to consider the afterimage carrier in the step portion from two directions.

One is the formation of a weak electric field region due to the potential distribution modulation due to the existence of the gap. When the underlying pixel electrode is in a solid state with no gap, when a certain reverse bias is applied, a spatially uniform electric field is generated in the photoelectric conversion diode. On the other hand, when the underlying pixel electrode has a gap, a non-uniform electric field is generated near the gap and a weak electric field region is formed in the gap. Considering the correlation between the electric field strength and the afterimage carrier, qualitatively, the afterimage value can be suppressed to a small value under a strong electric field in which the carrier is swept smoothly, and when the weak electric field region is formed, the afterimage value becomes large. Become. The relationship shown in the following formula (1) is also known quantitatively, and the increase in the afterimage value in the weak electric field region can be understood.

[0038] J (t) = q · W · k · T · g o (νt) -T / To · J (0) ν / (J (0) νt + N c · k · T · q · μ · F) (1) In the equation, J (t) is the current density t seconds after the light irradiation is blocked, q is the charge of the electron, W is the film thickness, k is the Boltzmann's constant, T is the absolute temperature, and g _o is the deep level. The density of states at the edge of the conduction band that gives the density of states distribution, ν is the departure frequency, t is the time after the light irradiation is blocked, T _o is the characteristic temperature that gives the distribution of the density of states in a deep level, and N _c is the conduction band. The state density at the edge, μ is the drift mobility of electrons, and F is the electric field strength of the diode.

The other is the direction of the electric field. When the underlying pixel electrode is in a uniform state with no step, the electric field is, as shown in FIG.
The photoelectric conversion diode 2 is applied in the film thickness direction from the electrode 3 toward the Ti pixel electrode 1 which is the lower electrode. However, when the underlying pixel electrode has a step, the electric field is
As shown in FIG. 1B, it is applied from the ITO electrode 3 through the photoelectric conversion diode 2 in the in-plane direction of the Ti pixel electrode 1. That is, for example, ITO / a-S
iC: H (p) / a-Si: H (i) / a-SiC: H
In the photoelectric conversion diode having the structure (i) / Ti, T
a-SiC: H (i) near the i pixel electrode or a-Si:
At the H (i) / a-SiC: H (i) interface (these regions are regions where the gap level density is particularly large in the diode described above), the distance according to the gap length becomes the afterimage generation region and the formula (1 2) becomes large, resulting in a large afterimage value.

In consideration of the above circumstances, it is found that it is effective to remove a portion having a large gap level density in the gap portion. As described above, in the photoelectric conversion diode having the above configuration, the portion that affects the afterimage generation in the gap portion is a-SiC: H (i) or a-Si:
It is considered to be the H (i) / a-SiC: H (i) interface. At this time, the configuration of the photoelectric conversion diode is IT
O / a-SiC: H (p) / a-Si: H (i) / Ti
By adopting the above configuration, it is possible to prevent the afterimage from occurring in the gap portion. However, a-SiC: H
Since the (i) layer plays a role as a hole injection blocking layer from the Ti pixel electrode, it is difficult to have a structure excluding the a-SiC: H (i) layer. Therefore, it is necessary to eliminate the structure of the photoelectric conversion diode and remove only the portion that affects the afterimage generation in the step portion.

As described above, the gap portion is a weak electric field region, and the area in contact with the lower electrode is small. Therefore, even if the a-SiC: H (i) layer in the gap portion is removed, the portion in that portion is removed. The effect of hole injection can be neglected. Therefore, by adopting the device structure shown in FIG. 6, that is, in the region of the Ti pixel electrode, the hole injection blocking layer a-SiC:
The afterimage value can be reduced by adopting a structure in which the H (i) layer is present and the a-Si: H (i) layer which is a photosensitive layer is directly formed between the Ti pixel electrodes. it can. In fact, the afterimage that was present in 0.4% in the conventional device structure is 0.2% by the device structure shown in FIG.
It was confirmed to be reduced to%. Further, the afterimage value can be reduced even with the element structure shown in FIG. In this case, an a-SiC: H (i) layer, which is a hole injection blocking layer, is also formed on the side wall of the Ti pixel electrode, but a photosensitive layer a is formed in most of the recessed area of the step portion. -Si: H
Since the (i) layer exists, there is no problem in characteristics.

