Browse Prior Art Database

Transfer Switches for Single Level Masking Bubble Devices

IP.com Disclosure Number: IPCOM000087202D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Hsieh, WJ: AUTHOR [+3]

Abstract

A procedure is provided for placing a conductor of a transfer line of a bubble-switching device very close to the bubble film without diminishing the effectiveness of the overall device.

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Transfer Switches for Single Level Masking Bubble Devices

A procedure is provided for placing a conductor of a transfer line of a bubble- switching device very close to the bubble film without diminishing the effectiveness of the overall device.

Fig. 1 shows schematically a conventional bubble circulating system. Element 2 is a generator of bubbles, which travel along a major loop 4 to a bubble annihilator 6. The bubbles are shifted through the major loop very much as binary information is shifted alone a shift register. On command, bubbles in the major loop can be transferred to a minor loop 8 by momentarily shutting off current through transfer line 10.

Fig. 2 illustrates how single-level lithography is employed to build the desired portions of the device of Fig. 1. Over the bubble-supporting garnet film 12 is deposited a thin layer 14 of SiO(2). A mask is made so that photoresist regions 16 define a minor loop channel 18, a transfer line channel 20 and a major loop channel 22. Into these channels are deposited successively a layer of NiFe 24 and a superposed layer of gold 26. The Au-NiFe lines are 1 micron wide and the gaps between the lines are 1/2 micron wide. When drive current is sent through the transfer line 20, gold, being less resistant to current than NiFe, carries most of the drive current. Since the Au is too far from a bubble 28 in the garnet, the current in the gold will not be sufficient to drive the bubble. Consequently, the gold from the transfer line 20 is removed, leaving only the NiFe, so that when drive current is applied only...