Shallow ohmic contacts to n-type GaAs and AlxGa1−xAs

Abstract

Sequential deposition of Pd/AuGe/Ag/Au and rapid thermal annealing are used to form shallow ohmic contacts to n-GaAs and n-AlxGa1−xAs. Ion backscattering measurements and cross-sectional transmission electron microscopy show limited metal-substrate reaction and uniform interfaces. The metallization on GaAs displays good electrical properties with a contact resistivity of 2.0×10−6 Ω cm2 at a carrier concentration of 2×1017 cm−3. The contacts formed on Al0.55Ga0.45As have a contact resistivity of 2.1×10−5 Ω cm2 at a carrier concentration of 7.5×1017 cm−3.