In the above description, the case where an amorphous silicon type material is used as the material used for the photoelectric conversion diode has been described, but the material used for the photoelectric conversion diode is limited to the amorphous silicon type material. However, for example, an amorphous germanium-based material or the like may be used. However, considering the development of process technology, amorphous silicon materials are desirable. For example, the material of the photosensitive layer is a-Si:
Although H (i) is used, a-Se is used as the material of the photosensitive layer.
Other materials such as Further, although a-SiC: H (i) is used as the material of the hole injection blocking layer, other material having a function of blocking the injection of holes may be used as the material of the hole injection blocking layer. .

[0043]

Embodiments of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) FIG. 2 is a sectional view showing an example of a solid-state imaging device according to the first invention of the present invention. This solid-state imaging device
The charge generating region A and the charge transfer region B are mainly included. Reference numeral 11 in the drawing denotes a Ti pixel electrode having a thickness of 50 nm in the charge generation region A provided on the charge transfer region B. The Ti pixel electrode 11 is partitioned for each pixel. Ti pixel electrode 1
1 and between the Ti pixel electrodes 11 adjacent to each other, the a-SiC: H (i) layer 1 having a thickness of 20 nm, which is a hole injection blocking layer.
2 is formed. On the a-SiC: H (i) layer 12, a wide-gap layer having a thickness of 10 nm a-Si:
The H (i) layer 13 is formed. a-Si: H (i)
On the layer 13, a photosensitive layer of a-S having a thickness of 1.8 μm is formed.
The i: H (i) layer 14 is formed. a-Si: H
(I) On the layer 14, a thickness of 20 n, which is an electron injection blocking layer, is formed.
m a-SiC: H (p) layer 15 is formed. Furthermore, a thickness of 35 n is formed on the a-SiC: H (p) layer 15.
The ITO transparent electrode 16 of m is formed. The Ti pixel electrode 11 to the ITO transparent electrode 16 form a photoelectric conversion diode.

In this embodiment, a-SiC: H
(I, p) layers 12, 15 and a-SiH (i) layer 1
3, 14 were formed by the parallel plate capacitive coupling type plasma CVD method. Further, the film forming conditions of the a-SiC: H (i) layer 12 are as follows: flow ratio SiH ₄ : CH ₄ : H ₂ = 15: 3.
The pressure was set to 5: 500 (sccm), the pressure was set to 0.5 Torr, and the RF power density was set to 170 mW / cm ² . The bulk characteristics of the a-SiC: H (i) layer 12 formed under these conditions are
The optical band gap is 1.93 eV, and the neutral defect density measured by electron spin resonance method is 1.5 × 10 ¹⁷ cm.
It was ^-3 . In addition, the film forming conditions of the a-Si: H (i) layer 13 are as follows: flow ratio SiH ₄ : H ₂ = 15: 500 (scc
m), pressure 0.5 Torr, RF power 170 mW / c
It was set to m ² . A-Si: H (i) formed under these conditions
The bulk properties of layer 13 have an optical bandgap of 1.8.
It was 8 eV and the neutral defect density was 3.9 × 10 ¹⁶ cm ⁻³ . Also, bonded hydrogen concentration determined from the infrared absorption spectrum was _{24.9%, (Si-H 2} ) / [(Si-
_{H) + (Si-H 2} )] binding ratio was 22%. In addition, the film forming condition of the a-Si: H (i) layer 14 is the flow rate ratio S.
iH ₄ : H ₂ = 20: 100 (sccm), pressure 0.8
Torr and RF power density were 170 mW / cm ² .
When formed under this condition, photoelectric conversion a-Si: H (i)
The bulk properties of layer 14 have an optical bandgap of 1.7.
The neutral defect density measured by an electron spin resonance method at 4 eV was 2.0 × 10 ¹⁶ cm ⁻³ . In addition, a-Si
The film forming conditions for the C: H (p) layer 15 are as follows: flow ratio SiH ₄ : C
_{H 4: B 2 H 6:} H 2 = 5: 12: 50: 50 (scc
m) (however, B ₂ H ₆ uses a gas diluted with H _{2 of} 100 ppm), pressure 0.8 Torr, RF power density 170
It was set to mW / cm ² . When formed under these conditions, aS
The bulk property of the iC: H (p) layer 15 was an optical band gap of 2.03 eV.

