A 512 × 320 element silicon imaging device

CHARGE-COUPLED DEVICE (CCD) technology has been used to fabricate a high-resolution, low-blooming, 512 x 320 element silicon image device that generates standard 525-line TV pictures. The choice of this cell count has been described previously??. The device uses a unique single-layer doped polysilicon gate structure. This structure maintains the basic simplicity of the original single-layer devices (self alignment of gates, no steps in gate structure causing opens, and single mask level for all CCD gates), but avoids the gap charging problem. The individual gates are formed by doping Nt regions in a P-layer of polysilicon on top of the channel oxide. This results in low leakage between gates. Since there are no exposed gaps, a stable sealed channel structure results. The polysilicon layer is transparent to most wavelengths and there are no opaque areas to cause aliasing. Aluminum is used for a low resistance, double-ended gate-bus connection and to supply bonding pads.