JPH02132859A - Photoelectric conversion device - Google Patents

Abstract

PURPOSE:To improve a photoelectric conversion device in sensitivity to blue light and in the speed of response by a method wherein a reverse conductivity type semiconductor region is composed of two regions, one is a region which stores charges occurred by incident light and the other is a region which is the control electrode region of a semiconductor transistor. CONSTITUTION:A p<-> region 4004 of a photodecting section, which stores charges occurred by the incidence of light, and a p<+> region 4005 to be the base region of a bipolar transistor are separately formed on an n<-> region 4003. By this constitution, manufacturing requirements such as impurity concentration, thick ness, and the like of the p<-> region 4003 which generates charges by the incidence of light and stores them and manufacturing requirements such as impurity concentration, the distribution of impurity concentration, thickness, and the like of the p<+> region to be the control electrode region of the semiconductor transistor can be optionally optimized at each semiconductor region, so that a photoelectric conversion element of this design can be improved in sensitivity to blue light and in the speed of response.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photoelectric conversion device, and particularly to a photoelectric conversion device that is composed of a light receiving section and a light shielding section and is capable of amplifying a photoelectric conversion output, and a photoelectric conversion device of the same conductivity type. irradiating light onto the semiconductor regions of opposite conductivity types of a semiconductor transistor comprising two semiconductor regions consisting of two semiconductor regions and a semiconductor region of opposite conductivity type to these two semiconductor regions; The present invention relates to a photoelectric conversion device that extracts an amplified output from at least one of the regions.

[Prior Art J] One of the photoelectric conversion devices used in image reading devices used in facsimile machines, copying machines, etc., accumulates charges generated by light irradiation, and extracts an amplified output corresponding to the accumulated charges. There is a photoelectric conversion device.

One such photoelectric conversion device is a photoelectric conversion device that irradiates a base region of a phototransistor with light to accumulate carriers (holes) and extracts an amplified current from an emitter region. In this case, the base region of the phototransistor is formed in the light receiving section, and the emitter region is formed in the light shielding section. Compared to photoelectric conversion devices that use photodiodes and do not have the function of amplifying photocurrent, photoelectric conversion devices that use phototransistors can amplify carriers in the light receiving section, improve sensitivity, and reduce random noise. and improve the S/N ratio.

FIG. 15 is a schematic cross-sectional view showing a conventional photoelectric conversion device.

In the figure, 1013 is an n-type layer and is the collector of the phototransistor, 1003 is an n-evitaxial layer, and 1
005 is a p layer which is the base region of the phototransistor;
1006 is the emitter region of the phototransistor n
H, 1007-2 is an emitter electrode made of A1, etc., and 8 is a LOGOS oxide film. L indicates a light receiving section, and D indicates a light shielding section.

When such a photoelectric conversion device is used as a color line sensor 1 101 as shown in FIG.
, green (G), and blue (B), and each line sensor has a light shielding part 1011 and a light receiving part 10.
It consists of 12.

The lengths of the light blocking section 1011 and the light receiving section 1012 in the line sensor arrangement direction (eight directions in the figure) are n bits and 1 bit, respectively.
It's a bit. One bit corresponds to the light receiving part of one photosensor cell, and has a square shape with one side of 1 OLLm, for example.

In this way, each line sensor corresponding to RGB has a different position, so when the R signal of a certain line of the document is obtained, the G signal is determined at the position of the (n+2)th line of the document from that line. The B signal becomes each signal at the position of the document on the (2n+3)th line. Therefore, in order to obtain RGB signals at the same document position, at least the GB signals that have been outputted first through the sample and hold circuit (S/H) 1014 and the A/D conversion circuit 1015 must be transferred to the external memory 1015.
It is necessary to store it in 02.

Furthermore, such a photoelectric conversion device is disclosed in, for example, European Patent Application Publication No. 0132076.

FIG. 17(A) is a schematic plan view for more specifically explaining one configuration example of a photoelectric conversion device, and FIG. 17(B) is a
FIG. 17 is a schematic cross-sectional view of FIG. 3(A) taken along the line AA' shown in FIG. 17(A).

In each figure, photoelectric conversion cells are arranged on an n silicon substrate 320l, and each cell is Sing, SisN4,
Or element isolation region 3202 made of polysilicon etc.
electrically isolated from adjacent cells by

Each cell has the following configuration.

n with low impurity concentration formed by epitaxial technology etc.
A p-type impurity (for example, boron, etc.) is present on one region 3203.
A p- base region 3204 and a p region 3205 are formed by doping, and an n1 emitter region 3206 is formed in the p base region 3204.

