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Ferroelectric Film Shift Register

IP.com Disclosure Number: IPCOM000074649D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 3 page(s) / 51K

Publishing Venue

IBM

Related People

Kazan, B: AUTHOR

Abstract

In the ferroelectric film shift register, shown in cross section in Fig. A, a thin film of semiconductor material in contact with a ferroelectric film acts to provide a simple bidirectional shift register, capable of retaining information for long periods of time without power maintenance.

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Ferroelectric Film Shift Register

In the ferroelectric film shift register, shown in cross section in Fig. A, a thin film of semiconductor material in contact with a ferroelectric film acts to provide a simple bidirectional shift register, capable of retaining information for long periods of time without power maintenance.

As shown, an insulating substrate 1 is arranged to accommodate a plurality of interdigitally-connected small conducting elements 3. Conducting elements 3 are coated with a thin layer of ferroelectric material 5 which may be deposited, for example, by sputtering. Ferroelectric material 5 may typically be of a composition akin to that described by D. W. Chapman in his article, "Some Thin-Film Properties of a New Ferroelectric Composition", J. Appl. Phys. 40, pages 2381- 2385 1969.

On the surface of ferroelectric film 5, isolated metallic electrodes 7 are provided in registry with respective lower electrodes 3. Covering electrodes 7 is a thin film of semiconductor material 9, which may be, for example, CdSe. The thin film of semiconductor material 9 is in turn coated with an insulator layer 11, the outer surface of which is provided with a plurality of conducting elements 13, which elements are positioned between the respective underlying metallic electrodes 7. As shown by the connections of conductor leads 15-17 and 19-21, the respective pluralities of conducting elements 3 and 13 are intergitally- connected into two groups.

For purposes of explanation of the operation of the device, it is assumed that ferroelectric elements, designated b', c', and d' are initially polarized in the downward direction, as shown by the arrows, while the elements designated a' and e' are polarized in the upward direction, likewise shown by the arrows. During clock pulse A, which is simultaneously applied to conductive leads 17 and 21, as depicted in Fig. B, a charge transfer takes place through loop L, shown in dashed form in Fig. A, which includes elements a' and b' in series....