Growth evolution and stress distribution in heteroepitaxial diamond with laser-patterned templates

The heteroepitaxial growth of large-area thick single-crystal diamond is strongly limited by stress accumulation and crack formation during prolonged deposition. Laser-patterned templates have been demonstrated as an effective approach for obtaining crack-free free­standing diamond layers. In this work, the influence of laser grooves on the growth behavior of diamond films grown on Ir/YSZ/Si (001) substrates by microwave plasma chemical vapor deposition (MPCVD) is systematically investigated. Laser grooves introduced into a thin diamond seed layer generate a spatially non-uniform growth template. During the early growth stage, polycrystalline diamond forms inside the grooves, whereas the surrounding regions maintain stable (001)-oriented epitaxial growth. As deposition proceeds, the faster vertical growth of single-crystal diamond progressively overgrows the groove regions, leading to gradual groove filling and closure, ultimately forming a laterally continuous epitaxial diamond film. The buried grooves with polycrystalline diamond act as mechanically compliant zones that facilitate stress redistribution during thick-film growth, thereby suppressing crack formation and enabling the fabrication of millimeter-scale freestanding diamond layers with high crystalline quality. This work clarifies how laser-patterned templates regulate growth evolution and stress accom­modation during diamond heteroepitaxy, providing insights for the controlled growth of large-area thick single-crystal diamond films on highly mismatched substrates.