High Density Ion Implanted Contiguous Disk Bubble Technology.

Abstract

Abstract : The main thrust of research carried out under this program was to develop high density ion-implanted contiguous-disk bubble memory devices. These devices offer order of magnitude higher bit density than presently manufactured bubble memory devices for a given lithographic resolution. In one phase of the research, a computer simulator was constructed and used to model the operation of ion-implanted contiguous-disk bubble devices. Input parameters for the simulator include the geometry of the implanted patterns, magnetic characteristics of the bubble film, implanted layer thickness, conductor geometry, amplitude and phase of currents in conductors, and the frequency and amplitude of the drive field. The fields acting upon the bubble include those from the conductors, implanted/unimplanted boundaries and charged walls. Using the model, the operation of various gates for ion-implanted devices was analyzed, including a trapping transfer gate and a dual conductor block replicate gate. A novel true swap gate for ion-implanted bubble devices was also devised and simulated. The simulated bias margins of both propagation structures and gates were found to correspond well with experimental measurements.