MICROMACHINING OF SEMICONDUCTOR-MATERIALS BY FOCUSED ION-BEAMS

A Ga+ focused ion beam (FIB) has been used to micromachine semiconductor materials, including III-V compounds. The FIB was operated at 10 keV; (100) substrates of InP, GaAs and Si and epilayers of Ga0.46In0.54As and Ga0.2In0.8As0.4P0.6 grown by metal organic chemical vapour deposition (MOCVD) on (100) InP substrates were used for the micromachining experiments. Large area, rectangular wells with different depths were micromachined in the above, from which material removal rates have been derived using Talysurf profiling and SEM examination, and sputter yields deduced. The uniformity in removal rates with respect to depth has also been examined. In addition, results for clear end-point signals, using sample absorbed current have been established for Ga0.46In0.54As-InP and Ga0.2In0.8As0.4P0.6-InP interfaces.