The ion-beam synthesis of InSb nanocrystals in the buried SiO2 layer of a silicon-on-insulator structure is investigated. The distributions of In and Sb atoms after annealing at a temperature of Ta = 500–1100°C are studied. It is established that the redistribution of implanted atoms is unsteadily dependent on the annealing temperature. The formation of InSb nanocrystals occurs at Ta ≥ 800°C near the Si/SiO2 interface and at a depth corresponding to the mean paths Rp. Analysis of the profiles of implanted atoms and of the structure and depth distribution of nanocrystals formed allows an inference regarding the two-stage character of formation of the InSb phase. In the initial stage, antimony precipitates are formed; further the precipitates serve as nuclei for indium and antimony to flow to them.
The Raman spectra of SiO2films containing InSb spherical nanocrystals produced by ion-beam synthesis are studied. TO- and LO-like modes in the spectra of the InSb nanocrystals are detected...
The formation of nanocrystalline Si films as a result of rapid thermal annealing of silicon-on-insulator structures implanted with high doses of H+ ions is studied. It is ascertained that the process of formation of Si nanocrystals is active even at temperatures of 300–400°C and is controlled by the hydrogen content in the silicon film and by the duration of annealing. It is concluded that the formation of nuclei of the crystalline phase occurs in silicon islands surrounded by microvoids and is caused by the ordering of Si-Si bonds in the course of release of hydrogen from the bound state. It is important that microvoids do not coalesce at temperatures up to ∼900°C in conditions of rapid thermal annealing. It is found that synthesized films exhibit luminescence in the green-orange region of the spectrum at room temperature.
Anodization of silicon-on-insulator (SOI) layers is studied as a function of the SOI layer thickness in the range from 5 to 500 nm. It is found that thinning of the silicon film to less than 100 nm is accompanied by a sharp decrease in the anodization rate. For SOI films thinner than or on the order of magnitude of ∼10 nm, the limiting thickness of the oxidized silicon layer is 0.4 nm. It is shown that the main cause of a decrease in the anode current efficiency during oxidation of nanoscale Si layers is an increase in the resistance of the silicon active layer, which limits the hole current in the film plane and, hence, the number of silicon cations coming to the SiO2/electrolyte interface for their subsequent oxidation.