阅读说明：本技术 一种减小交叠耦合的ccd栅结构 (CCD grid structure for reducing overlapping coupling ) 是由 王小东 汪朝敏 钟四成 白雪平 于 2019-09-09 设计创作，主要内容包括：本发明涉及电荷耦合器件的结构,特别涉及一种减小交叠耦合的CCD栅结构,所述栅结构包括至少两相、至少两个驱动栅平铺构成,在相邻的两个驱动栅中,第一驱动栅的上表面设置有至少两个凸式结构,第一驱动栅的凸式结构与第二驱动栅形成交叠区和非交叠区；其中交叠区由第一驱动栅上表面左右两边向上延伸形成突起,该突起部分向外延伸形成的凸式结构,该凸式结构与第二驱动栅形成上下交叠的状态,且第一驱动栅与第二驱动栅及其凸式结构之间无实质接触交叠；本发明制备的CCD结构与传统CCD结构相比,其驱动能力可以提高40％～50％,可减小CCD对复杂驱动电路的依赖,有利于简化CCD的驱动系统、减小耦合、提高CCD系统的性能。(The invention relates to a structure of a charge coupled device, in particular to a CCD (charge coupled device) gate structure for reducing overlapping coupling, which comprises at least two phases and at least two driving gates which are tiled, wherein at least two convex structures are arranged on the upper surface of a first driving gate in two adjacent driving gates, and the convex structures of the first driving gate and a second driving gate form an overlapping area and a non-overlapping area; the overlapped area is formed by upwards extending the left side and the right side of the upper surface of the first driving grid to form a protrusion, the protrusion part outwards extends to form a convex structure, the convex structure and the second driving grid form a vertically overlapped state, and the first driving grid, the second driving grid and the convex structure are not overlapped in a substantially contact mode; compared with the traditional CCD structure, the CCD structure prepared by the invention has the advantages that the driving capability can be improved by 40-50%, the dependence of the CCD on a complex driving circuit can be reduced, the simplification of a CCD driving system is facilitated, the coupling is reduced, and the performance of the CCD system is improved.)

1. The CCD gate structure is characterized in that the gate structure comprises at least two phases and at least two driving gates which are tiled, wherein one of the two adjacent driving gates is a first driving gate, the other one of the two adjacent driving gates is a second driving gate, at least two convex structures are arranged on the upper surface of the first driving gate, and the convex structures of the first driving gate and the second driving gate form an overlapped area and a non-overlapped area; the overlapped area is formed by upwards extending the left side and the right side of the upper surface of the first driving grid to form a protrusion, the protrusion part outwards extends to form a convex structure, the convex structure and the second driving grid form a vertically overlapped state, and the first driving grid, the second driving grid and the convex structure are not overlapped in a substantially contact mode.

2. The CCD gate structure for reducing overlapped coupling of claim 1, wherein the width of the overlapped structure formed by the first driving gate and the second driving gate is greater than or equal to 0.4 μm.

3. The CCD gate structure for reducing overlapped coupling as claimed in claim 1, wherein if the length of the first driving gate is L and N convex structures are disposed on the first driving gate, the length of each overlapped region and non-overlapped region is L/(2N-1).

4. The CCD gate structure for reducing overlapped coupling of claim 1, wherein the outward extending portions of both sides of the upper portion of the first driving gate are at an angle of 90 ° or 135 ° with the sides of the first driving gate, so that the outward extending portions of the first driving gate are rectangular or trapezoidal.

5. The CCD gate structure of claim 1, wherein the overlap region is a signal transfer region and the non-overlap region is a non-signal transfer region.

Technical Field

The present invention relates to a structure of a Charge Coupled Device (CCD) and, more particularly, to a CCD gate structure for reducing overlap coupling.

Background

A charge Coupled device (ccd) is a miniature image sensor, which has both photoelectric conversion function and signal storage, transfer, and conversion functions, and can convert an image distributed in a spatial domain into an electrical signal discretely distributed in a time domain. The method has the advantages of high sensitivity, wide spectral response, large dynamic range, small pixel size, high geometric precision, good imaging quality, vibration resistance, radiation resistance and the like.

