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Acoustic Surface Wave Fields to Move Carriers in a Charge Coupled Device

IP.com Disclosure Number: IPCOM000084339D
Original Publication Date: 1975-Oct-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 27K

Publishing Venue

IBM

Related People

White, JM: AUTHOR

Abstract

The optical scanner shown schematically employs a continuous surface acoustic wave propagating in a transparent base fabricated of a piezoelectric material, interacting with a semiconductor layer, to which a DC field is applied normal to the surface, so that the incident light may generate carriers in the depletion region.

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Acoustic Surface Wave Fields to Move Carriers in a Charge Coupled Device

The optical scanner shown schematically employs a continuous surface acoustic wave propagating in a transparent base fabricated of a piezoelectric material, interacting with a semiconductor layer, to which a DC field is applied normal to the surface, so that the incident light may generate carriers in the depletion region.

The strains produced by the continuous acoustic wave and the potentials produced thereby in the piezoelectric material "bunches" the carriers generated by the light into isolated pockets, which are transported or propagated in the direction of the acoustic wave to a collection region.

The apparatus thus operates as a sort of continuously moving shift register wherein the parallel optical input is converted in parallel to electrical signals, which are then serially read out under the influence of the acoustic wave. This structure eliminates the necessity of multiple electrodes.

Specifically the wafer 10 of LiNbO(3) has light rays 12 manifestive of an optical line image incident thereon. These rays pass through the transparent lithium niobate and impact the P-type silicon layer 14, where electrons are generated as a function of the intensity of the incident light in each microregion of the depletion layer. To induce this effect, a DC field is produced across the layer
14.

A continuous acoustic wave is induced in the layer 10 by a transducer 15. This produces a travelling acoustic wave and strains which produce a travelling electric field 18 in the piezoelectric material. The field bunches and propagates the electrons generated by the incident light in...