WIRE TRANSFER OF CHARGE PACKETS USING A CCD-BBD STRUCTURE FOR CHARGE-DOMAIN SIGNAL-PROCESSING

A structure for the virtual transfer of charge packets across metal wires is described theoretically and is experimentally verified. The structure is a hybrid of charge-coupled device (CCD) and bucket-brigade device (BBD) elements and permits the topological crossing of charge-domain signals in low power signal processing circuits. A test vehicle consisting of 8-, 32-, and 96-stage delay lines of various geometries implemented in a double-poly, double-metal foundry process was used to characterize the wire-transfer operation. Transfer efficiency ranging between 0.998 and 0.999 was obtained for surface n-channel devices with clock cycle times in the range from 40 ns to 0.3 ms. Transfer efficiency as high as 0.9999 was obtained for buried n-channel devices. Good agreement is found between experiment and simulation.