Prospects of novel hybrid methods for the activated chemical vapor deposition of diamond

Abstract

Abstract High-intensity activation of the vapor phase is a necessary condition for diamond synthesis in the customary chemical vapor deposition (CVD) of diamond. In this paper a novel approach to activated CVD (ACVD) of diamond based on the combined or hybrid ACVD techniques will be discussed. By hybrid diamond ACVD we mean a technique that employs more than one way of activating the crystallization medium. Together with the basic activation mode, the hybrid method includes different supplementary activation modes that influence the physical and physico-chemical processes in the vapor phase and also on the diamond crystal surface. The role of added activation in changing the growth kinetics of diamond film (DF) and microcrystals has been considered. The published research works and our own data are indicative of the remarkable influence of added activation in such hybrid ACVD techniques as chemical transport reaction, HF (Hot Filament) or DC arcjet in combination with electrical activation, and also in MW ACVD with the addition of ultraviolet-irradiation. Along with the increase in the DF growth rate there also may be changes in the constitution and crystalline perfection of DF and microcrystals grown by hybrid methods. Depending on the combination of the methods used as well as the ratio of the activation levels and crystallization temperature the linear growth rate of diamond can be raised by 1.2–6 times as compared to the rate gained via the single-activation technique. It is a striking fact that the added power of the secondary activation may amount from several to several tens of percent of the main activation power. In conclusion the possible reasons for the growth gain obtained in the novel hybrid ACVD of diamond will be considered.