Specific surface defects arising from diamond CVD-synthesis from methane-hydrogen plasma

Abstract

Diamond is unique material that have long been known to humanity. It has extra high hardness, thermal conductivity, as well as unique electrophysical characteristics that can be managed by changing its impurity composition. Therefore, this material has gained the potential of widespread use in engineering, which is currently complicated by the high cost of diamonds, difficulties of its synthesis, mechanical and physical processing. A promising direction for obtaining high-quality poly- and single crystals and, accordingly, expanding the areas of diamond use is the method of its deposition from the gas phase (CVD). The main problem that researchers face during deposition the diamond is the formation of surface defects in the growth zone. In this work, we discuss defects observed on single-crystal diamond CVD-films of 300-500 μm thick obtained from methane-hydrogen plasma with 3% methane. The surface was studied by scanning electron microscopy. As a result of the work, we revealed that during the diamond films CVD-growth mainly three types of defects are formed: etch pits, isolated diamond particles ("straying"diamonds) and coarse-grained diamond formed along the diamond plates periphery. Methods for eliminating these defects are proposed.