Abstract: A CMOS image sensor includes a substrate including silicon, a silicon germanium (SiGe) epitaxial layer formed over the substrate, the SiGe epitaxial layer formed through epitaxial growth and doped with a predetermined concentration level of impurities, an undoped silicon epitaxial layer formed over the SiGe epitaxial layer by epitaxial growth, and a photodiode region formed from a top surface of the undoped silicon epitaxial layer to a predetermined depth in the SiGe epitaxial layer.

Abstract: An epitaxial silicon wafer includes a bulk wafer having a first doping concentration, a first epitaxial layer formed over the bulk wafer, the first epitaxial layer having a second doping concentration which is higher than the first doping concentration, and a second epitaxial layer formed over the first epitaxial layer, the second epitaxial layer having a third doping concentration which is lower than the second doping concentration.

Abstract: A method for fabricating a complementary metal-oxide semiconductor (CMOS) image sensor includes providing a semi-finished substrate, forming a patterned blocking layer over a photodiode region of the substrate, implanting impurities on regions other than the photodiode region using a mask while the patterned blocking layer remains, and removing the mask.

Abstract: An image sensor includes a first conductivity type substrate with a trench formed in a predetermined portion thereof, a second conductivity type impurity region formed in the first conductivity type substrate below the trench and being a part of a photodiode, a second conductivity type first epitaxial layer filling the trench and being a part of the photodiode, and a first conductivity type second epitaxial layer formed over the second conductivity type first epitaxial layer.

Abstract: A CMOS image sensor includes a substrate including silicon, a silicon germanium (SiGe) epitaxial layer formed over the substrate, the SiGe epitaxial layer formed through epitaxial growth and doped with a predetermined concentration level of impurities, an undoped silicon epitaxial layer formed over the SiGe epitaxial layer by epitaxial growth, and a photodiode region formed from a top surface of the undoped silicon epitaxial layer to a predetermined depth in the SiGe epitaxial layer.

Abstract: A method for fabricating a complementary metal-oxide semiconductor (CMOS) image sensor includes performing an ion implantation process onto a photodiode region in a first conductivity type semiconductor layer to form a second conductivity type first impurity region, and performing an annealing process in a gas atmosphere including first conductivity type impurity atoms to form a first conductivity type second impurity region underneath a surface of the first conductivity type semiconductor layer in the second conductivity type first impurity region, wherein the first conductivity type second impurity region is doped with the diffused first conductivity impurity atoms.