High-quality AIN growth on 6H-SiC substrate using three dimensional nucleation by low-pressure hydride vapor phase epitaxy

摘要

There is a method of controlling nucleation and lateral growth using the three-dimensional (3D) and two-dimensional (2D) growth modes to reduce the dislocation density. We performed 3D-2D-AIN growth on 6H-SiC substrates to obtain high-quality and crack-free AIN layers by low-pressure hydride vapor phase epitaxy (LP-HVPE). First, we performed 3D-AIN growth directly on a 6H-SiC substrate. With increasing Ⅴ/Ⅲ ratio, the AIN island density decreased and the grain size increased. Second, 3D-2D-AIN layers were grown directly on a 6H-SiC substrate. With increasing the Ⅴ/Ⅲ ratio of 3D-AIN, the crystalline qualities of the 3D-2D-AIN layer were improved. Third, we performed 3D-2D-AIN growth on a trench-patterned 6H-SiC substrate. The crack density was reduced to relax the stress by voids. We also evaluated the threading dislocation density by using molten KOH/NaOH etching. As a result, the estimated edge dislocation density of the 3D-2D-AIN sample was 3.9 × 10~8 cm~(-2).