High performance magnetic bubble replicate gate design

The design and characterization of a novel magnetic bubble replicate gate are described. The gate can replace a previously reported design for memory chips with 16μm basic circuit period and 2μm minimum features. The improvements consist primarily of the elimination of the need for a pole enhancing "tail" and for the presence of conductor edges near critical regions, both of which existed in the old replicate gate design. The benefits are greatly improved bubble propagate margins and replicate phase margins. The test results presented show that phase margin ranges as wide at 60° are available, and storage loop propagate margins of over 25 Oe are typical for rotating drive field amplitudes of 35 Oe to 45 Oe and frequencies up to 357 kHz. Data pertinent to margin ranges in other operating parameters are also presented, and the failure modes imposing the margins are discussed.