IMPROVED EPITAXIAL GALLIUM ARSENIDE LAYER GROWTH ON SILICON SUBSTRATES

THE PROPOSED PROGRAM INVESTIGATES THE USE OF GAAS LAYERS EPITAXIALLY GROWN ON SILICON WAFERS AS SUBSTRATES FOR GAAS ELECTRONIC DEVICES. THE NEW GAAS-ON-SI SUBSTRATES WILL BE LARGER, MORE UNIFORM, MORE RUGGED, AND MORE THERMALLY CONDUCTIVE THAN THE BULK GAAS SUBSTRATES THEY ARE DESIGNED TO REPLACE. GAAS LAYER GROWTH WILL BE ACCOMPLISHED BY METALORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD), WHICH HAS A GREATER POTENTIAL FOR COMMERCIAL SCALEUP THAN COMPETING TECHNOLOGIES. IN PHASE I, UNIFORM GROWTH WILL BE DEMONSTRATED ON 100 MM SILICON SUBSTRATES. THE EFFECTS OF WAFER BOWING FROM THERMAL EXPANSION MISMATCH BETWEEN GAAS AND SI WILL BE MEASURED AND THEORETICALLY MODELED. METHODS FOR REDUCING THE EFFECTS OF GROWTH DEFECTS WILL BE INVESTIGATED. IN PHASE II, THE GROWTH WILL BE SCALED UP TO A LARGER REACTOR AND DETAILED OPTIMIZATION OF THE GROWTH PROCESS WILL BE PERFORMED. METHODS FOR ELIMINATING THE EFFECTS OF WAFER BOWING AND THREADING DISLOCATIONS WILL BE DEVELOPED. IN PHASE II, THE PROCESS WILL BE COMMERCIALIZED VIA SPIRE'S EPITAXIAL LAYER SERVICE AND MOCVD REACTOR SALES.