Microstructural characterization of AlGaAs‐GaAs modulation‐doped field‐effect transistor ohmic contacts formed by transient annealing

摘要: Transient annealing of a sequentially deposited metallization scheme, Au/Ni/Au/Ge/Ni, was used to obtain low resistivity ohmic contacts GaAs‐AlGaAs based modulation‐doped field‐effect transistors. Cross‐sectional transmission electron microscopy and energy dispersive x‐ray analysis techniques were employed determine the type distribution various phases formed. Three different phases, namely, Au rich, Ni‐Ge, Ni‐As(Ge), observed. The Ni‐As(Ge) phase found be in contact with GaAs. Ni‐Ge present localized regions Au‐rich phase. Also, direct either or region manifested itself as layered structure observed above As consequence anneal cycle, movement material both parallel perpendicular device surface occurred at edges.