Garnet film magnetic property control during growth and processing

High quality 2 in. diameter gallium and germanium substituted garnet films have been grown by the liquid phase epitaxy (LPE) dipping technique for magnetic bubble domain applications. The factors governing control and reproducibility of the film properties such as LPE melt composition, growth conditions and strategies will be reviewed. With the trend toward smaller bubbles requiring thinner films, control of the most critical parameter, the bubble collapse field, becomes more difficult. This problem is alleviated by a post-growth etching processing which involves controlled reduction in the film thickness by a phosphoric/sulphuric acid etch. Before device fabrication the films are ion implanted to suppress hard bubbles. Any elevated temperatures encountered during device fabrication will cause an annealing of the implanted layer which affects the bubble collapse field. New data will be presented to show how this depends on the thermal conditions (temperature, time) and how, by selection of the film implantation conditions, the effects may be minimized.