In the p-type silicon substrate 17 in the charge transfer region B, the channel blocking region 17a, the depletion region 17b,
And a storage diode 17c is formed. A polysilicon transfer electrode 18 is formed on the depletion region 17b via a silicon oxide film 19. A MoSi pixel wiring electrode 20 is formed on the polysilicon transfer electrode 18 via a silicon oxide film 19. A BPSG flattening insulating film 21 is formed on the MoSi pixel wiring electrode 20. The MoSi pixel wiring electrode 20 is electrically connected to the storage diode 17c. The Ti pixel electrode 11 in the charge generation region A and the MoSi pixel wiring electrode 20 are partially electrically connected.

In the solid-state image pickup device having the above structure, light incident through the ITO transparent electrode 16 and the a-SiC: H (p) layer 15 is incident on the a-Si: H (i) layer 14.
Photoelectric conversion is carried out, the electrons generated there are stored in the storage diode 17c, and the image signal is obtained by transferring the electrons from the storage diode 17c in accordance with the voltage applied to the polysilicon transfer electrode 18.

The effects of the solid-state image pickup device of the present invention will be described below. In addition, about Examples 1-3, each layer was formed in the said each layer thickness on the solid surface, and the characteristic was evaluated.
For this solid-state imaging device, the steady-state photocurrent density was 3 × 10 ⁻⁷ A / c when a reverse bias of 6 V was applied.
The 3-Field afterimage value when m ² is a-SiC:
The thickness of the H (i) layer 12 was determined as a parameter (a-SiC: H (i) layer thickness dependence of afterimage value). The results are shown in Table 1 below. Further, as a comparison, a solid-state imaging device having a photoelectric conversion diode having a structure in which the a-Si: H (i) layer 13 which is a wide band gap layer is not formed is manufactured, and the afterimage value of a-SiC: The H (i) layer thickness dependence was investigated. The results are shown in Table 2 below. In the photoelectric conversion diode having the above two structures,
A carbon composition modulation layer was provided at the interface between the a-Si: H (i) layer and the a-SiC: H (i) layer.

[0048]

[Table 1]

[0049]

[Table 2]

As is clear from Tables 1 and 2,
The a-SiC: H (i) layer thickness that minimizes the afterimage value is 10 nm with the wide band gap layer,
The thickness is 15 or 20 nm when the wide band gap layer is not provided. Thus, by providing the wide band gap layer, a-SiC: which minimizes the afterimage value.
The H (i) layer thickness could be reduced. Further, the afterimage value is 0.3 by providing the wide band gap layer.
It became as small as 0%. From these results, the a-SiC: H (i) layer thickness that minimizes the afterimage value exists, and the afterimage value increases in the region where the layer thickness is smaller than that. It is considered that this is because the afterimage component of recombination due to the injection of holes has appeared remarkably. (Example 2) In this example, the effect of the hydrogen concentration modulation layer is confirmed. Ti pixel electrode / hole injection blocking layer (a-S
iC: H (i)) / carbon composition modulation layer / wide bandgap layer (a-Si: H (i)) / hydrogen concentration modulation layer / photosensitive layer (a-Si: H (i)) / electron injection blocking layer (A-Si
C: H (p)) / a solid-state imaging device having a photoelectric conversion diode having an ITO transparent electrode structure, and a Ti pixel electrode / hole injection blocking layer (a-SiC: H (i)) / carbon composition modulation layer /
Wide band gap layer (a-Si: H (i)) / photosensitive layer (a-Si: H (i)) / electron injection blocking layer (a-Si)
C: H (p)) / a solid-state imaging device having a photoelectric conversion diode having an ITO transparent electrode structure was manufactured, and the 3-Field afterimage value of each was determined in the same manner as in Example 1. All layers were formed by the plasma CVD method.

As a result, the one having a hydrogen concentration modulating layer had a 3-Field afterimage value of 0.38%, and the one having no hydrogen concentration modulating layer had a 3-Field afterimage value of 0.44%. It was Thus, by providing the hydrogen concentration modulation layer, the afterimage value can be reduced. (Embodiment 3) In this embodiment, the correlation between the thickness of the wide band gap layer and the afterimage value is examined. The thickness of the a-SiC: H (i) layer that is the hole injection blocking layer is 10 nm, the thickness of the a-Si: H (i) layer that is the photosensitive layer is 1.8 μm, and the electron injection blocking layer is a. -Set the thickness of the SiC: H (p) layer to 2
0 nm, and the thickness of the a-Si: H (i) layer, which is a wide band gap layer formed at the interface between the hole injection blocking layer and the photosensitive layer, is changed to 0.5, 10, 15, 20, 40 nm. A solid-state imaging device was manufactured in the same manner as in Example 1 except that
In the same manner as in Example 1, each 3-Field afterimage value was obtained. The results are shown in Table 3 below.

