JPH0637297A - Solid-state imaging device and driving method thereof - Google Patents

Abstract

PURPOSE:To enable a surface irradiation frame transfer type solid-state image sensing element to be enhanced in sensitivity and lessened in false signals and noises. CONSTITUTION:Bus lines 111 to 114 are provided adjacent to N-type vertical charge transfer channels 131 to 134, vertical charge transfer gates 141 to 144 are formed of thin film, and furthermore convex lenses are provided, whereby light signals are enhanced in light concentration rate. Light signals are made to impinge, the impinged light signals are photoelectrically converted, and the surface of the N-type vertical charge transfer channels 131 to 134 is put in a pinning state while the converted signal charge is stored, whereby false signals and noises can be lessened. Furthermore, a voltage applied to an N-type semiconductor substrate is controlled to discharge excessive charge generated by light signal excessively incident on a photoelectric conversion part to the N-type substrate while signal charge generated by photoelectric conversion is stored, whereby a solid-state image sensing device of this design can be protected against false signals called as blooming.

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 a charge transfer element and its driving method.

[0002]

2. Description of the Related Art In a solid-state image pickup device using a charge transfer element, an image pickup region for photoelectrically converting light upon incidence of an optical signal and for accumulating and transferring signal charges generated by the photoelectric conversion, and a signal transferred from the image pickup region What has a storage region for storing and transferring charges and a horizontal charge transfer register for sequentially outputting signal charges transferred from the storage region is
It is called a frame transfer type solid-state imaging device. Also,
The frame transfer type solid-state imaging device can be roughly classified into a front-illuminated type in which an optical signal is incident from the front surface of the device and a back-illuminated type in which an optical signal is incident from the rear surface of the device.

FIG. 7 is a schematic plan view of an example of a conventional front-illuminated frame transfer type solid-state image pickup device, and FIG.
FIG. 8 is a partially enlarged view of the imaging area of the conventional example shown in FIG. 7. Figure 7
As shown in FIG. 3, an imaging region 401 that performs photoelectric conversion by the incidence of an optical signal and stores and transfers the signal charges generated by the photoelectric conversion, a storage region 402 that stores and transfers the signal charges transferred from the imaging region 401, And a horizontal charge transfer register 403 for sequentially outputting the signal charges transferred from the storage area 402, and the imaging area 40
Drive pulse voltage φ for transferring signal charge at 1
_V1, φ _V2, φ _V3, and supplies the φ _V4 bus line 411-4
14 is wired around.

As shown in FIG. 8, in the image pickup region 401, N-type vertical charge transfer channels 431 to 434 partitioned by a P-type channel stop 421 are also formed.
Vertical charge transfer gates 441 to 444 are provided on the mold vertical charge transfer channels 431 to 434. The vertical charge transfer gates 441 to 444 are connected to the bus lines 411 to 4 via the contact holes 451 to 454 around the imaging region.
14 is connected to the four-phase drive pulse voltage group φ _V1 ,
Receives φ _V2 , φ _V3 , and φ _V4 .

FIG. 9 is a sectional view taken along the line PP of FIG. 8, and FIG. 10 is a sectional view taken along the line QQ of FIG. N-type vertical charge transfer channels 431 to 434,
A P-type channel stop 421 for partitioning and forming N-type vertical charge transfer channels 431 to 434 is provided on the P-type semiconductor substrate 501, and the vertical charge transfer gate 44 is provided.
1 to 444 are N-type vertical charge transfer channels 431 to 43
4 is provided via an insulating film 503. P-type semiconductor substrate 501 and N-type vertical charge transfer channels 431 to 431
Reference numeral 434 denotes a region immediately below each of the vertical charge transfer gates 441 to 444, which have the same impurity concentration and junction depth.

11 and 12 are diagrams for explaining an example of the structure and driving method of a conventional frame transfer type solid-state image pickup device, and FIG.
Drive pulse voltages φ _V1 , φ _V2 , φ applied to 41 to 444
FIG. 12 (A) is a timing chart of _V3 and φ _V4 .
10 shows a so-called pinning state in which an inversion layer is formed on the surface of the vertical charge transfer channel group immediately below the vertical charge transfer gates of all phases of four-phase driving.
12B is a potential distribution diagram in the depth direction at each position indicated by middle R-R, S-S, T-T, and U-U, and FIG. 12B is a diagram in the period indicated by T3 in FIG. R in 10
It is a potential distribution diagram of the depth direction in each position shown by R, S-S, T-T, and U-U. Regarding the voltage and the potential, the P-type channel stop 421, which is electrically connected to the P-type semiconductor substrate 501, is used as the reference potential.

