JPH1155572A - Solid-state image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the configuration of a charge transfer means and to invert a charge transfer direction with a simple changeover. SOLUTION: The solid-state image pickup device 1 is provided with a horizontal transfer register 3 that transfers charges resulting from photoelectric conversion in a prescribed direction, pluralities of electrodes formed above the horizontal transfer register 3, a timing generating section 5 that generates a 1st transfer signal consisting of two transfer signals Hϕ1, Hϕ2 inverted to each other and fed to a 1st electrode group where its electrode is arranged at an interval among pluralities of the electrodes, integration circuits 51, 52 that use the transfer signals Hϕ1, Hϕ2, generate a 2nd transfer signal consisting of two integration signals Hϕ1', Hϕ2' inverted to each other and apply the 2nd transfer signal to a 2nd electrode group arranged at an interval different from the 1st electrode group among the electrodes and switch circuits SW1, SW2 that select the transfer signals Hϕ1, Hϕ2 or the integration signals Hϕ1', Hϕ2'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a solid-state imaging device for transferring a charge in a predetermined direction by applying a predetermined signal to a charge transfer means.

[0002]

2. Description of the Related Art FIG. 8 shows a CC in a conventional solid-state imaging device.
FIG. 3 is a schematic cross-sectional view illustrating a structure of a D (Charge Coupled Device) horizontal transfer register unit. In other words, the conventional CCD horizontal transfer register section is composed of the P-well region 11 of the N-type substrate 10.
, And a first-layer electrode D1 and a second-layer electrode D2 made of polysilicon formed through an insulating layer 13 on the N-type channel region 12.

In addition, below the second-layer electrode D2 in the N-type channel region 12, P-type impurity ions are implanted before the formation of the second-layer electrode D2, so that the potential of the N ⁻ channel is made shallower than other portions. A region 12a is formed.

In the solid-state imaging device having such a configuration, the horizontal transfer signal Hφ1 is applied to every other pair with the adjacent first-layer electrode D1 and second-layer electrode D2 as one set.
Two-phase driving is performed in which a horizontal transfer signal Hφ2 is applied to every other pair to transfer charges.

FIG. 9 is a timing chart of the horizontal transfer signals Hφ1 and Hφ2, and FIG. 10 is a diagram showing potential profiles at respective timings t1 to t3 in FIG. That is, at the timing of t1, Hφ1 becomes Hi.
gh level and Hφ2 are at the Low level.
The potential well at the portion corresponding to 1 becomes deeper. At this time, since the N ⁻ region 12a is formed below the second-layer electrode D2 as shown in FIG. 8, even if the same level of voltage is applied, the potential wells other than the N ⁻ region 12a are deep. The charge is stored there.

At the timing of t2, Hφ1 and Hφ2
Is at an intermediate level, the potential well in the portion corresponding to Hφ1 becomes shallower and the potential well in the portion corresponding to Hφ2 becomes deeper.

Then, at the timing of t3, Hφ1 becomes L
low level and Hφ2 become High level, the potential well of the portion corresponding to Hφ1 becomes further shallow, and H
The potential well at the portion corresponding to φ2 is further deepened. As a result, the electric charges stored in the portion other than the N ⁻ region 12a in the region to which Hφ1 is applied are transferred to the portion other than the N ⁻ region 12a in the region to which Hφ2 is applied.

By repeatedly performing the timings t1 to t3, charges can be sequentially transferred from the side where the N ⁻ region 12a is formed to the side where the N ⁻ region 12a is not formed, ie, to the left in the drawing.

[0009]

[SUMMARY OF THE INVENTION However, in such a solid-state imaging device, N below the second layer electrode of N-type channel region in order to determine the transfer direction of the two-phase drive ^- ion implanted region It is necessary to form by such as.
Further, since the amount of transferred charges is determined by the concentration of the N ⁻ region, it is very difficult to change the amount of handled charges. In addition, since the transfer direction of charges is structurally determined by the position of the N ⁻ region, there is a problem that it is not possible to cope with a case where the transfer direction needs to be changed.

