Effect of step-flow modulation on the large-size single crystal diamond through mosaic growth

In this paper, large-size single crystal diamond is grown by microwave plasma chemical vapor deposition using mosaic technique. The effects of the step-flow modulation on the surface morphology and crystal quality of epitaxial single crystal diamond layer are systematically investigated. It demonstrates that the two adjacent crystals can be merged into a single crystal layer with good surface morphology and uniform quality when their step-flow orientations are similar. Otherwise, over-lap is observed because of the overgrowth from one seed to another, resulting in stress concentration and a large number of crystalline defects at the mosaic boundaries. Finally, we demonstrate that the step-flow modulation method facilitates the mosaic growth of inch-scale single-crystal diamond with 10 CVD seeds arranged in a T-shape.