As shown in FIG. 12A, a P-type semiconductor substrate 501 and N-type vertical charge transfer channels 431 to 43 are formed.
Reference numeral 4 denotes a region immediately below each vertical charge transfer gate 441 to 444, and since the regions have the same impurity concentration and the same junction depth, the potential distribution in the depth direction at each position is the same. In the conventional driving method, as shown in FIG.
3, the vertical charge transfer gates 441 and 44 are provided in the period shown in FIG. 3, that is, in a period in which photoelectric conversion is performed by incidence of an optical signal and signal charges generated by the photoelectric conversion are accumulated.
By varying the voltage V _VH to be applied to the voltage V _VL and vertical charge transfer gates 443 and 444 to be applied to the 2,
It formed a potential well.

[0008]

In the front-illuminated frame transfer type solid-state image pickup device, an optical signal incident from the surface of the image pickup region is transmitted through the vertical charge transfer gate group,
Only the component absorbed by the N-type vertical charge transfer channel group contributes to photoelectric conversion. In order to improve the efficiency of photoelectric conversion and improve the sensitivity of the solid-state imaging device, it is necessary to reduce the optical signal absorbed in the vertical charge transfer gate group and increase the transmitted optical signal. The vertical charge transfer gate group is generally formed of a polycrystalline semiconductor layer, and it is necessary to reduce the film thickness in order to improve the transmittance of optical signals. There is an inconvenience that the sheet resistance of the group increases and the drive pulse voltage for transferring the signal charge does not propagate sufficiently.

Further, in the frame transfer type solid-state image pickup device, photoelectric conversion is performed by incidence of an optical signal, and signal charges generated by the photoelectric conversion are accumulated in a period.
A potential well must be formed in the vertical charge transfer channel group in the imaging region.At this time, not only the signal charge generated by photoelectric conversion but also the charge due to the leak current generated near the potential well is accumulated. Will end up. Particularly, in the state where the potential well is formed, N just below the vertical charge transfer gate
Since the surface of the type vertical charge transfer channel is depleted,
The leakage current increases due to the aid of the generated recombination centers existing at the interface with the insulating film on the surface of the vertical charge transfer channel group, resulting in an increase in spurious signals or noise.

An object of the present invention is to provide a solid-state image pickup device and a driving method thereof, which can improve the detection sensitivity of an optical signal and reduce the false signal or noise.

[0011]

SUMMARY OF THE INVENTION A first aspect of the present invention is directed to an image pickup area for photoelectrically converting light upon incidence of an optical signal and for accumulating and transferring signal charges generated by the photoelectric conversion, and a signal charge transferred from the image pickup area. In a solid-state imaging device of the surface irradiation type frame transfer system, which comprises a storage region for storing and transferring a charge and a horizontal charge transfer register for sequentially outputting signal charges transferred from the storage region, the imaging region is partitioned by channel stop. Vertical charge transfer channel group, a vertical charge transfer gate group provided on the vertical charge transfer channel group, continuous in the horizontal direction, and intersecting the vertical charge transfer channel group, and a channel for partitioning and forming the vertical charge transfer channel group. A bus line group provided on the stop and supplying a drive pulse voltage for transferring signal charges to the vertical charge transfer gate group; It is characterized in that it comprises.

A second invention is characterized in that, in the first invention, a convex lens group for converging an incident optical signal to an opening of the bus line group is provided on the vertical charge transfer channel group.

According to a third aspect of the present invention, an image pickup area for performing photoelectric conversion upon incidence of an optical signal and for storing and transferring signal charges generated by the photoelectric conversion, and a storage for storing and transferring signal charges transferred from the image pickup area. In a frame transfer type solid-state imaging device including a region and a horizontal charge transfer register that sequentially outputs signal charges transferred from the storage region, the imaging region is in a second conductivity type well on a first conductivity type semiconductor substrate. Or a four-phase having a first conductivity type vertical charge transfer channel group provided in the second conductivity type semiconductor substrate and first to fourth vertical charge transfer gate groups provided on the vertical charge transfer channel group. In the pinning state in which the inversion layer is formed on the surface of the vertical charge transfer channel group immediately below all the first to fourth vertical charge transfer gate groups, And the channel potential of the vertical charge transfer channel group immediately below the first and third vertical charge transfer gate groups is shallower than the channel potential of the vertical charge transfer channel group immediately below the second and fourth vertical charge transfer gate groups. I am trying.

