SURFACE ACOUSTIC WAVES ON FERROELECTRIC SUPERLATTICES

SUPERLATTICE BASED ACOUSTIC WAVE DEVICES WILL FORM THE BASIS OF A MAJOR BREAKTHROUGH IN THE FIELD OF RF FILTERS, RF SIGNAL PROCESSING, AND RF FREQUENCY SOURCES. THIS TECHNOLOGY SHOULD MOVE THE MAXIMUM OPERATING FREQUENCY FOR SURFACE ACOUSTIC WAVE DEVICES WELL INTO THE MICROWAVE RANGE BY OVERCOMING THE BARRIER POSED BY THE FABRICATION DIFFICULTIES AND THE ELECTRICAL RESISTANCE LOSSES ASSOCIATED WITH SMALL ELECTRODE GEOMETRIES IN THE 0.1 MICRON RANGE. A KEY TECHNICAL FEATURE OF ACOUSTIC WAVES IN A PROPERLY DESIGNED SUPERLATTICE STRUCTURE IS THAT THEY CAN HAVE A PHASE VELOCITY UP TO 10 TIMES HIGHER THAN THE NORMAL ACOUSTIC WAVES. THIS WILL REMOVE THE CURRENT HIGH FREQUENCY LIMITATION ON SURFACE ACOUSTIC WAVE DEVICES BECAUSE OF THE CORRESPONDING INCREASE IN THE SIZES OF ELECTRODE GEOMETRIES REQUIRED. THE EFFORT IS BASED ON AN INNOVATIVE METHOD FOR PRODUCING THE RQUIRED SUPERLATTICE STRUCTURE.