[0052]

[Table 3]

As is clear from Table 3, in the constitution of the present invention, the afterimage value is reduced by providing the wide band gap layer, and the afterimage value becomes minimum when the thickness is about 10 to 15 nm. . (Embodiment 4) In this embodiment, the influence of the structure of the pixel electrode, which is the base electrode, on the afterimage value is examined. In this example, in order to approximate the device shape, the shape of the Ti pixel electrode was evaluated as a shape having a gap.

The shape of the Ti pixel electrode is set to a gap 1 at a cycle of 6 μm.
The pixel pixel electrode / hole injection blocking layer (a-SiC: H (i)) / carbon composition modulation layer / wide bandgap layer (a-Si: H (i)) / photosensitive layer having a shape having a gap of μm. (A-Si: H (i)) / electron injection blocking layer (a-Si
C: H (p)) / a solid-state imaging device having a photoelectric conversion diode having an ITO transparent electrode structure, and a Ti pixel electrode / hole injection blocking layer (a-SiC: H (i)) / carbon composition modulation layer /
Photosensitive layer (a-Si: H (i)) / electron injection blocking layer (a-
A solid-state imaging device having a photoelectric conversion diode having a structure of SiC: H (p)) / ITO transparent electrode was manufactured, and Example 1
Similarly, the 3-field afterimage value of each was obtained. The result is shown in FIG. As is clear from FIG.
Even when the Ti pixel electrode has a gap, the afterimage value was reduced by providing the wide band gap layer. (Embodiment 5) In this embodiment, the insertion position of the wide band gap layer is examined. The thickness of the a-SiC: H (i) layer that is the hole injection blocking layer is 10 nm, the thickness of the a-Si: H (i) layer that is the photosensitive layer is 1.8 μm, and the electron injection blocking layer is a. -The thickness of the SiC: H (p) layer is 20 nm.
Then, a solid-state imaging device was manufactured in the same manner as in Example 1 except that the insertion position of the wide band gap layer having a thickness of 10 nm was changed, and each 3-Field was manufactured in the same manner as in Example 1.
d Afterimage value was determined. The Ti pixel electrode had a solid surface shape, and a carbon composition modulation layer or a hydrogen concentration modulation layer was provided at the interface of each layer. Further, in the measurement of this example, the wavelength of incident light was set to 650 nm. The insertion position of the wide band gap layer is in the middle of the photosensitive layer as shown in FIG. 4A and between the photosensitive layer and the hole injection blocking layer as shown in FIG. 4B. Those without layers were also measured. The results are shown in Table 4 below.

[0055]

[Table 4]

As is clear from Table 4, when the wide band gap layer is provided at the interface between the photosensitive layer and the hole injection blocking layer, the afterimage value becomes the lowest, but the wide band gap layer is placed in the middle of the photosensitive layer. Even in the case where the wide band gap layer is provided, the afterimage can be reduced as compared with the case where the wide band gap layer is not inserted.

In the above Examples 1 to 5, the effect of the wide band gap layer was described. As described above, the same effect can be obtained by replacing the wide band gap layer with the n-type semiconductor layer (lightly doped layer). (Example 6) FIG. 5 shows the results of measurement of the hydrogen concentration distribution in the film thickness direction for the structure shown in Example 1. The measurement was performed using the proton recoil (ERD method) with a fast ion beam. Since the wide band gap layer is formed in a high concentration hydrogen atmosphere, the region corresponding to the wide band gap layer contains a higher concentration of hydrogen than the photosensitive layer region. When an n-type semiconductor layer is inserted instead of the wide band gap layer, SIMS analysis shows that an n-type dopant such as phosphorus (P) or nitrogen (N) is used.
A region in which is present at a high concentration is confirmed. (Embodiment 7) FIG. 6 is a sectional view showing an example of a solid-state imaging device according to the second invention of the present invention. 6 that are the same as those in FIG. 2 are assigned the same reference numerals as those in FIG. 2 and their explanations are omitted.

