Permalloy-Sheet Transfluxor-Array Memory

Abstract

Annealed molybdenum Permalloy sheets of ⅛−1 mil thickness have been photoetched to form transfluxor-element memory arrays utilizing inhibited-flux storage. Operating characteristics are summarized for single elements switched in 21 nsec−3.2 μsec. Some findings are: one to zero information flux ratios of 5:1 to 16:1, one to disturb noise flux ratios greater than 30:1, and Sw values of 1.7 to 0.14 oe μsec. In addition, operation is possible over a temperature range of −70° to +150°C without drive-current compensation. Also, for a ⅛-mil thick element switched in times less than 0.1 μsec, Sw values less than 0.2 oe μsec are obtained, indicating that fast switching may occur partially by uniform flux rotation. Array photoetching is described. Arrays containing 128 and 1152 elements have been fabricated. The latter permit a storage density of 250 000 bits/cu in. to be attained. The arrays receive a stress-relief treatment which results in a signal uniformity of ±3%. Photofabrication of windings has been accomplished also. This process generates continuous windings linking the transfluxor apertures.

Review—Through-Mask Electrochemical Micromachining

“…This is exemplified by a commercial electro-etching unit from 1971, which could pattern aluminum thin-films on up to 50 silicon wafers at a time. 161 Apart from metalization layers, TMEMM was also applied to the fabrication of memory arrays, 204 resistance elements, 205,206 magnetic recording heads, 160,207,208 diodes, 209 detachable electrical contacts, 112,113 and slider suspensions. 113 Several review articles 1,14,15,19,80,92,210 have summarized microelectronic components machined via TMEMM.…”