As shown in fig. 1, the transfer gate overlapping area of the conventional CCD is a square overlapping area with two parallel sides, and the width of the overlapping area determines the transfer performance of the CCD. Due to certain process manufacturing deviation, if the overlapping width d in the X direction is small (typically less than 0.4 μm), the manufactured CCD may have an overlapped gate being over-etched, which may cause an electric field under the gate not to well control the transfer of signals, resulting in low transfer efficiency; if the overlap width d is large (typically greater than or equal to 0.4 μm), the driving capability of the driving phase with high frequency, large amplitude, high voltage and the like is limited due to the large area of the overlap region of the manufactured CCD, so that the working performance of the CCD is affected.

Disclosure of Invention

In order to improve the working performance of the CCD, the invention provides a CCD gate structure for reducing overlapping coupling, the gate structure comprises at least two phases and at least two driving gates which are tiled, one of the two adjacent driving gates is a first driving gate, the other one is a second driving gate, the upper surface of the first driving gate is provided with at least two convex structures, and the convex structures of the first driving gate and the second driving gate form an overlapping area and a non-overlapping area; the overlapped area is formed by upwards extending the left side and the right side of the upper surface of the first driving grid to form a protrusion, the protrusion part outwards extends to form a convex structure, the convex structure and the second driving grid form a vertically overlapped state, and the first driving grid, the second driving grid and the convex structure are not overlapped in a substantially contact mode.

Further, the overlapped width of the structure formed by the first driving gate and the second driving gate and overlapped up and down is more than or equal to 0.4 μm.

Further, if the length of the first driving gate is L and N convex structures are disposed on the first driving gate, the length of each overlapping region and each non-overlapping region is L/(2N-1).

Furthermore, the outward extending parts of the two sides of the upper part of the first driving grid form an angle of 90 degrees or 135 degrees with the edges of the first driving grid, so that the outward extending part of the first driving grid is rectangular or trapezoidal.

Furthermore, the overlapping area is a signal transfer area, and the non-overlapping area is a non-signal transfer area.

Further, the gate structure in the CCD device includes a tiled arrangement of two or more integer phase driving gates.

Compared with the traditional CCD structure, the CCD structure prepared by the invention has the advantages that the driving capability can be improved by 40-50%, the requirements of the CCD on high driving capability such as high frequency, large swing amplitude and high voltage can be met, the dependence on a complex driving circuit is reduced, the drive system of the CCD is simplified, the coupling is reduced, and the performance of the CCD system is improved.

Drawings

FIG. 1 is a schematic diagram of an overlapping structure between conventional CCD driving gates;

FIG. 2 is a structural diagram after over-etching when the overlap in the X direction between the driving gates of the conventional CCD is less than 0.4 μm;

FIG. 3 is a cross-sectional view of the driving gate overlapping structure of the present invention, wherein (a) is a cross-sectional view taken along line X1 in FIG. 3, and (b) is a cross-sectional view taken along line X2 in FIG. 3;

v1, a first drive gate; v2, second drive gate; x1, tangent at overlap region; x2, tangent at non-overlapping region; d. the width of the overlap between the drive gates.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to improve the working performance of the CCD, the invention provides a CCD gate structure for reducing overlapping coupling, the gate structure comprises at least two phases and at least two driving gates which are tiled, one of the two adjacent driving gates is a first driving gate, the other one is a second driving gate, the upper surface of the first driving gate is provided with at least two convex structures, and the convex structures of the first driving gate and the second driving gate form an overlapping area and a non-overlapping area; the overlapped area is formed by upwards extending the left side and the right side of the upper surface of the first driving grid to form a protrusion, the protrusion part outwards extends to form a convex structure, the convex structure and the second driving grid form a vertically overlapped state, and the first driving grid, the second driving grid and the convex structure are not overlapped in a substantially contact mode; aiming at the problems of the traditional CCD transfer gate overlapping area, the invention creatively provides a convex-concave overlapping covering structure instead of a conventional square overlapping structure with two parallel sides; therefore, the effective overlapping width (typically more than or equal to 0.4 mu m) of the convex overlapping region is met, and the electric field under the gate of the overlapping region can effectively control the normal transfer of charges; and the reduction of the area of the overlapping region is met, so that the overlapping capacitance is reduced, the coupling between the overlapping gates is reduced, and the overlapping area between every two adjacent driving gates can be reduced by 40-50%. The method is particularly suitable for the CCD with multi-stage transfer, and the total overlapping capacitance can be reduced by 40-50%.

