Image pickup apparatus and image pickup system

• US 20060043393A1
• Filed: 08/29/2005
• Published: 03/02/2006
• Est. Priority Date: 09/01/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ogura, Masanori, Okita, Akira, Watanabe, Takanori, Sakai, Seiichiro
• Granted Patent: US 7,514,732 B2
• Time in Patent Office: Days
• US Class Current: 257/93
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements

Abstract

To provide a solid-state image pickup apparatus with little or no difference in the dark currents between adjacent photoelectric conversion elements and providing a high sensitivity and a low dark current even in a high-speed readout operation.

A well 302 is formed on a wafer 301, and semiconductor layers 101a, 101b are formed in the well to constitute photodiodes. A well contact 306 is formed between the semiconductor layers 101a, 101b. Element isolation regions 303b, 303a are provided between the well contact and the semiconductor layers, and channel stop layers 307b, 307a are provided under the element isolation regions 303b, 303a. A conductive layer 304 is provided on the element isolation region 303b, and a side wall 308 is provided on a side face of the conductive layer 304. A distance a between an end of the element isolation region 303b and the conductive layer 304, a width b of the side wall 308 and a device isolation width c satisfy a relation c>a≧b.

Claims

1. An image pickup apparatus including a photoelectric conversion element which has a first semiconductor region of a first conductive type, and a second semiconductor region of a second conductive type constituting a junction with the first semiconductor region, a third semiconductor region of a first conductive type, provided in the first semiconductor region for providing a potential of the first semiconductor region for a predetermined potential, an element isolation region provided between the third semiconductor region and the second semiconductor region, a conductive layer provided on the element isolation region, and a fourth semiconductor region of a first conductive type provided under the element isolation region:

the apparatus comprising a side wall on a side of the conductive layer, wherein a width c of the element isolation region, a width b of the side wall and a distance a between an end of the element isolation region at the side of the third semiconductor region and an end of the conductive layer at the side of the third semiconductor region satisfy a relation c>

a≧

b.

2. An image pickup apparatus including a photoelectric conversion element which has a first semiconductor region of a first conductive type, and a second semiconductor region of a second conductive type constituting a junction with the first semiconductor region, a third semiconductor region of a first conductive type, provided in the first semiconductor region for providing a potential of the first semiconductor region for a predetermined potential, a element isolation region provided between the third semiconductor region and the second semiconductor region, a conductive layer provided on the element isolation region, and a fourth semiconductor region of a first conductive type provided under the element isolation region:

the apparatus comprising a side wall on a side of the conductive layer, wherein the side wall is provided on the element isolation region in such a manner that an external end of the side wall does not exceed an end of the element isolation region.

3. An image pickup apparatus according to claim 2, wherein the third semiconductor region is in contact with the four semiconductor region.

4. An image pickup apparatus according to claim 2, further comprising a transfer transistor for transferring carriers accumulated in the second semiconductor region, wherein the conductive layer constitutes a part of a gate electrode of the transfer transistor.

5. An image pickup apparatus according to claim 2, further comprising a floating diffusion region, a transfer transistor provided for each second semiconductor region for transferring carriers accumulated in the second semiconductor region to the floating diffusion region, an amplifying transistor of which a gate electrode is connected with the floating diffusion region, a selecting transistor connected to the amplifying transistor, and a reset transistor for resetting at least the floating diffusion region;

wherein the conductive layer constitutes a part of a gate electrode of the transfer transistor, a gate electrode of the amplifying transistor, a gate electrode of the selecting transistor or a gate electrode of the reset transistor.

6. An image pickup apparatus according to claim 2, wherein the second semiconductor regions are arranged one-dimensionally or two-dimensionally, in which the plural second semiconductor regions arranged along a direction form a group by every predetermined number, and the third semiconductor region is provided for each group;

and

the third semiconductor region is provided in the first semiconductor region between the second semiconductor regions which are at least partially adjacent within the group;

the element isolation regions are respectively provided between the third semiconductor region and the mutually adjacent second semiconductor regions and the conductive layer is provided on at least either of the element isolation regions.

7. An image pickup apparatus according to claim 2, wherein the second semiconductor regions are arranged one-dimensionally or two-dimensionally, in which the plural second semiconductor regions arranged along a direction form a group by every predetermined number;

and

the third semiconductor region is provided in the first semiconductor region between the second semiconductor region in a first group and the second semiconductor group in a second group, adjacent to the first group;

the element isolation regions are provided respectively between the third semiconductor region and the second semiconductor regions of the first and second semiconductor regions adjacent to the third semiconductor region; and

the conductive layer is provided on at least either of the element isolation regions.

8. An image pickup apparatus according to claim 7, further comprising a transfer transistor for transferring carriers accumulated in the second semiconductor region;

wherein the conductive layer constitutes a part of a gate electrode of the transfer transistor.

9. An image pickup apparatus according to claim 7, further comprising a floating diffusion region provided for each photoelectric conversion element, a transfer transistor provided for each second semiconductor region for transferring carriers accumulated in the second semiconductor region to the floating diffusion region, an amplifying transistor of which a gate electrode is connected with the floating diffusion region, a selecting transistor connected to the amplifying transistor, and a reset transistor for resetting at least the floating diffusion region;

wherein the conductive layer constitutes a part of a gate electrode of the transfer transistor, a gate electrode of the amplifying transistor, a gate electrode of the selecting transistor or a gate electrode of the reset transistor.

10. An image pickup apparatus according to claim 9, wherein the amplifying transistor is provided commonly for each group.

13. A solid-state image pickup system comprising:

an image pickup apparatus according to claim 2;

an optical system for focusing light onto the solid-state image pickup apparatus; and

a signal processing circuit for processing an output signal from the solid-state image pickup apparatus.

11. An image pickup apparatus including a photoelectric conversion element which has a first semiconductor region of a first conductive type, and a second semiconductor region of a second conductive type constituting a junction with the first semiconductor region, a third semiconductor region of a first conductive type, provided in the first semiconductor region and having a higher impurity concentration than in the first semiconductor region, a element isolation region provided between the third semiconductor region and the second semiconductor region, a conductive layer provided on the element isolation region, and a fourth semiconductor region of a first conductive type provided under the element isolation region and having a higher impurity concentration than in the first semiconductor region:

the apparatus comprising a side wall on a side of the conductive layer, wherein the side wall is provided on the element isolation region in such a manner that an external end of the side wall does not exceed an end of the element isolation region.

12. An image pickup apparatus including a photoelectric conversion element which has a first semiconductor region of a first conductive type, and a second semiconductor region of a second conductive type constituting a junction with the first semiconductor region, a third semiconductor region of a first conductive type, provided in the first semiconductor region for fixing a potential of the first semiconductor region at a predetermined potential, a element isolation region provided between the third semiconductor region and the second semiconductor region, a conductive layer provided on the element isolation region, and a fourth semiconductor region of a first conductive type provided under the element isolation region:

wherein the second semiconductor regions are arranged one-dimensionally or two-dimensionally, in which the plural second semiconductor regions arranged along a direction form a group by each predetermined number; and

the third semiconductor region is provided in the first semiconductor region between the second semiconductor region in a first group and the second semiconductor group in a second group, adjacent to the first group.