CMOS image sensor and method for fabricating the same
First Claim
1. A method for fabricating a CMOS image sensor, comprising the steps of:
- forming a device isolation film in a second conductive type semiconductor substrate, defining an active region having a photodiode region and a transistor region;
forming a gate insulating film and a gate electrode on the transistor region of the semiconductor substrate;
forming a lightly doped first conductive type impurity region in the photodiode region of the semiconductor substrate;
forming a medium concentration second conductive type impurity region at a surface of the lightly doped first conductive type impurity region; and
forming a heavily doped second conductive type impurity region adjacent to the device isolation film in the photodiode region of the substrate, the heavily doped second conductive type impurity region having a depth the same as a depth of the device isolation film, or a depth of the lightly doped first conductive type impurity region.
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Abstract
CMOS image sensor and method for fabricating the same, the CMOS image sensor including a second conductive type semiconductor substrate having an active region and a device isolation region defined therein, wherein the active region has a photodiode region and a transistor region defined therein, a device isolating film in the semiconductor substrate of the device isolation region, a first conductive type impurity region in the semiconductor substrate of the photodiode region, the first conductive type impurity region being spaced a distance from the device isolation film, and a second conductive type first impurity region in the semiconductor substrate between the first conductive type impurity region and the device isolation film, thereby reducing generation of a darkcurrent at an interface between the photodiode region and a field region.
26 Citations
20 Claims
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1. A method for fabricating a CMOS image sensor, comprising the steps of:
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forming a device isolation film in a second conductive type semiconductor substrate, defining an active region having a photodiode region and a transistor region; forming a gate insulating film and a gate electrode on the transistor region of the semiconductor substrate; forming a lightly doped first conductive type impurity region in the photodiode region of the semiconductor substrate; forming a medium concentration second conductive type impurity region at a surface of the lightly doped first conductive type impurity region; and forming a heavily doped second conductive type impurity region adjacent to the device isolation film in the photodiode region of the substrate, the heavily doped second conductive type impurity region having a depth the same as a depth of the device isolation film, or a depth of the lightly doped first conductive type impurity region. - View Dependent Claims (2)
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3. A method for fabricating a CMOS image sensor, comprising the steps of:
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forming a device isolation film in a second conductive type semiconductor substrate, defining an active region having a photodiode region and a transistor region; forming a gate insulating film and a gate electrode on the transistor region of the semiconductor substrate; forming a lightly doped first conductive type impurity region in the photodiode region of the semiconductor substrate; forming a medium concentration second conductive type impurity region at a surface of the lightly doped first conductive type impurity region; and forming a heavily doped second conductive type impurity region adjacent to the device isolation film in the photodiode region of the substrate, the heavily doped second conductive type impurity region having a width the same as a depth of the medium concentration second conductive type impurity region. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for fabricating a CMOS image sensor, comprising the steps of:
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forming a device isolation film in a second conductive type semiconductor substrate, defining an active region having a photodiode region and a transistor region; forming a gate insulating film and a gate electrode on the transistor region of the semiconductor substrate; forming a lightly doped first conductive type impurity region in the photodiode region of the semiconductor substrate; forming an insulating layer on an entire surface of the substrate inclusive of the gate electrode; selectively removing the insulating layer to expose the device isolating film and a predetermined portion of the photodiode region adjacent to the device isolating film, forming a photoresist film pattern to expose the photodiode region and the insulating layer; and injecting second conductive type impurity ions at a medium concentration into the photodiode region using the insulating layer and the photoresist pattern as a mask, to form medium concentration second conductive type impurity regions at an interface of the device isolating film and the photodiode region and at a surface of the lightly doped first conductive type impurity region, the medium concentration second conductive type impurity region at the interface of the device isolating film and the photodiode region having a depth deeper than a depth of the medium concentration second conductive type impurity region at the surface of the hightly doped first conductive type impurity region. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification