NON-DESTRUCTIVE/NON-INTRUSIVE OPTICAL PROBES OF SURFACE COMPOSITION (PC-105)

THIS PROPOSAL ADDRESSES THE NEED FOR IMPROVED NON-DESTRUCTIVE DIAGNOSTICS TO PROBE THE COMPOSITION OF SURFACES RELEVANT TO MATERIALS PROCESSING. IN PARTICULAR, THE RESEARCHERS PROPOSE TO DETECT PROCESS MATERIALS AND IMPURITIES IMPORTANT IN THE PRODUCTION OF SILICON AND GALLIUM ARSENIDE BASED SEMICONDUCTORS. THEY WILL EMPLOY NON-LINEAR MIXING OF LASER FREQUENCIES AT THE SURFACE OF THE MATERIAL OF INTEREST. THIS MIXING WILL CREATE EMISSION AT NEW FREQUENCIES WHICH ARE EASILY DETECTABLE AND ARE CHARACTERISTIC OF THE SURFACE COMPOSITION. IN PHASE I THEY WILL USE AN EXISTING UHV SURFACE SCIENCE APPARATUS AND PULSED LASER SYSTEM TO PROVE THE FEASIBILITY OF DETECTING ALUMINUM AND CARBON ON GAAS AND SILICON ON ALUMINUM. AUGER ELECTRON SPECTROSCOPY WILL BE EMPLOYED TO QUANTITATIVELY DETERMINE SURFACE COMPOSITION AND NON-LINEAR OPTICAL OUTPUT WILL BE CORRELATED WITH THE COMPOSITION. INTERFERENCES AFFECTING THE SIGNAL WILL BE PROBED. STANDARD CVD TECHNIQUES WILL BE EMPLOYED TO PREPARE THE DESIRED SURFACE COVERAGE. SUB-MONOLAYER SENSITIVITY IS EXPECTED USING THIS METHOD.