Growth studies of monocrystalline CVD-diamond with minimization of structural defects

Abstract

Our project on CVD Diamond and its Related Materials, DIMARE, obtained diamond in monocrystalline structure at low pressures, that is, via chemical reactions in the vapor phase (CVD) - Chemical Vapor Deposition. The objective of this project is to get advance the study of obtaining high purity diamond gems, focusing on the study of minimization of inclusions, dislocations and other defects. So, this work will have several fronts: the first one is the assembly of a new microwave plasma reactor at 2.45 GHz, with a high vacuum pumping system, in order to minimize the contaminant gases, mainly nitrogen, at the bottom pressure; introduce in this reactor a sample positioning control with micrometric control, with feedback of the growth surface temperature; prepare monocrystalline diamond seeds (initially acquired commercially), with adequate polishing to minimize structural defects (Ra<5nm roughness); Establish monocrystalline diamond growth conditions, including gas mixing and microwave power to achieve an optimal compromise between growth rate and development of structural defects. The applicability of this high-purity diamond can be in the areas of optics, electronics, heat sinks, detectors resistant to ionizing radiation, nuclear batteries and even as jewelry. It is desired to obtain the monocrystalline CVD-diamond highly pure and transparent in the form of blocks and showing the possibilities of cutting in various planes. Analyses via Raman scattering spectroscopy, X-ray diffraction, SEM, AFM, will be part of the daily characterizations of this study. Also it is fundamental in the analysis of defects the characterizations by luminescence at low temperature, for the analysis of inclusions and, cathodoluminescence images for the observation of structural defects. It will also be the firm objective of this work to seek direct application for space uses and then direct it immediately to the market, where several companies have already expressed interest, including from Brazil. (AU)