[0010]

SUMMARY OF THE INVENTION The present invention is a solid-state imaging device made to solve such a problem. That is, the present invention provides a charge transfer means for transferring a charge obtained by photoelectric conversion in a predetermined direction, a plurality of electrodes formed above the charge transfer means for applying a voltage for transferring the charge, and a plurality of electrodes. A signal generating means for generating a first transfer signal composed of two transfer signals having opposite phases to be applied to the first electrode group arranged every other one of the first electrode group, and a first transfer signal generated by the signal generating means. The two transfer signals are used, and two
A second transfer signal composed of two integration signals is generated, and a second transfer signal that is different from the first electrode group among the plurality of electrodes and is arranged every other
An integrated signal generating means to be applied to the electrode group, and a switching means for switching application positions of two transfer signals of the first transfer signal and two integrated signals corresponding to the two transfer signals, respectively.

In the present invention, since the integration signal of the first transfer signal generated by the signal generation means is applied as the second transfer signal applied to the second electrode group by the integration signal generation means, the first transfer signal and the second transfer signal are applied. The difference in the depth of the potential well can be formed by the two transfer signals, and the transfer direction can be determined according to the applied position. Also, the first transfer signal 2
By switching the application positions of the two transfer signals and the corresponding two integration signals by the switching means, the direction in which the difference in the depth of the potential well is formed can be reversed. Can be reversed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a solid-state imaging device according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram illustrating a solid-state imaging device according to the present embodiment, and FIG. 2 is a schematic cross-sectional view illustrating a structure of a horizontal transfer register unit.

As shown in FIG. 1, a solid-state imaging device 1 according to the present embodiment has a vertical transfer register for transferring electric charges obtained by photoelectric conversion by a plurality of light receiving units S arranged in a matrix in a vertical direction in the figure. 2, a horizontal transfer register 3 for transferring the charge transferred by the vertical transfer register 2 in the horizontal direction in the figure, and output units 4a and 4b for converting the charge transferred by the horizontal transfer register 3 into a signal voltage and outputting the signal voltage. , A timing generator 5 for generating a signal for charge transfer to be applied to the vertical transfer register 2 and the horizontal transfer register 3, and a timing generator 5
And integration circuits 51 and 52 for integrating the horizontal transfer signals Hφ1 and Hφ2 to the horizontal transfer register 3 and switch circuits SW1 and SW2 for switching between the horizontal transfer signals Hφ1 and Hφ2 and the corresponding integrated signals. It is provided with a configuration.

The timing generator 5 of the solid-state imaging device 1
Outputs, for example, four-phase vertical transfer signals Vφ1 to Vφ4 applied to the vertical transfer register 2 and two-phase horizontal transfer signals Hφ1 and Hφ2 applied to the horizontal transfer register 3.

The horizontal transfer signals Hφ1 and Hφ2 are signals whose phases are inverted, and the switch circuits SW1 and
The input to the SW2 and the input to the integration circuits 51 and 52 are divided.

The horizontal transfer signal Hφ1 and its integrated signal Hφ1 ′ are input to the switch circuit SW1, and the horizontal transfer signal Hφ2 and its integrated signal H are input to the switch circuit SW2.
.phi.2 'is input so that each application position can be switched.

Therefore, the two horizontal transfer signals H output from the timing generator 5 are stored in the horizontal transfer register 3.
Based on φ1 and Hφ2, the horizontal transfer signals Hφ1 and Hφ1 are transmitted through the integration circuits 51 and 52 and the switch circuits SW1 and SW2.
Four signals Hφ2 and integration signals Hφ1 ′ and Hφ2 ′ are input.

As shown in FIG. 2, the horizontal transfer register 3
Are first-layer electrodes D1 and D2 made of polysilicon formed through an N-type channel region 12 formed in a P-well region 11 of an N-type substrate 10 and an insulating layer 13 on the N-type channel region 12. And a layer electrode D2.

Of these, the horizontal transfer signals Hφ1 and Hφ2 described above are applied to the first-layer electrodes D1 arranged alternately.
Are applied alternately along the arrangement order, and the above-described integration signals Hφ1 ′ and Hφ2 ′ are applied alternately along the arrangement order to the other second-layer electrodes D2. You.

When such a signal is applied,
Even if the N ⁻ region (see FIG. 8) is not formed below the second-layer electrode D2 in the N-type channel region 12, charges can be sequentially transferred in a predetermined direction.

FIG. 3 is a circuit diagram showing an example of the integration circuits 51 and 52. That is, the integration circuits 51 and 52 are configured by a combination of a resistor R and a capacitor C, and generate the integration signals Hφ1 ′ and Hφ2 ′ using the horizontal transfer signals Hφ1 and Hφ2 as input signals.

