JPH07312726A - Solid-state image pickup element and its drive method - Google Patents

Abstract

PURPOSE:To obtain an infrared ray solid-state image pickup element having a small charge loss and a sufficient transfer efficiency even at a low temperature operation required to drive the infrared ray solid-state image pickup element. CONSTITUTION:At first a dummy charge 16a is given to a potential well 14 of an SCCD 17. Then the dummy charge 16a is transferred to a potential well 13 and a signal charge 11a is given to the empty potential well 14. Furthermore, the dummy 16b and the signal charge 11b are sequentially given to the SCCD 17. As a result, since the charge loss attending with capture of the signal charge is reduced, the transfer efficiency of the signal charge is improved.

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 and a driving method thereof, and more particularly to improvement of transfer characteristics of a charge-coupled device (hereinafter referred to as CCD) in an infrared solid-state image pickup device which requires low temperature operation.

[0002]

2. Description of the Related Art With the recent progress of silicon (Si) LSI technology, a large number of photodetectors are arranged in a one-dimensional or two-dimensional array on a semiconductor substrate, and a signal charge transfer circuit and an output amplifier are arranged on the same substrate. A large number of solid-state image pickup devices formed with and have been developed. Among them, the infrared solid-state imaging device using an infrared detector as a photodetector is put into practical use as an infrared camera in combination with an infrared lens, a device driving circuit, a signal processing circuit, a device cooler, etc.
It is used in various fields such as temperature measurement and remote sensing. The infrared detector has a wavelength of 3 to 5
PtSi / Si Schottky barrier diodes that can detect infrared rays in the μm band are used. Recently, as PtSi / Si Schottky barrier diodes that can detect infrared rays in the 10 μm band, those that use GeSi / Si heterojunction detectors and the like are also used. Being developed. Further, CCD is often used as the signal charge transfer circuit.

FIG. 12 is a plan view showing the basic structure of a conventional one-dimensional array infrared solid-state image pickup device. In FIG. 12, a plurality of photodetectors 2 composed of PtSi / Si Schottky barrier diodes or the like are formed on a P-type Si substrate 1.
It is arranged dimensionally. Moreover, on the P-type Si substrate 1,
A CCD 3 is formed in parallel as a signal charge transfer circuit along the photodetectors 2 arranged one-dimensionally, and a signal charge from the photodetector 2 to the CCD 3 is provided between each photodetector 2 and the CCD 3. Transfer gate 4 for controlling the sending of data
Is provided. The gate electrode of the transfer gate 4 is commonly connected to an input pin 5 for applying a gate voltage. Further, the signal charge transfer circuit 3 is connected to an output amplifier 6 for taking out a signal to the outside.

Next, the structure of the CCD 3 used in the conventional one-dimensional array infrared solid-state image pickup device will be described with reference to FIG. FIG. 13 shows a sectional view along the transfer direction of the CCD 3 and potential diagrams (a) to (c) for explaining the operation of the CCD 3. The CCD 3 is, for example, a four-phase drive embedded channel type CCD (hereinafter BCC).
(D).

In the sectional view of FIG. 13, a P-type Si substrate 1 is shown.
An N-type impurity region is formed as a CCD channel 9 on the upper surface side of. An insulating film 7 made of SiO ₂ or the like is formed on the CCD channel 9, and a plurality of electrically independent gate electrodes 8 are made of polysilicon or the like on the insulating film 7. Since it is a four-phase drive BCCD, in order to apply clock voltages of different phases to the gate electrode 8,
The input pins 10a, 10b, 10c and 10d are sequentially connected.

Further, the potential diagrams (a) to (a) of FIG.
In (c), the state in which the signal charges 11a to 11d are accumulated in the potential wells W1 to W4 formed in the CCD channel is schematically shown.

The operation of the conventional one-dimensional array infrared solid-state image sensor shown in FIG. 12 will be described below. P type Si
When infrared rays are incident on the photodetector 2 on the substrate 1, here,
A signal charge corresponding to the amount of incident light is generated. The generated signal charge is accumulated in the photodetector 2 while the transfer gate 4 is OFF. Next, when a voltage is applied to the input pin 5 and the transfer gate 4 is turned on, the signal charges accumulated in each photodetector 2 are sent to the CCD 3 through the transfer gate 4. The signal charges transferred to the CCD 3 are transferred by the CCD 3, and the signals from the photodetectors 2 are sequentially taken out to the outside through the output amplifier 6.

Next, the operation of the conventional CCD 3 will be described with reference to FIG. In FIG. 13, the gate electrode 8 is sequentially connected to the input pins 10a to 10d, and the repeated connection forms a four-phase drive BCCD. The input pins 10a to 10d are supplied with clock signals .phi.1 to .phi.4 whose phases differ by 90.degree., Respectively. First, FIG.
In the potential diagram (a) of FIG. 3, the clock signals φ1 and φ2 are at “H” level, and the clock signals φ3 and φ4 are at “L”.
If it is a level signal, potential wells W1 to W4 are formed below the gate electrode 8 to which the clock signals φ1 and φ2 are applied in order from the right side of the sectional view, and the potential wells W1 to W4 are provided with signal charges. 11a to 11d are retained. Then, in the potential diagram (b) of FIG. 13, when the clock signal φ3 becomes the voltage of “H” level,
The potential wells W1 to W4 extend below the gate electrode 8 to which the clock signal φ3 is applied, and the signal charges 11a to
The distribution of 11d also spreads in each well. Next, in the potential diagram (c) of FIG. 13, when the clock signal φ1 becomes the voltage of the “L” level, the potential of the corresponding portion of the potential wells W1 to W4 below the gate electrode 8 to which the clock signal φ1 is applied. Becomes higher,
The signal charges 11a to 11d are transferred into the potential well below the gate electrode 8 to which the clock signals φ2 and φ3 are applied. By repeating the above operation, the signal charges 11a to 11d are sequentially transferred to the right side of the potential diagram as indicated by arrows in the diagram.

By the way, in general, when a Schottky barrier diode or a heterojunction element is used as an infrared detecting element, it is necessary to cool the element to a low temperature in order to suppress the generation of dark current. Therefore, when an infrared camera or the like is configured with an infrared solid-state image sensor using these infrared detecting elements, a refrigerator for cooling the infrared detecting elements is used in combination.

The cooling temperature required for practical use in such an infrared solid-state image pickup device is about 80 K (Kelvin) in the infrared solid-state image pickup device in the wavelength range of 3 to 5 μm, and the wavelength range is 10.
In the infrared solid-state image sensor in the μm band, it is about 40K.
When the infrared detection element is cooled to such a low temperature, the charge loss in the CCD increases as the temperature decreases. This is because the emission time constants of various charge traps existing in the CCD channel increase as the temperature decreases, and once the signal charges are captured by the charge traps, they are less likely to be re-emitted within the transfer period. Therefore, the CCD used in the infrared solid-state image sensor is required to have a small charge loss in low temperature operation.

In the conventional CCD 3 shown in FIG. 13, the main charge traps involved in charge loss at low temperature operation are N-type impurity ions introduced to form the CCD channel 9. Therefore, the conventional wavelength range of 3 to 5 μm
The infrared solid-state image pickup device in the band is dealt with by reducing the N-type impurity concentration. On the other hand, since the operating temperature of the infrared ray solid-state imaging device having a wavelength range of 10 μm is further lowered, when BCCD is used as the CCD 3, the loss due to the N-type impurity ions is further increased, which makes transfer difficult.
Therefore, instead of BCCD, surface channel CCD
The use of (hereinafter referred to as SCCD) is also under consideration. In BCCD, the signal charge is CC inside the P-type Si substrate 1.
In the case of the SCCD, signal charges are transferred through the interface between the P-type Si substrate 1 and the insulating film 7, while being transferred through the D channel 9. In this case, there is no effect of bulk traps due to bulk defects as seen in BCCD. Instead, in the SCCD, the interface order existing at the interface between the insulating film 7 and the P-type Si substrate 1 acts as a trap, and its influence increases as the temperature decreases. Therefore, when the SCCD is used at a low temperature, it is necessary to reduce the charge loss due to the interface order. As an effective means for this, there is a method conventionally called fat-zero. less than,
This method will be described.

FIG. 14 shows a sectional view along the transfer direction of a four-phase driven SCCD and a potential diagram for explaining a conventional fat-zero method. In FIG. 14, an insulating film 7 is formed of SiO ₂ or the like on the upper surface of the P-type Si substrate 1, and a plurality of electrically independent gate electrodes 8 are formed of polysilicon or the like on the insulating film 7. Since it is a four-phase driving SCCD, input pins 10a, 1 are used to apply clock voltages having different phases to the gate electrode 8.
0b, 10c, and 10d are sequentially connected.

Further, the potential diagram of FIG. 14 schematically shows a state in which the bias charges 12a to 12d and the signal charges 11a to 11d to be transferred are accumulated in the potential wells W11 to W14 formed in the Si substrate 1. It is represented by

FIG. 15 is a partially enlarged view of a cross-sectional view of the SCCD shown in FIG. 14 taken in a direction perpendicular to the transfer direction, and SCCD.
7A and 7B are potential diagrams for explaining the operation of FIG. In FIG. 15, the same components as those in FIG. 14 are denoted by the same reference numerals, and the signal charge, the input pin, and the potential well are not individually distinguished. Reference numerals 13, 14, and 15 shown around the potential wells in potential diagrams (a) and (b) of FIG. 15 schematically indicate the interface states existing at the interface between the Si substrate 1 and the insulating film 7. It is a representation. The potential diagram (a) of FIG. 15 is a fat-zer.
The potential well state when the o method is not adopted, and the potential diagram (b) shows the potential well state when the fat-zero method is adopted.

