Back lighting type image sensor pixel structure

The utility model discloses a back lighting type image sensor pixel structure. In the image sensor pixel, a reset transistor, a source following transistor and a selection transistor are manufactured at the front surface of a semiconductor substrate, a charge transmission transistor is manufactured in the internal part of the semiconductor substrate, and a photodiode is manufactured in the semiconductor substrate arranged below a transistor device. The channel of the charge transmission transistor comprises three parts of a floating active region, an N-type ion region and a photodiode N-type region. The three parts are contacted with each other, and the N-type ion region is arranged below the floating active region and the photodiode N-type region is arranged below the N-type ion region. A P-type ion isolation region is arranged between the photodiodes of the adjacent pixels. The whole pixel area is occupied by the photodiodes to the largest extent, filling rate of the active regions of the photodiodes is enlarged and photosensitivity of the back lighting type image sensor pixel structure is effectively enhanced.