Evolution of bubble circuits processed by a single mask level

The design and operation of bubble circuits for mass memory applications processed through but a single mask level are presented. Control "conductors" are integrated within the propagate structure to effect generation, annihilation, transfer and replication. Several chevron expander detector designs are discussed including a curved guard rail detector as well as a nucleate generator in which the field threshold for domain nucleation is permanently lowered by a laser anneal. A memory organization featuring the replicate function is described.