Metal gate-HfO2 MOS structures on GaAs substrate with and without Si interlayer

In this letter, we studied the effects of post-deposition anneal (PDA) time and Si interface control layer (ICL) on the electrical characteristics of the MOS capacitor with high-kappa (HfO2) material on GaAs. Thin equivalent oxide thickness (EOT < 3 nm) with excellent capacitance-voltage (C-V) characteristics has been obtained. The thickness of the Si ICL and PDA time were correlated with C-V characteristics. It was found that high temperature Si ICL deposition and longer PDA time at 600 degrees C improved the C-V shape, leakage current., and especially frequency dispersion (< 5%).