JP3800515B2 - Solid-state imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state imaging device, and more particularly to a solid-state imaging device used for a video camera or the like.
[0002]
[Prior art]
In general, this type of solid-state imaging device has a charge coupled device (CCD) arranged in a one-dimensional manner and a signal charge provided at the end of the CCD and transferred by the CCD to a floating diffusion (FD) comprising an impurity diffusion layer. And an output circuit that detects and outputs potential fluctuations of the floating diffusion. The floating diffusion includes a reset transistor (RS) that discharges detected signal charges at a desired timing, and a reset drain (RD). The CCD is a two-phase drive type CCD, each phase is composed of two-layer electrodes, and the first channel formed under the first layer electrode is more than the second channel formed under the second layer electrode. It is formed at a deep potential, and is configured to primarily accumulate signal charges in the first channel under the first layer electrode during signal charge transfer.
[0003]
As shown in FIG. 21, the actual device configuration of such a solid-state imaging device includes a semiconductor substrate 1 of one conductivity type, a well 2 formed on the semiconductor substrate 1 and having an opposite conductivity type, and a well 2. First and second impurity layers 3 and 4 having a conductivity type opposite to that of the well and formed on the first and second impurity layers 3 and 4 through insulating layer 6 respectively. Further, the first layer electrode 7 and the second layer electrode 8 are formed. 9 is an output amplifier.
[0004]
Here, since each electrode forms a two-phase drive CCD, the electrodes are electrically connected to form a desired circuit configuration by a contact and wiring such as Al.
[0005]
The first and second layer electrodes 7 and 8 constitute an output gate (OG) by the second layer electrode 8 at the final stage of the transfer electrode, and the second impurity layer 4 is formed in the channel under the OG. In the preceding stage, the first layer electrode 7 and the second layer electrode 8 constitute the H1 potential, the channel under the first layer electrode 7 constituting the H1 potential is the first impurity layer 3, the second of the H1 potential. The channel below the layer electrode 8 is composed of the second impurity layer 4.
[0006]
Further, the first and second layer electrodes constituting H2 are formed in the direction opposite to the transfer, and the channel configuration is the same as the H1 potential. Further, the first layer electrode and the second layer electrode 8 constituting the H2 potential are formed on the upstream side, and the channel configuration is the same as the H1 potential. In this way, the H1 potential and the H2 potential are alternately arranged.
[0007]
On the other hand, the impurity layer 5 is connected to the lower OG channel end to form an FD formed so as to generate a voltage corresponding to the signal charge, and the signal output voltage is transmitted to the output circuit.
[0008]
Further, a transistor is connected to the FD to form a reset transistor.
This solid-state imaging device is driven by driving pulses as shown in FIG. Here, the drive pulses ΦRS and ΦH2 applied to the reset transistor gate drive pulses ΦRS, H1 and H2, respectively, are driven, and the output voltage from the output circuit at this time is denoted by OS. Here, H1 and H2 realize a well-known two-phase drive CCD operation with pulses of opposite phases, and are transferred to the FD via an OG to which a fixed voltage is applied by a DC bias.
[0009]
[Problems to be solved by the invention]
By the way, the floating diffusion FD is formed to be smaller in area in order to reduce the capacitance in order to obtain a higher output voltage even at a small signal. Accordingly, in order to secure a sufficient transfer capacity, in order to connect to a CCD channel having a wide width in the transfer direction, it is necessary to form the channel width narrower than the vicinity of the final transfer stage as shown in FIG.
[0010]
FIG. 23 shows the AA cross section of FIG. 21, and FIGS. 24A, 24B and 24C show the BB cross section and CC cross section of FIG. Further, as shown in FIG. 24C, there is a problem that the channel width becomes narrow in the BB portion close to the floating diffusion FD, and the potential becomes shallow due to a so-called narrow channel effect.
[0011]
FIGS. 25A and 25B are diagrams showing the potential at the aa ′ portion in FIG. 23. As shown in FIG. 24C, when a potential difference is generated under the same electrode, a reverse gradient occurs in the potential in the transfer direction. As shown in FIGS. May cause a so-called transfer failure that remains without being transferred normally.
