Mechanisms of concurrent SiO desorption with oxide layer formation at Si(001) surface

Abstract

SUMMARYOxidation reactions at Si(001) surfaces have been studied via real-time in situ photoemission spectroscopy with synchrotron radiation for chemical bonding states of Si and O atoms and mass spectrometry for desorption of SiO molecules with supersonic O 2 molecular beams in a temperature region from 900 K to 1300 K. In our previous studies, the SiO desorption yield decreased with increasing incident energy in a temperature region from 900 K to 1000 K. In that case, the time evolutions of Si 2p photoemission spectra showed that SiO 2 structure on the surface was easily formed by the action of larger incident energy and the increased SiO 2 coverage correlated with the decreased SiO desorption yield. In this study, simultaneous measurements of Si 2p photoemission spectra and SiO desorption yield revealed that the decrease of SiO correlated with the increase of Si 2+ component, and the SiO desorption was terminated at the oxide thickness of 0.22 nm. These facts suggest that the SiO desorption takes place at the topmost Si dimers and a precursor for SiO desorption is a so-called T site, in which O atoms are bonding with the dangling bonds of the dimers. Consequently, M1 and M2 in the Dual-Oxide-Species (DOS) model have been clarified to be a T site and a Si 2+ state, respectively.

Time-evolution of oxidation states at the Ni(111) surface: O2incident translational energy dependence

“…Using this technique, the effects of incident energy on O 2 adsorption at the Ni(111) surface have been studied using soft x-ray photoemission spectroscopic surface analysis with high brilliance and high energy-resolution synchrotron radiation (SR-PES). The surface chemistry experimental station (SUREAC2000) of BL23SU, one of Japan Atomic Energy Agency's (JAEA) contract beamlines at the SPring-8 facility was used in these experiments [6,7]. Both an O 2 SSMB and the soft x-ray monochromatic synchrotron radiation beam can be irradiated on a sample surface simultaneously at SUREAC2000.…”

Sn Spheres Embedded in a SiO2 Matrix: Synthesis and Potential Application As Self-Destructing Materials

“…Subsequently, they can rejoin the lattice and becomes substitutional atoms. SiO 2 /Si can be decomposed to form volatile SiO according to the following reaction Si(s) + Si O 2 (s) → 2SiO­(g) at a temperature higher than 600 °C and low oxygen partial pressure. , Therefore, silicon oxide decomposition can lead to the formation of microvoids in the oxide film, which can be easily occupied by Sn atoms . The diffusion of Sn atoms is restricted to the interface between SiO 2 film and Si substrate.…”

Effects of wet-oxidized 4H-SiC annealed in HNO3/H2O vapour

“…500 Å thickness and temperatures of 900-1,200 K (Starodub et al, 1999). The SiO desorption takes place at the topmost Si dimers and a precursor for SiO desorption is a so-called T site, in which O atoms are bonding with the dangling bonds of the dimers (Teraoka et al, 2008). Figure 5 shows the Si 2 and SiO 2 intensity at the SiO 2 bulk surface was found to be highest for wet-oxidized samples annealed in HNO 3 þ H 2 O vapor at 708C heating temperature of HNO 3 solution, followed by 908C and 1108C heating temperature of HNO 3 solution.…”