Complementary metal oxide semiconductor image sensor and fabrication method thereof
First Claim
1. A CMOS image sensor comprising:
- 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 external light 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.
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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
7 Claims
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1. A CMOS image sensor comprising:
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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 external light 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. - View Dependent Claims (2, 3, 4, 5)
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6. A method of fabricating a CMOS image sensor, comprising:
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forming a device isolation region by etching a semiconductor substrate of a first conductivity type;
forming a transistor portion including at least one transistor on the semiconductor substrate on which the device isolation region is formed;
forming a photocharge generating portion by injecting impurities of a second conductivity type opposite to the first conductivity type into an active region between the device isolation region and the transistor portion on the semiconductor substrate; and
forming a control terminal by injecting impurities of the second conductivity type into a boundary between the photocharge generating portion and the device isolation region in a halo junction form. - View Dependent Claims (7)
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Specification