Next, the operation of the fat-zero method will be described with reference to FIG. The fat-zero method is C
This is a method in which a constant amount of bias charge 12 is always input from the input end of CD (the end opposite to the end provided with the output amplifier, which corresponds to the left side in FIG. 14). As a method of inputting the bias charge, a method generally called a Fill and Spill method in which a plurality of transistors are provided on the input end side of the CCD and the input amount of the bias charge is controlled is used.

At this time, the charge packet (charge mass) transferred by the CCD is the sum of the signal charge 11 and the bias charge 12. By constantly inputting a fixed amount of the bias charge 12, the interface state acting as a trap is always filled with the bias charge 12, and the charge loss received by the signal charge 11 is reduced. This state is shown in FIG.
For further explanation.

The interface state is empty when the signal charge 11 is not present in the potential well W of the CCD. When the signal charge 11 is transferred into the potential well W of the CCD when the fat-zero method is not used, the signal charge 11 is filled up to a certain height of the potential well W of the CCD, and the empty space up to that height is filled. Encounter interface states. The signal charge 11 that encounters the empty interface state is captured,
On the other hand, the empty interface state is filled with the signal charge 11 and becomes the interface state 14 as shown in the potential diagram (a) of FIG. In the potential diagram (a), reference numeral 13 is attached to the empty interface state.

The interface state 14 emits charges with various time constants as the signal charges 11 pass. Some of the trapped charge is released fast enough to pass through the signal charge 11
, But most of the charge flows into the next signal charge 11, which is subsequently transferred. This is the preceding signal charge 1
Means charge loss from 1.

On the other hand, when the fat-zero method is used, at a certain height of the potential well W of the CCD,
It is filled with the bias charge 12 given in advance. When the signal charge 11 is transferred there, the signal charge 11 is added on the bias charge 12 and distributed as shown in the potential diagram (b) of FIG. In the potential diagram (b) of FIG. 15, reference numeral 15 is attached to the interface state in which the bias charge 12 is captured.

Since the interface level 15 is always filled with the bias charge, the interface level 14 acting as a trap for the signal charge 11 is only the interface level 14 existing on the side surface of the potential well W. Signal charge 11
The amount of charge loss from is reduced.

[0021]

In the conventional fat-zero method shown in FIGS. 14 and 15, as the amount of the bias charge 12 is increased, the amount of charge loss initially decreases, but eventually. When the bias charge 12 fills the bottom of the potential well W, the amount of charge loss becomes constant. This is due to the interface state 14 existing on the side surface of the potential well W.
Is filled with the signal charge 11, and even if the bias charge 12 is increased to raise the bottom of the potential well, the amount of the interface state 14 filled with the signal charge 11 does not change. Therefore, the conventional SCCD using the fat-zero method has a problem that the charge loss cannot be reduced to a certain value or less, that is, there is a so-called lower limit value of the charge loss. Moreover, since the lower limit value increases with a decrease in temperature, there is a problem in that the charge loss is too large and the charge transfer becomes difficult at the temperature required for driving the 10 μm band infrared solid-state imaging device.

The fat-zero method is effective for the SCCD, but its effect is small when applied to the BCCD. The reason for this is that in the case of BCCD, the transferred charges exist spatially in the CCD channel, and the N-type impurity ions serving as traps are uniformly distributed in the channel. Therefore, when the trap is filled with the bias charge, the signal charge spatially spreads around the trap and is trapped by the N-type impurity ions existing there. Moreover, fat-z is added to the BCCD.
Even when the ero method is used, it is similar to SCCD in that the charge loss also becomes large at low temperature, and BCCD has a larger charge loss due to the larger amount of charges to be captured, which makes it difficult to transfer charges. was there.

The present invention has been made to solve the above problems, and has a small charge loss, and an infrared solid having sufficient transfer efficiency even at a low temperature operation required for driving an infrared solid-state image pickup device. The purpose is to obtain an image sensor.

[0024]

According to a first aspect of the present invention, there is provided a method of driving a solid-state image pickup device, which comprises a photodetector array in which photodetectors which generate electric charges upon irradiation with light are arranged in a row, and the photodetector array. In a solid-state imaging device including a charge-coupled device that transfers the charge output from the container, the charge to be transferred is a signal charge, and a dummy charge having an amount equal to the signal charge precedes the signal charge. Is provided to the charge coupled device.

According to a second aspect of the present invention, there is provided the solid-state image pickup device according to the first aspect.
A solid-state image sensor driven by the solid-state image sensor driving method described above, wherein the photodetector has an opening / closing function for outputting the charges as first and second charges having equal charge amounts. First and second charge delivery paths are individually provided, and in the charge coupled device, the first charge delivery path is connected to an upstream side of the second charge delivery path in a charge transfer direction, and The first charge is the signal charge, and the second charge is the dummy charge.

According to a third aspect of the present invention, there is provided the solid-state image pickup device according to the first aspect.
A solid-state imaging device driven by the method for driving a solid-state imaging device according to claim 1, wherein the photodetector divides the electric charge into equal amounts of electric charge, and has an opening / closing function for outputting at a timing before and after. It is characterized in that each of the divided delivery paths is individually provided, and the electric charge given at the previous timing is the dummy electric charge and the electric charge given at the later timing is the signal electric charge.

According to a fourth aspect of the present invention, there is provided a solid-state image pickup device according to the first aspect.
A solid-state image sensor driven by the solid-state image sensor driving method described above, wherein the electric charge is a first electric charge, the photodetector is a first photodetector, and the photodetector array is a first photodetector array. The photodetector array of claim 1, wherein the first photodetector array is opposite to the first photodetector array with the charge coupled device interposed therebetween.
Second photodetector array arranged in the same manner as the second photodetector array, and the second photodetector constituting the second photodetector array is the same as the first photodetector. And receiving the same amount of light as the first photodetector, the first photodetector and the second photodetector generate the second charge having the same charge amount as the first charge. The second photodetector is
In the charge-coupled device, the first charge delivery path includes the first and second charge delivery paths each having an opening / closing function for outputting the first charge and the second charge. It is characterized in that the first charge is connected to the upstream side of the second charge delivery path in the charge transfer direction, the first charge is the signal charge, and the second charge is the dummy charge.

The solid-state image pickup device according to claim 5 is the same as that according to claim 1.
A solid-state image sensor driven by the solid-state image sensor driving method described above, wherein the electric charge is a first electric charge, the photodetector is a first photodetector, and the photodetector array is a first photodetector array. The photodetector array of claim 1, wherein the first photodetector array is opposite to the first photodetector array with the charge coupled device interposed therebetween.
Second photodetector array arranged in the same manner as the second photodetector array, and the second photodetector constituting the second photodetector array is the same as the first photodetector. And receiving the same amount of light as the first photodetector, the first photodetector and the second photodetector generate the second charge having the same charge amount as the first charge. The second photodetector is
First and second charge delivery paths each having an opening / closing function for outputting the first charge and the second charge are provided, and the first charge delivery path and the second charge delivery path are provided.
Are connected to the same position of the charge-coupled device, the first charge and the second charge are output at the timings before and after, and the second charge given at the previous timing is output to the dummy. An electric charge is used, and the first electric charge given at a later timing is used as the signal electric charge.

The solid-state image pickup device according to claim 6 is the same as that according to claim 5.
In the solid-state image pickup device described above, the second charge delivery path has a storage unit for temporarily storing the second charge.

According to a seventh aspect of the present invention, in the solid-state image pickup device, a photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors which generate charges upon irradiation with light, are arranged in parallel, A charge-coupled device that transfers the charges output from the photodetector is provided in each of the photodetector arrays, and a charge-coupled device array is provided at the downstream end of the charge-coupled device array. In a solid-state imaging device composed of an orthogonally arranged charge-coupled device connected so as to be orthogonal to the charge-coupled device array, the photodetectors in the photodetector array array provide the charges with equal charge amounts. First and second charge delivery paths each having an opening / closing function for outputting as the first and second charges of the first charge delivery device, and the first charge delivery path in the charge coupled device is the second charge delivery path. In the charge transfer direction rather than the charge delivery path Connected to the upstream side by the first
Is used as the signal charge and the second charge as the dummy charge, and the dummy charge is given prior to the signal charge. Even in the charge-coupled device in the orthogonal arrangement, the dummy charge is preceded by the signal charge. It is characterized in that a dummy charge is given.