The p base region 3204 and the p region 3205 are p base regions 3204 and 3205, which will be described later.
It also serves as the source and drain of the channel MOS transistor.

An oxide film 3207 is formed on the n-region 3203 where each region is formed in this way, and a gate electrode 3208 of the MOS transistor and a capacitor electrode 3209 are formed on the oxide film 32o7. Capacitor electrode 3
209 is a p base region 3204 with an oxide film 3207 in between.
and forms a capacitor for controlling the base potential.

In addition, an emitter electrode 3210 connected to the n1 emitter region 3206, and an electrode 32 connected to the p region 32o5.
11, and a collector electrode 3212 is formed on the back surface of the substrate 32o1 with an ohmic contact layer in between.

Next, the operation of the photoelectric conversion cell will be explained.

Light enters from the p base region 3204 side, and carriers (holes here) corresponding to the amount of light enter the p base region 3204.
(accumulation operation).

The base potential changes due to the accumulated carriers, and by reading out the potential change from the emitter electrode 321o, an electric signal corresponding to the amount of incident light can be obtained (readout operation).

Next, a refresh operation for removing balls accumulated in p base region 32o4 will be described.

FIG. 18(A) and FIG. 18(B) are voltage waveform diagrams for explaining the refresh operation, respectively.

As shown in FIG. 18(A), the Mos transistor is turned on only when a negative voltage equal to or higher than the threshold value is applied to the gate electrode 32o8.

Further, as shown in FIG. 18(B), in order to perform the refresh operation, the emitter electrode 3210 is grounded and the electrode 32l1 is set to the ground potential. and,
First, a negative voltage is applied to the gate electrode 3208 to turn on the p-channel MOS transistor. By this, p
The potential of the base region 3204 has a constant value regardless of the level of the accumulated potential. Subsequently, by applying a refreshing positive voltage pulse to the capacitor electrode 3209, the p base region 3204 is forward biased with respect to the n'' emitter region 3206, and the accumulated holes are transferred through the grounded emitter electrode 3210. Then, when the refresh pulse falls, the p base region 320
4 returns to the initial state of negative potential (refresh operation)
.

In this way, after the potential of the p base region 3204 is set to a constant potential by the MOS transistor, a refresh pulse is applied to erase the residual charge, so that a new accumulation operation is performed without depending on the previous accumulation potential. be able to. In addition, residual charges can be quickly eliminated,
High-speed operation is possible.

Thereafter, the operations of storage, readout, and refresh are repeated in the same way.

Here, the potential vP generated at the base due to holes accumulated in the base due to photoexcitation is given by Vp=Q/C. Q is the amount of charge of holes accumulated in the base, and C is the capacitance connected to the base. As is clear from this equation, when the cell size is highly integrated, both Q and C become smaller as the cell size decreases, so that the potential (2) generated by photoexcitation is kept almost constant. Therefore, the method proposed here is also advantageous for optical resolution.

[Problems to be Solved by the Invention] However, in the above-mentioned photoelectric conversion device, there are cases where it is necessary to further increase the blue sensitivity and to speed up the response of the semiconductor transistor, and further improvement of the characteristics is desired. It was rare.

Furthermore, when performing image processing using the color line sensor 1101 explained using FIGS. 15 and 16, in order to obtain RGB signals at the same document position, the previously output GB
In order to store signals in an external memory, the capacity of the external memory is required to be at least a certain value, but there has been a desire to reduce the required memory capacity due to demands such as cost reduction.

Furthermore, there is a problem in that the size, impurity concentration, etc. of the base region of a phototransistor are difficult to optimize because the optimal conditions for a photoelectric conversion region and the optimal conditions for a bibolar transistor are different. , further improvement was desired.

The present invention has even higher sensitivity, particularly blue sensitivity, and
It is an object of the present invention to provide a photoelectric conversion device that can respond quickly to input signals.

The present invention also aims to optimize the sensor part and the switching part, and more specifically, to optimize the optimal conditions for the base region of the phototransistor and the optimal conditions for the bibolar transistor. Another object of the present invention is to provide a photoelectric conversion device that can perform the following steps.

A further object of the present invention is to provide a photoelectric conversion device that can increase the degree of freedom in system design and optical design including the photoelectric conversion device and simplify the design.

