SUBLIMATION GROWTH OF LARGE SINGLE CRYSTALS OF BETA SILICON CARBIDE

BETA SILICON CARBIDE (B-SIC) POSSESSES A UNIQUE COMBINATION OF PROPERTIES IMPORTANT FOR APPLICATION IN HIGH FREQUENCY ELECTRONIC DEVICES CAPABLE OF OPERATING AT HIGH POWER. THE COMBINATION OF ITS WIDE BANDGAP, HIGH SATURATED ELECTRON DRIFT VELOCITY, HIGH BREAKDOWN ELECTRIC FIELD, LOW DIELECTRIC CONSTANT, AND HIGH THERMAL CONDUCTIVITYGIVE IT A FIGURE OF MERIT FOR HIGH POWER MICROWAVE APPLICATIONS THAT IS 1100 TIMES BETTER THAN THAT OF SILICON AND 183 TIMES BETTER THAN THAT OF GALLIUM-ARSENIDE. RECENT RESEARCH ON SIC HAS RESULTED IN THE FABRICATION OF VARIETY OF ELECTRONIC DEVICES FROM BOTH A ALPHAAND BETA-SIC. THE RECENT PRODUCTION OF LARGE 6H-SIC CRYSTALS AND THEIR USE AS SUBSTRATES FOR SUBSEQUENT CHEMICAL VAPOR DEPOSITION (CVD) HAS RESULTED IN A DRAMATIC DECREASE IN THE DEFECT DENSITY IN THE CVD GROWN 6H-SIC FILMS AND AN INCREASE IN DEVICE PERFORMANCE. CURRENTLY, THERE IS NO SOURCE OF B-SIC CRYSTALS LARGER THAN 2 MM IN DIAMETER. THE FEASIBILITY IS BEING INVESTIGATED OF GROWING LARGE SINGLE CRYSTALSOF B-SIC SUITABLE FOR USE AS SUBSTRATES FOR CVD GROWTH OF B-SIC THIN FILMS, USING A SUBLIMATION TECHNIQUE SIMILAR TO THAT DEVELOPED FOR GROWING LARGE 6H-SIC SINGLE CRYSTALS. WHEN SUCCESSFULLY DEMONSTRATED,PRODUCTION OF LARGE SINGLE CRYSTALS OF B-SIC WOULD MAKE POSSIBLE THE DEVELOPMENT OF SOLID STATE HIGH POWER MICROWAVE DEVICES FROM THIS MATERIAL.