JPH0316231A - Charge transfer device - Google Patents

Abstract

PURPOSE:To improve transfer efficiency by arranging the constitution such that the effective electrode region inside a transfer electrode inclines at an angle excluding 90 deg. to the irregularity or transfer direction. CONSTITUTION:One or more transfer electrodes are provided, each of which has such structure that the effective electrode region 9, which gives potential to a charge transfer region 4 at the region excluding the region 10 for performing superposition with an adjacent electrode, inclines at an angle excluding 90 deg. to the irregularity or transfer direction. By this constitution, the length 9 of effective electrode region becomes short, so a region 6 with no potential gradient under the transfer electrode 1 becomes narrow, and a region 7 with a potential gradient can be widened. Accordingly, the quantity of charge which remains at the the region 6 with no gradient under the transfer electrode decreases, and the transfer electrode 1 can be driven by transfer pulses of low voltage. Hereby, transfer efficiency can be improved.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electrode transfer device.

2. Description of the Related Art In recent years, solid-state imaging devices incorporating charge transfer devices have been developed, and efforts have been made to improve the performance of solid-state imaging devices.

FIG. 6 is a block diagram of a conventional charge transfer device.

1 is a transfer electrode, 2 is a charge input section, 3 is a charge output section, 4 is a charge transfer region, and 5 is a repetition pitch of the transfer electrodes.

The charges in the charge input section 2 are transferred to the charge output section 3 by applying transfer pulses φ2, φ3, φ4, and φ5 to the transfer electrode 1.

FIG. 7 is a cross-sectional potential diagram taken along line AA' in FIG. 6 is a potential flat area that is not affected by the adjacent transfer electrode, 7 is a potential gradient area that is affected by the adjacent transfer electrode, 8 is a charge, and 9 is an effective electrode area that applies a potential to the charge transfer area and transfers the charge. The length 10 is the length of the area for overlapping with the adjacent electrode. FIG. 7 is a potential diagram when there is a potential relationship of φ1, φ2, and φ3. The charge under the transfer electrode 1 to which φ1 is applied is φ! It is accelerated by the potential gradient region 7 at the boundary of the transfer electrode 1 where φ2 is applied and moves below the transfer electrode 1 where φ2 is applied. The charges under the transfer electrode 1 to which φ2 is applied are accelerated by the potential gradient region 7 at the boundary between the electrodes 1 to which φ2 and φ3 are applied, and move under the transfer electrode 1 to which φ3 is applied. As described above, the charge under the transfer electrode 1 where jff of φ1 is transferred to the transfer electrode where φ3 is added.

FIG. 8 is a diagram showing the potential flat region 6 under the transfer electrode 1 of FIG. 6. The potential flat region 6 under the transfer electrode 1 is wide, and when the charge 8 injected from the charge input section 2 is transferred by applying a pulse to the transfer electrode 1 and taken out to the charge output section 3, the charge 7 becomes potential flat many times. It will pass through the area.

Problems to be Solved by the Invention However, in the above structure, since the length 9 of the effective electrode area is equal to the repeat pitch 5 of the transfer electrode, the potential flat area 6 becomes wide, and the potential flat area 6 has no charge. A portion remains, and the transfer efficiency of the charge-coupled device deteriorates.

In view of the above drawbacks, the present invention provides a charge transfer device having a short transfer electrode length so that the potential flat region 6 under the transfer electrode 1 is narrow.

Means for Solving the Problems In order to solve the above problems, the charge transfer device of the present invention includes a charge transfer device including a plurality of transfer electrodes, in which adjacent electrodes in the transfer electrodes are overlapped. At least the transfer electrode is a region other than the region for the charge transfer device, and the effective electrode region that applies a potential to the charge transfer region is uneven or has a structure inclined at an angle other than 90' with respect to the transfer direction of the charge transfer device. , is configured to have one or more.

Effect: With this configuration, the length of the effective electrode area is shortened, so the potential flat area under the transfer electrode is narrowed, and the potential gradient is increased. The fl region 7 can be made wider. Therefore, the amount of charge remaining in the potential flat region 6 under the transfer electrode is reduced, and the transfer efficiency of the charge-coupled device can be improved. Furthermore, since the potential gradient region 7 is widened, the transfer electrode can be driven with a low voltage transfer pulse.

EXAMPLE Hereinafter, a first example of the present invention will be described with reference to the drawings. FIG. 1 is a structural diagram of a charge transfer device in an embodiment of the present invention. The transfer electrode 1 has an uneven structure.

