In situ formation, reactions, and electrical characterization of molecular beam epitaxy-grown metal/semiconductor interfaces Available to Purchase

In situ electrical characterization is used to study the interface properties and the contact penetration during reactions at metal/semiconductor interfaces. Ni contacts were formed in situ by deposition through a removable molybdenum shadow mask on molecular beam epitaxy-grown n-type GaAs(100) c(4×4) As-rich surfaces. Annealing at 300 °C resulted in $NixGaAs (x≈3)$ formation. Subsequent exposure of the $NixGaAs$ to an $As4$ flux at 350 °C resulted in the formation of NiAs at the surface and the epitaxial regrowth of GaAs at the $Ni3$GaAs/GaAs interface. The Schottky barrier height $(φbn=0.68$ V, as deposited) increased with $NixGaAs$ formation $(φbn=0.87$ V) and decreased slightly with subsequent $As4$ exposure $(φbn=0.85$ V). A thin buried $n+$ marker layer was used to determine changes in the metal/semiconductor interface position from in situ capacitance–voltage measurements. The marker-layer movement demonstrated consumption and subsequent regrowth of GaAs beneath the contact. The ideality factor obtained from current–voltage measurements for the contacts on regrown GaAs was ⩽1.11, which is indicative of the high electrical quality of the regrown GaAs.