Charge-coupled devices

Article By:

Guidry, Mark R. Fairchild Camera and Instrument Corporation, Mountain View, California.

Onishi, Steven Lockheed Martin Fairchild Systems, Milpitas, California.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.125200

Semiconductor devices wherein minority charge is stored in a spatially defined depletion region (potential well) at the surface of a semiconductor, and is moved about the surface by transferring this charge to similar adjacent wells. The formation of the potential well is controlled by the manipulation of voltage applied to surface electrodes. Since a potential well represents a nonequilibrium state, it will fill with minority charge from normal thermal generation. Thus a charge-coupled device (CCD) must be continuously clocked or refreshed to maintain its usefulness. In general, the potential wells are strung together as shift registers. Charge is injected or generated at various input ports and then transferred to an output detector. By appropriate design to minimize the dispersive effects that are associated with the charge-transfer process, well-defined charge packets can be moved over relatively long distances through thousands of transfers.

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