Self-aligned contiguous-disk chip using 1µm bubbles and charged-wall functions

A fully-operational, contiguous-disk bubble chip is described which employs a self-aligned circuit and simplified fabrication. Only one mask is required to define the propagation structures and all of the current control functions. This not only relaxes the demands on photolithography and reduces the number of process steps, but it also provides for more effective implementation of all device functions. Major-minor loop storage arrays with a 5μm period and 1μm bubbles have been fabricated by conventional photolithographic techniques. Operation at 150 kilohertz has been achieved error-free for 10⁵read-write operations.