Ge interface engineering using ultra-thin La2O3 and Y2O3 films: A study into the effect of deposition temperature

摘要: A study into the optimal deposition temperature for ultra-thin La2O3/Ge and Y2O3/Ge gate stacks has been conducted in this paper with aim to tailor interfacial layer effective passivation of Ge interface. detailed comparison between two lanthanide oxides (La2O3 Y2O3) terms band line-up, features, reactivity using medium energy ion scattering, vacuum ultra-violet variable angle spectroscopic ellipsometry (VUV-VASE), X-ray photoelectron spectroscopy, diffraction is shown. La2O3 found be more reactive than Y2O3, forming LaGeOx a sub-oxide at interface all studied, range from 44 °C 400 °C. In contrast, deposited 400 °C allows an GeO2 interface, which can eliminated during annealing temperatures higher 525 °C leaving pristine YGeOx/Ge The stack lower shows sub-band gap absorption feature fitted Urbach tail 1.1 eV. latter correlates sub-stoichiometric germanium oxide optical estimated 5.7 ± 0.1 eV Tauc-Lorentz modelling VUV-VASE experimental data. For (400 °C), exhibits conduction offset (>2.3 eV) (∼2 eV), larger (by about 0.3 eV), free leakage current (∼10−7 A/cm2 1 V) five orders magnitude respective stack. Our strongly points superiority system engineering achieve high performance Complementary Metal Oxide Semiconductor technology.