Growth of GaN and improvement of lattice curvature using symmetric hexagonal SiO2 patterns in HVPE growth

Abstract

We implemented facet and flattening (FF) growth via hydride vapor phase epitaxy, and applied hexagonal SiO2 mask patterns to minimize the final threading dislocation density (TDD). We found that the FF growth technique with hexagonal masks significantly mitigates the lattice curvature. Following multiple growth steps, an isotropic curvature could be observed owing to the planar symmetry of the mask patterns; the radius of curvature was 55 m. Furthermore, TDD was significantly reduced to 6.8 × 105 cm-2. These results indicate that the hexagonal mask technique is effective for improving both lattice curvature and crystalline quality of a GaN substrate.