Quasistatic Bubble Propagation in 1.5 μm Period Ion-Implanted Tracks for 64 Mbit Magnetic Bubble Memory Devices

Ion-implanted tracks with a 1.5 μm period for use in 64 Mbit magnetic bubble memory devices have been fabricated and operated. The bubble material used was (BiSmLu) 3 (FeAl) 5 O 12 garnet film, supporting 0.45 μm bubbles. The resist mask patterns for implantation were formed using a 1/10 reduction projection aligner, using rectangular patterns on a reticle. The bubble propagation tracks were fabricated by double deuterium implantation and annealed at 400°C for 30 minutes, with an SiO 2 layer deposited on the garnet surface to stabilize the implanted layer. An operating bias field margin in excess of 7% was stably obtained in quasistatic bubble propagation. This shows that the ion-implanted devices have great potential for use in 64 Mbit magnetic bubble memory devices.