Influence of Temperature and Electron Energy on Solid-Phase Epitaxy of Implanted Si Induced at Low Temperature by Electron Irradiation in the Electron Microscope

Abstract

AbstractElectron beam induced solid-phase epitaxy has been obtained on cross sections of implanted Si layers, by in-situ irradiation in the electron microscope, with electrons of energies of 200 and 300 keV, in the temperature range −170≤T≤20°C. The rate of the induced transformation is shown to depend very weakly on temperature (activation energies of the order of 10−2 eV ), and to be basically related to the nuclear energy loss of electrons, even if the ratio of the rates observed for irradiation at 300 and 200 keV slightly increases with T, thus deviating from the exact theoretical ratio between displacement cross sections. These facts are likely to be related to a temperature dependence of the rate of defect production and to the effect of a ionization-enhanced diffusion mechanism, rather than to a thermal mechanism of defect migration. Furthermore, the linear dependence of epitaxial rate from the dose rate leads, in the framework of a simple diffusion model, to infer that mutual interaction (recombination, clustering) between defects must be negligible. These features are discussed and compared with the results and models of ion-beam induced crystallization, which occurs in the range 200≤T≤400°C. It is concluded that different assumptions on defect kinetics must be made in the different temperature ranges where electron and ion-beam induced epitaxy occur, in order to reproduce their dependence on the main irradiation parameters.