According to a fourth aspect of the present invention, in the method for driving a solid-state image pickup device according to the third aspect, photoelectric conversion is performed by incidence of an optical signal, and signal charges generated by the photoelectric conversion are accumulated during the period from the first aspect. Applying to each of the first to fourth vertical charge transfer gate groups a voltage that causes the surfaces of the vertical charge transfer channel groups immediately below all of the fourth vertical charge transfer gate groups to be in a pinning state by inversion. It has a feature.

According to a fifth aspect of the present invention, a photoelectric conversion is performed by incidence of an optical signal, and an image pickup region for storing and transferring the signal charge generated by the photoelectric conversion, and a storage for storing and transferring the signal charge transferred from the image pickup region. In a frame transfer type solid-state imaging device including a region and a horizontal charge transfer register that sequentially outputs signal charges transferred from the storage region, the imaging region is in a second conductivity type well on a first conductivity type semiconductor substrate. A first-conductivity-type vertical charge transfer channel group, and a four-phase drive charge transfer element having first to fourth vertical charge transfer gate groups provided on the vertical charge transfer channel group, A first reverse bias voltage is applied between the first-conductivity-type semiconductor substrate and the second-conductivity-type well, and vertical charge transfer channels directly under all the first to fourth vertical charge transfer gate groups. In the pinning state in which the inversion layer is formed on the surface of the vertical charge transfer channel groups under the first and third vertical charge transfer gate groups, the channel potentials of the vertical charge transfer channel groups under the second and fourth vertical charge transfer gate groups are vertical. The vertical charge transfer channel groups which are shallower than the channel potentials of the charge transfer channel groups and whose potentials of the second conductivity type wells immediately below the second and fourth vertical charge transfer gate groups are directly below the first and third vertical charge transfer gate groups Is deeper than the channel potential of the first conductivity type semiconductor substrate,
, The potential of the second conductivity type well immediately below the second and fourth vertical charge transfer gate groups is the channel potential of all the vertical charge transfer channel groups immediately below the vertical charge transfer gate groups. It is characterized by a shallower depth.

According to a sixth aspect of the present invention, in the method for driving a solid-state image pickup device according to the fifth aspect, the first reverse operation is performed during a period in which photoelectric conversion is performed by incidence of an optical signal and signal charges generated by the photoelectric conversion are accumulated. A pinning in which a bias voltage is applied between the first conductivity type semiconductor substrate and the second conductivity type well, and the surface of the vertical charge transfer channel group immediately below all the first to fourth vertical charge transfer gate groups is inverted. A voltage to be applied is applied to all of the first to fourth vertical charge transfer gate groups, photoelectric conversion is performed by incidence of an optical signal, and a period other than a period during which signal charges generated by photoelectric conversion are accumulated. The second reverse bias voltage is applied between the first conductivity type semiconductor substrate and the second conductivity type well.

[0017]

According to the first aspect of the invention, the low-resistance bus line group for supplying the drive pulse voltage for transferring the signal charge to the vertical charge transfer gate group is located near the vertical charge transfer channel group. Even if the sheet resistance of the vertical charge transfer gate group increases, the drive pulse voltage can be sufficiently propagated to the vertical charge transfer gate group. For this effect,
It is possible to reduce the thickness of the vertical charge transfer gate group, and increase the optical signal that is transmitted, so that the sensitivity of the solid-state imaging device can be improved.

In the first invention, the optical signal incident on the upper part of the bus line group may be reflected or absorbed in the bus line group and may be restricted in improving the sensitivity. However, according to the second invention, the convex lens is used. Due to the effect of the group, the incident optical signal can be focused on the opening of the bus line group, so that the sensitivity of the solid-state imaging device can be further improved.

According to the third and fourth aspects of the invention, photoelectric conversion is performed by incidence of an optical signal, and in a period in which signal charges generated by the photoelectric conversion are accumulated, all the vertical charge transfer gate groups in the image pickup region are directly under. The surface of the vertical charge transfer channel group can be inverted to a pinning state. At this time, on the surface of the vertical charge transfer channel group,
Since the generated recombination centers existing at the interface with the insulating film are filled with charge carriers (electrons or holes), the leak current, which had been increased by the assistance of the generated recombination centers, is reduced, and false signals and noise are reduced. Is reduced.

