标题： 4H-SiC的Si面硼碳化物异质外延生长机制 显示英文标题

标题： Mechanism of Heteroepitaxial Growth of Boron Carbide on the Si-Face of 4H-SiC

摘要： 异质外延硼碳化物（BxC）可以通过两步法在Si面4H-SiC(0001)上生长，包括在1200$^\circ$C下在BCl3 + H2环境中进行基底硼化，然后在1600$^\circ$C下通过添加C3H8前驱体进行化学气相沉积（CVD）生长步骤。 然而，对早期生长阶段的深入研究发现，在高温下开始CVD之前会发生复杂的反应。 确实，在硼化之后，35 nm的BxC缓冲层被一个非晶的含硼层覆盖，该层在1200到1600$^\circ$C之间的温度上升过程中发生演变和反应。尽管形成了新相（Si、SiB6），这可能由通过薄的BxC层的Si、C和B元素的显著固态扩散所解释，但当达到1600$^\circ$C时，CVD外延再生长似乎不受这些相的影响。 所得的单晶BxC层显示了外延关系[1010]BxC(0001)||[1010]4H-SiC(0001)。 这些层表现出B4C组成，例如，BxC固溶体中可能的最高C含量。 显示英文摘要

摘要： Heteroepitaxial boron carbide (BxC) can be grown on Si face 4H-SiC(0001) using a two-step process involving substrate boridation at 1200$^\circ$C under BCl3 + H2 followed by a chemical vapor deposition (CVD) growth step at 1600$^\circ$C by adding C3H8 precursor. However, in-depth investigation of the early growth stages revealed that complex reactions occur before starting the CVD at high temperature. Indeed, after boridation, the 35 nm BxC buffer layer is covered by an amorphous B-containing layer which evolves and reacts during the temperature ramp up between 1200 to 1600$^\circ$C. Despite the formation of new phases (Si, SiB6), which could be explained by significant solid-state diffusion of Si, C and B elements through the thin BxC layer, the CVD epitaxial re-growth upon reaching 1600$^\circ$C does not seems to be affected by these phases. The resulting single crystalline BxC layers display the epitaxial relationships [1010]BxC(0001)||[1010]4H-SiC(0001). The layers exhibit a B4C composition, e.g. the highest possible C content for the BxC solid solution.