In the solid-state imaging device shown in FIG. 6, the a-SiC: H (i) layer 12 which is the hole injection blocking layer is formed only on the Ti pixel electrode 11, and the Ti pixel electrode 11 is formed.
A-Si: H (i) which is a photosensitive layer directly on the end portion 11a of
The layer 14 is formed. With such a structure, it is possible to suppress the occurrence of an afterimage component due to the gap portion of the Ti pixel electrode 11 and reduce the afterimage value.

FIGS. 7A to 7D are cross-sectional views showing a part of the manufacturing process of the solid-state imaging device shown in FIG. Figure 7
As shown in (A), a Ti layer is formed and patterned on the p-type silicon substrate 17 in which the charge transfer regions are formed, and Ti is divided for each pixel (having a gap).
The pixel electrode 11 is formed. Further, an a-SiC: H (i) layer 12 which is a hole injection blocking layer is formed on the entire surface. Then, as shown in FIG. 7B, a-SiC: H
(I) A resist layer 22 is formed on the layer 12, and the resist layer is patterned using the mask used for patterning the Ti layer. Then, as shown in FIG. 7C, CDE (Chemical Dry Etching) using, for example, CF ₄ + O ₂ plasma is performed in that state,
A-SiC: H (i) layer 12 existing between Ti pixel electrodes
Is etched. Then, by removing the resist layer 22, as shown in FIG. 7D, a-SiC: H
(I) A structure in which the layer 12 is formed only on the Ti pixel electrode 11 is obtained. Then, the photosensitive layer a-Si: H (i)
Form the layer 14.

As shown in FIG. 8, the a-SiC: H (i) layer 12, which is the hole injection blocking layer, is formed on the Ti pixel electrode 11.
And a-SiC in the region between the adjacent Ti pixel electrodes 11 formed on the end 11a of the Ti pixel electrode 11:
Even in the structure without the H (i) layer 12 (the structure in which the photosensitive layer 14 is directly formed on the charge transfer region in the region between the Ti pixel electrodes 11), the afterimage component due to the gap portion of the Ti pixel electrode 11 Can be suppressed, and the afterimage value can be reduced. (Example 8) Ti pixel electrode / hole injection blocking layer (a-Si)
C: H (i)) / photosensitive layer (a-Si: H (i)) / electron injection blocking layer (a-SiC: H (p)) / ITO transparent electrode solid-state imaging device having a photoelectric conversion diode structure A hole injection blocking layer a-SiC: H (i) layer formed only on a Ti pixel electrode divided into pixels with a thickness of 10 nm, and a hole injection blocking layer a-SiC: H
For the case where the (i) layer is provided also between adjacent pixels, 8
3-Field when the steady-state photocurrent density is 1 × 10 ⁻⁷ A / cm ² when a reverse bias of V is applied
d Afterimage value was determined. The results are shown in Table 5 below.

In the case where the a-SiC: H (i) layer is provided also between adjacent pixels, a-SiC: H
(I) The thickness of the layer was changed to 10, 20, and 40 nm for measurement. Further, the film forming conditions of the a-SiC: H (i) layer are as follows: flow ratio SiH ₄ : CH ₄ : H ₂ = 15: 35: 500 (sc
cm), pressure 0.5 Torr, discharge power 170 mW / c
m ² and the film formation conditions of the a-Si: H (i) layer are as follows: flow ratio SiH ₄ : H ₂ = 20: 100 (sccm), pressure 0.
The discharge power was 8 Torr and the discharge power was 170 mW / cm ² . The thickness of the a-Si: H (i) layer was 1 μm. Further, all the layers were formed by the parallel plate capacitive coupling type plasma CVD method.

[0062]

[Table 5]

As is clear from Table 5, by adopting the structure shown in FIG. 6, the afterimage value is reduced to a level (0.2% or less) at which there is no problem when the afterimage of the human eye and the system afterimage are taken into consideration. Could be reduced. (Embodiment 9) In this embodiment, a thin film forming method capable of improving throughput will be described.

For example, in forming a thin film of a-Si,
First, in order to prevent generation of dust due to peeling of an unnecessary film adhered to the inner wall of the reaction furnace in the previous step, for example, CF
An unnecessary film attached to the inner wall of the reaction furnace is removed by plasma etching gas using ₄ gases, and then a target thin film is formed after pre-deposition of a-Si. In order to remove the unnecessary film adhering to the inner wall of the reaction furnace, it is preferable to use plasma etching in order to improve the throughput, but when plasma etching is performed, the etching gas component remains and remains on the inner wall of the reaction furnace. However, the adhered substances are mixed as impurities in the film formed. Therefore, pre-deposition is performed after plasma etching and before thin film formation to prevent impurities from being mixed.

