Interactions of fragment ions of tetradecane with solid surfaces

Abstract

The vapors of tetradecane (C14H30) were ionized by an electron bombardment method. Fragment ions such as C3H7, C6H13 and C12H25 ions were separated by E  B filter (Wien filter), and accelerated toward the Si(100) substrates. Thickness measurement showed that thin films were deposited on the Si substrates by C3H7 and C6H13 ion irradiation, although Si substrate surface was sputtered by C12H25 ion irradiation. RBS measurement showed that the irradiation damage by the fragment ion beams decreased with increasing the molecular weight of fragment ions at the same acceleration voltage. Furthermore, Raman spectra as well as XPS measurement showed that DLC films were formed by C3H7 and C6H13 ion irradiation, and the film thickness was larger for C3H7 ion irradiation. On the contrary, for C12H25 ion irradiation, chemical sputtering was occurred by surface reaction of hydrogen and methyl radicals with silicon atoms. The chemical reaction on the irradiated substrate surface could be enhanced owing to higher temperatures, which were performed by high-density irradiation effect of the polyatomic ions.