Early Periods of Low-Temperature Linear Antenna CVD Nucleation and Growth Study of Nanocrystalline Diamond Films

Abstract

Low-temperature growth of diamond films using the chemical vapor deposition (CVD) method is not so widely reported and its initial periods of nucleation and growth phenomenon are of particular interest to the researchers. Four sets of substrates were selected for growing diamond films using linear antenna microwave plasma-enhanced CVD (LA-MPCVD). Among them, silicon and sapphire substrates were pre-treated with detonation nanodiamond (DND) seeds before diamond growth, for enhancement of its nucleation. Carbon nanotube (CNT) films on Si substrates were also used as another template for LA-MPCVD diamond growth. To enhance diamond nucleation during CVD growth, some of the CNT films were again pre-treated by the electrophoretic deposition (EPD) of diamond nanoparticles. All these substrates were then put inside the LA-MPCVD chamber to grow diamond films under variable processing conditions. Microwave input powers (1100–2800 W), input power modes (pulse or continuous), antenna-to-stage distances (5–6.5 cm), process gas recipes (with or without CO2), methane gas percentages (3%–5%), and deposition times (11–120 min) were altered to investigate their effect on the growth of diamond film on the pre-treated substrates. The substrate temperatures were found to vary from as low as 170 °C to a maximum of 307 °C during the alteration of the different processing parameters. Contrary to the conventional MPCVD, it was observed that during the first hour of LA-MPCVD diamond growth, DND seeds and the nucleating structures do not coalesce together to make a continuous film. Deposition time was the most critical factor in fully covering the substrate surfaces with diamond film, since the substrate temperature could not become stable during the first hour of LA-MPCVD. CNTs were found to be oxidized rapidly under LA-MPCVD plasma conditions; therefore, a CO2-free process gas recipe was used to reduce CNT burning. Moreover, EPD-coated CNTs were found to be less oxidized by the LACVD plasma during diamond growth.

Influence of Thickness on the Structure and Biological Response of Cu-O Coatings Deposited on cpTi

“…Currently, one of the most promising methods for the modification of the surface properties of the materials is the deposition of thin films and coatings. Many techniques and methods exist for the deposition of thin films, such as chemical vapor deposition (CVD) [19,20], physical vapor deposition (PVD) [21,22], and others. Nowadays, the direct current (DC) magnetron sputtering technology, which belongs to the PVD technologies, exhibits several advantages, such as a high reproducibility rate and good control of the technological conditions of the deposition process, and therefore, of the structure and properties of the film.…”

Low-Temperature Deposition of Diamond Films by MPCVD with Graphite Paste Additive

“…Microwave plasma chemical vapor deposition (MPCVD) of diamond exhibits strong effects of substrate temperature on the growth rate [1,2], secondary nucleation rate, and the ratio of sp 3 /sp 2 carbon contents in a diamond film [3]. For most micrometers-thick diamond films, MPCVD is carried out at a substrate temperature higher than 700 • C and typically around 900 • C [4]. For integrated-circuit applications, diamond films must be deposited at a low temperature, which does not cause degradation of already fabricated structures.…”