JPS6346770A - Change coupled device - Google Patents

Abstract

PURPOSE:To obtain a high density charge coupled device adapted for 2-phase drive by not overlapping the electrode of a device first phase second layer with that of a second phase first layer, and not overlapping the electrode of a second phase second layer with that of a first phase first layer. CONSTITUTION:The electrodes of a first layer, such as electrodes 11, 14 are electrically connected, for example, to those of a second layer, such as electrodes 13, 16 to form one transfer electrode phi1, and the electrode 12 is electrically connected, for example, to the electrode 15 to form another transfer electrode phi2, there by forming a 2-phase driving transfer electrode. Here, the electrode of the second layer which forms the electrode phi1, such as the electrode 14 and the electrode of the first layer which forms the electrode phi2, such as the electrode 12 are not overlapped, and the electrode of the second layer which forms the electrode phi2, such as the electrode 15 and the electrode of the first layer which forms the electrode phi1, such as the electrode 13 are not overlapped. Thus, the size of an element can be largely reduced to form a high density charge coupled device.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a two-phase drive charge-coupled device, and in particular a two-phase drive charge-coupled device that enables high density and low power consumption. Regarding.

[Conventional technology]

In recent years, two-dimensional solid-state image sensing devices using charge-coupled devices have tended to increase the number of pixels in the horizontal direction in order to achieve higher image quality and higher resolution. On the other hand, the miniaturization of cameras,
Reducing chip size has become an essential issue in order to improve device yield. In order to simultaneously achieve such high resolution and reduction in chip size, it is inevitable to increase the density of elements.

By the way, in order to increase the density of such a two-dimensional solid-state image sensor, it is necessary to form horizontal registers constituting the two-dimensional solid-state image sensor at a high density.

Conventionally, horizontal registers have generally adopted a two-phase drive system that allows high-speed drive, and an overlapping electrode structure that facilitates element formation. FIG. 2 shows a cross section of the main part of a conventional horizontal register. Note that in the following description, for convenience of explanation, the case of N channel will be described, but the same concept can be applied to the case of P channel. In the figure, 1 is a semiconductor substrate, for example, P-type silicon. Reference numeral 2 denotes a semiconductor layer of a conductivity type opposite to that of the semiconductor substrate 1, in this case an N-type semiconductor layer, which constitutes a buried channel charge-coupled device. 3
is an oxide film, 4 to 6 are electrodes of the first layer, 7°8 are electrodes of the second layer, 9 and 10 are formed directly under the electrodes 7 and 8 of the second layer, and have a lower concentration than the semiconductor layer 2. A potential barrier is generated in a semiconductor region to give directionality to the transfer of signal charges. Here, for example, the electrode 4 of the first layer and the electrode 7 of the second layer are electrically connected to each other and constitute the first phase φ1 of the two-phase drive, and the electrode 5 of the first layer and the electrode 7 of the second layer are The electrodes 8 are electrically connected to each other and form a second phase φ2 of two-phase drive. In addition, in this charge coupled device, the first layer electrodes 4 to 6
Immediately below constitutes a signal charge accumulation region, the second layer electrode 7,
The area directly below 8 constitutes a potential barrier region.

In such conventional two-phase drive charge-coupled devices, in order to transfer signal charges inside the channel without any problems,
A stacked electrode structure as shown in FIG. 2 is employed. Therefore, the electrode length t, o per -transfer pole is:
The electrode gap length of the first layer, for example, the gap length G1 between electrodes 4 and 5
, the electrode gap length of the second layer, for example, the gap length G2 of electrodes 7 and 8, the first layer electrode that constitutes φ1, for example electrode 4, and the second layer electrode that also constitutes φ1, for example electrode 7. a second layer electrode constituting an overlap length 01 and φ1,
For example, the sum of the overlap length 02 between the electrode 7 and the first layer electrode forming ψ2, for example, the electrode 5, that is, t, o=G,
+Q2+Q, given by +02.

Therefore, the electrode length of the unit element of the two-phase drive charge-coupled device is given by 2XL. In general, these values c
, , G2, 01 and 02 are exposure techniques.

