Electrical properties and interfacial chemical environments of in situ atomic layer deposited Al2O3 on freshly molecular beam epitaxy grown GaAs

Interfacial chemical analyses and electrical characterization of in situ atomic layer deposited (ALD) Al2O3 on freshly molecular beam epitaxy (MBE) grown n- and p- GaAs (001) with a (4 × 6) surface reconstruction are performed. The capacitance–voltage (C–V) characteristics of as-deposited and 550 °C N2 annealed samples are correlated with their corresponding X-ray photoelectron spectroscopy (XPS) interfacial analyses. The chemical bonding for the as-deposited ALD-Al2O3/n- and p-GaAs interface is similar, consisting of Ga2O (Ga1+) and As-As bonding (As0) without any detectable arsenic oxides or Ga2O3; the interfacial chemical environments remained unchanged after 550 °C N2 annealing for 1hr. Both as-deposited and annealed p-GaAs metal–oxide-semiconductor capacitors (MOSCAPs) exhibit C–V characteristics with small frequency dispersion (<5%). In comparison, n-GaAs MOSCAPs shows much pronounced frequency dispersion than their p-counterparts.