The solid-state image pickup device according to claim 8 is a photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors which generate electric charges upon irradiation with light, are arranged in parallel. A charge-coupled device that transfers the charges output from the photodetector is provided in each of the photodetector arrays, and a charge-coupled device array is provided at the downstream end of the charge-coupled device array. In a solid-state imaging device configured with an orthogonally arranged charge-coupled device connected so as to be orthogonal to the charge-coupled device array, the charge is provided at an end of the charge-coupled device array on the downstream side in the charge transfer direction, A branched charge delivery path including a first and a second path having an opening / closing function is provided, which is divided into the first and second charges having the same charge amount and output by passing through the two branched paths. , In the orthogonally arranged charge-coupled device , The first path is connected to the upstream side in the charge transfer direction with respect to the second path, the first charge is the signal charge, the second charge is the dummy charge, The orthogonally arranged charge coupled device is characterized in that the dummy charges are applied prior to the signal charges.

According to a ninth aspect of the present invention, in the solid-state image pickup device, a photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors which generate charges upon irradiation with light, are arranged in parallel, A charge-coupled device that transfers the charges output from the photodetector is provided in each of the photodetector arrays, and a charge-coupled device array is provided at the downstream end of the charge-coupled device array. In a solid-state imaging device configured with an orthogonally arranged charge-coupled device connected so as to be orthogonal to the charge-coupled device array, the charge is provided at an end of the charge-coupled device array on the downstream side in the charge transfer direction, A charge dividing / delivery path having an opening / closing function for dividing into equal charge amounts and outputting at the timings before and after is provided, and the charge given at the earlier timing is used as the dummy charge, and the charge given at the later timing is used. A serial signal charge in the charge coupled device of the orthogonal arrangement is characterized in that the dummy charge prior to the signal charge is supplied.

According to a tenth aspect of the present invention, in the solid-state image pickup device, a photodetector array row in which a plurality of photodetector arrays, each of which has a row of photodetectors which generate electric charges upon irradiation with light, are arranged in parallel, A charge-coupled device that transfers the charges output from the photodetector is provided in each of the photodetector arrays, and a charge-coupled device array is provided at the downstream end of the charge-coupled device array. In a solid-state imaging device including an orthogonally arranged charge-coupled device connected so as to be orthogonal to the charge-coupled device array, the charge-coupled device includes first and second charge-coupled devices on both sides of the photodetector array. The photodetector is provided as a charge-coupled device, and the photodetector has first and second charge delivery paths each having an opening / closing function for outputting the charges as first and second charges having equal charge amounts. To prepare for the first charge The output path is connected to the first charge coupled device, and the second charge delivery path is connected to the second charge coupled device. In the charge coupled device in the orthogonal arrangement, the first charge coupled device array of the first charge coupled device is connected. An end portion on the downstream side in the charge transfer direction is connected to an upstream side with respect to the charge transfer direction with respect to an end portion on the downstream side in the charge transfer direction of the second charge-coupled device row, and the first charge is connected to the signal charge. The second charge is the dummy charge, and the charge coupled device in the orthogonal arrangement is provided with the dummy charge prior to the signal charge.

[0034]

According to the solid-state image pickup device driving method of the present invention, the dummy charge having the same charge amount as the signal charge is applied to the charge coupled device prior to the signal charge, whereby the movement of the charge in the charge coupled device is performed. Since the dummy charge is first captured by the charge trapping mechanism that prevents the signal charge, the rate of capturing the signal charge is reduced, and the charge loss accompanying the capture of the signal charge is reduced.

According to another aspect of the solid-state imaging device of the present invention, the photodetector is provided with the first and second charge delivery paths, and the first charge delivery path of the charge coupled device is the second charge delivery path. Since the first charge is the signal charge and the second charge is the dummy charge, the charge amount is equal to the signal charge prior to the signal charge because the first charge is the signal charge and the second charge is the dummy charge. The dummy charges can be given to the charge coupled device, and the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the charges in the charge coupled device. Charge loss associated with capture is reduced.

According to the solid-state image pickup device of the third aspect, the signal charges are supplied from the charge division / delivery path by using the charges given at the previous timing as the dummy charges and the charges given at the latter timing as the signal charges. Prior to, the dummy charge of the same amount as the signal charge can be given to the charge coupled device, and the dummy charge is first captured by the charge trapping mechanism that prevents the movement of the charge in the charge coupled device. Is reduced, and the charge loss associated with the capture of the signal charge is reduced.

According to the solid-state imaging device of the fourth aspect, the first charge delivery path is connected to the upstream side of the second charge delivery path in the charge transfer direction. Is used as the signal charge and the second charge is used as the dummy charge, dummy charges having the same charge amount as the signal charge can be given to the charge coupled device prior to the signal charge, and the charge transfer in the charge coupled device is prevented. Since the dummy charge is first captured by the charge trapping mechanism that prevents the signal charge, the rate of capturing the signal charge is reduced, and the charge loss accompanying the capture of the signal charge is reduced.

According to the solid-state imaging device of the fifth aspect, the second photodetector array is provided on the opposite side of the first photodetector array, and the first photodetector and the second photodetector are provided. , Individually comprising a first charge delivery path and a second charge delivery path,
The first charge delivery path and the second charge delivery path are connected to the same position of the charge-coupled device, and the first charge and the second charge are output at the timings before and after and the second charge given at the previous timing. By using the electric charge as a dummy electric charge and the first electric charge given at a later timing as the signal electric charge, the dummy electric charge is first captured by the electric charge trapping mechanism that prevents the movement of the electric charge in the charge coupled device. The rate of trapping is reduced and the charge loss associated with trapping the signal charge is reduced.

According to the solid-state image pickup device of the sixth aspect, in the solid-state image pickup device of the fifth aspect, the second charge delivery path has a storage means for temporarily storing the second charge. Therefore, the second electric charge generated in the second photodetector is accumulated in the accumulating means, and the second electric charge is accumulated while the next electric charge is generated in the empty second photodetector. Since it can be given to the charge-coupled device as dummy charges, it is possible to obtain a solid-state imaging device in which the transfer cycle of the second charges is made efficient and the operation time is shortened.

According to the solid-state imaging device of the seventh aspect, the first charge delivery path of the photodetector is a charge-coupled device,
Since it is connected to the upstream side with respect to the charge transfer direction with respect to the second charge transmission path, the first charge is given to the charge coupled device as the signal charge and the second charge is given to the charge coupled device as the dummy charge, so that the signal charge is changed. The dummy charges are given in advance, and the dummy charges are given in advance of the signal charges even in the charge-coupled elements arranged in the orthogonal arrangement. Since the dummy charges are first captured by the charge trapping mechanism that prevents movement, the rate of trapping the signal charges is reduced, and the charge loss due to the trapping of the signal charges is reduced.

According to the solid-state image pickup device of the eighth aspect, the first path of the branch charge transmission path is connected to the upstream side of the second path in the charge transfer direction in the charge coupled device in the orthogonal arrangement. Since the first charge is given as the signal charge and the second charge is given as the dummy charge to the charge-coupled device, the dummy charge is given prior to the signal charge. Since the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the signal charges, the rate at which the signal charges are trapped is reduced, and the charge loss due to the trapping of the signal charges is reduced.

According to the solid-state image pickup device of the ninth aspect, the charges applied from the charge division / delivery path at the timing earlier are used as dummy charges, and the charges applied at the timing later are signal-charged, thereby leading the signal charges. Then, the dummy charges are given, and the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the charges in the charge coupled device in the orthogonal arrangement. The charge loss associated with charge capture is reduced.

According to the solid-state imaging device of the tenth aspect,
The charges of the photodetector are given to the first and second charge-coupled devices via the first and second charge-delivery paths, respectively, and the charge transfer of the first charge-coupled device is performed in the charge-coupled devices arranged orthogonally. Since the end portion on the downstream side in the direction is connected to the upstream side in the charge transfer direction with respect to the end portion on the downstream side in the charge transfer direction of the second charge-coupled device, the first charge is connected to the signal charge and the second charge By giving the charge of 4 to the charge-coupled device as a dummy charge, the dummy charge is given prior to the signal charge, and in the charge-coupled device in the orthogonal arrangement,
Since the dummy charges are first captured by the charge trapping mechanism that hinders the movement of the charges, the ratio of trapping the signal charges is reduced, and the charge loss due to the trapping of the signal charges is reduced.

[0044]

【Example】

<First Embodiment: Driving Method of Solid-State Imaging Device> FIG. 1 is a diagram for explaining a driving method of a solid-state imaging device as a first embodiment according to the present invention.
A cross-sectional view along the transfer direction and a potential diagram are shown in the same figure. In a cross-sectional view of the SCCD 17 of FIG. 1 along the transfer direction, an insulating film 7 made of SiO ₂ or the like is formed on the upper surface of the P-type Si substrate 1, and a plurality of electrically independent gate electrodes 80 are formed thereon. It is made of polysilicon or the like. Since it is a four-phase driving SCCD, the gate electrodes 80 are sequentially connected to the input pins 10a, 10b, 10c and 10d in order to apply clock voltages having different phases.

In the potential diagram of FIG. 1, P-type Si is used.
In the potential wells W11 and W13 formed in the substrate 1, the dummy charges 16a and 16b are
12, signal charges 11a and 11b to be transferred into W14
The state in which is accumulated is schematically shown.

