Papers by Author: M.B. Gulyaev

Abstract: Samples with layer of silicon nanocrystals embedded in SiO2 (the single phase Si content in oxide ranged between 5 and 92 volume %) were subjected to high energy ion implantation. Implantation-induced modifications of SiO2-ncSi properties discussed in this paper include a shift of the major ncSi-related photoluminescence peak and intensification of the high-photon energy peaks, that accompany the change in amount and type of the charge trapped on the nanocrystals. A unified model is suggested for all these phenomena.

Abstract: The electrical properties of structures included 1-octadecene (CnH2n, n=18) monolayers deposed onto the oxide-free silicon surface or Si/SiGe/Si layers were analyzed as a function of surface pretreatment (hydrogen- or iodine-terminated silicon surface) and layer deposition regime (thermal- or photo-activated process). Two types of traps (for electrons and holes) were found at the interface between the monolayers and substrate. The density of traps was shown to depend on the, H- or I-termination of the silicon surface, the illumination intensity and deposition time during photo-activated deposition, and the temperature of thermal-activated deposition. The optimal regimes can be chosen for minimization of the surface charge in the structures covered with 1- octadecene monolayers, which provides a high conductivity of thin near-surface layers.

Abstract: Transformations of the SiGe/Si superlattice structures, either annealed at high pressure, or irradiated by high energy ions and subjected to post-implantation annealing, were studied and compared. Both types of treatments were found to lead to the formation of recharged defects clusters, resulting in the appearance of peaks on C-V characteristics, shrinkage of Ge profiles registered by SIMS technique after annealing, and disappearance of peaks in the free carrier profiles. The effects were more pronounced in the case of high energy ion implantation. The results are explained by the vacancy - assisted precipitation of Ge in SiGe layers.