According to the fifth and sixth aspects of the invention, the effects of the third and fourth aspects of the invention are realized, and excess signal charges generated when an excessive optical signal is incident are discharged to the semiconductor substrate. Therefore, it is possible to prevent a false signal called blooming caused by excessive signal charges diffusing in the vertical charge transfer channel.

[0021]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a schematic plan view showing an embodiment of the first invention, and FIG. 2 is a partially enlarged view of an image pickup area of the embodiment shown in FIG. As shown in FIG. 1, an image pickup region 101 that performs photoelectric conversion by incidence of an optical signal and stores and transfers the signal charge generated by the photoelectric conversion, and a storage that stores and transfers the signal charge transferred from the image pickup region 101. A region 102 and a horizontal charge transfer register 103 for sequentially outputting the signal charges transferred from the accumulation region 102 are provided, and drive pulse voltage groups φ _V1 , φ _V2 for transferring the signal charges in the imaging region 101, Low resistance bus lines 111 to 111 made of metal for supplying φ _V3 and φ _V4
114 is wired above the imaging region 101.

Further, as shown in FIG.
, N-type vertical charge transfer channels 131 to 134 partitioned by the P-type channel stop 121 are provided, and vertical charge transfer gates 141 to 141 formed of a polycrystalline semiconductor are provided on the N-type vertical charge transfer channels 131 to 134.
144 is provided, and the bus line groups 111 to 114 are provided on the P-type channel stop 121. The vertical charge transfer gates 141 to 144 are P-type channel stops 1
21 are connected to bus lines 111 to 114 via contact holes 151 to 154, and supplied with four-phase drive pulse voltages φ _V1 , φ _V2 , φ _V3 , and φ _V4 .

FIG. 3 is a sectional view taken along the line CC of FIG. 2, and FIG. 4 is a sectional view taken along the line D-D of FIG. As shown in FIG. 3, N-type vertical charge transfer channels 131 to 133 and N-type vertical charge transfer channel 13
P-type channel stop 121 for partitioning and forming 1 to 133
Is provided in the P-type well 202 on the N-type semiconductor substrate 201, the vertical charge transfer gate 142 is provided on the N-type vertical charge transfer channels 131 to 133 via the insulating film 203, and the bus line 111. , 112 are insulating films 2
Is provided on the P-type channel stop 121 via 04, the vertical charge transfer gate 142 and the bus line 112.
Are connected via a contact hole 152.
Further, convex lenses 211 to 213 for focusing the incident optical signal on the opening of the bus line group are provided on the N-type vertical charge transfer channel group. Further, as shown in FIG. 4, in the region directly below the vertical charge transfer gates 141 and 143 and the region directly below the vertical charge transfer gates 142 and 144,
P-type well 202 and N-type vertical charge transfer channel 13
The film thicknesses of 4 are different.

As described above, in this embodiment, since the low resistance bus lines 111 to 114 made of metal are located near the N-type vertical charge transfer channels 131 to 134, a sufficient drive pulse voltage is applied. Vertical charge transfer gate 141
To 144, the vertical charge transfer gates 141 to 144 can be thinned to about 100 nm, the optical signal transmitted through the vertical charge transfer gate group is increased, and the sensitivity of the solid-state imaging device is improved. Can be made. Further, due to the effect of the convex lens group, the incident optical signal can be focused on the opening of the bus line group,
Furthermore, the sensitivity of the solid-state imaging device can be improved.

5 and 6 are views for explaining one embodiment of the third, fourth, fifth and sixth inventions,
FIG. 5 is a timing chart of the drive pulse voltages φ _V1 , φ _V2 , φ _V3 , and φ _V4 applied to the vertical charge transfer gates 141 to 144, and FIG. 6A is for the period indicated by T1 in FIG. , In FIG. 4, EE, FF, GG, H
6B is a potential distribution diagram in the depth direction at each position shown by -H, and FIG. 6B shows each of E-E and FF in FIG. 4 at the time indicated by T2 in FIG. It is a potential distribution diagram of the depth direction in a position. The voltage and potential are
The P-type channel stop 121, which is electrically connected to the P-type well 202, is used as the reference potential.

