Galaxycore Shanghai Limited Corporation

Ze Xu

Jie Li

Lixin Zhao

Wenqiang Li

A backside illumination image sensor and a method for reducing a dark current of the backside illumination image sensor. The backside illumination image sensor comprises: a photodiode, a first conductive type isolated layer (); a gate structure of a pass transistor, corresponding to the first conductive type isolated layer () and formed on an upper surface of a first conductive type semiconductor substrate (), the gate structure () comprising: gate oxide (), a gate layer (), and a gate sidewall (), and the gate structure () correspondingly covering the photodiode; and a floating diffusion zone (), formed in the first conductive type semiconductor substrate () and having second conductive type heavy doping. In the backside illumination image sensor, a defect does not easily appear on a surface, right above the photodiode, of the first conductive type semiconductor substrate (), so that a dark current is effectively prevented from being produced.

Backside illumination image sensor and method for reducing dark current of backside illumination image sensor

An image sensor and a manufacturing method thereof are provided. The image sensor includes: a photo diode; a first-conductive-type isolating layer; a second-conductive-type lightly-doped region formed in the first-conductive-type semiconductor substrate; a first-conductive-type lightly-doped region formed under the second-conductive-type lightly-doped region, where the second-conductive-type lightly-doped region is isolated from the second-conductive-type region by the first-conductive-type lightly-doped region; a gate structure of a transfer transistor; and a floating diffusion region which is second-conductive-type heavily-doped. In the image sensor, the second-conductive-type lightly-doped region is formed to be connected with the floating diffusion region, thus, a distance between the floating diffusion region and the photo diode may be reduced which may enable photo-induced carriers to be transmitted from the photo diode to the floating diffusion region more rapidly, and further increase the transmission efficiency of the photo-induced carriers.

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Shanghai, China

Ze Xu