IN-SITU MASKLESS SELECTIVE-AREA EPITAXY OF GAAS USING A LOW-ENERGY GA FOCUSED ION-BEAM

In-situ maskless selective area epitaxy of GaAs was performed for the first time with a low-energy Ga focused ion beam (FIB) and an As4 molecular beam. A newly developed low-energy FIB system was employed in the experiments, which can be utilized in the retarding mode with a substrate bias of zero. The low energy Ga FIB and the As4 molecular beam were supplied simultaneously on the GaAs(100) substrate. The incident energy (E(i)) of Ga FIB and the substrate temperature (T(s)) Were varied from 30 to 500 eV and from 270 to 500-degrees-C, respectively. The maskless selective deposition of GaAs with a diameter of approximately 180 mum can be achieved below E(i) of 200 eV. The results of mu-RHEED measurement showed that the GaAs film was a single crystal above T(s) of 400-degrees-C. All the selective grown GaAs had flat surfaces.