In the period indicated by T1, that is, in the period in which photoelectric conversion is performed by incidence of an optical signal and signal charges generated by photoelectric conversion are accumulated, the vertical charge transfer gates 141 to 144 have voltages V _V1L , V _V2L , V _V3L , V _V4L
Are respectively applied, and the voltage V _SH is applied to the N-type semiconductor substrate 201. At this time, the channel potential φ1 at the positions of EE and GG is FF and HH.
Is shallower than the channel potential φ2 at the position
Moreover, an inversion layer is formed on the surface of the N-type vertical charge transfer channel 134 at all the positions of EE, FF, GG, and H-H, and is in a pinning state. For this reason, the generated recombination centers existing at the interface with the insulating film on the surface of the vertical charge transfer channel group are filled with holes, and the leak current increased by the assistance of the generated recombination centers is reduced. Signals and noise can be reduced.

The potential φ3 of the P-type well 202 at the positions FF and HH is deeper than the channel potential φ1 at the positions E-E and GG. Therefore, excess signal charges generated when an excessive optical signal is incident are discharged to the semiconductor substrate without being diffused in the vertical charge transfer channel. This makes it possible to prevent a false signal called blooming.

In a period other than the period shown by T1, for example, at time T2, the vertical charge transfer gates 141, 14 are provided.
4, 142 and 143 have voltages V _V1L , V _V4L , V _V2H and V
_V3H is applied to each, and the N-type semiconductor substrate 201 is also applied.
The voltage V _SL is applied to. At this time, the potential φ5 of the P-type well 202 at the position FF is shallower than the channel potential φ4 at the position EE. For this reason,
The potential of the P-type well 202 does not limit the maximum transfer charge amount.

[0030]

As described above, according to the present invention, since the bus line group is located near the vertical charge transfer channel group, the drive pulse voltage can be sufficiently propagated to the vertical charge transfer gate group. , The vertical charge transfer gate group is
The thickness can be reduced to about 100 nm, the optical signal transmitted through the vertical charge transfer gate group is increased, and the sensitivity of the solid-state imaging device can be improved. Further, due to the effect of the convex lens group, the incident optical signal can be focused on the opening of the bus line group, so that the sensitivity of the solid-state imaging device can be further improved.

In addition, during the period in which photoelectric conversion is performed by incidence of an optical signal and the signal charges generated by photoelectric conversion are accumulated, the surface of the vertical charge transfer channel group immediately below all the vertical charge transfer gate groups in the imaging region is removed. Due to the inverted pinning state, the generated recombination centers existing at the interface with the insulating film on the surface of the vertical charge transfer channel group are filled with holes and increased by the aid of the generated recombination centers. The leak current that has been used is reduced, and false signals and noise can be reduced.

Further, by controlling the voltage applied to the semiconductor substrate, photoelectric conversion is performed by incidence of an optical signal,
In addition, during the period in which the signal charge generated by photoelectric conversion is accumulated, the excessive signal charge generated when an excessive optical signal is incident can be discharged to the semiconductor substrate, and a false signal called blooming can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the first invention.

FIG. 2 is a partially enlarged view of an image pickup area of the embodiment shown in FIG.

3 is a cross-sectional view taken along the line CC of FIG.

FIG. 4 is a sectional view taken along the line DD in FIG.

FIG. 5 is a timing chart of a drive pulse voltage applied to a vertical charge transfer gate.

6 is a potential distribution diagram in the depth direction at each position in FIG.

FIG. 7 is a schematic plan view of a conventional example.

FIG. 8 is a partially enlarged view of an imaging area of a conventional example.

9 is a sectional view taken along the line PP of FIG.

10 is a sectional view taken along the line QQ in FIG.

FIG. 11 is a timing chart of a drive pulse voltage applied to a vertical charge transfer gate.

12 is a potential distribution diagram in the depth direction at each position in FIG.

[Explanation of symbols]

101, 401 Imaging area 102, 402 Storage area 103, 403 Horizontal charge transfer register 111-114, 411-414 Bus line 121, 421 P-type channel stop 131-134, 431-434 N-type vertical charge transfer channel 141-144 441 to 444 Vertical charge transfer gates 151 to 154, 451 to 454 Contact hole 201 N type semiconductor substrate 202 P type well 203, 204, 503 Insulating film 211 to 213 Convex lens

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9056-4M H01L 29/76 301 F

Claims (6)