[Means for Solving the Problems] A photoelectric conversion device of the present invention includes two semiconductor regions having the same conductivity type and a semiconductor region having the opposite conductivity type from these two semiconductor regions. In a photoelectric conversion device that irradiates a semiconductor region of a type with light and extracts an amplified output from at least one of two semiconductor regions made of the same conductivity type regions, the semiconductor region of the opposite conductivity type is generated by light incidence. The semiconductor device is characterized in that it is formed separately into a semiconductor region that stores charges and a semiconductor region that becomes a control electrode region of a semiconductor transistor.

Further, the photoelectric conversion device of the present invention is a photoelectric conversion device that is composed of a light receiving section and a light shielding section and is capable of amplifying charging conversion output, wherein the photoelectric conversion section is formed in the light receiving section, and an amplifying section is formed in the light shielding section. The photoelectric conversion section and the manual power area of the amplification section are connected by wiring, and the light receiving section and the light shielding section are separated by a certain distance.

In addition, the photoelectric conversion device of the present invention has a first conductivity type.
a semiconductor region; a second semiconductor region of a first conductivity type provided in contact with the first semiconductor region; a third semiconductor region of a second conductivity type provided in contact with the second semiconductor region; A fourth semiconductor region of a second conductivity type provided in contact with the third semiconductor region and the second semiconductor region, and a fifth semiconductor region of a first conductivity type provided in contact with the fourth semiconductor region. and a sixth semiconductor region of a second conductivity type provided in contact with the second semiconductor region, wherein the third semiconductor region is a light incident region, and the first, second, fourth, and The fifth semiconductor region and the second, fourth, and sixth semiconductor regions are each an element constituting a transistor.

Furthermore, the photoelectric conversion device of the present invention includes: a first semiconductor region of a first conductivity type; a second semiconductor region of the first conductivity type provided in contact with the first semiconductor region; and the second semiconductor region. a third semiconductor region of a second conductivity type provided in contact with the third semiconductor region; and a second conductive region provided in contact with the second semiconductor region and electrically connected to the third semiconductor region via a conductive material. a fourth semiconductor region of a type, and a fifth semiconductor region of a first conductivity type provided in contact with the fourth semiconductor region, the third semiconductor region is a light incident region, and the first, It is characterized in that the second, fourth, and fifth semiconductor regions are elements constituting a transistor.

[Function] The photoelectric conversion device of the present invention is realized by forming a semiconductor region of opposite conductivity type into a semiconductor region that accumulates charges generated by incident light, and a semiconductor region that becomes a control electrode region of a semiconductor transistor. , the manufacturing conditions such as the impurity concentration and thickness of the semiconductor region that generates and accumulates charges by light incidence, and the manufacturing conditions such as the impurity concentration, impurity concentration distribution, and thickness of the semiconductor region that becomes the control electrode region of the semiconductor transistor. Optimization can be made arbitrarily for each semiconductor region.

Further, in the photoelectric conversion device of the present invention, a photoelectric conversion section is formed in the light receiving section, an amplification section is formed in the light shielding section, and the photoelectric conversion section and the input area of the amplification section are connected by wiring. , the light receiving part and the light blocking part are separately formed at a certain distance to provide an amplification function, and the light receiving part and the light blocking part are fabricated separately, and the light receiving parts are formed adjacent to each other. This is what makes it possible.

[Example] Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a schematic configuration diagram for explaining the first embodiment of the photoelectric conversion device of the present invention, FIG. 1(A) is a schematic plan view of a charging conversion cell, and FIG. A schematic vertical cross-sectional view taken along line AA' of the schematic plan view of FIG. 1(A) is shown.

This photoelectric conversion cell is constructed as shown in Fig. 1 (A) and (B).
, a silicon substrate 1 or boron (B) doped with atoms belonging to group V of the periodic table such as phosphorus (Ph), antimony (sb), and arsenic (As) as impurities to make it n-type;
A silicon substrate 4 doped with atoms belonging to Group Ⅰ of the periodic table such as aluminum (A1) as impurities to make it p-type.
001, a buried region (n'') 4002 formed on this substrate 4001, an n-region 4003 with a low impurity concentration formed by an epitaxial technique etc. on this buried region 4002, and an n-region 4003 on the n-region 4003. The bibolar transistor is fabricated using the same technology as the photodetector p-region 4004 and p' region 4004 doped with impurities such as boron (B), which are formed using impurity diffusion, ion implantation, and epitaxial techniques. Base and MOS
p0 region 4005 which becomes the source of the transistor, n0 region 4006 which becomes the emitter of the bipolar transistor formed in the p2 region 4005, p'''' region 4007 which becomes the drain of the MOS transistor, and n'' region 4008 which becomes the channel stop. , n9 region 4009 to lower collector resistance of bibolar transistor, M
An electrode 4101 made of polysilicon, metal, etc. that becomes the gate of the OS transistor, an electrode wiring 4108 connected to the electrode 4101, and an electrode wiring 4102 made of polysilicon, metal, etc. connected to the emitter of the bibolar transistor.
, 4103.4104, electrode wiring 4109 connected to the drain of the MOS transistor, n3 region 4009
Insulating films 4105, 4106, 410 for separating wiring electrodes 4l10, electrodes, wiring, and elements connected to
7. Note that the insulating films 4105, 4106, 4107 and the electrode wiring 4104 are omitted in FIG. 5A for the sake of simplicity.

