A theoretical study on the fundamental chemical reactions in titanium plasma-enhanced cvd

摘要

The important intermediates in the Ti plasma-enhanced CVD using TiCl_4/Ar/H_2 are investigated by ab initio molecular orbital (MO) calculations. From the experimental point of view, it is pointed out that TiCl_3 is a key species for the Ti deposition reaction. So, its reactivity with the Si and SiO_2 substrates is estimated theoretically from the stabilization energy. The difference of the stabilization energies of TiCl_3 between them, which is 12.3kcal/mol in Hartree-Fock level calculations with using the on-top deposition reacton model, indicates a longer existing time by the factor of 10~2 on SiO_2 than on Si. In addition to these calculations, the stabilization energies on the silicide substrates are also calculated and compared with the results on the Si and SiO_2 substrates. But other reaction paths may have to be considered because the growth rates of Ti thin films onto between Si and SiO_2 don't necessarily coincide with the tendency of calculated results.