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US 7,405,437 B2Granted
CMOS image sensor and method for fabricating the same
AssigneeDongbu Electronics Co., Ltd.
InventorsHee Sung Shim, Tae Woo Kim
Life of this patent
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Abstract
A CMOS image sensor includes a first conductive type semiconductor substrate defined by a photodiode area and a transistor area, a trench formed in the semiconductor substrate corresponding to a transfer transistor of the transistor area, a gate electrode of the transfer transistor, formed in the trench, a second conductive type impurity ion area formed in the semiconductor substrate of the photodiode area, and a first conductive type impurity ion area formed on a surface of the second conductive type impurity ion area.
Claims8
A CMOS image sensor comprising:
- a first conductive type semiconductor substrate having a photodiode area and a transistor area;
- a trench formed in the semiconductor substrate corresponding to a transfer transistor of the transistor area;
- a gate electrode of the transfer transistor formed in the trench;
- a plurality of gate electrodes formed on the semiconductor substrate of the transistor area, excluding the transistor area of the transfer transistor;
- source and drain impurity ion areas formed in the semiconductor substrate between the respective gate electrodes;
- an impurity ion implantation area for controlling a threshold voltage formed on the semiconductor substrate only below the gate electrode;
- a second conductive type impurity ion area formed in the semiconductor substrate of the photodiode area;
- and
- a first conductive type impurity ion area formed on a surface of the second conductive type impurity ion area,
- wherein a top surface of the gate electrode of the transistor including a reset transistor and excluding the transfer transistor is higher than a top surface of the gate electrode of the transfer transistor.
7 more elements
A method for fabricating a CMOS image sensor comprising:
- forming a first insulating film on an entire surface of a first conductive type semiconductor substrate having a photodiode area and a transistor area;
- selectively removing the first insulating film on the transistor area for a transfer transistor;
- forming a trench in the semiconductor substrate corresponding to a portion where the first insulating film is removed;
- forming an impurity ion implantation area for controlling a threshold voltage of the transfer transistor only below the trench;
- forming a gate insulating film and a gate electrode of the transfer transistor in the trench;
- and depositing a second insulating film on the entire surface of the semiconductor substrate and removing the first and second insulating films on the transistor area, excluding the transfer transistor;
- forming a plurality of gate insulating films and a plurality of gate electrodes on the semiconductor substrate where the first and second insulating films are removed and removing all of the first and second insulating films.
4 more elements
Dependencies are inferred from the claim text.