The charge transfer operation of the SCCD 17 is almost the same as that of the conventional CCD 3 shown in FIG.
At D17, the dummy charges of substantially the same amount as the signal charges are transferred prior to the signal charges to be transferred. In the procedure, first, the dummy charge 16a is applied to the potential well W14. Next, the dummy charge 16a is transferred to the potential well W13, and the empty potential well W14 is supplied with the signal charge 11a. Next, the dummy charge 16a is transferred to the potential well W12, the signal charge 11a is transferred to the potential well W13, and the empty potential well W14 is transferred.
To the dummy charge 16b. Next, the dummy charge 16a is transferred to the potential well W11, the signal charge 11a is transferred to the potential well W12, the dummy charge 16b is transferred to the potential well W13, and the empty potential well W14 is supplied with the signal charge 11b.

The conventional fat shown in FIG. 14 and FIG.
In the case of transfer by the −zero method, there is an interface state filled with signal charges because the sum of transferred charges (signal charge + bias charge) is larger than the bias charge. Therefore, although there is always a certain amount of charge loss, in the method for driving a solid-state image sensor according to the present invention shown in FIG. 1, the dummy charge amount preceding the signal charge and the signal charge amount subsequently applied are almost equal to each other. Since they are equal, the charge loss is reduced. This will be described with reference to FIG. 1. When the empty interface state is filled with the dummy charge 16a applied first, the signal charge 11a applied subsequently has the same charge amount as the dummy charge 16a. It will not be captured by the levels.

In the conventional fat-zero method, BC is used.
Although the effect of reducing the transfer loss with respect to the CD was small, in the method for driving the solid-state image sensor according to the present invention shown in FIG. 1, the charge loss was sufficiently reduced for the BCCD for the same reason as above. Has the effect of

When the CCD transfer is performed by the above operation, the signal output obtained through the output amplifier is the output by the dummy charge (hereinafter referred to as the dummy output) and the output by the signal charge (hereinafter referred to as the signal output). Appear alternately.
Therefore, when the signal output is displayed as an image in the solid-state imaging device, signal processing is performed so that only the signal output is selectively displayed excluding the dummy output.

<Second Embodiment: Infrared solid-state image pickup device A>
Next, as a second embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 2 is a plan view showing the basic configuration of the infrared solid-state image sensor A which is one-dimensionally arranged. In FIG. 2, PtSi / Si is formed on the P-type Si substrate 1.
A plurality of photodetectors 20 composed of Schottky barrier diodes and the like are arranged one-dimensionally. In addition, P-type Si
On the substrate 1, a four-phase driving SCCD 17 is formed in parallel as a signal charge transfer circuit along the one-dimensionally arranged photodetectors 20, and charges are transferred from the left side to the right side of FIG. It In addition, the individual photodetector 20 and the SCCD
17 and a transfer gate 4a for controlling the transmission of signal charges from the photodetector 20 to the SCCD 17.
And 4b are provided symmetrically, and the space between them is CCD1.
It is connected to the SCCD 17 at a distance of four steps (four gates in FIG. 2). The transfer gates 4a and 4b
Are electrically connected.

The gate electrode of the four-phase driving SCCD 17 is 4
The gate electrode connected to the transfer gate 4a is set to 80a, and reference numerals 80b, 80c, and 80d are attached in this order from the upstream side in the charge transfer direction. The electrode also becomes 80a. In addition, a portion shown by a broken line in the drawing represents a region (active region) in which charges can move.
This also applies to the subsequent FIGS. 3 to 11.

The operation of the solid-state image sensor A will be described below. When both the transfer gates 4a and 4b are turned on, half of the signal charge generated in the photodetector 20 passes through the transfer gate 4a and the other half is sent out to the SCCD 17 through the transfer gate 4b. At this time, the charges that have passed through the transfer gate 4a are used as signal charges, and the charges that have passed through the transfer gate 4b are used as dummy charges to be transferred by the SCCD 17. With this configuration, the dummy charges of almost the same amount as the signal charges are supplied to the SCCD 1.
7, and a solid-state image sensor that realizes the method for driving the solid-state image sensor described with reference to FIG. 1 can be obtained.

According to the second embodiment of the present invention described above, the dummy charges are given first to the signal charges initially given to only one CCD after passing through the transfer gate 4a. Not transferred area, so
Although this portion suffers charge loss, there is an advantage that the structure and driving method of the element are simple.

<Third Embodiment: Infrared Solid State Image Pickup Device B>
Next, as a third embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 3 is a plan view showing the basic configuration of the infrared solid-state image sensor B having a one-dimensional array.
In FIG. 3, a plurality of photodetectors 20 composed of PtSi / Si Schottky barrier diodes or the like are arranged one-dimensionally on a P-type Si substrate 1. Further, on the P-type Si substrate 1, four-phase driven SCCDs 17 are formed in parallel as signal charge transfer circuits along the photodetectors 20 arranged one-dimensionally, and the charges move from the left side to the right side in FIG. Is transferred as. In addition, the individual photodetector 20 and the SCCD 17
Between them and control gates 18 to 22 made of polysilicon or the like are provided in order from the photodetector 20 side in order to control the sending of signal charges from the photodetector 20 to the SCCD 17, and other light Control gates 180, 190, 2 provided between the detector 20 and the SCCD 17
00, 210, 220 are electrically connected to each other.

The control gates 180, 190,
By dividing the signal charges in 200, 210, and 220 into two, one is used as the signal charge and the other is used as the dummy charge.
The gate electrodes of the CCD 17 can be alternately applied to 80a to 80d, and the solid-state image sensor realizing the method for driving the solid-state image sensor described with reference to FIG. 1 can be obtained.

The gate electrode of the four-phase driving SCCD 17 is 4
And a gate electrode connected to the control gate 220 is 80a, and reference numerals 80b, 80c, and 80d are provided in this order from the upstream side in the charge transfer direction.
It is repeated below Control gate 18
The operation of dividing the signal charges by 0, 190, 200, 210, 220 will be described with reference to FIG. FIG. 4 is FIG.
FIG. 3 is a diagram showing a cross-sectional view taken along line AA ′ in FIG. 4 and potential diagrams (a) to (h) showing temporal changes of the potential well at positions corresponding to the cross-sectional view. In the cross-sectional view of FIG. 4, an insulating film 7 made of SiO ₂ or the like is formed on the upper surface of the P-type Si substrate 1, and the PtSi layer 23 and the gate electrode 80a which form the photodetector 20 are formed on the insulating film 7. In between, electrically independent control gates 180, 1
90, 200, 210, 220 are sequentially provided from the PtSi layer 23 side. Note that the signal charges are from the left side (PtSi layer 23 side) to the right side (gate electrode 80) of the potential diagram.
First, as shown in the potential diagram (a), the signal charge 24 generated in the PtSi layer 23 during the OFF period of the control gate 180 is a potential well formed under the PtSi layer 23. It is accumulated in W21. At this time, the control gates 190, 200, 2
10 and the gate electrode 80a are in the ON state, and the potential well W22 is formed under the control gates 190, 200, 210, and the potential well 23 is formed under the gate electrode 80a. In addition, the depth of the potential well becomes deeper in the order of W21, W22, and W23.

Next, as shown in the potential diagram (b),
When the control gate 180 is turned on, the potential barrier between the potential wells W21 and W22 disappears and the signal charge 24 flows into the potential well W22.

Next, as shown in the potential diagram (c),
After the signal charge 24 moves to the potential well W22,
When the control gate 180 is turned off and a potential barrier is formed under the control gate 180, the transmission of the signal charge 24 to the potential well 22 is completed.

Next, as shown in the potential diagram (d),
The control gate 200 is turned off, the bottom of the potential well W22 corresponding to the bottom of the control gate 200 partially rises, and the potential well W22
22 is divided to form potential wells W24 and W25. Along with this, the signal charge 24 is also divided into two, and thereafter, the charge accumulated in the potential well W24 on the upstream side (PtSi layer 23 side) in the charge transfer direction is converted into the signal charge 25.
Then, the charges accumulated in the potential well W25 on the downstream side (gate electrode 80a side) are used as dummy charges 26.

Next, as shown in the potential diagram (e),
When the control gate 220 is turned on, the potential barrier between the potential wells W25 and W23 disappears and the dummy charges 26 flow into the potential well W23.

Next, as shown in the potential diagram (f),
The dummy charge 26 of the potential well W23 is SCCD1.
Control gate 2 after CCD transfer by 7
20 is turned off and the control gate 220
If a potential barrier is formed under the
Is completed.

Next, as shown in the potential diagram (g),
When the control gates 200 and 220 are turned on, the control gates 200 and 22 are
The potential barrier under 0 disappears and the signal charge 25 is sent to the potential well 23.

By the above operation, the signal charge 24 generated in the photodetector 20 is divided into two, and the transmission to the SCCD 17 is completed. After that, as shown in FIG. 4H, the signal charge 25 is delayed from the dummy charge 26 by one CCD stage, and
Transferred.

As described above, according to the third embodiment of the present invention, the structure and driving method are slightly complicated,
Since the dummy charge and the signal charge are given in the same path,
Since the dummy charges are always applied prior to the signal charges, it is possible to obtain a solid-state imaging device that prevents charge loss for one CCD stage when the dummy charges and the signal charges are applied through different paths.

