Low energy ion beam modification of the titanium silicide (100) reaction

This research investigated the effects of the ion beam assisted deposition process on the interdiffusion and reaction of Ti thin films deposited on Si (100). The analytical techniques employed for the characterization of these thin films included transmission electron microscopy, scanning electron microscopy, scanning transmission electron microscopy, Auger electron spectroscopy, x-ray energy dispersive spectroscopy, and x-ray diffraction. The ion assisted deposition parameters which were investigated in this study include: ion energy, ion flux, ion to depositing atom ratio, evaporant atom flux, deposition time, average energy of bombardment per depositing atom, and substrate temperature.This research successfully demonstrated that the selection of ion beam assisted deposition process parameters is critical to producing films of a particular structure and chemistry. These films consist of a partially reacted Ti rich overlayer on a Si (100) substrate. For the ion to depositing (neutral) atom ratio: (1) the amount of interdiffusion or mixing increases with increasing ion to neutral ratio (in the absense of efficient point defect sinks) and (2) the reaction between Ti and Si (100) can be stimulated at low temperature by sufficiently high bombardment energy per depositing atom and (3) increasing the time of deposition results in the formation of a crystalline phase within the amorphous Ti silicide phase. For the ion flux: the effect of increasing ion flux during deposition results in increasing vacancy fluxes through the film during growth which consumes more Si. For the ion energies investigated (100, 200, and 400 eV): the reaction between Ti and Si (100) was more significant than evaporated films although the amount of the reaction and interdiffusion was independent of ion energy. For films deposited with a constant average bombardment energy per depositing atom: (1) the average bombardment energy per depositing atom does not characterize the deposition process sufficiently to determine the resultant film structure, and (2) the deposition rate is important for coupling the effects of ion induced defect production to the growth of the amorphous Ti silicide phase (by radiation enhanced diffusion) to thicknesses far in excess of any reported thermal reaction.U of I OnlyETDs are only available to UIUC Users without author permissio