Interfacial Characteristics for LaAlO3 Gate Dielectric on S Passivated GaAs Substrate

Abstract

In this work, we present the results of an investigation into the effectiveness of varying ammonium sulphide (NH4)2S concentrations in the passivation of n-type GaAs. Samples were degreased and immersed in aqueous (NH4)2S solutions of concentrations 22% and 10%for 10 min at 295 K, immediately prior to plasma enhanced atomic layer deposition of LaAlO3. The chemical bonding state of (NH4)2S treated GaAs surface were investigated by X-ray photoelectron spectroscopy (XPS), which indicate that Sulfur passivation can reduce intrerfacial GaAs-oxide formation. Transmission electron microscopy (TEM) was implemented to characterize the interface morphology. Finally, capacitance-voltage (C-V) and leakage current density-voltage (J-V) measurement were used to characterize the electrical properties of LaAlO3 films.