CMOS image sensor with dark current reduction
First Claim
1. A CMOS image sensor comprising:
- a device isolation region and an active region in a semiconductor substrate;
a photocharge generating portion in the active region for absorbing external light and generating and accumulating charges;
a separating film between the device isolation region and the photocharge generating portion;
a transistor portion including at least one transistor for processing the charges accumulated in the photocharge generating portion; and
a control terminal in the active region having a maximum depth greater than that of the photocharge generating portion, at a boundary with the device isolation region and having the same conductive type as the photocharge generating portion for preventing dark current from being introduced from the device isolation region into the photocharge generating portion, and ejecting the dark current after temporally storing the dark current.
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Accused Products
Abstract
Disclosed are a CMOS image sensor and a fabrication method thereof, which is adequate to reduce dark current. The CMOS image sensor comprises a device isolation region and an active region, which are formed on a semiconductor substrate; a photocharge generating portion formed on the active region for absorbing light externally and generating and accumulating charges; a transistor portion including at least one transistor for processing the charges accumulated in the photocharge generating portion; and a control terminal for preventing dark current from being introduced into the photocharge generating portion, and ejecting the dark current after temporally storing the dark current. The control terminal is operated to store the dark current for an integration time when a photodiode as the photocharge generating portion receives light, and eject the stored dark current by being grounded when the reset transistor is turned on.
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Citations
18 Claims
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1. A CMOS image sensor comprising:
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a device isolation region and an active region in a semiconductor substrate; a photocharge generating portion in the active region for absorbing external light and generating and accumulating charges; a separating film between the device isolation region and the photocharge generating portion; a transistor portion including at least one transistor for processing the charges accumulated in the photocharge generating portion; and a control terminal in the active region having a maximum depth greater than that of the photocharge generating portion, at a boundary with the device isolation region and having the same conductive type as the photocharge generating portion for preventing dark current from being introduced from the device isolation region into the photocharge generating portion, and ejecting the dark current after temporally storing the dark current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification