JPH06268189A - Solid-state image sensing device - Google Patents

Abstract

PURPOSE:To prevent a deterioration in characteristics even for a highly integrat ed device effectively, by providing two photoelectric conversion-element rows on a projected or recessed side, and a transfer means including two registers and a common transfer electrode on the other side. CONSTITUTION:Two photoelectric conversion-element rows 41 and 42 are provided on a face of a projected part, while two registers 61 and 62 formed by ion-implantation and a transfer stage 5 in a transfer electrode 8 for driving these registers 61 and 62, are provided at a recessed part. Each photosensitive part 4a1 or 4a2 of the photoelectric conversion-element rows 41 and 42 formed on the projected part is insulated through a shield layer 4b. The two registers 61 and 62 at the transfer stage 5 formed on the side and lower face of the recessed part are insulated through a device isolation layer 7 and covered with the transfer electrode 8 through an insulating film 9 in between. After the registers 61 and 62 receive each signal charge from the photosensitive part 4a1 or 4a2 at the left or right photoelectric conversion-element row 41 or 42, the registers 61 and 62 generate each output signal to the outside.

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.

[0002]

2. Description of the Related Art A plan view of a conventional solid-state image pickup device is shown in FIG. 6, and a sectional view taken along a section line YY 'is shown in FIG. In FIG. 6, the plurality of photoelectric conversion elements 4 are arranged in a matrix, and a transfer stage 5 is provided between each column of the photoelectric conversion elements 4. The transfer stage 5 is provided corresponding to the photoelectric conversion element array (the element array on the left side in FIG. 6), and the register 6 for transferring the signal charge converted by the corresponding photoelectric conversion element array, It has a transfer electrode 8 for driving the register 6 (see FIG. 7). Also, although it is adjacent,
The register 6 and the photosensitive portion 4a of the photoelectric conversion element 4 that do not correspond to each other
A shield layer 4b made of an insulating material is provided between and. The photosensitive portion 4a, the shield layer 4b, and the transfer electrode 8 are covered with a transparent insulating film 9.

In the solid-state image pickup device shown in FIG. 7, the register 6 of the transfer stage 5 and the photosensitive portion 4a of the photoelectric conversion element 4 are formed on substantially the same surface of the semiconductor substrate (for example, P-type substrate) 1. . However, as shown in the cross-sectional views of FIG. 8 and FIG. 9, the transfer stage 5 including the register 6 and the transfer electrode 8 is not formed on the same plane as the photosensitive portion 4a, and the step portion of the surface of the semiconductor substrate 1 is not formed. Some are formed in concave portions or convex portions. The solid-state image pickup devices shown in FIGS. 7, 8 and 9 are all formed on the P-type semiconductor substrate 1, but there are also those formed on the P-well 3 on the N-type substrate 2 as shown in FIG. .

[0004]

When such a conventional solid-state image pickup device is highly integrated, the number of photoelectric conversion elements for the same light receiving area increases, so that the area occupied by each photosensitive portion 4a and the register 6 becomes small. Therefore, there is a problem that the characteristics of the solid-state imaging device are deteriorated.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a solid-state image pickup device capable of preventing deterioration of characteristics as much as possible even with high integration. .

[0006]

A solid-state image pickup device according to the present invention is provided with a plurality of stepped portions formed on a surface of a semiconductor substrate, the convex portions and concave portions extending in the same direction, and one of the convex portions and the concave portions has two rows. Row of photoelectric conversion elements is formed, and the first row is formed on the other side.
And a second register and a transfer stage having a common transfer electrode for driving these registers are formed, and the first and second registers are formed along the other side wall and are adjacent to each other. It is characterized in that the signal charge is received and transferred from the photosensitive section of the column, and the transfer electrode is formed so as to cover the first and second registers.

[0007]

According to the solid-state image pickup device of the present invention configured as described above, two rows of photoelectric conversion element rows are formed in one of the convex portion and the concave portion, and two registers and a common transfer electrode are formed in the other. A transfer stage is formed having Thereby, without reducing the area of the photosensitive portion of the photoelectric conversion element, that is,
High integration can be achieved without deteriorating the characteristics.

