PHOTOLITHOGRAPHIC PATTERNING OF PROTECTIVE ARSENIC CAPPING ON MOLECULAR-BEAM EPITAXY-GROWN ALXGA1-XAS(001)

Patterning of an arsenic capping layer deposited in situ on AlxGa1-xAs(100) epilayer surfaces is demonstrated, using standard photolithography and subsequent etching in a hydrogen radical (H*) beam. These data suggest that the protection offered by such capping during ambient storage, may be exploited for molecular beam epitaxy overgrowth and device processing purposes. The technique needs further refinement, however, as trace amounts of surface oxide and carbon impurities were found on the H* etched surfaces by core-level photoelectron spectroscopy. Moreover, the scanning electron micrographs unveil residues of the As cap along the photomask edges, after completed etching.