[0012]
Such a transfer failure appears, for example, when the two-phase drive CCD is used as a horizontal CCD of a solid-state imaging device in which photodiodes are arranged two-dimensionally, resulting in a lateral flow of an image and a deterioration in resolution. Further, when a color signal is obtained by laminating a color filter on a photodiode, it may appear as a color false signal. Such a transfer failure causes deterioration of the image in any case.
[0013]
In addition, when the channel width is narrowed sequentially from the vicinity of the final transfer stage, the electrode length of the electrode with the reduced channel width is equal to or greater than the channel under the electrode in order to obtain the same transfer capacity as the channel without narrowing the width. In order to obtain the area, there is a problem that the electrode length of the first layer electrode for accumulating signal charges must be formed long.
[0014]
Therefore, as shown in FIG. 26, the electrode length L1 of the electrode whose channel width is narrowed is formed longer than the electrode length L2 which is not narrowed.
FIGS. 27A and 27B are diagrams showing potential diagrams of the AA ′ part in FIG. Here, FIG. 27A shows a state in which signal charges are accumulated under the electrode length L1 region shown at t1 in FIG. 22, and FIG. 27B shows a state through OG shown at t2 in FIG. It is a figure which shows the state which transfers a signal charge to FD.
[0015]
When the channel length is long, more transfer time is required. On the other hand, when the driving pulse is used for a horizontal CCD such as a solid-state imaging device arranged in a two-dimensional manner, the reading speed is increased to speed up the system. Therefore, there are many cases where transfer time is not sufficient and transfer failure occurs.
[0016]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device with high reliability by preventing transfer failure near the final transfer stage where the channel width of the horizontal CCD transfer path becomes narrow.
[0017]
[Means for Solving the Problems]
A solid-state imaging device of the present invention includes a plurality of electrodes arranged in a one-dimensional manner on the surface of a one-conductivity-type semiconductor substrate, and a charge-coupled device including a channel region formed correspondingly under the electrodes, A signal detection unit for detecting a signal transferred from the charge coupled device; and an output unit for outputting a signal detected by the signal detection unit; and in the vicinity of a connection portion between the charge coupled device and the signal detection unit The channel region is a solid-state imaging device in which a narrowed region in which the channel width of the charge coupled device is narrowed is formed, and is a final stage located at a connection portion between the charge coupled device and the charge detection unit. channel region under electrode is formed such that a portion of the potential of the width direction of the channel is deeper than the potential of other portions of the channel region, the channel region under the transfer electrodes of the last stage electrode immediately before the The portion of the channel that is continuous with the portion formed so that the potential below the final electrode is deep, and the potential of the portion of the channel in the width direction and the portion of the channel downstream in the charge transfer direction is It is characterized by being formed so as to be deeper than the potential of the other part of the region .
[0018]
The solid-state imaging device of the present invention includes one in which the region formed so that the potential of the channel region is deeper is a high-concentration impurity region formed so as to have a higher concentration than other regions.
[0019]
The solid-state imaging device of the present invention includes one in which the other part of the channel region is a reverse conductivity type semiconductor region.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a solid-state imaging device according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the solid-state imaging device according to the first embodiment of the present invention includes a second imaging device in the channel below the output gate electrode OG and adjacent to the readout terminal RD side below the output gate electrode OG. A high-concentration layer 4B having the same conductivity type as that of the impurity layer 4 is formed. As shown in FIG. 3C, the potential peak formed by the high-concentration layer 4B is a second peak on the upstream side below the output gate electrode OG. This is characterized in that it is configured to be deeper than the potential peak formed by the impurity layer 4 so as to generate a potential gradient toward the FD5 direction in the transfer direction.
[0023]
That is, FIG. 1 is a diagram showing a transfer electrode array unit and a readout unit of the solid-state imaging device according to the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. c) shows the BB cross section and CC cross section of FIG. FIG. 3 (c) shows those potentials.
[0024]
4 (a) and 4 (b) are diagrams showing the potential at the aa ′ portion in FIG. As shown in FIG. 3C, a good potential difference is generated under the same electrode due to the presence of the high concentration layer 4B, so that a favorable potential gradient is formed in the transfer direction. As shown in b), charge transfer is achieved satisfactorily without causing a so-called transfer failure in which signal charges remain without being transferred normally.