[Claims] 1. An image pickup region for performing photoelectric conversion upon incidence of an optical signal and storing and transferring signal charges generated by the photoelectric conversion, and a storage region for storing and transferring signal charges transferred from the image pickup region. In a solid-state imaging device of a surface irradiation type frame transfer system, which includes a horizontal charge transfer register that sequentially outputs signal charges transferred from a region, the imaging region includes a vertical charge transfer channel group defined by a channel stop, and a vertical charge transfer channel group. A vertical charge transfer gate group which is provided on the charge transfer channel group and which is continuous in the horizontal direction and intersects with the vertical charge transfer channel group, and a channel stop which partitions and forms the vertical charge transfer channel group and transfers the signal charge. And a bus line group for supplying a drive pulse voltage for driving to a vertical charge transfer gate group. Imaging device. 2. The solid-state image pickup device according to claim 1, wherein a convex lens group for focusing an incident optical signal to an opening of the bus line group is provided on the vertical charge transfer channel group. . 3. An image pickup area for performing photoelectric conversion upon incidence of an optical signal and for storing and transferring signal charges generated by the photoelectric conversion, and a storage area for storing and transferring signal charges transferred from the image pickup area. In a frame transfer type solid-state imaging device including a horizontal charge transfer register that sequentially outputs signal charges transferred from a region, the imaging region is in a second conductivity type well on a first conductivity type semiconductor substrate, or in a second conductivity type well. Four-phase drive charge transfer having a first conductivity type vertical charge transfer channel group provided in a conductivity type semiconductor substrate and first to fourth vertical charge transfer gate groups provided on the vertical charge transfer channel group In the pinning state in which the inversion layer is formed on the surface of the vertical charge transfer channel group immediately below all of the first to fourth vertical charge transfer gate groups. Solid-state imaging characterized in that the channel potential of the vertical charge transfer channel group directly below the third vertical charge transfer gate group is shallower than the channel potential of the vertical charge transfer channel group immediately below the second and fourth vertical charge transfer gate group. apparatus. 4. The method for driving a solid-state imaging device according to claim 3, wherein photoelectric conversion is performed by incidence of an optical signal, and signal charges generated by the photoelectric conversion are accumulated during the first to fourth periods. A voltage for bringing the surfaces of the vertical charge transfer channel groups immediately below all of the vertical charge transfer gate groups into a pinning state that is inverted is applied to all the first to fourth vertical charge transfer gate groups. Method for driving solid-state imaging device. 5. An image pickup region for performing photoelectric conversion upon incidence of an optical signal, and storing and transferring signal charges generated by the photoelectric conversion, and a storage region for storing and transferring signal charges transferred from the image pickup region. In a frame transfer type solid-state imaging device including a horizontal charge transfer register that sequentially outputs signal charges transferred from the region, the imaging region is provided in a second conductivity type well on a first conductivity type semiconductor substrate. A first conductivity type vertical charge transfer channel group; and a four-phase drive charge transfer element having first to fourth vertical charge transfer gate groups provided on the vertical charge transfer channel group. The first reverse bias voltage is applied between the semiconductor substrate and the second conductivity type well, and the surface of the vertical charge transfer channel group immediately below all the first to fourth vertical charge transfer gate groups is reversed. In the pinning state where the layer inversion is formed,
The channel potential of the vertical charge transfer channel group immediately below the first and third vertical charge transfer gate groups is shallower than the channel potential of the vertical charge transfer channel group immediately below the second and fourth vertical charge transfer gate groups, and the second and The potential of the second conductivity type well immediately below the fourth vertical charge transfer gate group becomes deeper than the channel potentials of the vertical charge transfer channel groups immediately below the first and third vertical charge transfer gate groups, and the first conductivity type semiconductor substrate is formed. In the state where the second reverse bias voltage is applied between the second conductivity type wells, the potential of the second conductivity type well immediately below the second and fourth vertical charge transfer gate groups is directly below all the vertical charge transfer gate groups. Solid-state imaging device characterized by being shallower than the channel potential of the vertical charge transfer channel group. 6. The method for driving a solid-state imaging device according to claim 5, wherein the first reverse bias voltage is applied during a period in which photoelectric conversion is performed by incidence of an optical signal and signal charges generated by the photoelectric conversion are accumulated. Is applied between the first-conductivity-type semiconductor substrate and the second-conductivity-type well, and the pinning state is obtained by inverting the surface of the vertical charge transfer channel group immediately below all of the first to fourth vertical charge transfer gate groups. Is applied to all of the first to fourth vertical charge transfer gate groups, photoelectric conversion is performed by incidence of an optical signal, and a period other than a period during which signal charges generated by photoelectric conversion are accumulated is Two
2. A method for driving a solid-state imaging device, wherein the reverse bias voltage is applied between a first conductivity type semiconductor substrate and a second conductivity type well.