CMOS image sensor and method of fabricating the same
First Claim
1. A CMOS image sensor comprising:
- a device isolation layer formed in a substrate to define an active region;
a photodiode formed in the active region;
a floating diffusion region formed at a position spaced apart from the photodiode;
first and second gates overlapped with one end of the photodiode and one end of the floating diffusion region, respectively;
a third gate disposed between the first gate and the second gate and overlapped with an upper portion of the device isolation layer and a predetermined portion of the floating diffusion region;
an insulating layer formed on the resulting structure where the third gate is formed; and
a buried contact having a first contact and a second contact, the first contact and the second contact being sequentially stacked to pass through the insulating layer and the third gate and to connect the third gate to the floating diffusion region disposed under the third gate.
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Abstract
A CMOS image sensor and a method of fabricating the same are provided. In the CMOS image sensor, a device isolation layer is formed in a substrate to define an active region, and a photodiode is formed in the active region. A floating diffusion region is formed at a position spaced apart from the photodiode, and first and second gates are overlapped with one end of the photodiode and one end of the floating diffusion region, respectively. A third gate is disposed between the first gate and the second gate and overlapped with an upper portion of the device isolation layer and a predetermined portion of the floating diffusion region. An insulating layer is formed on the resulting structure where the third gate is formed. A buried contact has a first contact and a second contact, which are sequentially stacked to pass through the insulating layer and the third gate and to connect the third gate to the floating diffusion region disposed under the third gate.
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Citations
15 Claims
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1. A CMOS image sensor comprising:
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a device isolation layer formed in a substrate to define an active region;
a photodiode formed in the active region;
a floating diffusion region formed at a position spaced apart from the photodiode;
first and second gates overlapped with one end of the photodiode and one end of the floating diffusion region, respectively;
a third gate disposed between the first gate and the second gate and overlapped with an upper portion of the device isolation layer and a predetermined portion of the floating diffusion region;
an insulating layer formed on the resulting structure where the third gate is formed; and
a buried contact having a first contact and a second contact, the first contact and the second contact being sequentially stacked to pass through the insulating layer and the third gate and to connect the third gate to the floating diffusion region disposed under the third gate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of fabricating a CMOS image sensor, comprising:
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forming a device isolation layer in a substrate to define an active region;
forming a photodiode and a floating diffusion region in the active region, the photodiode and the floating diffusion region being spaced apart from each other;
forming a first gate and a second gate to overlap one end of the photodiode and one end of the floating diffusion region, and forming a third gate between the first gate and the second gate, the third gate being partially overlapped with an upper portion of the device isolation layer and a predetermined portion of the floating diffusion region;
etching a predetermined portion of the third gate to form a first contact hole exposing an upper surface of the floating diffusion region;
forming an insulating layer on the entire surface of a resulting structure where the first contact hole is formed;
etching the insulating layer disposed at a position corresponding to the first contact hole so as to form a second contact exposing an upper surface of the floating diffusion region through the first contact hole; and
filling the first contact hole and the second contact hole with metal so as to form a buried contact. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification