GAAS, WHICH HAS BEEN USED FOR MONOLITHIC SURFACE ACOUSITC WAVE (SAW) DEVICES, IS ALSO THE MICROELECTRONIC MATERIAL OF CHOICE FOR HIGH SPEED, HIGH-FREQUENCY APPLICATIONS, AD ITS COMBINATION OF PIEZOELECTRIC AND SEMICONDUCTING PROPERTIES OFFERS THE

GAAS, WHICH HAS BEEN USED FOR MONOLITHIC SURFACE ACOUSITC WAVE (SAW) DEVICES, IS ALSO THE MICROELECTRONIC MATERIAL OF CHOICE FOR HIGH SPEED, HIGH-FREQUENCY APPLICATIONS, AD ITS COMBINATION OF PIEZOELECTRIC AND SEMICONDUCTING PROPERTIES OFFERS THE OPPORTUNITY TO INTEGRATE SAW AND ELECTRONIC DEVICES IN THE SAME CHIP. SPIRE PROPOSES TO IMPLEMENT THIS INTEGRATION BY THE EPITAXIAL DEPOSITION OF THINFILM GAASON SAPPHIRE SUBSTRATES, WHICH WOULD PROVIDE BOTH ACOUSTIC COUPLING AND DIELECTRIC ISOLATION WITH MINIMAL PARASTIC CAPACITANCE. SPECIFICALLY, THE PHASE I FEASIBILITY RESEARCH IS INTENDED TO DEMONSTRATE THAT HIGH-QUALITY (100) GAAS/(0112) SAPPHIRE EPITAXY CAN BE ACHIEVED; THIS ORIENTATION, WHICH IS PREFERRED BOTH FOR SAW PRO PAGATIO AND FOR MICROELECTRONIC COMPONENT FABRICATION, HAS NOT YET BEEN OBTAINED IN LARGE-AREA GAAS LAYERS ON SAPPHIRE. METALORGANIC CHEMICAL VAPOR DEPOSITION (MO-CVD) WILL BE USED, SINCE THE ABSENCE OF CHLORIDE AND THE LOWER DEPOSITION TEMPERATURES PERMITTED BY THE REACTIONS SHOULD ENHANCE THE PROBABILITY OF SUCCESS. THE DEPOSITION TEMPERATURES, THE REACTNT RATIO, AND THE DEPOSITION RATE WILL BE EXERCISED OVER RANGES CENTERED UPON THE VALUES USED FOR (111) GAAS(0001) SAPPHIRE EXPITAXY. THE GAAS LAYER WILL BE CHARACTERIZED AND THE DEPOSITION PROCESS WILL BE OPTIMIZED.