HfO_2-based Metal-Oxide-Semiconductor Capacitors on n-InGaAs Substrate with a Thin Germanium Passivation Layer

摘要

The effect of a germanium (Ge) interfacial passivation layer (IPL) on the capacitance-voltage (C-V) and current density-voltage (J-V) characteristics of TaN/HfO_2/Ge-InGaAs metal-oxide-semiconductor capacitors(MOSCAPs) were studied. In comparison to MOSCAPs on GaAs, the results from the accumulation region were quite similar, while the C-V curves in the inversion region were substantially different owing to the different energy bandgap. By using 8 ～ 10 A Ge IPL and 60～70 A HfO_2, MOSCAPs on InGaAs exhibited an equivalent oxide thickness (EOT) of ～ 11 A and gate dielectric leakage current density (J_g) of ～ 10~(-5) A/cm~2 at V_g-V_(FB)=1 V with good C-V frequency dispersion, whereas poor electrical characteristics were obtained from the devices without a thin Ge IPL. These results show that a thin Ge IPL in optimal conditions passivates InGaAs surface effectively and provides a high quality interface.