The operation of the photoelectric conversion device will be described below.

FIG. 2(A) is a schematic enlarged view showing a cut surface when FIG. 1(B) is cut at a part B-B° shown in the same figure, In the depth direction of Figure (A) (Figure 2 (
It is a potential diagram in the left-right direction of A).

In FIG. 2(A), W is the depletion layer width, X prxn is the depletion layer width of the p region and n region, respectively, and the depth of the p region is x.
It is shown as J.

In FIG. 2(B), W indicates the depletion layer width, and xd indicates the neutral region of the p-region.

When light is absorbed in the depletion N (within the depletion layer width W), the generated electrons and holes move quickly due to drift, and recombination does not occur, so the sensitivity to light is high. When light absorption occurs within the region width xd), the generated electrons move by diffusion, causing recombination with holes and decreasing the sensitivity to light. Therefore, in the light-receiving section, it is better to have as few neutral regions as possible on the surface. However, when the surface is depleted, carriers are generated at the interface between the semiconductor and the insulating layer, regardless of the incidence of light, resulting in noise, so the surface is preferably a neutral region.

FIG. 3 is a characteristic diagram for explaining the absorption coefficients of SL and Ge with respect to the wavelength of light.

As shown in the figure, Si. For any Ge, the shorter the wavelength, the larger the absorption coefficient. Now, considering SL as a material, blue (λ = 0.45 μm) and green (λ =
0.53 μm) in the red color (n = 0.65 μm), the absorption coefficient is blue ~2 X 10'cm-' respectively
．． Green ~ 7.5 X lO"cm-", Red ~ 3
*LO"cm-', half width of color is 0.05μm
Considering this, light absorption in the SL is sufficiently carried out at a depth of blue to 1 μm, green to 2 μm, and red to 5 μm.

Therefore, the blue color is most affected by the thickness xd of the neutral region on the semiconductor surface, and the confusion decreases depending on this thickness.

The depletion layer width is expressed by the following relational expression.

W: depletion layer width, xp: p-region depletion layer width, NA: p-region impurity density, ND: n-region impurity density, εS: dielectric constant, ni: true carrier density, ■R: reverse bias voltage.

FIG. 4 is a characteristic diagram illustrating the relationship between the p-impurity density NA and the total depletion layer width W at a reverse bias voltage VR=5V.

In the figure, the horizontal axis is p - impurity density NA. The vertical axis shows the total depletion layer width W, and the parameter is n-region impurity density ND
shows. For example, to efficiently detect all of blue, green, and red, the total depletion layer width would need to be about 5 um.
At that time, it can be seen from this characteristic diagram that NO must be less than 2X 10"cm-".

The spectral sensitivity of the photoelectric conversion device is approximately expressed by the following equation.

X (1-exp (-aW))・T[A/W]
(4) N: wavelength of light, α: absorption coefficient of light (cm-'
)xd: Insensitive region (neutral region), W: High sensitivity region (depletion layer width), T2 Ratio of the amount of light incident on the semiconductor (transmittance)
.

As can be seen from the above equation (4), depending on the thickness of the sensitivity xd,
The thinner the xd is, the more sensitive it will be. Furthermore, the sensitivity is wavelength dependent, and the sensitivity is lower for blue than for red. In addition, in order to relatively correct the spectral sensitivity, W is made small《
It is also possible to optimize by

As can be seen from FIG. 4, this is possible by controlling the density of the n-region. In order to increase the blue sensitivity, it is better to make the neutral region xd smaller.

Figure 5 shows p- impurity density NA and p-layer depletion layer thickness xp.
FIG.

In the figure, the horizontal axis shows the p-type impurity density NA, the vertical axis shows the thickness xp of the p-layer depletion layer, and the parameter shows the n-region impurity density ND.

In the same figure, for example, if N D = 1014 am-3 and NA of the p region = 10"cm-', x
p=0.6 μm.