FIG. 4 is a circuit diagram showing an example of the switch circuit SW1. The switch circuit SW1 switches between the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ described above. When the contact a is selected by the switching signal, the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are output as they are. , B contact is selected, the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are switched and output.
Note that the switch circuit SW2 is the same circuit as the switch circuit SW1, and the horizontal transfer signal Hφ2 and the integration signal Hφ
Switch to 2 '.

Next, the charge transfer operation of the solid-state imaging device according to the present embodiment will be described based on the timing chart of FIG. 5 and the potential profile of FIG. The horizontal transfer registers in the solid-state imaging device according to the present embodiment are applied with the horizontal transfer signals Hφ1 and Hφ2 and their integrated signals Hφ1 ′ and Hφ2 ′ as described above.

In FIG. 5, signals indicated by broken lines indicate horizontal transfer signals Hφ1 and Hφ2, signals indicated by solid lines indicate integrated signals Hφ1 ′ and Hφ2 ′, and t1 to t1 in FIG.
The potential profile shown at t4 is t1 shown in FIG.
Ｔt4.

First, at the timing t1 shown in FIG. 5, the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are both at the High level, and the horizontal transfer signal Hφ2 and the integration signal Hφ.
Since both 2 ′ are at the low level, t1 in FIG.
As shown in the figure, a potential well is formed in a portion corresponding to Hφ1 ′ and Hφ1, and a charge (shaded portion in the figure) is formed there.
Is accumulated.

Next, at the timing of t2 shown in FIG.
Both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are High
Level to the low level, and the horizontal transfer signal Hφ2,
Both the integration signal Hφ2 ′ changes from the Low level to the High level, but the change speed is slower for Hφ1 ′ and Hφ2 ′ than for Hφ1 and Hφ2, so that the transition signal t
The potential profile shown in FIG.

That is, from the portion corresponding to Hφ1 ′, Hφ
The portion corresponding to 1 has a deeper potential well,
The charge is transferred to the portion of Hφ1 ′.

Next, at the timing of t3 shown in FIG.
Both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are L
ow level, the horizontal transfer signal Hφ2, the integration signal H
Both φ2 ′ further change to the High level. As a result, as shown at t3 in FIG. 6, the potential well becomes deeper in the portion corresponding to Hφ2 than in the portion corresponding to Hφ1 ′, and charges are transferred from the portion of Hφ1 ′ to the portion of Hφ2.

At the timing t4 shown in FIG. 5, both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are at L level.
The low level, the horizontal transfer signal Hφ2, and the integration signal Hφ2 ′ are all at the High level, and as shown at t4 in FIG. 6, a potential well is formed at the portions of Hφ2 and Hφ2 ′, and electric charges are transferred there.

By repeating these operations, electric charges are sequentially transferred from the right side to the left side in the figure, and are output via the output unit 4a provided on the left side in the figure of the horizontal transfer register 3 shown in FIG. Will be.

In the solid-state imaging device of the present embodiment, the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′, and the horizontal transfer signal Hφ2 and the integration signal Hφ2 ′ are switched by switching the switch circuits SW1 and SW2 shown in FIG. By applying, the transfer direction of the charges in the horizontal transfer register 3 can be switched.

FIG. 7 shows a potential profile when switching is performed. The potential profiles shown at t1 to t4 in FIG. 7 correspond to the timings t1 to t4 shown in FIG.

That is, as shown in FIG. 7, switching by the switch circuits SW1 and SW2 (see FIG. 1) causes
The application positions of Hφ1 and Hφ1 ′ shown in FIG.
The application positions of φ2 and Hφ2 ′ are switched.

First, at the timing t1 shown in FIG. 5, the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are both at the High level, and the horizontal transfer signal Hφ2 and the integration signal Hφ.
Since both 2 ′ are at the Low level, t1 in FIG.
As shown in (1), a potential well is formed at a portion corresponding to Hφ1 ′ and Hφ1, and electric charges are stored therein.

Next, at the timing of t2 shown in FIG.
Both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are High
Level to the low level, and the horizontal transfer signal Hφ2,
Both the integrated signal Hφ2 ′ changes from the Low level to the High level, but the change speed is slower in Hφ1 ′ and Hφ2 ′ than in Hφ1 and Hφ2, so that the transition time t in FIG.
The potential profile shown in FIG.