<Fourth Embodiment: Infrared solid-state image pickup device C>
Next, as a fourth embodiment of the present invention, a configuration of a solid-state image sensor for realizing the method of driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 5 is a plan view showing the basic configuration of the infrared solid-state image sensor C having a one-dimensional array.
In FIG. 5, PtS is formed on the semiconductor substrate 1 such as P-type Si.
A plurality of photodetectors 27 composed of i / Si Schottky barrier diodes and a dummy charge generation photodetector 2
8 are arranged one-dimensionally, and photodetectors 27 and 28 are arranged two-dimensionally as a whole.

Further, on the P-type Si substrate 1, both photodetectors 27 which are arranged one-dimensionally and photodetectors 28 for dummy charge generation which are also arranged one-dimensionally are arranged between the two detectors. A four-phase drive SCCD 17 is formed in parallel as a signal charge transfer circuit along the line, and charges are transferred from the left side to the right side of FIG. The individual photodetectors 27 and the dummy charge generation photodetectors 28 are arranged so as to face each other with the SCCD 17 interposed therebetween. The photodetector 27 and the dummy charge generation photodetector 28 are
Both have the same performance and configuration.

Between the photodetector 27 and the SCCD 17,
A transfer gate 4c for controlling the transmission of signal charges from the photodetector 27 to the SCCD 17 is provided, while the dummy charge generating photodetector 28 and the SCCD which face each other are provided.
17 between the photodetector 28 for dummy charge generation and S
A transfer gate 4d for controlling the transmission of signal charges to the CCD 17 is provided.

The transfer gate 4c is connected to the SCCD 17 on the upstream side (left side in FIG. 5) in the charge transfer direction with respect to the transfer gate 4d.
The distance between c and 4d is one CCD (4 gates in Fig. 5).
Just away. In addition, the transfer gates 4c and 4d
Are electrically independent. Further, since the configuration of the SCCD 17 has been described with reference to FIG. 1, redundant description will be omitted.

Generally, when two-dimensional image information is obtained by using a one-dimensional solid-state image pickup device, mechanical movement is performed in a direction perpendicular to the photodetector array (direction shown by an arrow as a sub-scanning direction in FIG. 5). Need to scan. For example, when applied to remote sensing of the ground surface using an artificial satellite or an aircraft, the flight direction of the artificial satellite or aircraft equipped with the solid-state imaging device is adjusted to the sub-scanning direction of the solid-state imaging device, or By changing the angle of the solid-state image pickup device in accordance with the flight direction of an aircraft or the like, the device is devised so that the sub-scanning direction of the solid-state image pickup device and the flight direction match.

The operation of the solid-state image sensor C will be described below. When the temporal change of the observation target such as remote sensing is gradual, in the solid-state imaging device C shown in FIG. 5, first, the dummy charge generation photodetector 28 emits light (infrared light) from a position on the ground surface. Receives and accumulates dummy charges.
Next, after a certain time has elapsed, the photodetector 27 receives light (infrared light) from the same position on the ground surface and accumulates signal charges. As a result, the photodetector 27 and the dummy charge generating photodetector 28 receive light (infrared light) from the same position, and the amount of charge accumulated in each is the same.

Next, the transfer gate 4c is turned on and the signal charge of the photodetector 27 is sent to the SCCD 17. The signal charge sent to the SCCD 17 is
Therefore, the transfer gate 4d is turned on at the timing when one CCD (4 gates in FIG. 5) is transferred.
The dummy charge of the photodetector 28 for dummy charge generation is sent to the SCCD 17 in the N state. As a result, the dummy charges having the same charge amount are given prior to the signal charges, and charge loss is prevented when the charges are transferred in the SCCD 17 of the next stage.

As described above, according to the fourth embodiment of the present invention, since the dummy charge of the same charge amount can be given to the SCCD 17 prior to the signal charge, the solid state with reduced charge loss. An image sensor can be obtained.

<Fifth Embodiment: Infrared Solid State Image Pickup Device D>
Next, as a fifth embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 6 is a plan view showing the basic configuration of the infrared solid-state image sensor D having a one-dimensional array.
In FIG. 6, a transfer gate 4c for controlling transmission of signal charges from the photodetector 27 to the SCCD 17
Is the same gate electrode 80a of the SCCD 17 as opposed to the transfer gate 4d for controlling the transmission of the signal charge from the dummy charge generation photodetector 28 to the SCCD 17.
It is connected to the. Other configurations are the same as those of the solid-state image pickup device C of the fourth embodiment according to the present invention described with reference to FIG. 5, and thus redundant description will be omitted.

The operation of the solid-state image sensor D will be described below. Similar to the solid-state image sensor C described with reference to FIG. 5 in the fourth embodiment, the basic operation is the same as that given with a time difference when the temporal change of the observation target such as remote sensing is gradual. The light (infrared light) from the portion is received by the photodetector 27 and the dummy charge generation photodetector 28, and the charges generated by the respective detectors are temporarily accumulated, and are then sent to the SCCD 17 at a timing and transferred to the CCD. Is to do.

Here, the difference from the solid-state image pickup device C of the fourth embodiment is that the transfer gates 4c and 4d are connected to the same gate electrode 80a of the SCCD 17 opposite to each other. Therefore, the charge transfer timing is also different. First, the transfer gate 4d is turned on and dummy charges generated by the dummy photodetector 28 are supplied to the SCCD 17.
Then, the transfer gate 4c is turned on and the signal charges generated by the photodetector 27 are sent to the SCCD 17 and transferred.

Therefore, according to the fifth embodiment of the present invention, the dummy charges can always be given prior to the signal charges, and one stage of CCD when the dummy charges and the signal charges are given through different paths. It is possible to obtain a solid-state image sensor in which charge loss is prevented.

<Sixth Embodiment: Infrared Solid State Image Pickup Device E>
Next, as a sixth embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 7 is a plan view showing the basic configuration of the infrared solid-state image sensor E having a one-dimensional array.
In FIG. 7, between the individual dummy charge generation photodetectors 28 and the SCCD 17, control gates 30 to 32 made of polysilicon or the like are provided in order from the dummy charge generation photodetector 28 side, and control is performed. Gate 3
2 is connected to the gate electrode 80a of the SCCD 17. On the other hand, the transfer gate 4c for controlling the transmission of the signal charge from the photodetector 27 to the SCCD 17 is connected to the same gate electrode 80a of the SCCD 17 opposite to the control gates 30-32. The control gate 31 provided between the control gates 30 and 32 is an electrode for forming a potential well for temporarily storing the dummy charges generated by the dummy charge generation photodetector 28. Is an electrode for controlling the entry / exit of dummy charges to / from the potential well formed by the control gate 31. The charge path composed of these control gates 30 to 32 is called a delay circuit because of its function. Other configurations are the same as those of the solid-state image pickup device D according to the fifth embodiment of the present invention described with reference to FIG. 6, and thus the duplicate description will be omitted.

The operation of the solid-state image pickup device E will be described below. Similar to the solid-state image sensor D described in the fifth embodiment with reference to FIG. 6, the basic operation is the same as that given with a time difference when the temporal change of the observation target such as remote sensing is gradual. The light (infrared light) from the portion is received by the photodetector 27 and the dummy charge generation photodetector 28, and the charges generated by the respective detectors are temporarily accumulated, and are then sent to the SCCD 17 at a timing and transferred to the CCD. Is to do.

In the solid-state image pickup devices C and D described with reference to FIGS. 5 and 6, the SCCD 17CCD transfer is performed during the sub-scanning period until the photodetector 27 observes the spot observed by the dummy charge generation photodetector 28. Is not done. In other words, the CCD transfer is performed after the two photodetectors 27 and 28 have accumulated charges in both photodetectors until they obtain signals at the same observation point. Therefore, the solid-state image sensor C
The time required for D and D to observe one point and to be ready for observation at the next point depends on the photodetector 2 for dummy charge generation.
After 8 receives the light (infrared light), the photodetector 27 becomes the SCCD
It is the time until the series of operations is completed after the signal charges are sent to 17 (hereinafter referred to as operation time). Since an artificial satellite or an aircraft equipped with the solid-state imaging device moves at a constant speed, it moves a fixed distance during this operation time. That is, the operating time determines the resolution of observation, and shortening the operating time increases the resolution of observation.

In order to shorten the operation time, it is considered that the distance between the photodetectors 27 and 28 is narrowed.
There is a physical limitation in reducing the distance between the photodetectors 27 and 28.

Therefore, in the sixth embodiment according to the present invention shown in FIG. 7, the charge transfer cycle is made efficient to shorten the operation time. In FIG. 7, the dummy charges generated by the dummy charge generation photodetector 28 are temporarily stored in the potential well formed under the control gate 31.
During this period, the photodetector 27 reaches a predetermined position and the signal charge is accumulated. However, the dummy charge accumulated in the potential well formed under the control gate 31 is controlled before the signal charge is transmitted. Is turned on to give the signal charge to the SCCD 17 prior to the signal charge, and then the transfer gate 4c is turned on to give the signal charge of the photodetector 27 to the SCCD 17. At this point, the dummy charge generation photodetector 2 has already been
The next dummy charge generated in 8 is the control gate 3
Accumulated in the potential well formed under
Ready to send to CD17.

By thus preliminarily accumulating the dummy charges, the photodetector 27 can send out the signal charges to the SCCD 17 without an extra waiting period.
The operation time can be shortened and the observation resolution can be increased.

As described above, according to the sixth embodiment of the present invention, it is possible to obtain a solid-state image pickup device in which the operation time is shortened and the observation resolution is increased.