If xj of the p region is 0.7 μm, the dead area is 0.1 μm.
m, and optimization to increase blue sensitivity is possible. It is also good to increase the impurity density only in the surface 0.1 μm, lower the impurity density in the deep region, and deplete the region deeper than the surface 0.1 μm.

In the present invention, the light-receiving surface has a neutral region by forming it separately into the p° region of the light-receiving section, which accumulates charges generated by radiation, and the p-region, which becomes the base region of the bibolar transistor. The thickness of the entire depletion layer can be determined by using the spectral sensitivity, and the concentration of the n region can be determined by depleting the region deeper than near the surface.

FIG. 6 is a schematic circuit diagram for explaining one embodiment of a drive circuit for a photoelectric conversion device according to the present invention.

In this embodiment, a line sensor in which sensors (Sl, S3, . . . ) are arranged in a line will be described.

Each sensor S consists of a bipolar transistor and a reset transistor Q res connected to its base. Carriers excited by the incident light are accumulated at the pace of the bibolar transistor and read out to the emitter. Then, by turning on Q res, it is reset to a constant potential.

The gate electrode of Qres of each sensor S has ON/OFF
A pulse φres for control is input, and Q res
A constant voltage Vbg is applied to the other main electrode.

A constant positive voltage is applied to the collector electrode of each sensor S, and the emitter electrode is connected to the vertical line L (LL, L2...
・) are connected to each other.

A constant voltage Veg is applied to each vertical line L via a transistor Qvrs, and a pulse φres for ON/OFF control is input to the gate electrode of Qvrs.

Further, each vertical line L is connected to a storage capacitor Ct, and a signal is outputted from the bipolar transistor BPT2 via a transistor Qt.

Other embodiments of the photoelectric conversion device of the present invention will be described below. Note that the same components as those in the embodiment shown in FIG. 5 (Al) and FIG.

FIG. 7 is a schematic sectional view for explaining a second embodiment of the present invention.

As shown in the figure, in this embodiment, a p''' region 4010 is formed only on the surface of a p-region 4004 serving as a light-receiving region, and an n-region 40 with high impurity density is formed under the base of the bibolar transistor.
11 is provided to lower the collector resistance.

FIG. 8 is a schematic sectional view for explaining a third embodiment of the present invention.

As shown in the figure, this embodiment has a structure in which the p-region 4004 serving as the light receiving region is extended to the lower part of the emitter of the bibolar transistor, and the bibolar transistor is made into a drift base type to achieve high speed. It goes without saying that the bipolar transistor BPT2 on the output side shown in FIG. 6 can also have this structure.

FIG. 9 is a schematic sectional view for explaining a fourth embodiment of the present invention.

As shown in the figure, in this embodiment, the n-region 401l is deepened to reach the buried region to lower the collector resistance.

FIG. 10 is a schematic sectional view for explaining a fifth embodiment of the present invention.

As shown in the figure, this embodiment has a structure in which the buried region is limited to only the locations of bibolar transistors and the like.

As shown in the figure, by design, considering the n region and p substrate of the light receiving section, there is no neutral region between the n and p substrates, eliminating the cause of lateral carrier diffusion in the sensor cell. , smear, and NTF improvements.

The embodiments described above can be applied not only to Si but also to other semiconductor materials. Furthermore, a structure in which n and p are completely replaced can also be used.

Further, as in the above embodiments, the characteristics of the transistor can be improved by lowering the collector resistance (specifically, the amplification characteristics, switching characteristics, etc. of the transistor can be improved).

The above-described embodiments enable the above-mentioned objectives to be achieved even more effectively.

FIG. 11 is a schematic cross-sectional view for explaining a sixth embodiment of the photoelectric conversion device of the present invention.

This example is a photoelectric conversion device in which the anode of the photodiode and the space region of the bibolar transistor are manufactured in separate steps.

In the figure, 1001 is a p-type substrate, 1002 is an n-type buried layer which is the collector of the bibolar transistor, 1003 is an n-evitaxial layer, and 1004 is a p-layer which is the base region of the bibolar transistor as an amplification section. , 1005 is a pH anode of a photodiode as a photoelectric conversion section, 1006 is an n layer that is an emitter region of a bibolar transistor, and 100'l. is made of a conductive material such as A1, and connects the p-layer 1005, which is the anode of the photodiode, and the p-layer 1004, which is the base region of the bibolar transistor; 1oo7-* is A1.
1. Emitter electrode made of conductive material such as polysilicon, 1
008 is a LOCOS oxide film. L indicates the light receiving part,
D indicates a light shielding part.

