Formation of misoriented blocks during single-crystal CVD diamond growth

This paper presents the results of a CVD diamond crystal growth experiment on an HPHT type IIa substrate (9 × 9 mm). Data acquired through cathodoluminescence and EBSD methods shed light on the aspects of the formation of a polycrystalline shell around a single crystal of CVD diamond. CVD diamond exhibits orientation features of the polycrystalline shell, microblocks, low-angle boundaries, and linear hexagonal macrostructures of dislocation origin. Crystal splitting occurs when the dislocation density increases from the geometric center to the periphery. Such CVD diamonds exhibit a continuous transition from single crystal to polycrystal through a block-type crystal.