[0025]
That is, as shown in FIGS. 1 to 3, this solid-state imaging device forms a photodiode portion (not shown) in a P-type well region 2 formed on the surface of an n-type semiconductor substrate 1, and a horizontal CCD region. As a result, a second impurity layer 4 made of an N-type region and a first impurity layer 3 made of an N-type region are formed. A first layer electrode 7 made of a polysilicon electrode and a second layer electrode 8 are formed via the silicon oxide film 6. Here, a high-concentration layer 4B having the same conductivity type as that of the second impurity layer 4 is formed in the second impurity layer 4 so as to be adjacent to the read terminal RD side below the output gate electrode OG, as shown in FIG. As shown in c), the potential peak formed by the high concentration layer 4B is formed to be deeper than the potential peak formed by the second impurity layer 4 on the upstream side under the output gate electrode OG. ing. Wherein the first and second impurity layers are those having an impurity concentration of about 5.0 e ¹⁷ cm ^-3, The high concentration layer 4B is about 4.0e ¹⁷ cm ^-3.
[0026]
The semiconductor substrate 1 is an N-type silicon substrate. A P-type well region 2 is formed along one main surface of the semiconductor substrate 1. Impurities are selectively diffused from one main surface side of the semiconductor substrate 1 into the P-type well region 2 so that the N-type region of the photodiode portion and the N-type regions of the horizontal CCD portion are first and second. Impurity layers 3 and 4 are formed at intervals of a predetermined dimension.
[0027]
A first layer electrode 7 is formed on the silicon oxide film 6 by laminating a light shielding film made of polysilicon, tungsten, or a silicide thereof by low pressure CVD. A silicon oxide film 6 is formed so as to cover the side surface of the first layer electrode 7 and further the side surface of the oxide film 7. In this upper layer, a second layer electrode is formed by laminating polysilicon and a light shielding film made of tungsten or its silicide.
[0028]
The operation of the solid-state imaging device configured as described above will be described.
Signal charges are generated by photoelectric conversion in a photodiode portion (not shown) made of an N-type region formed in a P-type well region 2 in the semiconductor substrate 1. Then, by applying a pulse voltage to the first layer electrode 8, the signal charge is moved from the photodiode region to the N-type region 4 of the horizontal CCD section below the first layer electrode 8. Next, pulse signals are alternately applied between the first layer electrode 7 and the second layer electrode 8 as the second layer to transfer signal charges.
[0029]
In this solid-state imaging device, the charge transfer electrodes are alternately distinguished into the first layer electrode and the second layer electrode, and a pulse voltage is sequentially applied to these electrodes, thereby passing through the FD region 5 shown in FIG. The signal charge is moved to the reading terminal RD. That is, the signal charges are transferred by alternately applying pulse signals to the first layer electrode and the second layer electrode.
[0030]
The signal charge is transferred in this way. However, due to the presence of the high concentration layer 4B, a good potential difference is generated under the same electrode, so that a good potential gradient is formed in the transfer direction. Thus, charge transfer can be achieved satisfactorily without causing a so-called transfer failure that remains without being transferred normally.
[0031]
Therefore, even when this two-phase drive type CCD is used for a horizontal CCD of a solid-state imaging device in which photodiodes are two-dimensionally arranged, there is no lateral flow of the image or deterioration of resolution.
[0032]
Also, when a color filter is stacked on a photodiode to obtain a color signal, it does not appear as a color false signal, and it is possible to reduce image deterioration.
In manufacturing, it is only necessary to add an impurity diffusion step, and if necessary, additional diffusion may be performed by self-alignment.
[0033]
(Second Embodiment)
Next, a second embodiment of the present invention will be described. In this example, when the channel width is narrowed sequentially from the vicinity of the final transfer stage, the electrode length of the electrode with the reduced channel width is the same as the channel under the electrode in order to obtain the same transfer capacity as the channel without reducing the width. The electrode layer of the first layer electrode for accumulating signal charges is formed long enough to obtain a larger area. In this case, as shown in FIG. 4, the output gate is placed in the channel below the output gate electrode OG. A second high-concentration layer 4C having the same conductivity type as that of the second impurity layer 4 is formed so as to be adjacent to the readout terminal RD side below the electrode OG and to be below the first layer electrode, and FIG. ), The potential peak formed by the high concentration layer 4B is deeper than the potential peak formed by the second impurity layer 4 on the upstream side under the output gate electrode OG. FD5 direction in the transfer direction This is characterized in that a potential gradient is generated in the direction.
