CCD shift register trench region

摘要

The shift register includes a covered layer and two gate electrodes, one being in a longitudinal direction next to the other. The buried layer is of a doped semiconductor material which also has an etched region having a second larger doping level. The two gate electrodes are provided on different surfaces of the covered layer to define respective surfaces of the covered layer. One surface of the covered layer is larger than the other surface. The two electrodes cover respective etched regions of the covered layer to define respective trench surfaces, with one surface being larger then the other. The two covered layer surfaces define respective load memory elements which are a function of the respective trench surface. The memory capacitance of one element is larger than or equal to the other capacitance.