Effect of Ti ion implantation, abrasion with particles, and thin film evaporation on the formation of CVD diamond on Si substrates

In previous studies it has been shown that diamond nucleation and growth on Si substrates may be enhanced by substrate abrasion with a mixture of diam ond and Ti metal particles. In this work, a gradual change in the surface c omposition of Si was designed to enable a controlled study of chemical effe cts induced by Ti additives at the initial stages of diamond CVD formation. Diamond was deposited on Si substrates pre-abraded with diamond or a mixtu re of diamond and titanium powders. Also, Si implanted with different energ ies and doses of Ti (50, 100, 134 KeV, and 10(14), 10(15) ions/cm(2)) and a braded with diamond powder served as a substrate for diamond deposition. In order to study the reactions of Ti additives during the deposition process , additional Si substrates were covered by thin Ti films (100 nm) and expos ed to CVD conditions. AFM, SEM, FTIR, mu-Raman, AES, and SIMS were utilized in this study. The incorporation of Ti into the Si surface region modified its reactivity towards the formation of CVD diamond. However, its exact lo cation relative to the gas phase was found to be of crucial importance: the highest nucleation enhancement was obtained when the Ti was placed on the Si surface, and was in direct interaction with the gas phase. It is suggest ed that C is accumulated in the Ti rich zone, resulting in faster carbon sa turation and enhancement in SiC formation, which is believed to be a templa te for diamond growth on Si. (C) 1999 Elsevier Science B.V. All rights rese rved.