[0034]
That is, FIG. 5 is a diagram illustrating a transfer electrode array unit and a readout unit of the solid-state imaging device according to the second embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line AA in FIG. b) (c) shows the BB cross section and CC cross section of FIG. FIG. 7 (c) shows those potentials.
[0035]
FIGS. 8A and 8B are diagrams showing the potential at the aa ′ portion in FIG. 6. As shown in FIG. 3C, the presence of the second high-concentration layer 4C causes a good potential difference to reach the region below the first layer electrode and the region below the output gate OG. A potential gradient is formed, and as shown in FIGS. 8A and 8B, charge transfer is achieved satisfactorily without causing a so-called transfer failure in which signal charges remain without being transferred normally. .
[0036]
Therefore, even when this two-phase drive type CCD is used for a horizontal CCD of a solid-state imaging device in which photodiodes are two-dimensionally arranged, there is no lateral flow of the image or deterioration of resolution.
Also, when a color filter is stacked on a photodiode to obtain a color signal, it does not appear as a color false signal, and it is possible to reduce image deterioration.
The
[0037]
(Third embodiment)
Next, a third embodiment of the present invention will be described. In this example, as shown in FIG. 9, the formation region of the high concentration layer 4B in the first embodiment is defined. The sectional view is the same as that in the first embodiment.
[0038]
That is, in the first embodiment, the high-concentration layer 4B is formed so as to have the same width as the impurity layer gradually widening from the FD 5, but only a part in the width direction may be formed. Good.
[0039]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0040]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In this example, the formation region of the high concentration layer 4B in the first embodiment is defined.
That is, in the first embodiment, the boundary surface between the high concentration layer 4B and the second impurity layer 4 is formed so as to form a straight line. However, as shown in FIG. You may form so that an end surface may protrude partially in a transfer direction. Note that the end surface in the width direction is formed to have the same width as the second impurity layer 4 that gradually becomes wider from the FD 5.
[0041]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0042]
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. In this example, as shown in FIG. 11, the formation region of the high concentration layer 4B in the second embodiment is defined. The sectional view is the same as that of the second embodiment.
[0043]
That is, in the second embodiment, the second high-concentration layer 4C is formed so as to have the same width as the second impurity layer 4 that gradually increases from the FD 5, but only a part in the width direction. It may be formed.
[0044]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0045]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. In this example, the formation region of the second high concentration layer 4C in the second embodiment is defined.
[0046]
That is, in the second embodiment, the boundary surface between the high concentration layer 4C and the second impurity layer 4 is formed in a straight line. However, as shown in FIG. You may form so that an end surface may protrude partially in a transfer direction. Note that the end surface in the width direction is formed to have the same width as the second impurity layer 4 that gradually becomes wider from the FD 5.
[0047]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0048]
(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. In this example, as shown in FIGS. 13 and 14, instead of the formation of the high concentration layer 4B in the first embodiment, the inversion is performed with respect to the high concentration layer 4B in the second impurity layer 4. The reverse conductivity type layer 4D is formed in the region. 14 is a cross-sectional view taken along the line AA in FIG.
[0049]
That is, in the first embodiment, the high-concentration layer 4C is formed in the second impurity layer 4 so as to form a good potential gradient. The reverse conductivity type layer 4D is formed in the inversion region.
[0050]
According to such a configuration, the boundary of the reverse conductivity type layer 4D on the opposite side in the transfer direction can be formed by self-alignment of the first layer electrode, and the reverse conductivity under the first layer electrode due to the manufacturing process misalignment. There is an effect that the entry of the mold layer 4D can be prevented, and the second impurity layer 4 formed for forming the first impurity layer 3 can also serve as self-alignment implantation of impurities of the opposite conductivity type.
