Browse Prior Art Database

Improved ROM Cell

IP.com Disclosure Number: IPCOM000051218D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Faris, SM: AUTHOR

Abstract

An earlier article (*) shows a read-only memory (ROM) cell which consists of a dummy junction, an interferometer and a bridge' When the bridge is broken, the cell is programmed to switch, and if not broken, the cell is programmed to not switch. This article shows a more compact ROM cell in which one of the previously disclosed dummy junctions of a pair of cells is eliminated.

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Improved ROM Cell

An earlier article (*) shows a read-only memory (ROM) cell which consists of a dummy junction, an interferometer and a bridge' When the bridge is broken, the cell is programmed to switch, and if not broken, the cell is programmed to not switch. This article shows a more compact ROM cell in which one of the previously disclosed dummy junctions of a pair of cells is eliminated.

As shown in Fig. 1, two cells, each made of a pair of interferometer junctions J1 and J2, share one dummy junction D1. Base electrode M2 provides a current path for current I directly from input terminal T1 to output terminal T2 if breakable portions B1 and B2 of M2 remain intact. In this mode, current I does not pass through either of the junctions J1 and J2 and neither of these devices switch when current is applied to their respective control lines C1 and C2.

If, however, breakable portion B1 is severed, current I(g) is constrained to pass through junction J1 and from thence, via the counter electrode M3 of dummy junction D1 and breakable portion B2 to output terminal T2. When control line C1 is energized, in the presence of current I(g) through junction J1, that device switches.

Similarly, if only breakable portion B2 is severed, current I passes via B1, breakable portion of base electrode M2 through D1 to the counter-electrode M3 of J2 and through J2 to output terminal T2. When control line C2 is energized, in the presence of current I(g) through junction J2, that devi...