The image sensor Cmos

The present invention relates to a CMOS image sensor. In an embodiment of the present invention, CMOS image sensors comprising a semiconductor substrate having an active region. A plurality of transistors and a photodiode may be formed on the active region. The active region has a variable width portion below the reset transistor. COMS image sensor of the present invention can prevent from the photodiode to the potential of the reset transistor leakage.