[0051]
(Eighth embodiment)
Next, an eighth embodiment of the present invention will be described. In this example, as shown in FIGS. 15 and 16, instead of forming the high concentration layer 4B in the second embodiment, the inversion is performed with respect to the high concentration layer 4B in the second impurity layer 4. The reverse conductivity type layer 4E is formed in the region. FIG. 16 is a cross-sectional view taken along the line AA in FIG.
[0052]
That is, in the second embodiment, the high-concentration layer 4C is formed in the second impurity layer 4 so that the potential gradient is well formed. The reverse conductivity type layer 4D is formed in the inversion region.
[0053]
(Ninth embodiment)
Next, a ninth embodiment of the present invention will be described. In this example, the region where the high concentration layer 4B is formed in the third embodiment is replaced with the high concentration layer 4B instead of the high concentration layer 4B as shown in FIG. A reverse conductivity type layer 4D is formed in a region inverted with respect to 4B.
[0054]
That is, in the third embodiment, the high concentration layer 4B is formed in the second impurity layer 4 so as to form a favorable potential gradient. However, in this example, instead of this, The reverse conductivity type layer 4D is formed in the inversion region.
[0055]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0056]
(Tenth embodiment)
Next, a tenth embodiment of the present invention will be described. In this example, the region where the high concentration layer 4B is formed in the fourth embodiment is replaced with the high concentration layer 4B instead of the high concentration layer 4B as shown in FIG. A reverse conductivity type layer 4D is formed in a region inverted with respect to 4B.
[0057]
That is, in the fourth embodiment, the high-concentration layer 4C is formed in the second impurity layer 4 so that the potential gradient is well formed. The reverse conductivity type layer 4D is formed in the inversion region.
[0058]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0059]
(Eleventh embodiment)
Next, an eleventh embodiment of the present invention will be described.
In this example, the region where the high concentration layer 4B is formed in the fifth embodiment is replaced with the high concentration layer 4C instead of the high concentration layer 4C as shown in FIG. A reverse conductivity type layer 4E is formed in a region inverted with respect to 4C.
[0060]
That is, in the sixth embodiment, the high-concentration layer 4C is formed in the second impurity layer 4 so that the potential gradient is well formed. The reverse conductivity type layer 4E is formed in the inversion region.
[0061]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
[0062]
(Twelfth embodiment)
Next, a twelfth embodiment of the present invention will be described. In this example, the formation region of the second high concentration layer 4C in the sixth embodiment is replaced with the second impurity layer instead of the formation of the high concentration layer 4C in this example, as shown in FIG. The reverse conductivity type layer 4 </ b> E is formed in a region inverted with respect to the high concentration layer 4 </ b> C in 4.
[0063]
That is, in the sixth embodiment, the high-concentration layer 4C is formed in the second impurity layer 4 so that the potential gradient is well formed. The reverse conductivity type layer 4E is formed in the inversion region.
[0064]
According to such a configuration, since a potential gradient is formed not only in the width direction but also in the length direction near the entrance of the FD 5, charge transfer can be performed more efficiently.
In the above-described embodiment, the case where the step of the potential under each single electrode is two steps has been described. However, by changing the profile of the impurity layer provided in the second impurity layer 4, the second step is performed. Needless to say, two or more potential steps may be formed in the impurity layer.
[0065]
【The invention's effect】
As described above, according to the present invention, the remaining signal charges generated when the channel width is sequentially narrowed from the vicinity of the final transfer stage is reduced and charge transfer is performed well. Can be used in a horizontal CCD of a solid-state imaging device arranged two-dimensionally, it is possible to provide a solid-state imaging device with high reliability without causing lateral flow of images and deterioration of resolution.
[0066]
Further, when a color filter is stacked on a photodiode to obtain a color signal, it is possible to provide a good image quality without causing a color suspicion.
[Brief description of the drawings]
FIG. 1 is a plan view showing a solid-state imaging device according to a first embodiment of the present invention.
2 is a cross-sectional view taken along line AA of the solid-state imaging device shown in FIG.
3A is a BB cross-sectional view of the solid-state imaging device shown in FIG. 1, FIG. 3B is a CC cross-sectional view of the solid-state imaging device shown in FIG. 1, and FIG. ) Is a diagram showing the potential.
