La2O3/In0.53Ga0.47As metal-oxide-semiconductor capacitor with low interface state density using TiN/W gate electrode

Abstract Effect of W and TiN/W gate metal on the interface quality of La 2 O 3 /InGaAs metal–oxide-semiconductor (MOS) interface is investigated. Hard X-ray photoelectron spectroscopy revealed that gate metal greatly affects the oxidation states at La 2 O 3 /InGaAs interface after post-metallization annealing (PMA). Results demonstrate that TiN/W gate metal can effectively control the reaction at La 2 O 3 /InGaAs interface and also suppress the formation of As, Ga, and In oxides. As a result, superior capacitance–voltage (C–V) characteristics with low interface state density ( D it ) of 4.6 × 10 11  cm −2 /eV (∼0.1 eV from midgap) and leakage current below 10 −5  A/cm 2 was obtained for TiN/W/La 2 O 3 (10 nm)/InGaAs MOS capacitors. The MOS structure integrity was preserved for annealing temperature up to 620 °C.