Infrared ellipsometric study on the initial stages of oxide growth on Si(001)

Abstract

The initial stages of native oxide growth on an etched Si(001) surface have been studied by infrared (IR) spectroscopic ellipsometry. The mid-infrared ellipsometric spectra show characteristic vibrational bands of Si-H stretching vibrations between 2100 and 2200 cm −1 , and bands of silicon oxide between 1000 and 1290 cm −1 . The most intense band in the range of Si-H stretching vibrations is assigned to a vibration of SiH 2 groups, while the most prominent bands from the oxide interface can be assigned to bands originating from different Si-O stretching vibrations. By monitoring these bands during degradation of the passivated surface in atmospheric conditions different steps of the oxide growth at the interface are identified. The frequencies of the Si-O bands differ from those in thicker films. It is concluded that at the very beginning the top Si atoms are oxidized by replacement of the hydrogen bonds allowing the subsequent oxidation of the back bonds.

Microfocus-infrared synchrotron ellipsometer for mapping of ultra thin films

“…Additional bands that can not be attributed to nitrobenzene are marked with an asterisk. ides on H/Si(1 1 1) and H/Si(0 0 1) surfaces [20]. The set-up is currently upgraded.…”

“…The detection limits improved further with the advances in IR technology and most recently it was shown that also ultra thin organic films [19,8] and submonolayers of adsorbates [20] on nonmetallic substrates can be investigated. The instrument presented in this article furthermore allows to achieve this sensitivity for sample areas with diameters of only a few 100 lm.…”

Theoretical study on photon–phonon coupling at (001)‐(2 × 1) surfaces of Ge and α‐Sn

“…So, RAS can be used as a complementary technique to other infrared (IR) spectroscopies (e.g., IR absorption [18,19], IR ellipsometry [20], IR attenuated total reflection [21,22], Raman scattering [23,24], and sumfrequency generation [25,26]), which have a prominent bulk signal that might obstruct the detection of surface phonons. The far-infrared reflectance anisotropy spectroscopy (FIR-RAS), being an optical technique, does not damage the sample and can be applied to investigate surfaces of samples embedded not only in vacuum, but also in a gas or a liquid.…”

Photoluminescence and surface photovoltage of ethynyl derivative‐terminated Si(111) surfaces

“…Hydrogenated Si(111) surfaces have a low rate of surface charge carrier recombination, which means that this surface is well-passivated [8]. However, this surface is not stable and oxidizes rapidly in contact with ambient air [9]. For this reason, a way to avoid this degradation is to form covalent Si-C bonds which can be obtained by various methods initiated chemically [10], electrochemically [11,12], thermally [13] or photochemically [14].…”