From the viewpoint of throughput, it is desirable that the predeposition time be short. On the other hand, from the viewpoint of suppressing the mixing of impurities, a certain thickness of the film is required, so it is desirable to carry out the etching for a certain time or longer. As described above, the predeposition is required to be able to sufficiently prevent impurities from being mixed in a short time.

In the case of predeposition using a-Si, when the film thickness of a-Si formed after predeposition becomes large, a large internal stress of a-Si causes
The film peels off from the inner wall of the reaction furnace, and the generation of dust becomes remarkable.

The peeling of the a-Si film on the inner wall of the reaction furnace occurs at the bonding surface between the inner wall of the reaction furnace and the a-Si film. Therefore, the film peeling can be solved by interposing a film having high adhesion to both the reactor material and the a-Si on the bonding surface. On the other hand, there is also a method in which a film having a small internal stress is provided on the outermost side to suppress film peeling from the outside. We have a reactor material and a-
It has been found that the film is a-SiC, which has high adhesion to both Si and relatively small internal stress.

Therefore, when forming the amorphous silicon type thin film, the present inventors preliminarily laminated (pre-formed) amorphous silicon carbide (a-SiC) and amorphic silicon (a-Si) on the inner wall of the reaction furnace. It has been found that by performing the deposition, the predeposition time is shortened and the depositable film thickness is increased while the generation of dust is suppressed. That is, by pre-deposition and stacking a-SiC and a-Si, which have small internal stress and excellent adhesion, a-S is formed thereafter.
The film peeling of i is suppressed, thereby preventing the generation of dust and increasing the depositable film thickness. As a result, the throughput of the thin film forming process is improved.

In this case, the film thickness is to some extent, that is, a- is sufficient to suppress the mixing of impurities from the inner wall of the reaction furnace.
The film thickness of the Si film and the film thickness of the a-SiC sufficient to suppress the peeling of the a-Si film may be about 200 angstroms in total, so that the throughput due to the low film formation rate of the a-SiC is sufficient. Does not occur. Note that a
Since the carbon contained in -SiC is chemically bonded in the film, the carbon is not desorbed from the film and is not mixed with a-Si formed later to be an impurity. Therefore, there is no problem even if a-SiC is exposed to the outermost layer of the inner wall of the reaction furnace.

This means that by forming a-SiC every time immediately before forming a-Si, it is possible to prevent impurities from being mixed in, suppress the generation of dust, and reduce the etching process due to film peeling. It means that the throughput is improved.

The effects of this embodiment will be described below.
First, the relationship between the predeposition film thickness when forming an a-Si film by the plasma CVD method and the impurities contained in the a-Si film was examined. The results are shown in Table 6 below. For the plasma etching before predeposition, (SF ₆ + O ₂ ) was used as an etching gas. The impurity concentration in the a-Si film is sulfur (S).
The concentration and the fluorine (F) concentration were examined.

[0072]

[Table 6]

As is clear from Table 6, both the sulfur concentration and the fluorine concentration are reduced by forming the predeposition film to a thickness of about 0.4 μm or more. Therefore, the film thickness of the a-Si predeposition is required to be about 0.4 μm. Further, FIG. 9 shows the relationship between the predeposition film thickness, the impurity concentration (sulfur, fluorine) and the minimum localized level density of the a-Si film. As can be seen from FIG. 9, the sulfur concentration and the fluorine concentration have a positive correlation with the minimum localized level density. That is, as the impurity concentration decreases, the minimum localized level density also decreases.

Next, the relationship between the film thickness of the thin film and the number of generated dusts in the formation of the a-Si film by the plasma CVD method was examined. The results are shown in Table 7 below. It should be noted that the number of generated dusts is 0.2μ in diameter in a 6-inch wafer.
Dust of m or more was defined as the number confirmed by laser light scattering.

[0075]

[Table 7]

As is clear from Table 7, the number of dust particles increased extremely when the film thickness of a-Si formed was about 2.2 μm. Next, the effect of providing the a-SiC film between the inner wall of the reaction furnace and the a-Si film was examined. The result is the 8th below.
Shown in the table.

