# US 7,745,859 B2 · Solid-state image sensing apparatus and fabrication method thereof

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- Number: US 7,745,859 B2
- Document ID: US7745859B2
- Status: Granted
- Kind: B2
- Application number: 11/651,022
- Filed: 2007-01-09
- Published: 2007-10-18
- Granted: 2010-06-29
- Earliest claimed: 2006-04-17
- Assignees: Panasonic Corporation
- Inventors: Tatsuya Hirata; Shouzi Tanaka; Ryohei Miyagawa; Kazunari Koga
- Web page: https://patentgrep.com/patent/US7745859B2

## CPC

- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/014: {of CMOS image sensors}
- H10F 39/026: {Wafer-level processing}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A solid-state image sensing apparatus has a signal storage portion of a second conductivity type provided within a substrate, a surface shield layer of the first conductivity type provided in a surface portion of the substrate which is located above the signal storage portion, a gate electrode provided over the substrate in adjacent relation to at least one end of the signal storage portion, and a drain region of the second conductivity type provided in a surface portion of the substrate which is on the side opposite to the surface shield layer when viewed from the gate electrode. A read control layer of the first conductivity type is further provided in a surface portion of the substrate which is located under the gate electrode in adjacent relation to one end of the surface shield layer.

## Claims

### Claim 1

A solid-state image sensing apparatus comprising:
first and second signal storage portions of a second conductivity type provided within a semiconductor substrate or a well each of a first conductivity type to store a signal charge obtained through a photoelectric conversion;
a first surface shield layer of the first conductivity type provided in a surface portion of the semiconductor substrate or the well which is located above the first signal storage portion;
a second surface shield layer of the first conductivity type provided in a surface portion of the semiconductor substrate or the well which is located above the second signal storage portion;
a first gate electrode provided over the semiconductor substrate or the well in adjacent relation to at least one end of the first signal storage portion;
a second gate electrode provided over the semiconductor substrate or the well in adjacent relation to at least one end of the second signal storage portion;
a drain region of the second conductivity type provided in a surface portion of the semiconductor substrate or the well which is located between the first gate electrode and the second gate electrode;
a first read control layer of the first conductivity type provided in a surface portion of the semiconductor substrate or the well which is located under the first gate electrode in adjacent relation to one end of the first surface shield layer; and
a second read control layer of the first conductivity type provided in a surface portion of the semiconductor substrate or the well which is located below the second gate electrode in adjacent relation to one end of the second surface shield layer,
wherein the first signal storage portion overlaps the entire first gate electrode and at least a part of the drain region, and
the second signal storage portion overlaps the entire second gate electrode and at least a part of the drain region.

### Claim 2 (depends on 1)

The solid-state image sensing apparatus of claim 1, wherein an impurity concentration in the first and second read control layers is higher than that in the semiconductor substrate or the well and lower than that in the first and second surface shield layers.

### Claim 3 (depends on 1)

The solid-state image sensing apparatus of claim 1, wherein an off-state leakage prevention layer of the first conductivity type is provided to cover side and bottom surfaces of the drain region.

### Claim 4 (depends on 3)

The solid-state image sensing apparatus of claim 3, wherein the off-state leakage prevention layer extends to positions under end portions of the first and second gate electrodes.

### Claim 5 (depends on 3)

The solid-state image sensing apparatus of claim 3, wherein an impurity concentration in the off-state leakage prevention layer is not less than 4×1016 atom/cm3.

### Claim 6 (depends on 1)

A method for fabricating the solid-state image sensing apparatus of claim 1, the method comprising the steps of:
forming at least one of the first surface shield layer and the first signal storage portion each by using an ion implantation mask so that the first signal storage portion overlaps the entire first gate electrode and at least a part of the drain region; and
forming at least one of the second surface shield layer and the second signal storage portion each by using an ion implantation mask so that the second signal storage portion overlaps the entire second gate electrode and at least a art of the drain region.