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Initial oxidation processes on Si(001) have been studied by means of surface differential reflectance (SDR). The time courses of the SDR spectra measured during thermal oxidation at 820 and 920 K allowed two different growth modes, Langmuir-type adsorption and two-dimensional island growth, to be distinguished. No photon energy dependence was observed in the time course of the SDR intensity at either temperature. On the other hand, different uptake curves were observed at different photon energies for oxidation at 300 K. The difference between the oxidation mechanisms at 300 K and at high temperatures was qualitatively apparent from SDR results, because significant photon energy dependence was observed only at 300 K. Possible assignments of the spectral components in the SDR spectra are discussed.

Recovery process in GaSb crystals with Ga ion implantation and subsequent annealing by rapid thermal annealing (RTA) or furnace annealing (FA) methods are studied by Raman scattering. The intensity of the GaSb LO phonon mode decreases with increasing ion implantation fluence. It is found that the threshold fluence to the amorphization for the Ga ion implanted GaSb is 5×1013 cm−2. It is much lower than that for InP (1×1014 cm−2). In the face-to-face FA, the recovery processes in the Ga ion implanted GaSb are very different above and below the fluence of 5×1014 cm−2. For the 5×1014 cm−2 Ga ion implantation, no recovery is observed. Below 5×1014 cm−2 implantation, the GaSb LO mode intensity increases with increasing annealing temperature and with time up to 400 °C and 15 min, respectively. However, the recovery of damage is very poor compared with that of GaAs, InP, and GaP. On the other hand, in the Si3N4 caped RTA the recovery is observed even for the 5×1014 cm−2 implantation. New modes are observed at around 114 and 150 cm−1 in the implanted and annealed GaSb samples. These two modes are related to Eg and A1g modes of Sb—Sb bond vibrations, respectively, and are produced due to the outdiffusion of Sb atoms. It is found that the face-to-face annealing enhances the outdiffusion of Sb, and that the Si3N4 caped RTA process is superior to the face-to-face FA process for the healing of the damaged layers. These anomalous behaviors are closely related to the weak bond strength of Sb containing materials. The degree of the recovery as a function of annealing temperature, annealing time, and ion implantation fluence is also investigated in both RTA and FA methods.

The initial process of dry oxidation on a Si(001)-(2×1) surface was investigated using surface differential reflectance (SDR) spectroscopy. The photon energy dependence of the difference spectra and their time courses during oxidation were analysed. It is suggested that oxidation processes at different adsorption sites can be identified from the SDR spectra. The temperature dependence of the time courses was investigated in order to obtain the activation energies. Finite activation energies for monolayer oxidation were found in the temperature range of 623-823 K, corresponding to Langmuir-type adsorption. The photon energy dependence of the activation energies could reflect the involvement of different reaction processes. Chemical reaction processes of both oxygen and silicon during oxidation in a monolayer regime are discussed.