Bubble rectifiers and reverse rotation transfer gates based on gaps in ion implanted propagation patterns

Abstract

Gaps between unimplanted disks in ion implanted propagation patterns (I2P2’s) can allow bubbles to pass through in one direction and not in the opposite direction. These ’’bubble rectifiers’’ have been shown to perform a merge function. In a major‐minor I2P2 bubble memory, a horizontal major line with a gap for each minor loop has been designed. Bubbles transferred out of minor loops down to this major line pass through the gaps and then propagate on the lower side past all the gaps to a detector, preserving the order of data tranferred in at the upper ends of the minor loops. For propagation on these multi‐gapped lines, good bias field margins, somewhat lower than those for minor loop propagation, have been achieved with 2 μm gaps in 8 μm patterns and 1 μm gaps in 4 μm patterns. Using appropriately oriented gaps, bubbles can be transferred from one propagation track to another by temporary reversal of the drive field rotation direction. A family of reverse rotation transfer gates has been designed which provide selective transfer in or out of either end of the minor loops, depending on the starting phase and the number of reverse rotations, without disrupting adjacent data. The major advantage of these transfer gates is the absence of conductors.