As shown in the figure, the photodiode installed in the light receiving section and the bibolar transistor installed in the light shielding section are wired with 100 liters of wiring.
, and it is possible to form a light receiving part and a light shielding part separated by a certain distance.

When the photoelectric conversion device of the present invention is used as a color line sensor, it can be provided outside the line sensors for red (R), green (G), and blue (B) as shown in FIG. It becomes possible to form the green light-receiving part adjacent to the green light-receiving part. Therefore, when the R signal for a certain line of the original is obtained, the G signal is the position of the second line of the original from that line, and the B signal is
The signals are each signal at the document position on the (n+3)th line,
Compared to the color line sensor shown in FIG. 16 described above, the amount of previously output GB signals to be stored is reduced, and the capacity of the external memory can be smaller.

In this example, impurity diffusion is independently controlled in pllo04, which is the base region of the bibolar transistor, and pH1005, which is the anode of the photodiode, and the size of the diffusion region, impurity concentration, etc. can be independently controlled. It becomes possible to match the spectral sensitivity characteristics of the photodiode to the desired wavelength sensitivity, and it also becomes possible to set the characteristics such as the amplification factor and response speed of the pibora transistor to the desired optimal values. .

FIG. 12 is a schematic cross-sectional view for explaining a seventh embodiment of the photoelectric conversion device of the present invention.

This example is a photoelectric conversion device in which a p9 region is formed in a bibolar transistor and a collector region of the bibolar transistor is separately manufactured. Incidentally, the same constituent members as those of the first embodiment described above are given the same reference numerals and the explanation thereof will be omitted.

In the figure, 1004-+ is a p-layer which is an anode of a photodiode, and 1004-* is a p-layer which is a base region of a bibolar transistor, which are manufactured at the same time.

1006-'* is an n layer which is an emitter region of a bibolar transistor.

1009 is a p'' layer in which a high impurity concentration region is provided to improve frequency characteristics.

1010 is the n-layer which is the collector region of the bibolar transistor; 1001. 1007-s is an n''' layer, and 1007-s is a collector electrode made of a conductive material such as Al or polysilicon.

As shown in the figure, the photodiode provided in the separately formed light receiving part and the bibolar transistor wiring 1007:+ provided in the light shielding part are connected to each other by a bipolar transistor wiring 1007:+, and the same effect as in the first embodiment can be obtained. The color line sensor shown in FIG. 13 can be constructed.

Next time. An example of an image reading device to which the photoelectric conversion device of the invention described above is applied is shown.

FIG. 14 is a schematic configuration diagram of an example of an image reading device.

In the figure, a document 5201 is mechanically moved in the direction of arrow Y relative to a reading unit 5205. Further, the image is read by the image sensor 5204 using the arrow
This is done by scanning in the direction.

First, the light from the light source 5202 is reflected by the original 5201,
The reflected light passes through an imaging optical system 5203 and forms an image on an image sensor 5204, which is a photoelectric conversion device of the present invention. As a result, carriers corresponding to the intensity of the incident light are accumulated in the image sensor 5204, photoelectrically converted, and output as an image signal. This image signal is sent to the AD converter 5
206, the image is digitally converted and taken into the memory in the image processing unit 5207 as image data. Then, processing such as shading correction and color correction is performed, and the image is sent to a personal computer 5208, a printer, or the like.

When the image signal transfer for scanning in the X direction is completed, the original 5201 moves relatively in the Y direction, and by repeating the same operation, the previous image of the original 5201 is converted into an electrical signal and converted into image information. It can be taken out.

[Effects of the Invention] As explained in detail above, the semiconductor region of opposite conductivity type is formed by dividing it into a semiconductor region that accumulates charges generated by incident light and a semiconductor region that becomes a control electrode region of a semiconductor transistor. According to the photoelectric conversion device of the present invention, the input region of the amplification section and the photoelectric conversion section can be manufactured independently, and the size, impurity concentration, configuration, etc. of the diffusion region can be independently controlled. This makes it possible to match the spectral sensitivity characteristics of the photoelectric conversion section to the desired wavelength sensitivity.
Further, it becomes possible to set the characteristics such as the amplification factor and response speed of the amplifier section to desired optimum values, and it is possible to design a device having desired performance.

Furthermore, according to the above-mentioned photoelectric conversion device, the optimum manufacturing conditions such as the impurity concentration and thickness of the semiconductor region that generates and accumulates charges by light incidence, and the impurity concentration and impurity concentration of the semiconductor region that becomes the control electrode region of the semiconductor transistor are determined. Optimum manufacturing conditions such as distribution and thickness can be arbitrarily set for each semiconductor region. As a result, the light receiving section and the semiconductor transistor section can be designed separately, and it is possible to increase the blue sensitivity and at the same time increase the speed of the semiconductor transistor.