FIG. 4 is a diagram showing a potential gradient in the vicinity of an output gate of the solid-state imaging device.
FIG. 5 is a plan view showing a solid-state imaging device according to a second embodiment of the present invention.
6 is a cross-sectional view of the solid-state imaging device shown in FIG. 5 taken along the line AA.
7A is a BB cross-sectional view of the solid-state imaging device shown in FIG. 5, FIG. 7B is a CC cross-sectional view of the solid-state imaging device shown in FIG. 5, and FIG. ) Is a diagram showing the potential.
FIG. 8 is a diagram showing a potential gradient in the vicinity of an output gate of the solid-state imaging device.
FIG. 9 is a plan view showing a solid-state imaging device according to a third embodiment of the present invention.
FIG. 10 is a plan view showing a solid-state imaging device according to a fourth embodiment of the present invention.
FIG. 11 is a plan view showing a solid-state imaging device according to a fifth embodiment of the present invention.
FIG. 12 is a plan view showing a solid-state imaging device according to a sixth embodiment of the present invention.
FIG. 13 is a plan view showing a solid-state imaging device according to a seventh embodiment of the present invention.
14 is a cross-sectional view taken along line AA of the solid-state imaging device shown in FIG.
FIG. 15 is a plan view showing a solid-state imaging apparatus according to an eighth embodiment of the present invention.
16 is a cross-sectional view of the solid-state imaging device shown in FIG. 15 taken along line AA.
FIG. 17 is a plan view showing a solid-state imaging device according to a ninth embodiment of the present invention.
FIG. 18 is a plan view showing a solid-state imaging device according to a tenth embodiment of the present invention.
FIG. 19 is a plan view showing a solid-state imaging device according to an eleventh embodiment of the present invention.
FIG. 20 is a plan view showing a solid-state imaging apparatus according to a twelfth embodiment of the present invention.
FIG. 21 is a plan view showing a conventional solid-state imaging device.
FIG. 22 is a diagram illustrating drive timing of the solid-state imaging device.
23 is a cross-sectional view of the solid-state imaging device shown in FIG. 21 taken along line AA.
24A is a BB cross-sectional view of the solid-state imaging device shown in FIG. 21, FIG. 24B is a CC cross-sectional view of the solid-state imaging device shown in FIG. 21, and FIG. ) Is a diagram showing the potential.
FIG. 25 is a diagram showing a potential gradient in the vicinity of the output gate of the solid-state imaging device.
FIG. 26 is a plan view showing a conventional solid-state imaging device.
27 is a diagram showing a potential gradient of the solid-state imaging device shown in FIG. 26. FIG. Sectional drawing of other examples of conventional solid-state imaging device
DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 P-type well area | region 3 1st impurity layer 4 2nd impurity layer 5 Impurity layer (FD)
6 Insulating film 7 First layer electrode 8 Second layer electrode 9 Output amplifier

Claims (3)

A charge coupled device comprising a plurality of electrodes arranged in a one-dimensional manner on the surface of a semiconductor substrate of one conductivity type, and a channel region formed correspondingly under the electrodes;
A signal detection unit for detecting a signal transferred from the charge coupled device;
An output unit for outputting a signal detected by the signal detection unit,
In the vicinity of the connection portion between the charge coupled device and the signal detection unit , the channel region forms a narrowed region in which the channel width of the charge coupled device is narrowed down.
The channel region below the last-stage electrode located at the connection portion between the charge-coupled device and the charge detection unit is formed so that a potential of a part in the channel width direction is deeper than a potential of another part of the channel region. ,
The channel region under the transfer electrode immediately before the final stage electrode is a part continuous with a part formed so that the potential under the final stage electrode is deep, and is a part in the channel width direction and the channel region. A solid-state imaging device, characterized in that the potential of a part of the downstream portion in the charge transfer direction is deeper than the potential of another part of the channel region . The solid-state imaging according to claim 1, wherein the region formed so that the potential of the channel region is deeper is a high-concentration impurity region formed so as to have a higher concentration than other regions. apparatus. 2. The solid-state imaging device according to claim 1, wherein another part of the channel region is a reverse conductivity type semiconductor region .

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