HYDROGEN RADICAL ASSISED METAL-ORGANIC CHEMICAL VAPOR DEPOSITION (HRAMOCVD) OF GAAS AND ALGAAS EXPITAXIAL LAYERS

IMPROVED COMPOSITIONAL CONTROL AND ENHANCEMENT OF SEMICONDUCTOR AND OPTO-ELECTRONIC MATERIALS ARE NECESSARY FOR THE FUTURE DEVELOPMENT OF DEVICES WHICH ARE DEPENDENT ON COMPLEX ULTRA-STRUCTURES. THIS INVESTIGATION WOULD DIRECTLY EXAMINE THE EFFECTS OF HYDROGEN RADICALS ON THE GROWTH AND QUALITY OF DOPED AND UNDOPED GAAS AND ALGAAS. CARBON IMPURITIES ARE OFTEN A PROBLEM IN GAAS AND ALGAAS AND GIVE RISE TO P-TYPE MATERIAL. PRELIMINARY RESULTS AT EMCORE AND ELSEWHERE INDICATE THAT HRAMOCVD MAY IMPROVE MATERIAL PROPERTIES BY ELIMINATING CARBON IMPURITIES. THIS IS SUGGESTED BECAUSE P-TYPE MATERIAL IS CONVERTED TO N-TYPE WHEN A HYDROGEN PLASMA IS INTRODUCED. HYDROGEN RADICALS WILL BE PRODUCED UPSTREAM BY A MICROWAVE PLASMA SOURCE. PARTICULAR ATTENTION WILL BE PAID TO DISTINGUISHING BETWEEN PLASMA-GENERATED UV RADIATION GROWTH EFFECTS FROM HYDROGEN RADICAL EFFECTS. CHARACTERIZATION WOULD INCLUDE ROOM AND LOW TEMPERATURE PHOTOLUMINESCENCE (PL) AND HALL MEASUREMENTS. CHANGES IN GROWTH RATE WILL ALSO BE DOCUMENTED. PHASE I WOULD DEMONSTRATE THE EFFECTIVENESS OF THIS PROCESS ENHANCEMENT TECHNIQUE.