[0077]

[Table 8]

As is clear from Table 8, after the a-SiC film was formed to a thickness of 200 angstroms, a-S
When the i film is formed to a thickness of 2.2 μm, the a-Si film is formed to a thickness of 2.2 μm and then the a-SiC film is formed to a thickness of 200 μm.
In the case of forming by angstrom, in any case, the number of generated dust was extremely smaller than that in the case where only the a-Si film was directly formed on the inner wall of the reaction furnace to have a thickness of 2.2 μm. This is because in the former case, the a-SiC film was interposed between the inner wall of the reaction furnace and the a-Si film to improve the adhesion, and in the latter case, a-SiC film having a small internal stress was used. Si
It is considered that this is because the C film suppressed film peeling from the outside.

Next, in the case of alternately forming the a-Si film and the a-SiC film, the depositable cycle with the number of generated dusts suppressed was examined. The results are shown in Table 9 below.

[0080]

[Table 9]

As is apparent from Table 9, an a-SiC film having a thickness of 200 Å and an a-S film having a thickness of 2 μm are used.
When i films were formed alternately, the number of generated dust was small up to 10 cycles.

As described above, in this embodiment, a-SiC and a-Si, which have a small internal stress and excellent adhesion, are predeposited and pre-deposited on the inner wall of the reaction furnace to form them thereafter. The peeling of the a-Si film is suppressed, which prevents the generation of dust and increases the depositable film thickness. As a result, the throughput of the thin film forming process can be improved.

[0083]

As described above, the solid-state image pickup device according to the first aspect of the present invention is a solid-state image pickup device having a structure in which a charge generation region including a photoelectric conversion diode is stacked on a charge transfer region. Since the layer or the n-type semiconductor layer is provided in the region between the photosensitive layer and the positive electrode in the photoelectric conversion diode, it is possible to balance the reduction of the gap level and the hole injection blocking characteristic, and to achieve the afterimage. The value can be reduced.

A solid-state image pickup device according to a second aspect of the present invention is a solid-state image pickup device having a structure in which a charge generation region including a photoelectric conversion diode is stacked on a charge transfer region.
The positive electrode is divided into pixels and has a step portion, and the hole injection blocking layer is provided only on the positive electrode. Therefore, when the afterimage of human eyes and the system afterimage of a monitor are considered, The afterimage value can be suppressed to such a low level that the afterimage can be ignored. Furthermore, according to the method for manufacturing a solid-state imaging device of the present invention, the solid-state imaging device according to the first and second aspects of the present invention can be efficiently obtained.

[Brief description of drawings]

1A and 1B are schematic views showing an electric field applied between an ITO electrode and a pixel electrode.

FIG. 2 is a sectional view showing a solid-state imaging device according to the first aspect of the present invention.

FIG. 3 is a graph showing a relationship between a 3-Field afterimage value and an applied electric field.

4A and 4B are cross-sectional views showing the insertion position of the wide band gap layer.

FIG. 5 is a graph showing the relationship between the depth of the photoelectric conversion diode and the hydrogen concentration.

FIG. 6 is a cross-sectional view showing an example of a solid-state imaging device according to a second invention of the present invention.

7A to 7D are cross-sectional views showing a part of a manufacturing process of the solid-state imaging device shown in FIG.

FIG. 8 is a sectional view showing another example of the solid-state imaging device according to the second invention of the present invention.

FIG. 9 is a graph showing the relationship between the predeposition film thickness, the minimum localized level density, and the impurity concentration.

FIG. 10 is a sectional view showing a conventional solid-state imaging device.

[Explanation of symbols]

