A study of chemical bonding in suboxides of silicon using Auger electron spectroscopy

Abstract

We have studied the chemical bonding in thin films of SiOx (x<2) by Auger electron spectroscopy (AES). We have compared the AES Si LVV spectra of suboxides of silicon with the AES Si LVV spectrum of stoichiometric SiO2 and have observed that the spectra of the suboxides are characterized by the emergence of a feature associated with Si–Si bonds that are present in the suboxides but not in stoichiometric SiO2. We have taken care to distinguish between spectral features that are associated with departures from SiO2 bulk stoichiometry, and features that are generated by ion and electron beam induced surface damage. Ion and electron beam induced damage produces changes in the surface composition that also generates AES spectral features associated with Si–Si bonds. We have based our interpretation of the additional AES spectral feature in the silicon suboxides on an empirical tight-binding model calculation for the electronic structure. This calculation shows that Si–Si bonding states in the suboxides appear near the middle of the energy gap of stoichiometric SiO2. The position of the new spectral feature in the suboxides is in agreement with the predictions of the model calculation.

Growth and Characterization of Crystalline Silica Films on Pd(100)

“…The stoichiometries of the silica films were characterized at each processing step using AES. The Si LVV AES peak position and shape are extremely sensitive to the Si oxidation state: the main peak for elemental Si is centered 92 eV while that for SiO 2 is positioned at 76 eV. − Reduction of SiO 2 leads to a characteristic defect peak at 89 eV . Despite some overlap with Pd peaks, Figure a shows that the Si AES peak recorded immediately after depositing 2.4 ML of Si in background oxygen is similar to that seen on a Si wafer oxidized at 1275 K for 10 min, which yields an amorphous Si layer roughly 10 nm thick, far in excess of the AES sampling depth.…”

Integrated atomistic chemical imaging and reactive force field molecular dynamic simulations on silicon oxidation

“…To date, the experimental characterization of this interfacial layer has been studied using photoelectron spectroscopy, 3,12-16 Medium Energy Ion Scattering Spectroscopy (MEIS) and Secondary Ion Mass Spectroscopy (SIMS), 9,10 Rutherford Backscattering Spectroscopy (RBS), 17 Augur Electron Spectroscopy (AES), 18 and Fourier Transform Infrared Spectroscopy (FTIR). 8 However, few of these studies could detect the different suboxides and their distribution variation with temperature and oxide thickness.…”

Grassy Silica Nanoribbons and Strong Blue Luminescence

“…The Si LVV AES peak position and shape are extremely sensitive to the Si oxidation state 21 . The main peak for elemental Si is centered around 90 eV while that for SiO 2 is located at 76 eV 21 23 . Figure 2b depicts the AES spectra acquired at different sample locations in Fig.…”