In situ electrical determination of reaction kinetics and interface properties at molecular beam epitaxy grown metal/semiconductor interfaces

Abstract

In situ patterning and electrical characterization are used to study the electrical properties, reaction kinetics, and interface properties during reactions at Ni/n-GaAs interfaces. Ni contacts were formed in situ by deposition through a removable molybdenum shadow mask onto a GaAs(100) c(4×4) As-rich surface. Annealing at 300 °C resulted in Ni3GaAs formation. Subsequent exposure of the Ni3GaAs to an As4 flux at 350 °C resulted in the formation of NiAs at the surface and the epitaxial regrowth of GaAs at the NixGaAs/GaAs interface. The GaAs regrowth thickness and the regrown GaAs electrical properties were determined electrically by in situ capacitance–voltage and current–voltage measurements. An interlayer model was applied to explain the Schottky barrier height discrepancy between capacitance–voltage and current–voltage measurements for metal/GaAs contacts with regrown GaAs. The model predicts that the regrown GaAs interlayer is p type with a hole concentration of ∼3×1015 holes/cm3.