Minimum dimensions are required due to various factors such as alignment technology and processing technology, which determines the electrode length of a unit device, which naturally limits the ability to increase the density of two-phase drive charge-coupled devices. .

[Problem that the invention seeks to solve]

As described above, in the conventional technology, stacked electrodes are used as the electrode structure of a two-phase drive charge-coupled device, and it is difficult to realize a high-density device.

An object of the present invention is to provide a high-density charge coupled device suitable for two-phase drive by solving such conventional problems.

[Means for solving problems]

In the present invention, a first layer electrode and a second layer electrode are connected to each other to form one transfer electrode, and the two transfer electrodes form a pair of transfer electrodes consisting of a first phase and a second phase. In a two-phase drive charge-coupled device configured with The electrodes of the layer are characterized in that they do not overlap the electrodes of the first layer of the first phase.

[Effect]

In the two-phase drive charge coupled device of the present invention, the electrodes of the second layer of the first phase do not overlap the electrodes of the first layer of the second phase, and the electrodes of the second layer of the second phase do not overlap with the electrodes of the first layer of the second phase. Since the electrodes of the layer do not overlap with the electrodes of the first layer of the first phase, the mold length 02 is unnecessary, high density is achieved, and the interphase dielectric of the first and second phases Capacity is reduced.

〔Example〕

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

FIG. 1 shows the main parts of an embodiment according to the present invention, and shows a sectional view of the main parts of a two-phase drive charge-coupled device. In the figure, the same numbers as in FIG. 2 indicate the same components. Reference numerals 11 to 13 indicate the electrodes of the first layer, and 14 to 16 indicate the electrodes of the second layer. One transfer electrode φ1 is formed by electrically connecting the electrodes 12 and 15, and another transfer electrode φ2 is formed by electrically connecting the electrodes 12 and 15, thereby forming a two-phase drive transfer electrode. There is. The main difference between this embodiment and the conventional example is that the second layer electrode, for example, electrode 14, which constitutes transfer electrode φ1, and the first layer electrode, for example, electrode 12, which constitutes transfer electrode φ2, do not overlap. First, similarly, a second layer electrode, for example electrode 15, which constitutes transfer electrode φ2, and a first layer electrode, for example electrode 1, which constitutes transfer electrode φ1.
3 do not overlap. Therefore, the two-phase drive according to the invention! is the length L of one transfer electrode of the charge-coupled element
N is given by r-N=c, +c2+Q. That is, compared to the conventional element, 02 parts are unnecessary. As a result,
The electrode length per unit element is 2×02 compared to conventional elements.
It can be composed as short as possible. Looking at specific numbers, for example,
If G+ = 02 = O1 = 02 = 1.5 μm, then Lo -6.0 μm in the prior art and LN -4.5 μm in the present invention. The electrode length per unit device can be shortened by 3.0 μm, allowing a significant reduction in device dimensions and forming a high-density charge-coupled device.

Another advantage of the two-phase drive charge-coupled device according to the present invention is that the transfer electrode φI and the transfer electrode φ2 do not overlap each other, so that the interphase dielectric capacitance is significantly reduced compared to conventional devices. .

As a result, the load capacity of the external drive circuit that drives transfer electrode φ1 and transfer electrode φ2 is reduced, and the power consumption of the drive circuit can be reduced.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize a two-phase drive charge coupled device with extremely high density and low power consumption.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part of a charge coupled device according to the present invention, and FIG. 2 is a sectional view of the main part of a conventional charge coupled device. Process: Semiconductor substrate 2: Buried channel semiconductor layer 3: Oxide film

Claims (1)

[Claims] (1) The first layer electrode and the second layer electrode are connected to each other to form one transfer electrode, and these two transfer electrodes form a pair of transfer electrodes consisting of a first phase and a second phase. In a two-phase drive charge-coupled device configured, the electrode of the second layer of the first phase does not overlap the electrode of the first layer of the second phase, and the electrode of the second layer of the second phase does not overlap with the electrode of the first layer of the second phase. A charge coupled device characterized in that the electrodes of the layers do not overlap the electrodes of the first layer of the first phase.