Low resistance ohmic contacts on wide band-gap GaN
نویسنده
چکیده
We report a new metallization process for achieving low resistance ohmic contacts to molecular beam epitaxy grown n-GaN (--Or7 cme3) using an Ah% bilayer metallization scheme. Four different thin-film contact metallizations were compared during the investigation, including Au, Al, Ti/Au, and Ti/Al layers. The metals were first deposited via conventional electron-beam evaporation onto the GaN substrate, and then thermally annealed in a temperature range from 500 to 900 “C! in a N2 ambient using rapid thermal annealing techniques. The lowest value for the specific contact resistivity of 8X 10-s fi cm’, was obtained using Ti/Al metallization with anneals of 900 “C for 30 s. X-ray diffraction and Auger electron spectroscopy depth profile were employed to investigate the metallurgy of contact formation.
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