Metal gate-HfO2 metal-oxide-semiconductor capacitors on n-GaAs substrate with silicon/germanium interfacial passivation layers

In this letter, the authors present the capacitance-voltage and current-voltage characteristics of TaN/HfO2/n-GaAs metal-oxide-semiconductor capacitors with thin silicon and germanium interfacial passivation layers (IPLs). Physical vapor deposition high-k dielectric films and silicon/germanium IPLs were deposited on GaAs substrate which has been cleaned with HCl and (NH4)(2)S solutions. Equivalent oxide thickness (EOT) of 12.5 angstrom and dielectric leakage current density of 2.0x10(-4) A/cm(2) at parallel to V-G-V-FB parallel to=1 V with low capacitance-voltage frequency dispersion have been obtained. The results indicate that the use of a thin silicon/germanium IPL assists in scaling EOT below 13 angstrom, while improving the quality of the interface. (c) 2006 American Institute of Physics.