[0008]

1 is a plan view of a first embodiment of a solid-state image pickup device according to the present invention, and FIG. 1 is a sectional view thereof. In the solid-state imaging device of this embodiment, the semiconductor substrate 1 is provided with a step formed of a convex portion and a concave portion by etching or the like (see FIG. 5B). Two rows of photoelectric conversion elements 4 ₁ and 4 ₂ are provided on the upper surface of the convex portion, and in the concave portion, two registers 6 ₁ and 6 ₂ formed by ion implantation and these registers are formed. A transfer stage 5 including a transfer electrode 8 that drives 6 ₁ and 6 ₂ is provided.
The photosensitive portions 4a and 4a ₂ of the two rows of photoelectric conversion element rows 4 ₁ and 4 ₂ provided on the convex portion are insulated via the shield layer 4b. The two registers 6 ₁ and 6 ₂ of the transfer stage 5 provided on the side wall and the lower surface of the recess are insulated by the element isolation layer 7 and covered by the transfer electrode 8 via the insulating film 9. The register 6 ₁ receives a signal charge from the photosensitive portion 4a of the photoelectric conversion element array 4 _{1 on} the left side thereof, and the register 6 ₂ receives the photoelectric conversion element array 4 on the right side thereof.
_The signal charge is received from the _second photosensitive portion 4a ₂ . Then, these signal charges are respectively transferred in the registers 6 ₁ and 6 ₂ by a driving pallet applied to the transfer electrode 8 and sent to a horizontal transfer stage (not shown), and output to the outside via this horizontal transfer stage.

As described above, the concave portion of the step portion is provided with two registers driven by the same transfer electrode 8, and the convex portion is provided with two rows of photoelectric conversion elements. If the width of the recess is set to be the width of the conventional single register, high integration can be achieved without reducing the area of the photosensitive portion of the photoelectric conversion element. That is, it is possible to prevent the deterioration of the characteristics as much as possible even with high integration.

In the above embodiment, two rows of photoelectric conversion element arrays 4 ₁ and 4 ₂ are provided in the convex portion of the stepped portion, and two registers 6 ₁ and 6 ₂ and one transfer portion are provided in the concave portion. Although the transfer stage 5 including the electrodes 8 is provided, as shown in FIG. 2, a transfer stage including two registers 6 ₁ and 6 ₂ and one transfer electrode 8 is provided in the convex portion, and two rows of photoelectric cells are provided in the concave portion. The conversion element arrays 4 ₁ and 4 ₂ may be provided. The surface shape of the substrate 1 at this time (X-
The X'section) has a shape as shown in FIG.

The cross-sectional shape of the convex portion may be trapezoidal as shown in FIG. 5 (d). A cross-sectional view of the solid-state imaging device in this case is shown in FIG. Further, the cross-sectional shape of the recess may be trapezoidal as shown in FIG.

Further, in the above embodiment, the photoelectric conversion element array and the transfer stage are formed on the P-type substrate 1, but as shown in FIG. 4, the P-well 3 is provided on the N-type substrate 2 and the P-well 3 is formed. The photoelectric conversion element arrays 4 ₁ and 4 ₂ and the transfer stage 5 may be formed thereover.

[0013]

As described above, according to the present invention, high integration can be achieved without deteriorating the characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a first embodiment of a solid-state imaging device according to the present invention.

FIG. 2 is a sectional view showing the structure of the second embodiment.

FIG. 3 is a sectional view showing the structure of a third embodiment.

FIG. 4 is a sectional view showing the structure of the fourth embodiment.

FIG. 5 is an explanatory diagram illustrating a step structure of the solid-state imaging device of the present invention.

FIG. 6 is a plan view of a conventional solid-state imaging device.

FIG. 7 is a sectional view of a conventional solid-state imaging device.

FIG. 8 is a sectional view of another conventional solid-state imaging device.

FIG. 9 is a sectional view of another conventional solid-state imaging device.

FIG. 10 is a sectional view of another conventional solid-state imaging device.

[Explanation of symbols]

1, 2 Semiconductor substrate 3 Well 4 ₁ , 4 ₂ Photoelectric conversion element 4a ₁ , 4a ₂ Photosensitive portion 4b Shield layer 5 Transfer stage 6 ₁ , 6 ₂ Register 7 Element separation layer 8 Transfer electrode 9 Insulation film

Claims (1)

[Claims] 1. A semiconductor substrate is provided with a plurality of step portions formed of a convex portion and a concave portion extending in the same direction on the surface of the semiconductor substrate, two photoelectric conversion element rows are formed on one of the convex portion and the concave portion, and the other is formed on the other side. A transfer stage having first and second registers and a common transfer electrode for driving the registers is formed, and the first and second registers are formed along the other side wall and are adjacent to each other. A solid-state imaging device, wherein signal charges are received and transferred from a photosensitive section of an element array, and the transfer electrodes are formed so as to cover the first and second registers.