Complementary metal-oxide-semiconductor (CMOS) image sensor including a junction field effect transistor

An image sensor includes a sensing node to sense photo charges output from a photodiode. The sensing node includes a first dopant region of a first conductivity type and a second dopant region of a second conductivity type. The second dopant region surrounds the first dopant region. A third dopant region of the first conductivity type is adjacent to the second dopant region and is disposed around the sensing node. The first, second, and third dopant regions operate as a source, a gate, and a drain of a junction field effect transistor, respectively.