Although FIG. 7 shows a case where one stage of delay circuit is provided, a plurality of stages may be provided by increasing the number of control gates.

<Seventh Embodiment: Infrared Solid State Image Pickup Device F>
Next, as a seventh embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 8 is a plan view showing the basic configuration of the infrared solid-state image sensor F having a two-dimensional array.

In FIG. 8, Pt is formed on the P-type Si substrate 1.
A plurality of photodetectors 20 composed of Si / Si Schottky barrier diodes and the like are arranged one-dimensionally. Further, on the P-type Si substrate 1, a 4-phase drive SC is provided as a signal charge transfer circuit along the photodetectors 20 arranged one-dimensionally.
CDs 33 are formed in parallel, and charges are transferred from the upper side to the lower side in FIG. Also, the individual photodetector 20
From the photodetector 20 to the SCCD 33.
Transfer gates 4e and 4f for controlling the transmission of the signal charge to 33 are provided symmetrically in the vertical direction, and their intervals are separated by one CCD stage (4 gates in FIG. 8) and SC.
It is connected to CD33. The transfer gates 4e and 4f are electrically connected.

The structure of the SCCD 34 and the transfer gates 4e and 4f is the SCC of the infrared solid-state image pickup device A of the one-dimensional array described in the second embodiment with reference to FIG.
Since it is the same as D17 and the transfer gates 4a and 4b, duplicated description will be omitted.

In FIG. 8, a plurality of one-dimensionally arranged infrared solid-state image pickup elements, each of which is composed of a photodetector 20 arranged one-dimensionally and an SCCD 33 attached to the photodetector 20, are formed in parallel to form a two-dimensional array of infrared solid-state image pickup devices. It constitutes the element F. The plurality of SCCDs 33 are connected to the SCCDs 34 arranged vertically to the SCCDs 33. SCCD
Reference numeral 34 is a CCD for receiving the signal charge from the photodetector 20 transferred by each SCCD 33 and further transferring it. The signal charge transfer direction is from the left side to the right side in FIG.

The structure of the SCCD 34 is also a four-phase drive like the SCCD 17 of the infrared solid-state image pickup device A of the one-dimensional array described with reference to FIG. 2 as the second embodiment, and four gate electrodes form one set. , 90a as the gate electrode connected to the SCCD 33, and 90 from the upstream side in the charge transfer direction.
The symbols are assigned in the order of b, 90c, and 90d, and thereafter, they are repeatedly assigned. In FIG. 8, it is separated from the adjacent SCCD 33 by 1c by two CCDs (8 gates), and the adjacent SCCD 33 is also connected to the gate electrode 90a.

The operation of the solid-state image sensor F will be described below. When both the transfer gates 4e and 4f are turned on, half of the signal charge generated in the photodetector 20 passes through the transfer gate 4e and the other half is sent out to the SCCD 33 through the transfer gate 4f. At this time, CCD transfer is performed by using the charge passing through the transfer gate 4e as a signal charge and the charge passing through the transfer gate 4f as a dummy charge, which is the same as the infrared solid-state image sensor A of FIG. 2 described as the second embodiment. Similarly, the solid-state imaging device driving method according to the present invention described with reference to FIG. 1 is realized.

Further, the charges are transferred from the SCCD 33 to the SCCD 34 by sending dummy charges from the SCCD 33 to the SCCD 34, transferring the dummy charges by one CCD in the SCCD 34, and then transferring the dummy charges from the SCCD 33 to the SCC 34.
The signal charge is sent to D34. By the above operation, the dummy charges are always transferred prior to the signal charges in the SCCD 34, and the method for driving the solid-state image sensor according to the present invention described with reference to FIG. 1 is realized.

As described above, according to the seventh embodiment of the present invention, it is possible to obtain a two-dimensional array solid-state image pickup device having a simple structure and a simple driving method and preventing charge loss.

In FIG. 8, the photodetector 20 is connected to the SCCD.
The transfer gate 4 of the infrared solid-state imaging device A of the one-dimensional array described with reference to FIG.
transfer gates 4e and 4 similar to a and 4b
Although f is used, instead of this, the signal charge sending mechanism including the control gates 180, 190, 200, 210, 220 of the infrared solid-state image sensor B of the one-dimensional array described with reference to FIG. 3 may be used. good.

<Eighth Embodiment: Infrared Solid State Image Pickup Device G>
Next, as an eighth embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 9 is a plan view showing the basic configuration of the infrared solid-state image sensor G having a two-dimensional array.

In FIG. 9, Pt is formed on the P-type Si substrate 1.
A plurality of photodetectors 20 composed of Si / Si Schottky barrier diodes and the like are arranged one-dimensionally. Further, on the P-type Si substrate 1, a 4-phase drive SC is provided as a signal charge transfer circuit along the photodetectors 20 arranged one-dimensionally.
The CDs 35 are formed in parallel, and the charges are transferred from the upper side to the lower side in FIG. Also, the individual photodetector 20
From the photodetector 20 to the SCCD 35.
A transfer gate 4g for controlling the sending of the signal charge to 35 is provided. The transfer gate 4g is electrically connected to the transfer gate 4g of the other photodetector 20.

Since the SCCD 35 is not a CCD which operates based on the driving method of the solid-state image pickup device according to the present invention described with reference to FIG. 1 but a conventional four-phase driving CCD, detailed operation and The description of the configuration is omitted.

In FIG. 9, the SCCD 35 is a branch junction 3
It is connected to the SCCD 34 via 6. The branch junction 36 has a structure that divides a given charge into two, and two output terminals are formed so as to have a space of one CCD stage (4 gates) when connected to the SCCD 34.
The branch junction 36 has a structure in which a region capable of moving charges (active region) is bifurcated, and a gate electrode is provided on the region. Two gate electrodes are shown in the figure. However, this may be an integrated gate electrode.

The operation of the solid-state image sensor G will be described below. Generally, in a two-dimensional array of solid-state image pickup devices, the transfer speed of a CCD (for convenience referred to as a vertical CCD) attached to a one-dimensionally arrayed photodetector 20 is vertically connected to the vertical CCD. Since it is slower than a CCD (referred to as a horizontal CCD for convenience), the vertical CCD has a conventional transfer method, such as a method of increasing the clock fall time.
In some CDs, the charge loss may be reduced to a level that does not pose a problem in practical use. In such a case, the horizontal CC
By applying the driving method of the solid-state image pickup device according to the present invention only to D, the charge loss in the horizontal CCD can be reduced.

That is, in FIG. 9, the signal charges generated in the photodetector 20 are given to the SCCD 35 and transferred to the SCCD 34 by the conventional transfer method. The signal charge reaching the branch junction 36 is divided into two equal amounts in the branch junction 36, and each of the CCDs of the SCCD 34
It is given at a position one step away (4 gates). In this case, the charges applied to the upstream side (left side in FIG. 9) of the SCCD 34 in the charge transfer direction are used as signal charges, and the charges applied to the downstream side (right side in FIG. 9) are used as dummy charges. The dummy charge is given in advance.

As described above, according to the eighth embodiment of the present invention, it is possible to obtain a two-dimensional array solid-state image pickup device having a simple structure and a simple driving method and preventing charge loss.

<Ninth Embodiment: Infrared Solid State Image Pickup Device H>
Next, as a ninth embodiment according to the present invention, a configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 1 will be described. FIG. 10 is a plan view showing the basic configuration of the infrared solid-state image sensor H having a two-dimensional array.

In FIG. 10, SCCD 35 and SCCD
34, control gates 37 to 41 made of polysilicon or the like are provided between the SCCD 35 and the SCCD 35 in order to control transmission of signal charges from the SCCD 35 to the SCCD 35.
They are provided in order from the side. Control gate 37 ~
41 is also provided between the other SCCD 35 and the SCCD 34, and is electrically connected to each other.

In FIG. 10, control gates 37-
The configuration other than 41 is the same as that of the infrared solid-state imaging device G of FIG. 9 described as the eighth embodiment, and the eighth embodiment is
While the signal charge is divided into two by the branch junction 36 provided between the SCCD 35 and the SCCD 34, in the present embodiment, the signal charge is divided into two by the control gates 37 to 41, and the dummy charge and the signal charge are divided into two. SCCD3
It is characterized by giving to 4.

The structure of the control gates 37 to 41 in the BB 'section of FIG. 10 is as shown in FIG.
And the infrared solid-state image sensor B described with reference to FIG.
Control gates 180, 19 in the section AA '
The configuration is the same as that of 0, 200, 210, 220, and only the reference numerals in the figure are changed as follows. That is,
PtSi layer 23 and control gate 18 in FIG.
0, 190, 200, 210, 220, gate electrode 80
a is the SCCD 35 and the control gate 3 respectively
7, 38, 39, 40, 41, and the gate electrode 90a. Therefore, it goes without saying that the operation of dividing the signal charge into two and using the dummy charge and the signal charge is similar.

Therefore, according to the ninth embodiment of the present invention, although the structure and the driving method are slightly complicated, since the dummy charges and the signal charges are given through the same path, the dummy charges are always converted into the signal charges. The CCD in the case where the dummy charge and the signal charge are given in advance and are given through different paths.
It is possible to obtain a solid-state imaging device having a two-dimensional array in which charge loss of one stage is prevented.

