Abstract We investigate the relation between growth mode and crystalline quality of AlN directly grown on an on-axis 6H-SiC(0001) substrate under various supersaturation conditions by metal-organic chemical vapor deposition. Although 500-nm-thick AlN fabricated by a two-dimensional (2D) growth mode had smooth surfaces, high threading dislocation density (TDD) and cracks were observed. In contrast, a three-dimensional (3D) growth mode produced spiral growth and crack-free AlN with low TDD. We analyze behaviors of surface morphology, TDD, and strain relaxation of AlN by the change in growth mode, revealing that TDD is correlated with crack generation due to relaxation of compressive strain during AlN growth. To obtain atomically flat AlN on 6H-SiC(0001) to suppress crack generation by the decreased TDD, we performed multi-step 3D and 2D AlN growth. We describe successful fabrication of 600-nm-thick AlN with no crack generation, low TDD, and a 500-nm-wide terrace on an on-axis 6H-SiC(0001) substrate.

中文翻译：

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通过控制生长模式在 SiC 衬底上生长高结晶质量的 AlN

摘要 我们研究了在各种过饱和条件下通过金属有机化学气相沉积在轴上 6H-SiC(0001) 衬底上直接生长的 AlN 的生长模式和晶体质量之间的关系。尽管通过二维 (2D) 生长模式制造的 500 nm 厚的 AlN 具有光滑的表面，但仍观察到高螺纹位错密度 (TDD) 和裂纹。相比之下，三维 (3D) 生长模式产生了具有低 TDD 的螺旋生长和无裂纹 AlN。我们通过生长模式的变化分析了 AlN 的表面形貌、TDD 和应变松弛的行为，表明 TDD 与由于 AlN 生长过程中压缩应变松弛导致的裂纹产生相关。为了在 6H-SiC(0001) 上获得原子级平坦的 AlN，以通过降低 TDD 来抑制裂纹的产生，我们进行了多步 3D 和 2D AlN 生长。