Further, the overlapped width of the structure formed by the first driving gate and the second driving gate and overlapped up and down is more than or equal to 0.4 μm; as shown in fig. 2, when the overlap between the conventional CCD driving gates is less than 0.4 μm, after the overlap region is over-etched, due to existence of non-ideal factors such as process deviation, the two-phase overlap region may be too small or not overlapped, so that a potential barrier exists in an electric field under the gate of the two-phase overlap region, which causes a decrease in transfer efficiency and affects CCD performance, and thus the overlap width selected by the present invention is greater than or equal to 0.4 μm.

Further, if the length of the first driving gate is L, N convex-concave overlapping structures are arranged on the driving gate, and if the length of the driving gate is L and N convex structures are arranged on the first driving gate, the length of each overlapping region and each non-overlapping region is L/(2N-1).

Furthermore, the outward extending parts of the two sides of the upper part of the first driving grid form an angle of 90 degrees or 135 degrees with the edges of the first driving grid, so that the outward extending parts of the first driving grid are rectangular or trapezoidal; preferably, as shown in fig. 3, in the present embodiment, an angle of 135 ° is used, so that the outward extension portion of the first driving gate is trapezoidal.

Further, the gate structure in the CCD device includes two or more phases of driving gates; as shown in fig. 3, the total number of two-phase driving gates and driving gates is 4, wherein the number of the first driving gates is 2, the two driving gates are in phase, the number of the second driving gates is 2 and in phase, the number of the convex structures on the first driving gate is 4, the overlapping areas of the adjacent two phases at different positions are different in a concave-convex overlapping manner, the non-overlapping area is a concave part of the second driving gate V2 and is flush with the gate of the adjacent first driving gate V1, a non-overlapping barrier is formed under the gate between the two phases, the non-overlapping area is not a special signal transfer area, see the tangential structure of X2 in fig. 3(b), and the barrier in the non-overlapping area is as shown in fig. 3 (b); the overlapping area is a protruding part of the second driving gate V2, covers the adjacent first driving gate V1, the typical width of the two phases overlapping is greater than or equal to 0.4 μm, the problem of two phases overlapping caused by etching process deviation is avoided, and the overlapping capacitance of the two phases is greatly reduced, the area is a special signal transfer area, see an X1 tangent structure in fig. 3(a), and the potential barrier of the overlapping area is as shown in fig. 3 (a).

The invention can be used in a structure which is not limited to 2-phase driving, and more than two integer driving grids can be used.

In the invention, the first driving gate is a driving gate with a convex structure, and the width and the phase of the first driving gate can be selected according to actual conditions; similarly, the second driving gate is a driving gate without a convex structure, and the width and the phase of the second driving gate can be selected according to actual conditions; the first driving gates and the second driving gates are alternately tiled to form the gate structure in the present invention, for example, the four driving gates in fig. 3 have the same length, but the phases of the four driving gates may be different.

In the description of the present invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inner", "outer", "front", "center", "both ends", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "disposed," "connected," "fixed," "rotated," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; the terms may be directly connected or indirectly connected through an intermediate, and may be communication between two elements or interaction relationship between two elements, unless otherwise specifically limited, and the specific meaning of the terms in the present invention will be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.