Further, a photoelectric conversion section is formed in the light receiving section, an amplification section is formed in the light shielding section, and the photoelectric conversion section and the input area of the amplification section are connected by wiring, so that the light receiving section and the light shielding section are fixed at a constant level. According to the photoelectric conversion device of the present invention, which is characterized in that the photoelectric conversion device is formed separately at a distance, it has an amplification function, and the light receiving part and the light shielding part are manufactured separately, and the light receiving part is formed adjacent to each other. becomes possible. As a result, system design and optical design can be simplified.

The photoelectric conversion device of the present invention is characterized in that semiconductor regions of opposite conductivity types are formed separately into a semiconductor region that accumulates charges generated by incident light and a semiconductor region that becomes a control electrode region of a semiconductor transistor. A photoelectric conversion section is formed in the light receiving section, an amplification section is formed in the light shielding section, and the photoelectric conversion section and the input area of the amplification section are connected by wiring, so that the light receiving section and the light shielding section are fixed at a constant level. By combining the photoelectric conversion device with the photoelectric conversion device of the present invention, which is characterized in that it is formed separately at a distance, the performance can be further improved.

[Brief explanation of drawings]

FIGS. 1A and 1B are schematic configuration diagrams for explaining a first embodiment of a photoelectric conversion device of the present invention, respectively.
Figure (A) is a schematic plan view, and Figure 1 (B) is a schematic longitudinal sectional view. FIG. 2(A) is a schematic enlarged view of FIG. 1(CB) cut along the line BB' in FIG. 1(B).
B) is a potential diagram in the depth direction of FIG. 2(A). FIG. 3 is a characteristic diagram illustrating the absorption coefficients of Si and Ge with respect to the wavelength of light. FIG. 4 is a characteristic diagram illustrating the relationship between the p-impurity density NA and the total depletion layer width W at a reverse bias voltage VR=5V. Figure 5 shows p - impurity density NA and pH depletion layer thickness xp
FIG. FIG. 6 is a schematic circuit diagram for explaining one embodiment of a drive circuit for a photoelectric conversion device according to the present invention. FIG. 7 is a schematic sectional view for explaining a second embodiment of the present invention. FIG. 8 is a schematic sectional view for explaining a third embodiment of the present invention. FIG. 9 is a schematic sectional view for explaining a fourth embodiment of the present invention. FIG. 10 is a schematic sectional view for explaining a fifth embodiment of the present invention. FIG. 11 is a schematic cross-sectional view for explaining a sixth embodiment of the photoelectric conversion device of the present invention. FIG. 12 is a schematic cross-sectional view for explaining a seventh embodiment of the photoelectric conversion device of the present invention. FIG. 13 is a schematic configuration diagram for explaining an image reading system using the photoelectric conversion device of the present invention. FIG. 14 is a schematic configuration diagram of an example of an image reading device. FIG. 15 is a schematic cross-sectional view illustrating the configuration of a conventional photoelectric conversion device. FIG. 16 is a schematic configuration diagram for explaining an image reading system using a conventional photoelectric conversion device. FIG. 17(A) is a schematic plan view of one configuration example of a photoelectric conversion device, and FIG. 17(B) is a cross-section of FIG. 17(A) along line AA' in FIG. 17(A). FIG. FIG. 18(A) and FIG. 18(B) are voltage waveform diagrams for explaining the refresh operation, respectively. 4001: Silicon substrate, 4002: Embedded region,
4003: n one area, 4004: 1) one area,
4005: p' region, 4006: n'' region, 400
7: p' region, 4008: n'''' region, 4o0
9: n'' region, 4101: electrode, 4102, 4103
, 4104, 4108, 4109.4110: Electrode wiring, 4105, 4106, 4107: Insulating film. Agent Patent Attorney Johei Yamashita (A) Figure tear chart (JJm) Figure P 4R A J L (NA cm-3) Figure P=9'4 4 J Cliff (Na cm3) Figure Figure 13 Figure Figure Figure Figure Figure (A)

Claims (19)

