Unit pixel in CMOS image sensor with enhanced reset efficiency
First Claim
1. A unit pixel for use in a complementary metal oxide semiconductor (CMOS) image sensor, comprising:
- a semiconductor substrate including an epitaxial layer in which an active area and a field oxide (FOX) area are defined;
a photodiode formed in a predetermined location of the epitaxial layer;
a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion region, wherein a transfer control signal is applied to a gate thereof;
a reset transistor including source/drain regions disposed between the floating diffusion region and a power supply voltage (VDD) terminal, wherein a reset control signal is applied to a drain thereof;
a drive transistor of which a gate is connected to the floating diffusion region and a drain is connected to the VDD terminal; and
a selection transistor of which a drain is connected to a source of the drive transistor and a source is connected to an output terminal, wherein a select control signal is applied to a gate thereof.
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Accused Products
Abstract
A unit pixel in a CMOS image sensor is employed to reduce a threshold voltage of a reset transistor by modifying a unit pixel circuit. The unit pixel in the CMOS image sensor including: a semiconductor substrate including an epitaxial layer in which an active area and a FOX area are defined; a photodiode formed in the epitaxial layer; a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion node, wherein a control signal is applied to a gate thereof; a reset transistor including source/drain regions disposed between the floating diffusion node and a VDD terminal, wherein a control signal is applied to a drain thereof; a drive transistor of which a gate is connected to the floating diffusion node and a drain is connected to the VDD terminal; and a selection transistor of which a drain is connected to the drain of the drive transistor and a source is connected to an output terminal, wherein a control signal is applied to a gate thereof.
191 Citations
18 Claims
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1. A unit pixel for use in a complementary metal oxide semiconductor (CMOS) image sensor, comprising:
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a semiconductor substrate including an epitaxial layer in which an active area and a field oxide (FOX) area are defined;
a photodiode formed in a predetermined location of the epitaxial layer;
a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion region, wherein a transfer control signal is applied to a gate thereof;
a reset transistor including source/drain regions disposed between the floating diffusion region and a power supply voltage (VDD) terminal, wherein a reset control signal is applied to a drain thereof;
a drive transistor of which a gate is connected to the floating diffusion region and a drain is connected to the VDD terminal; and
a selection transistor of which a drain is connected to a source of the drive transistor and a source is connected to an output terminal, wherein a select control signal is applied to a gate thereof. - View Dependent Claims (2, 3, 4, 5)
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6. A unit pixel for use in the CMOS image sensor comprising:
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a semiconductor substrate including an epitaxial layer in which an active area and a field oxide (FOX) area are defined;
a photodiode formed in a predetermined location of the epitaxial layer;
a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion node, wherein a transfer control signal is applied to a gate thereof;
a reset transistor including source/drain regions disposed between the photodiode and a power supply voltage (VDD) terminal, wherein a reset control signal is applied to a drain thereof;
a drive transistor of which a gate electrode is connected to the floating diffusion region and a drain is connected to the VDD terminal; and
a selection transistor of which a drain is connected to the drain of the drive transistor and a source is connected to an output terminal, wherein a select control signal is applied to a gate thereof. - View Dependent Claims (7, 8, 9, 10)
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11. A CMOS image sensor having a plurality of unit pixels, said each unit pixel comprising:
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a semiconductor substrate including an epitaxial layer in which an active area and a field oxide (FOX) area are defined;
a photodiode formed in a predetermined location of the epitaxial layer;
a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion region, wherein a transfer control signal is applied to a gate thereof;
a reset transistor including source/drain regions disposed between the floating diffusion region and a power supply voltage (VDD) terminal, wherein a reset control signal is applied to a drain thereof;
a drive transistor of which a gate is connected to the floating diffusion region and a drain is connected to the VDD terminal; and
a selection transistor of which a drain is connected to a source of the drive transistor and a source is connected to an output terminal, wherein a select control signal is applied to a gate thereof. - View Dependent Claims (12, 13, 14)
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15. A CMOS image sensor having a plurality of unit pixels, said each unit pixel comprising:
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a semiconductor substrate including an epitaxial layer in which an active area and a field oxide (FOX) area are defined;
a photodiode formed in a predetermined location of the epitaxial layer;
a transfer transistor including source/drain regions disposed between the photodiode and a floating diffusion node, wherein a transfer control signal is applied to a gate thereof;
a reset transistor including source/drain regions disposed between the photodiode and a power supply voltage (VDD) terminal, wherein a reset control signal is applied to a drain thereof;
a drive transistor of which a gate electrode is connected to the floating diffusion region and a drain is connected to the VDD terminal; and
a selection transistor of which a drain is connected to the drain of the drive transistor and a source is connected to an output terminal, wherein a select control signal is applied to a gate thereof. - View Dependent Claims (16, 17, 18)
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Specification