Interfacial self-cleaning in atomic layer deposition of HfO2 gate dielectric on In0.15Ga0.85As

Abstract

An interfacial self-cleaning phenomenon was found in the atomic layer deposition of $\mathrm{Hf}{\mathrm{O}}_2$ on ${\mathrm{In}}_{0.15}{\mathrm{Ga}}_{0.85}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ substrate using $\mathrm{Hf}{\left(\mathrm{N}\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_2{\mathrm{H}}_5\right)}_4$ , i.e., TEMAH, and ${\mathrm{H}}_2\mathrm{O}$ as the precursors. The native oxides of InGaAs were all satisfactorily removed from the interface through ligand exchange (substitution) reactions with the TEMAH precursor. It relieves the Fermi-level pinning in the $\mathrm{Hf}{\mathrm{O}}_2∕\mathrm{In}\mathrm{Ga}\mathrm{As}$ heterostructure, as verified by the clear transition from accumulation to depletion in high-frequency capacitance-voltage relations and inversion in quasistatic measurement. A very low leakage current was also found from the metal-oxide-semiconductor capacitors of $\mathrm{Au}∕\mathrm{Ti}∕\mathrm{Hf}{\mathrm{O}}_2∕\mathrm{In}\mathrm{Ga}\mathrm{As}$ .