That is, from the portion corresponding to Hφ1 ′, Hφ
The portion corresponding to 1 has a deeper potential well,
The charge is transferred to the portion of Hφ1 ′ which is at the opposite position to the state shown at t2 in FIG.

Next, at the timing of t3 shown in FIG.
Both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are L
ow level, the horizontal transfer signal Hφ2, the integration signal H
Both φ2 ′ further change to the High level. As a result, as shown at t3 in FIG. 7, the potential well becomes deeper at the portion corresponding to Hφ2 than at the portion corresponding to Hφ1 ′, and the potential of Hφ1 ′ becomes opposite to the state shown at t3 in FIG. Charge is transferred from the portion to the portion of Hφ2.

At the timing t4 shown in FIG. 5, both the horizontal transfer signal Hφ1 and the integration signal Hφ1 ′ are at L level.
The ow level, the horizontal transfer signal Hφ2, and the integration signal Hφ2 ′ are all at the High level, and as shown at t4 in FIG. 7, potential wells are formed in the portions of Hφ2 and Hφ2 ′, and charges are transferred there.

By repeating these operations, the charges are sequentially transferred from the left side to the right side in the figure, and are output via the output unit 4b provided on the right side in the figure of the horizontal transfer register 3 shown in FIG. Will be.

As described above, the switch circuits SW1, SW2
, The direction of charge transfer in the horizontal transfer register 3 can be easily switched. That is, assuming that a normal image is obtained by the charge transfer operation shown in FIG. 6, for example, a mirror image can be obtained by performing inversion transfer of the charge as shown in FIG. 7 only by switching with the switch circuits SW1 and SW2. become.

In this embodiment, the output units 4a and 4b are provided at both ends of the horizontal transfer register 3 shown in FIG. 1 so that an output signal can be obtained regardless of the direction in which the charges are transferred. However, the present invention is not limited to such a configuration, and the same applies to a case where an output unit is provided at another position. Further, the integration circuits 51 and 52 shown in FIG. 3 and the switch circuit SW1 shown in FIG. 4 are also examples, and other circuit configurations may be used.

[0042]

As described above, the solid-state imaging device according to the present invention has the following effects. That is, in the present invention, the charge transfer direction of the charge transfer means can be controlled by the first transfer signal and the integration signal thereof, so that the charge transfer means can have a uniform configuration. Further, with the uniform configuration of the charge transfer means, it is possible to increase the amount of handled charges that can be transferred by increasing the amplitude of the transfer signal.

Further, the switching means selects the first transfer signal 2
The charge transfer direction can be reversed only by reversing the phase of the two transfer signals, and the normal image / mirror image can be switched only by simple switching.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a solid-state imaging device according to an embodiment.

FIG. 2 is a schematic cross-sectional view illustrating a structure of a horizontal transfer register unit.

FIG. 3 is a circuit diagram illustrating an example of an integration circuit.

FIG. 4 is a circuit diagram illustrating an example of a switch circuit.

FIG. 5 is a timing chart of a transfer signal and an integration signal.

FIG. 6 shows a potential profile (part 1).
It is.

FIG. 7 shows a potential profile (part 2).
It is.

FIG. 8 is a schematic cross-sectional view illustrating a structure of a horizontal transfer register unit in a conventional solid-state imaging device.

FIG. 9 is a timing chart of a transfer signal.

FIG. 10 is a diagram showing a potential profile in a conventional horizontal transfer register.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Solid-state imaging device, 2 ... Vertical transfer register, 3 ... Horizontal transfer register, 5 ... Timing generation part, 51 ... Integration circuit,
52: integrating circuit, SW1: switch circuit, SW2: switch circuit

Claims (1)

[Claims] A charge transfer unit configured to transfer a charge obtained by photoelectric conversion in a predetermined direction; a plurality of electrodes formed above the charge transfer unit to apply a voltage for transferring the charge; Signal generating means for generating a first transfer signal composed of two transfer signals of opposite phases to be applied to a first electrode group arranged every other one of the electrodes, and the first signal generated by the signal generating means. Using two transfer signals of the transfer signal, a second transfer signal composed of two integration signals having phases opposite to each other is generated, and the first transfer signal of the plurality of electrodes is generated.
Integration signal generating means for applying to every other second electrode group different from the electrode group; two transfer signals of the first transfer signal; and the two integration signals corresponding to the two transfer signals And a switching unit for switching each application position of the solid-state imaging device.