Atomic-layer-deposited tantalum silicate as a gate dielectric for III–V MOS devices

[Display omitted] ► An atomic-layer deposition process for TaSiO x thin films is described. ► SiCl 4 and TaCl 5 were used as precursors in combination with H2O as oxidizer. ► SiCl 4 incorporation was found to be efficient only on Ta-OH terminated surfaces. ► TaSiO x thin films were suitable as gate dielectrics for InGaAs-based MIS devices. TaSiO x thin films with Si/(Ta + Si) mole fractions between 0 and 0.6 have been deposited using atomic-layer deposition on Si and InGaAs at 250 °C. Interface defects on InGaAs were on the order of 10 12 cm −2 eV −1, which is comparable to state-of-the-art Al 2O 3 deposited by atomic-layer deposition using Al(CH 3) 3 and H 2O while the dielectric permittivity of TaSiO x is considerably higher.