[Claims] (1) Light is irradiated to the semiconductor region of the opposite conductivity type of a semiconductor transistor consisting of two semiconductor regions of the same conductivity type and a semiconductor region of the opposite conductivity type to these two semiconductor regions, and the semiconductor region of the same conductivity type is irradiated with light. In a photoelectric conversion device that extracts an amplified output from at least one of two semiconductor regions, the semiconductor region of opposite conductivity type is used as a semiconductor region that accumulates charges generated by incident light, and a control electrode region of a semiconductor transistor. A photoelectric conversion device characterized in that it is formed separately from a semiconductor region and a semiconductor region. (2) In a photoelectric conversion device that includes a light receiving section and a light blocking section and is capable of amplifying photoelectric conversion output, a photoelectric conversion section is formed in the light receiving section, an amplification section is formed in the light blocking section, and the photoelectric conversion section and an input region of the amplifying section are connected by wiring, and the light receiving section and the light shielding section are separated by a certain distance and formed separately. (3) a first semiconductor region of a first conductivity type; a second semiconductor region of a first conductivity type provided on the first semiconductor region; and a second semiconductor region provided in contact with the second semiconductor region. a third semiconductor region of a conductivity type; a fourth semiconductor region of a second semiconductor type provided in contact with the third semiconductor region and the second semiconductor region; and a fourth semiconductor region provided in contact with the fourth semiconductor region. a fifth semiconductor region of a first conductivity type provided in contact with the second semiconductor region; and a sixth semiconductor region of a second conductivity type provided in contact with the second semiconductor region, the third semiconductor region serving as a light incident region. the first, second, fourth and fifth semiconductor regions;
The fourth and sixth semiconductor regions are photoelectric conversion devices each serving as an element constituting a transistor. (4) The photoelectric conversion device according to claim 3, wherein the second semiconductor region is of the same conductivity type and has a region with a low impurity concentration and a region with a high impurity concentration. (5) The second semiconductor region has a low impurity concentration region and a high impurity concentration region of the same conductivity type, and the high impurity concentration region is the fourth, fifth, and sixth semiconductor regions. 4. The photoelectric conversion device according to claim 3, wherein the photoelectric conversion device is provided between the first semiconductor region and the first semiconductor region. (6) At least a portion of the third semiconductor region
4. The photoelectric conversion device according to claim 3, wherein the photoelectric conversion device is provided between a semiconductor region and the second semiconductor region. (7) The second semiconductor region has a low impurity concentration region and a high impurity concentration region of the same conductivity type, and the high impurity concentration region is the same as the fourth, fifth, and sixth semiconductor regions. The third semiconductor region is provided between the first semiconductor region and the fourth semiconductor region.
4. The photoelectric conversion device according to claim 3, wherein the photoelectric conversion device is provided between a semiconductor region and the second semiconductor region. (8) Claim 3, wherein the first semiconductor region is provided excluding at least a region corresponding to the third semiconductor region.
The photoelectric conversion device described. (9) The photoelectric conversion device according to claim 3, wherein the first semiconductor regions are formed on substrates of the same conductivity type. (10) The photoelectric conversion device according to claim 3, wherein the first semiconductor regions are formed on substrates of different conductivity types. (11) The photoelectric conversion device according to claim 3, wherein the first conductivity type is n-type. (12) The photoelectric conversion device according to claim 3, wherein the second conductivity type is p-type. (13) The third,
A seventh semiconductor region of the first conductivity type that serves as a channel stop surrounds a region in which the fourth, fifth, and sixth semiconductor regions are formed.
4. The photoelectric conversion device according to claim 3, wherein a semiconductor region is formed. (14) The photoelectric conversion device according to claim 7, wherein the third semiconductor region is provided between the fourth semiconductor region and the region with high impurity concentration. (15) The photoelectric conversion device according to claim 10, wherein the different conductivity type is p-type. (16) A first semiconductor region of a first conductivity type, a second semiconductor region of a first conductivity type provided in contact with the first semiconductor region, and a second semiconductor region provided in contact with the second semiconductor region. a third semiconductor region of a second conductivity type; and a fourth semiconductor region of a second conductivity type that is electrically connected to the third semiconductor region via a conductive material and provided in contact with the second semiconductor region. , a fifth semiconductor region of the first conductivity type provided in contact with the fourth semiconductor region, the third semiconductor region being a light incident region, and the first, second, fourth, and third semiconductor regions. 5. A photoelectric conversion device in which a semiconductor region is an element constituting a transistor. (17) The second semiconductor region has the same conductivity type and includes a region with a low impurity concentration and a region with a high impurity concentration.
The photoelectric conversion device described. (18) The second semiconductor region has a low impurity concentration region and a high impurity concentration region of the same conductivity type, and the low impurity concentration region and the third semiconductor region are in contact with each other. The photoelectric conversion device described. (19) The photoelectric conversion device according to claim 18, wherein the region with high impurity concentration and an electrode are electrically connected.