<Tenth Embodiment: Infrared solid-state image sensor I
Next, as a tenth embodiment of the present invention, the configuration of a solid-state image sensor for realizing the method for driving the solid-state image sensor described with reference to FIG. 11 will be described. FIG. 11 is a plan view showing the basic configuration of the infrared solid-state image sensor I having a two-dimensional array.

In FIG. 11, a plurality of photodetectors 20 composed of PtSi / Si Schottky barrier diodes or the like are one-dimensionally arranged on a semiconductor substrate 1 of P-type Si or the like. In addition, on the P-type Si substrate 1, four-phase driven SCCDs 35A and 35B are formed in parallel as signal charge transfer circuits along both sides of the one-dimensionally arranged photodetectors 20, and the charges are on the upper side of FIG. Is transferred from the bottom to the bottom. In addition, the individual photodetector 20 and the SCCD 35
Between A and 35B, from the photodetector 20 to the SCCD
Transfer gates 4g and 4h for controlling the delivery of signal charges to 35A and 35B are provided symmetrically. The transfer gates 4h and 4i are electrically connected at a portion not shown in the figure.

The configurations of the SCCDs 35A and 35B and the transfer gates 4h and 4i are the same as those of the SCCD 35 and the transfer gate 4g of the infrared solid-state image pickup element G of the two-dimensional array described with reference to FIG. 9 as the eighth embodiment. , Duplicate description will be omitted.

In FIG. 11, a plurality of one-dimensionally arranged infrared solid-state image pickup devices, each of which includes a photodetector 20 arranged one-dimensionally and SCCDs 35A and 35B provided on both sides of the photodetector 20, are formed in parallel. An infrared solid-state image sensor I is configured. The SCCDs 35A and 35B are S
S arranged vertically to the CCDs 35A and 35B
The CCD 34 is connected to a position separated by one CCD.

The operation of the solid-state image sensor I will be described below. When both the transfer gates 4h and 4i are turned on, half of the signal charges generated by the photodetector 20 pass through the transfer gate 4h and the SCCD 35A.
And the other half goes through the transfer gate 4i
It is sent to CD35B. At this time, the charge passing through the transfer gate 4h is used as a signal charge, and the charge passing through the transfer gate 4i is used as a dummy charge to perform CCD transfer, thereby performing the method for driving the solid-state imaging device according to the present invention described with reference to FIG. Can be realized.

As described above, the tenth aspect of the present invention
According to the embodiment, it is possible to obtain a two-dimensional array solid-state image pickup device having a simple structure and a simple driving method and preventing charge loss.

<Modification 1> In the above second to tenth embodiments, the case of a four-phase driving CCD has been described. However, the operation and effects are the same for any other phase driving CCD. is there. Further, in the potential diagram for explaining the driving method of the solid-state imaging device according to the present invention, C
The case of the double clock system (the system in which two of the four phases are always "H") has been described as the CD clock, but the effect is the same even in the case of the single clock system. In addition, the CCD transfer according to the present invention can be performed by the conventional fat-
It is also possible to use in combination with the zero method, and at this time, f
The charge loss can be further reduced as compared with the case of only the at-zero method.

<Modification 2> In the above second to tenth embodiments, the infrared solid-state image pickup device operating at a low temperature has been described, but the transfer loss is similarly reduced even in the solid-state image pickup device operating at room temperature. Has the effect of Therefore, the photodetector 2
The same effect can be obtained when a photodetector having a configuration other than 0 is used.

[0114]

According to the method for driving a solid-state image pickup device of the first aspect, the charge in the charge-coupled device is supplied by giving the charge-coupled device a dummy charge having a charge amount equal to the signal charge prior to the signal charge. Since the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the signal charges, the rate of trapping the signal charges is reduced and the charge loss due to the trapping of the signal charges is reduced, thus improving the transfer efficiency of the signal charges. be able to.

According to the solid-state image pickup device of the second aspect, the photodetector is provided with the first and second charge delivery paths, and the first charge delivery path in the charge coupled device is the second charge delivery path. Since the first charge is the signal charge and the second charge is the dummy charge, the charge amount is equal to the signal charge prior to the signal charge because the first charge is the signal charge and the second charge is the dummy charge. The dummy charges can be given to the charge coupled device, and the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the charges in the charge coupled device. Since the charge loss due to the trapping is reduced, it is possible to obtain a solid-state image sensor with improved signal charge transfer efficiency.

According to the solid-state image pickup device of the third aspect, the signal charges are supplied from the charge division transmission path by using the charges given at the previous timing as the dummy charges and the charges given at the latter timing as the signal charges. Prior to, the dummy charge of the same amount as the signal charge can be given to the charge coupled device, and the dummy charge is first captured by the charge trapping mechanism that prevents the movement of the charge in the charge coupled device. Since the charge ratio is reduced and the charge loss due to the capture of the signal charge is reduced, it is possible to obtain the solid-state imaging device with the improved transfer efficiency of the signal charge.

According to the solid-state image pickup device of the fourth aspect, the first charge delivery path is connected to the upstream side of the second charge delivery path in the charge transfer direction. Is used as the signal charge and the second charge is used as the dummy charge, dummy charges having the same charge amount as the signal charge can be given to the charge coupled device prior to the signal charge, and the charge transfer in the charge coupled device is prevented. Since the dummy charge is first captured by the charge trapping mechanism that prevents the signal charge, the rate of capturing the signal charge is reduced and the charge loss due to the capture of the signal charge is reduced. An element can be obtained.

According to the solid-state image pickup device of the fifth aspect, the second photodetector array is provided on the opposite side of the first photodetector array, and the photodetector and the second photodetector have the first photodetector array. Are individually provided, the first charge delivery path and the second charge delivery path are connected to the same position of the charge coupled device, and the first charge and the second charge are The second charge, which is output at the timing before and after and is given at the earlier timing, is used as the dummy charge, and the first charge, which is provided at the later timing, is used as the signal charge, thereby preventing the movement of the charge in the charge-coupled device. Since the dummy charges are first captured by the charge trapping mechanism, the rate of trapping the signal charges is reduced, and the charge loss due to the trapping of the signal charges is reduced. Obtainable.

According to the solid-state image pickup device of the sixth aspect, in the solid-state image pickup device of the fifth aspect, the second charge delivery path has a storage unit for temporarily storing the second charge. Therefore, the second electric charge generated in the second photodetector is accumulated in the accumulating means, and the second electric charge is accumulated while the next electric charge is generated in the empty second photodetector. Since it can be given to the charge coupled device as dummy charges, it is possible to obtain a solid-state imaging device in which the second charge transfer cycle is made efficient and the operation time is shortened.

According to the solid-state imaging device of the seventh aspect, the first charge delivery path of the photodetector is a charge-coupled device,
Since it is connected to the upstream side with respect to the charge transfer direction with respect to the second charge transmission path, the first charge is given to the charge coupled device as the signal charge and the second charge is given to the charge coupled device as the dummy charge, so that the signal charge is changed. The dummy charges are given in advance, and the dummy charges are given in advance of the signal charges even in the charge-coupled elements arranged in the orthogonal arrangement. Since the dummy charge is first captured by the charge trapping mechanism that prevents movement, the rate of trapping the signal charge is reduced, and the charge loss due to the trapping of the signal charge is reduced, so that the transfer efficiency of the signal charge is improved. An image sensor can be obtained.

According to the solid-state image pickup device of the eighth aspect, the first path of the branched charge delivery path is connected to the upstream side of the second path in the charge transfer direction in the charge coupled device arranged orthogonally. Since the first charge is given as the signal charge and the second charge is given as the dummy charge to the charge-coupled device, the dummy charge is given prior to the signal charge. The dummy charges are first captured by the charge trapping mechanism that prevents the transfer of the signal charges, so that the ratio of the signal charges to be captured is reduced, and the charge loss due to the capture of the signal charges is reduced, so that the transfer efficiency of the signal charges is improved. A solid-state image sensor can be obtained.

According to the solid-state image pickup device of the ninth aspect, the charges given from the charge division / delivery path at the earlier timing are used as the dummy charges, and the charges given at the latter timing are signal-charged, thereby leading the signal charges. Then, the dummy charges are given, and the dummy charges are first captured by the charge trapping mechanism that prevents the movement of the charges in the charge coupled device in the orthogonal arrangement. Since the charge loss associated with charge capture is reduced,
It is possible to obtain a solid-state imaging device with improved signal charge transfer efficiency.

According to the solid-state imaging device of the tenth aspect,
The charges of the photodetector are given to the first and second charge-coupled devices via the first and second charge-delivery paths, respectively, and the charge transfer of the first charge-coupled device is performed in the charge-coupled devices arranged orthogonally. Since the end portion on the downstream side in the direction is connected to the upstream side in the charge transfer direction with respect to the end portion on the downstream side in the charge transfer direction of the second charge-coupled device, the first charge is connected to the signal charge and the second charge By giving the charge of 4 to the charge-coupled device as a dummy charge, the dummy charge is given prior to the signal charge, and in the charge-coupled device in the orthogonal arrangement,
Since the dummy charges are first captured by the charge trapping mechanism that hinders the transfer of charges, the rate of trapping the signal charges is reduced, and the charge loss due to the trapping of the signal charges is reduced, thus improving the transfer efficiency of the signal charges. It is possible to obtain the solid-state imaging device.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a driving method of a solid-state image sensor according to a first embodiment of the present invention.

