CMOS image sensor and fabricating method thereof
A CMOS image sensor and fabricating method thereof are disclosed, by which a dark current can be reduced. The present invention includes a first conductive type semiconductor substrate divided into an active area and a field area, an STI layer formed in the field area to divide the first conductive type semiconductor substrate into active area and the field area, a second conductive type photodiode region formed in the active area of the first conductive type semiconductor substrate, a readout circuit formed in the active area of the first conductive type semiconductor substrate to read out data of the photodiode regions, and a first conductive type well formed between the second conductive type photodiode region and the STI layer.
1 . A CMOS image sensor comprising:
a first conductive type semiconductor substrate divided into an active area and a field area;
an STI layer formed in the field area to divide the first conductive type semiconductor substrate into active area and the field area;
a second conductive type photodiode region formed in the active area of the first conductive type semiconductor substrate;
a readout circuit formed in the active area of the first conductive type semiconductor substrate to read out data of the photodiode regions; and
a first conductive type well formed between the second conductive type photodiode region and the STI layer.
2 . The CMOS image sensor of claim 1 , wherein the first conductive type semiconductor substrate comprises an epitaxial wafer having either a 0° or 4° tilt.
3 . The CMOS image sensor of claim 1 , further comprising a first conductive type heavily doped layer on a surface of the second conductive type photodiode regions.
4 . A CMOS image sensor comprising:
a first conductive type semiconductor substrate divided into an active area and a field area;
an STI layer formed in the field area to divide the first conductive type semiconductor substrate into active area and the field area;
a second conductive type photodiode region formed in the active area of the first conductive type semiconductor substrate;
a readout circuit formed in the active area of the first conductive type semiconductor substrate to read out data of the photodiode regions; and
a first conductive type well formed between the STI layer and the active area of the first conductive semiconductor substrate.
5 . The CMOS image sensor of claim 4 , wherein the first conductive type semiconductor substrate comprises an epitaxial wafer having either a 0° or 4° tilt.
6 . The CMOS image sensor of claim 4 , further comprising a first conductive type heavily doped layer on a surface of the second conductive type photodiode regions.
7 . A method of fabricating a CMOS image sensor, comprising the steps of:
forming a trench in a field area of a first conductive type semiconductor substrate wherein an active area and the field area are defined on the first conductive type semiconductor substrate and wherein a photodiode region and a readout circuit region to read out data of the photodiode region are defined in the active area;
forming a first conductive type well by implanting a first conductive type impurity into the trench neighboring the photodiode region; and
forming an STI layer by filling the trench with an insulating layer.
8 . A method of fabricating a CMOS image sensor, comprising the steps of:
forming a trench in a field area of a first conductive type semiconductor substrate wherein an active area and the field area are defined on the first conductive type semiconductor substrate and wherein a photodiode region and a readout circuit region to read out data of the photodiode region are defined in the active area;
forming a first conductive type well by implanting a first conductive type impurity into the trench in the vicinity of the active area; and
forming an STI layer by filling the trench with an insulating layer.
9 . A method of fabricating a CMOS image sensor, comprising the steps of:
preparing a first conductive type semiconductor substrate wherein an active area and a field area are defined on the first conductive type semiconductor substrate and wherein a photodiode region and a readout circuit region to read out data of the photodiode region are defined in the active area;
forming a trench in the field area;
forming a first conductive type well by implanting a first conductive type impurity into the trench in the vicinity of the active area;
forming an STI layer by filling the trench with an insulating layer;
implanting a second conductive type impurity into the photodiode region; and
heavily implanting the first conductive type impurity into a surface of the photodiode region implanted with the second conductive type impurity.