A new process for the fabrication of double positioning boundary (DPB) free 3C-SiC was demonstrated by utilizing the threading screw dislocations of 6H-SiC, using the following two steps: (1) formation of a spiral structure with six bilayer steps on a seed 6H-SiC; and (2) nucleation of 3C-SiC on the seed. In the first step, the six-bilayer step structure was formed via spiral dissolution using a molten Fe–Si alloy. The formation of a spiral structure on both the 6H-SiC (0001) and (0001̅) faces could be explained by BCF theory. In the second step, we observed that the nucleation and growth of 3C-SiC occurred only on the 6H-SiC (0001) face, while step-flow growth of 6H-SiC was observed on the (0001̅) face. The different growth modes presumably arose from the smaller step energy at the 6H-SiC (0001)/alloy interface than that at 6H-SiC (0001̅)/alloy interface, which was predicted from the width of the steps fabricated by the spiral dissolution. The obtained 3C-SiC on the continuous spiral steps of the seed 6H-SiC substrate had the same stacking structure as the seed, even at the 6H-SiC/3C-SiC interface. Consequently, we successfully obtained a DPB-free region of 3C-SiC from the start of the growth.

中文翻译：

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6H-SiC的螺旋结构诱导3C-SiC的形核控制

利用以下两个步骤，通过利用6H-SiC的丝杠位错，演示了一种无双定位边界（DPB）的3C-SiC制备的新工艺：（1）在六面体上形成具有六个双层步骤的螺旋结构晶种6H-SiC; （2）3C-SiC在晶种上成核。在第一步中，使用熔融的Fe-Si合金通过螺旋溶解形成六层台阶结构。可以用BCF理论解释在6H-SiC（0001）和（0001̅）面上都形成螺旋结构。在第二步中，我们观察到3C-SiC的形核和生长仅发生在6H-SiC（0001）面上，而6H-SiC的逐步流动生长则在（0001 step）面上观察到。据推测，不同的生长方式是由6H-SiC（0001）/合金界面处的阶跃能比6H-SiC（0001）/合金界面处的阶跃能小所致，这是通过螺旋溶解法制备的台阶宽度来预测的。即使在6H-SiC / 3C-SiC界面处，在种子6H-SiC衬底的连续螺旋台阶上获得的3C-SiC也具有与种子相同的堆叠结构。因此，我们从生长开始就成功获得了不含DPB的3C-SiC区域。