FIG. 2 is a plan view for explaining the configuration of a solid-state image sensor according to a second embodiment of the present invention.

FIG. 3 is a plan view for explaining the configuration of a solid-state image sensor according to a third embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the solid-state image sensor according to the third embodiment of the present invention.

FIG. 5 is a plan view for explaining the structure of a solid-state image sensor according to a fourth embodiment of the present invention.

FIG. 6 is a plan view for explaining the structure of a solid-state image sensor according to a fifth embodiment of the present invention.

FIG. 7 is a plan view for explaining the structure of a solid-state image sensor according to a sixth embodiment of the present invention.

FIG. 8 is a diagram for explaining the operation of the solid-state imaging device of the seventh embodiment according to the present invention.

FIG. 9 is a plan view for explaining the configuration of a solid-state image sensor according to an eighth embodiment of the present invention.

FIG. 10 is a plan view for explaining the structure of a solid-state image sensor according to a ninth embodiment of the present invention.

FIG. 11 is a plan view for explaining the structure of a solid-state image sensor according to a tenth embodiment of the present invention.

FIG. 12 is a plan view for explaining the basic configuration of a conventional solid-state image sensor.

FIG. 13 is a diagram for explaining the operation of the conventional solid-state image sensor.

FIG. 14 is a diagram for explaining the operation of the conventional solid-state imaging device by the fat-zero method.

FIG. 15 is a potential diagram for explaining the operation of the conventional solid-state imaging device by the fat-zero method.

[Explanation of symbols]

17, 33-35, 35A, 35B SCCD, 20,
27 photodetectors, 24, 25, 11a, 11b signal charges, 26, 16a, 16b dummy charges, 28 dummy charge generating photodetectors, 30 to 32, 37 to 41, 180,
190, 200, 210, 220 control gates, 36 branch junctions, 4a to 4i transfer gates, W11 to W14, W21 to W25 potential wells, 80a to 80d, 90a to 90d gate electrodes.

Claims (10)

[Claims] 1. A photodetector array in which photodetectors that generate charges upon irradiation with light are arranged in a row, and a charge-coupled device that transfers the charges output from the photodetectors. In the solid-state imaging device according to claim 1, the charge to be transferred is a signal charge, and a dummy charge having a charge amount equal to the signal charge is given to the charge-coupled device prior to the signal charge. Method. 2. The solid-state imaging device driven by the method for driving a solid-state imaging device according to claim 1, wherein the photodetector outputs the charges as first and second charges having equal charge amounts. First with opening and closing function
And a second charge delivery path, and the first charge delivery path in the charge coupled device is
A solid-state imaging device, which is connected to an upstream side of a charge transfer direction with respect to the second charge delivery path, wherein the first charge is the signal charge and the second charge is the dummy charge. element. 3. The solid-state imaging device driven by the method for driving a solid-state imaging device according to claim 1, wherein the photodetector divides the electric charge into equal amounts of electric charge, and outputs the electric charges at a timing before and after. A solid-state image pickup device, comprising: individual charge-dividing / delivering paths having an opening / closing function, wherein charges given at a previous timing are used as the dummy charges, and charges given at a later timing are used as the signal charges. 4. The solid-state imaging device driven by the method for driving a solid-state imaging device according to claim 1, wherein the electric charge is a first electric charge, the photodetector is a first photodetector, and The detector array is a first photodetector array, and is arranged on the opposite side of the first photodetector array in the same manner as the first photodetector array with the charge coupled device interposed therebetween. And a second photodetector array, wherein the second photodetector constituting the second photodetector array has the same structure as the first photodetector, and the first photodetector array has the same structure as the first photodetector.
Receiving the same amount of light as the photodetector, the second charge having the same charge amount as the first charge is generated, and the first photodetector and the second photodetector are: The charge-coupled device includes first and second charge delivery paths each having an opening / closing function for outputting the first charge and the second charge. A solid-state imaging device, which is connected upstream of a second charge delivery path in the charge transfer direction, wherein the first charge is the signal charge and the second charge is the dummy charge. . 5. The solid-state imaging device driven by the method for driving a solid-state imaging device according to claim 1, wherein the electric charge is a first electric charge, the photodetector is a first photodetector, and The detector array is a first photodetector array, and is arranged on the opposite side of the first photodetector array in the same manner as the first photodetector array with the charge coupled device interposed therebetween. And a second photodetector array, wherein the second photodetector constituting the second photodetector array has the same structure as the first photodetector, and the first photodetector array has the same structure as the first photodetector.
Receiving the same amount of light as the photodetector, the second charge having the same charge amount as the first charge is generated, and the first photodetector and the second photodetector are: First and second charge delivery paths each having an opening / closing function for outputting the first charge and the second charge, respectively, the first charge delivery path and the second charge delivery path. Is
The first charge and the second charge are connected at the same position of the charge-coupled device and are output at the timings before and after, and the second charge given at the previous timing is used as the dummy charge, and the later timing. The solid-state imaging device, wherein the first charge given by the above is used as the signal charge. 6. The solid-state image sensor according to claim 5,
The solid-state imaging device, wherein the second charge delivery path has a storage unit for temporarily storing the second charge. 7. A photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors that generate electric charges upon irradiation with light, are arranged in parallel, and output from the photodetector. A charge-coupled device array in which charge-coupled devices that transfer the charges are provided in each of the photodetector arrays, and an end of the charge-coupled device array on the downstream side in the charge transfer direction is orthogonal to the charge-coupled device array. In the solid-state imaging device composed of the orthogonally arranged charge-coupled devices connected as described above, the photodetectors in the photodetector array row include the charges,
In the charge-coupled device, the first charge delivery path includes first and second charge delivery paths each having an opening / closing function for outputting as first and second charges having an equal charge amount.
The second charge is connected upstream of the second charge delivery path in the charge transfer direction, and the first charge is the signal charge and the second charge is the dummy charge, and the signal charge is preceded by the signal charge. A solid-state imaging device, wherein dummy charges are applied, and the dummy charges are applied prior to the signal charges even in the orthogonally arranged charge coupled device. 8. A photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors that generate electric charges upon irradiation with light, are arranged in parallel, and the photodetector array is output from the photodetector array. A charge-coupled device array in which charge-coupled devices that transfer the charges are provided in each of the photodetector arrays, and an end of the charge-coupled device array on the downstream side in the charge transfer direction is orthogonal to the charge-coupled device array. In the solid-state imaging device configured with the orthogonally arranged charge-coupled device connected in such a manner, the end of the charge-coupled device row on the downstream side in the charge transfer direction is
Branched charge delivery including first and second paths having an opening / closing function, which outputs the charges by dividing them into first and second charges having equal charge amounts by passing through the two branched paths. A path is provided, and in the charge coupled device in the orthogonal arrangement, the first path is connected to an upstream side in the charge transfer direction with respect to the second path, and the first charge is the signal charge. The solid-state imaging device, wherein the second charge is the dummy charge, and in the charge coupled device in the orthogonal arrangement, the dummy charge is given prior to the signal charge. 9. A photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors that generate electric charges upon irradiation with light, are arranged in parallel, and output from the photodetector. A charge-coupled device array in which charge-coupled devices that transfer the charges are provided in each of the photodetector arrays, and an end of the charge-coupled device array on the downstream side in the charge transfer direction is orthogonal to the charge-coupled device array. In the solid-state imaging device configured with the orthogonally arranged charge-coupled device connected in such a manner, the end of the charge-coupled device row on the downstream side in the charge transfer direction is
A charge division / delivery path having an opening / closing function for dividing the electric charge into equal electric charge amounts and outputting the electric charges at the front and rear timings is provided. A solid-state imaging device, wherein the applied charge is the signal charge, and in the charge coupled device in the orthogonal arrangement, the dummy charge is applied prior to the signal charge. 10. A photodetector array row in which a plurality of photodetector arrays, each of which has one row of photodetectors that generate electric charges upon irradiation with light, are arranged in parallel, and output from the photodetector. A charge-coupled device array in which charge-coupled devices that transfer the charges are provided in each of the photodetector arrays, and an end of the charge-coupled device array on the downstream side in the charge transfer direction is orthogonal to the charge-coupled device array. In the solid-state imaging device configured with the charge-coupled devices arranged orthogonally to each other, the charge-coupled devices are provided as first and second charge-coupled devices on both sides of the photodetector array, respectively. The photodetector has a first opening / closing function for outputting the charges as first and second charges having equal charge amounts.
And a second charge delivery path, wherein the first charge delivery path is connected to the first charge coupled device,
The second charge delivery paths are respectively connected to the second charge coupled devices, and in the orthogonally arranged charge coupled devices, an end portion of the first charge coupled device row on the downstream side in the charge transfer direction is the first charge coupled device array. The second charge coupled device array is connected to the upstream side in the charge transfer direction with respect to the downstream end portion in the charge transfer direction, the first charge is the signal charge, and the second charge is the dummy charge. In the orthogonally arranged charge coupled device, the dummy charge is applied prior to the signal charge.