About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
JES
Paper
Effects of Conductor Stress on Bubble Propagation in Contiguous Disk Devices
Abstract
Stress gradients associated with overlay conductors significantly degrade the propagation margins in ion-implanted contiguous-disk bubble devices. A study has been made of the influence of various conductor metallurgies, including Au, AlCu, and Cr deposited by vacuum evaporation and electroplating, on the bias margins of 1 μm bubble propagation along tracks with 5 μm circuit period. The conductors were 2.5 μm wide by 0.5 μm thick and were spaced 0.2 μm from the garnet surface. Annealing the devices at 250° and 350°C for 30 min in a helium atmosphere generally resulted in an increase in conductor stress and a further reduction in propagation margin. The bias margin loss due to the presence of the overlays depended upon track orientation, but for the so-called “good” tracks was typically 20% for evaporated Au and 27% for AlCu after the final anneal. A correlation between margin loss and the stress level in sheet films of the conductor metals was established and reveals a monotonic loss of margin with increasing stress. The results imply that for a margin reduction of no more than 10%, the conductor stress should not exceed ~108 dynes/cm2. © 1980, The Electrochemical Society, Inc. All rights reserved.