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Electrically Alterable Amorphous Memory Device

IP.com Disclosure Number: IPCOM000074784D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR [+2]

Abstract

An amorphous memory element which contains intentionally dispersed nonmeltable nuclei for crystallization (at the temperature of device operation) will insure greater reliability of operation than elements presently employed in which the nuclei for crystallization originate haphazardly during the preparation of films.

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Electrically Alterable Amorphous Memory Device

An amorphous memory element which contains intentionally dispersed nonmeltable nuclei for crystallization (at the temperature of device operation) will insure greater reliability of operation than elements presently employed in which the nuclei for crystallization originate haphazardly during the preparation of films.

A schematic cross-section of an amorphous memory element is shown in Fig.
1. It consists of a layer of amorphous material 1 between electrodes 2. The small irregular squares 3 symbolize nucleating centers, e.g., small crystalline islands which either form during the deposition of the amorphous layers 1 or during the early stages of the 1st "set" pulse. The first "set" pulse, i.e., the first time more than a critical amount of electrical power is passed through the device for a sufficiently long time, results in the growth of these nuclei. Once a connecting path 4 is established, Fig. 2, the current will be channeled into a crystalline path and the growth of nuclei far away from the current channel will essentially cease. At the end of the first set pulse the situation illustrated in Fig. 2 results. The reset pulse consists in passing enough energy through the connecting path 4 established in the first set pulse, to melt it. The thermal conditions of the device must, of course, be such that the melt is quenched into an amorphous state upon termination of the pulse. It would seem to be impossible to prevent two occurrences during this reset pulse, e.g., melting at least some of the original nuclei, and growth of nuclei in the proximity of the current path 4. Both of these effects are illustrated in Fig. 3. Because of...