Optimizing single crystal diamond mosaic growth: A study on seed thickness variation and pre-growth treatment

Abstract

The limitations on the size of single-crystal diamond applications still need to be addressed for practical use. This study systematically investigates the impact of variations in seed crystal thickness and pre-growth treatments on step bonding, defect formation, and stress distribution in the mosaic growth of single-crystal diamond films. The findings suggest that variations in seed crystal thickness within 50 μm result in a smooth mosaic junction and high crystal quality, while a 100 μm variation results in noticeable defects and stress concentrations, hindering adequate bonding. Pre-growth treatment improves crystal quality by reducing polycrystalline formations and stress concentrations. Optical microscopy and Raman mapping confirm that pre-growth treated mosaic regions exhibit smooth steps and seamless bonding, with FWHM values between 3 and 5 cm⁻¹, consistent with the quality of non-mosaic growth regions.