A single-layer metal-electrode CCD image sensor

A small pixel is required to reduce CCD image sensor chip size for commercial application. However, the shrinkage of pixel size adversely affects such characteristics as smear noise, sensitivity and charge-handling capability. Furthermore, a conventional overlapping double-layer polysilicon (polySi) electrode is complicated and difficult to fabricate for CCD image sensors. For process step simplicity of the transfer electrodes, aiming at low cost sensors and the smear noise reduction, a single-layer metal-electrode CCD image sensor is introduced.