1, 11 ... Ti pixel electrodes, 2 ... Photoelectric conversion diode,
3, 16 ... ITO electrode, 11a ... End portion, 12 ... a-Si
C: H (i) layer, 13, 14 ... a-Si: H (i) layer,
15 ... a-SiC: H (p) layer, 17 ... P-type silicon substrate 17, 17a ... Channel blocking region, 17b ... Depletion region, 17c ... Storage diode, 18 ... Polysilicon transfer electrode, 19 ... Silicon oxide film, 20 ... MoSi pixel wiring electrode, 21 ... BPSG flattening insulating film, 22 ... Resist layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Yamaguchi No. 1 Komukai Toshiba Town, Saiwai-ku, Kawasaki City, Kanagawa Prefecture, Corporate Research & Development Center, Toshiba Corporation (72) Yoshinori Iida, Komukai Toshiba, Kawasaki City, Kanagawa Prefecture Town No. 1 Incorporated company Toshiba Research and Development Center (72) Inventor Akihiko Furukawa No. 1 Komukai Toshiba Town, Kouki-ku, Kawasaki City, Kanagawa Prefecture Incorporated company Toshiba Research and Development Center (72) Inventor Hisanori Ihara Yuuki Kawasaki, Kanagawa Prefecture Komukai-Toshiba-cho No. 1 Inside the Toshiba R & D Center Co., Ltd. (72) Inventor Hideo Ichinose No. 1 Komukai-Toshiba Town Co. Ltd. Kawasaki-shi, Kanagawa Inside the Toshiba Research and Development Center Co.

Claims (10)

[Claims] 1. A charge transfer region formed on a semiconductor substrate for accumulating and transferring charges generated by photoelectric conversion, and a charge stacked on the charge transfer region for generating charges by photoelectric conversion from incident light. A charge generation region, the charge generation region is composed of a positive electrode, a hole injection blocking layer, a photosensitive layer, an electron injection blocking layer, and a negative electrode, which are sequentially formed on the charge transfer region. A solid-state imaging device comprising the hole injection blocking layer and a wide bandgap layer having a bandgap larger than that of the photosensitive layer provided in a region between the photosensitive layer and the positive electrode. 2. The solid-state imaging device according to claim 1, wherein the wide band gap layer is provided in contact with the photosensitive layer, and the hydrogen concentration near the interface between the two changes gradually. 3. The solid-state imaging device according to claim 1, wherein the wide band gap layer has a hydrogen concentration higher than that of the photosensitive layer. 4. A charge transfer region formed on a semiconductor substrate for accumulating and transferring charges generated by photoelectric conversion, and a charge stacked on the charge transfer region for generating charges by photoelectric conversion from incident light. A charge generation region, the charge generation region is composed of a positive electrode, a hole injection blocking layer, a photosensitive layer, an electron injection blocking layer, and a negative electrode, which are sequentially formed on the charge transfer region. A solid-state imaging device comprising a hole injection blocking layer and an n-type semiconductor layer provided in a region between the photosensitive layer and the positive electrode. 5. The solid-state imaging device according to claim 4, wherein the n-type semiconductor layer is provided in contact with the photosensitive layer, and the hydrogen concentration near the interface between the two gradually changes. 6. A charge transfer region formed on a semiconductor substrate for accumulating and transferring charges generated by photoelectric conversion, and a charge stacked on the charge transfer region for generating charges by photoelectric conversion from incident light. A charge generation region, the charge generation region is composed of a positive electrode, a hole injection blocking layer, a photosensitive layer, an electron injection blocking layer, and a negative electrode, which are sequentially formed on the charge transfer region. The solid-state imaging device, wherein the positive electrode is partitioned at intervals for each pixel, and the hole injection blocking layer is provided only on the partitioned positive electrode. 7. The solid-state imaging device according to claim 6, wherein the photosensitive layer is provided on an end portion of the positive electrode in the interval. 8. A step of forming a charge transfer region for accumulating and transferring charges generated by photoelectric conversion on a semiconductor substrate, and a positive electrode, a hole injection blocking layer, a photosensitive layer in sequence on the charge transfer region, Forming an electron injection blocking layer and a negative electrode; and providing a wide bandgap layer having a bandgap larger than that of the photosensitive layer in a region between the photosensitive layer and the positive electrode. A method for manufacturing a solid-state imaging device, comprising: 9. When the wide band gap layer is formed so as to be in contact with the photosensitive layer, hydrogen gas is supplied at a flow rate which is at least 30 times the flow rate of a raw material gas to form the wide band gap layer by a plasma CVD method. Claim 8
A method for manufacturing the described solid-state imaging device. 10. A step of forming, on a semiconductor substrate, a charge transfer region for storing and transferring charges generated by photoelectric conversion, a step of forming a positive electrode having a step portion on the charge transfer region, Forming a hole injection blocking layer only on the positive electrode; forming a photosensitive layer on the end face of the step and the hole injection blocking layer; and through an electron injection blocking layer on the photosensitive layer. And a step of forming a negative electrode, the method for manufacturing a solid-state imaging device.