IN-SITU PROCESS MONITORING OF MOCVD BY PHOTOREFLECTANCE

METAL-ORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD) IS A VAPOR-PHASE METHOD OF EPITAXIAL GROWTH WHICH YIELDS HIGH-PURITY SEMICONDUCTORS. COMPOSITIONAL AND STRUCTURAL CONTROL HAVE BEEN ACHIEVED BY UTILIZING PROCESS PARAMETERS/MATERIALS PROPERTIES RELATIONSHIPS DERIVED FROM EX-SITU MATERIALS CHARACTERIZATION DATA. THE PRODUCTION CAPABILITY OF THE MOCVD TECHNIQUE GREATLY EXCEEDS THAT OF MOLECULAR BEAM EPITAXY (MBE). THIS ADVANTAGE MAY NOT BE FULLY REALIZED UNTIL AN ACCURATE AND RELIABLE IN-PROCESS SENSOR IS DEVELOPED. THE GOAL OF THIS PROPOSED RESEARCH IS TO ESTABLISHED PHOTOREFLECTANCE (PR) AS A VIABLE IN-SITU PROCESS MONITOR OF THE MOCVD EXPITAXIAL GROWTH TECHNIQUE. THIS OBJECTIVE WILL BE ACCOMPLISHED BY (1) OBTAINING A USABLE AND REPRODUCIBLE PR SIGNAL, FROM GAAS IN THE GROWTH CHAMBER AT ROOM TEMPERATURE, GROWTH TEMPERATURE, AND DURING GROWTH; (2) ACHIEVIG THE SAME RESULTS FROM ALGAAS SAMPLES WITH A VARIETY OF AL CONCENTRATIONS; AND (3) MONITORING THE PR SIGNAL, IN-SITU, DURING GROWTH OF GAAS/ALGAAS HETEROSTRUCTURES. THE DATABASE ESTABLISHED IN STEPS (1) AND (2), AS WELL AS OTHER EXISTING DATA, WILL BE USED TO EVALUATED THIS PR SIGNAL AND TO DETERMINE THE AL COMPOSITION PRESENT AS THE HETEROSTRUCTURE IS GROWN. THE EFFECTIVENESS OF THIS TECHNIQUE WILL THEN BE CONFIRMED BY EX-SITU MATERIALS ANALYSIS.