Optical and structural characterization of thermal oxidation effects of erbium thin films deposited by electron beam on silicon

Abstract

Thermal oxidation effects on the structural, compositional, and optical properties of erbium films deposited on silicon via electron beam evaporation were analyzed by x-ray diffraction, x-ray photoelectron spectroscopy, Auger electron spectroscopy, and spectroscopic ellipsometry. A gradual rise in oxidation temperature from 700 to 900 °C resulted in a transition from ErO- to Er2O3-rich phase. Additional increase in oxidation temperature above 1000°C led to the formation of erbium silicate due to further oxygen incorporation, as well as silicon out-diffusion from the substrate. A silicon oxide interfacial layer was also detected, with its thickness increasing with higher oxidation temperature. Additionally, film refractive index decreased, while its Tauc bandgap value increased from ∼5.2 eV to ∼6.4 eV, as the oxidation temperature was raised from 700 °C to above 900 °C. These transformations were accompanied by the appearance of an intense and broad absorption band below the optical gap. Thermal oxidation effects are discussed in the context of film structural characteristics and defect states.

Thermally induced evolution of optical and structural properties of Er2O3 films grown on Si substrates by thermal atomic layer deposition

“…1S,d), using general Tauc model and assuming Er 2 O 3 films as allowed transitions indirect bandgap material similar to Ref. [13], showed that the annealing results in some decrease of bandgap value from E g = 5.28 eV (as-deposited films) down to E g = 4.95 eV (T A = 1100°C) ( Fig. 1S,d).…”

“…As-deposited films demonstrated the refractive index n = 1.85 9-1.861 (at 1.95 eV) similar to that reported for Er 2 O 3 in Refs. [12,13]. Thermal treatment results in its non-monotonic variation (Fig.…”

XPS Analysis of 2- and 3-Aminothiophenol Grafted on Silicon (111) Hydride Surfaces

“…An examination of the S2p spectra was deemed necessary to understand how the reaction differed between both molecules. In most situations, interpreting S2p on silicon (111) substrate is challenging due to the satellite peaks induced from the nearby Si2s (~152 eV), which is a result of surface plasmon (silicon’s plasmon energy is ~17 eV) being excited by the photoelectrons [ 27 , 28 , 29 ]. Hence, obtaining a clean S2p peak is often difficult on silicon surfaces.…”

Single step electrodeposition process using ionic liquid to grow highly luminescent silicon/rare earth (Er, Tb) thin films with tunable composition

“…The maximum PL intensity was obtained from the thin lm containing 12 at% of Er in the deposit. The higher Er 3+ concentrations may lead to the formation of micro-clusters of erbium silicates such as Er 2 SiO 5 48,49 or Er 2 Si 2 O 7 , 50,51 which are also luminescent in nature. However, it is observed that further increase in Er content than 12 at% results in the quenching of the PL emission.…”