FIG. 2 is a cross-sectional potential diagram taken along line BB' in FIG. The length 9 of the effective electrode area between B and B' is shorter than the conventional transfer electrode repetition pitch 5 shown in FIG.
Under the transfer electrode 1 where the transfer electrode 2 is applied, there is only a potential gradient region 7 due to the influence of the adjacent transfer electrode. Therefore, there is no potential flat region 6 between B-8', and no charges are left behind in the potential flat region 6, so that the transfer efficiency of the charge coupled device can be improved.

FIG. 3 is a diagram showing the potential flat region 6 under the transfer electrode 1 of FIG. 1. Compared to FIG. 6, the potential flat area 6 is extremely small, and the amount of charge left behind in the potential flat area 6 is reduced. Therefore, the transfer efficiency when taking out the charge 8 injected from the charge input section 2 to the charge output section 3 can be significantly improved.

FIG. 4 1-1 is a configuration diagram of a charge transfer device in a second embodiment of the present invention. The transfer electrode 1 has a structure inclined at 45 degrees with respect to the transfer direction of the charge transfer device.

FIG. 5 is a diagram showing the potential flat region 6 under the transfer electrode 1 of FIG. 4. Since the length 9 of the effective electrode area is shorter than the repeat pitch 5 of the transfer electrode, the width of the potential flat area 6 is extremely narrow compared to FIG.
The amount of charge left behind in the potential flat region 6 is reduced. Therefore, the transfer efficiency when taking out the charge 8 injected from the charge input section 2 to the charge output section 3 can be significantly improved.

The first embodiment and the second embodiment of the present invention are examples of five transfer electrodes having the same repetition bit 5 of the transfer electrodes.
A similar effect can be obtained even when there is only one repetition.

In addition, if the length of the effective electrode area of the transfer electrode outside the range where repetition is performed is shorter than the length of the effective power region of the range where repetition is performed, Transfer efficiency can also be improved in certain transfer electrode regions.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a charge transfer device according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line BB' in FIG. 1, and FIG. 3 is a potential flat region under the transfer electrode in FIG. 1. 4 is a block diagram of the charge transfer device in the second embodiment, FIG. 5 is a diagram showing the potential flat region under the transfer electrode in FIG. 4, and FIG. 7 is a cross-sectional potential diagram taken along line AA' in FIG. 6, and FIG. 8 is a diagram showing a potential flat region under the transfer electrode in FIG. 6. 1... Transfer electrode, 2... Charge input section,
3...Charge output section, 4...Charge transfer region, 5...Repetition pitch of transfer electrode, 6...
...Potential flat region, 7...Potential gradient region, 8...Charge, 9...
Effective transfer electrode length, 10...A region for overlapping with the adjacent electrode.

Claims (5)

[Claims] (1) The effective electrode area that applies a potential to the charge transfer area, other than the area that is provided with a plurality of transfer electrodes and is overlapped with an adjacent electrode in the transfer electrode, is uneven or in the transfer direction of the charge transfer device. A charge transfer device comprising at least one transfer electrode having a structure inclined at an angle other than 90° with respect to the charge transfer device. (2) To superimpose the transfer electrodes with adjacent electrodes in the range in which the transfer electrodes are repeated M times with a period of length L using N transfer electrodes in the transfer direction of the charge transfer device. Claim 1, wherein each of the transfer electrodes has a structure in which the shortest length of an effective electrode area that applies a potential to the charge transfer area is shorter than L/N, other than the area. charge transfer device. (3) In order to overlap the transfer electrode with the adjacent electrode in the range where the transfer electrode is repeated M times at a period of length L using N transfer electrodes in the transfer direction of the charge transfer device. No matter where you measure from any point on the charge input side end of the effective electrode area that applies the potential to the charge transfer area, other than the area
The charge transfer device according to claim 1, wherein each of the transfer electrodes has a structure in which the shortest distance to the charge output side is equal to or less than L/N. (4) With respect to the transfer direction of the charge transfer device, in the transfer electrode in a range other than the range in which the transfer electrode is repeated M times with a period of length L using N transfer electrodes, adjacent transfer electrodes in the transfer electrode The shortest length of the effective electrode area that applies a potential to the charge transfer area, other than the area for overlapping with the electrode, is L.
2. The charge transfer device according to claim 1, wherein each of said transfer electrodes has a structure shorter than /N. (5) With respect to the transfer direction of the charge transfer device, in the transfer electrode in a range other than the range in which the transfer electrode is repeated M times with a period of length L using N transfer electrodes, adjacent transfer electrodes in the transfer electrode The shortest distance to the charge output side of the effective electrode area is measured from any point on the charge input side of the effective electrode area that applies a potential to the charge transfer area other than the area for overlapping with the electrode. 2. The charge transfer device according to claim 1, wherein each of said transfer electrodes has a structure of L/N or less.