发表机构
University of Aveiro（阿威罗大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用杂化密度泛函方法研究4H-SiC中硼和铝受主的电子结构，发现B_Si具有大俘获截面导致n型材料寿命退化，并预测B_C存在新的施主跃迁。
AI 中文摘要
对4H-SiC中p型掺杂剂的精确建模对于理解掺杂效率和载流子输运的机制至关重要。在本工作中，我们使用杂化密度泛函方法重新审视了与硼和铝相关的受主的电子结构。除了缺陷形成能和热力学跃迁能级外，我们还对多声子发射框架内的载流子俘获动力学进行了定量分析。我们的结果揭示了两种最相关的p型掺杂剂之间的显著差异。虽然B_Si和B_C表现出几乎相同的形成能，这与两种缺陷的同时出现一致，但在本征条件下Al_C的形成能比Al_Si高出约6.5 eV，证实了先前关于前者不太可能出现的发现。我们进一步发现B_Si具有较大的电子和空穴俘获截面，将其确定为受硼污染的n型材料少数载流子寿命退化的可能来源。此外，我们预测了B_C的一个先前未探索的施主跃迁。如果实验证实，这种缺陷将对p型掺杂和硼污染的4H-SiC都造成额外的问题，不仅因为它作为电掺杂剂无效，还因为它会俘获多达两个自由空穴，降低自由空穴浓度并增加散射效应。
英文摘要
Accurate modeling of p-type dopants in 4H-SiC is essential for understanding the mechanisms governing doping efficiency and carrier transport. In this work, we revisit the electronic structure of boron- and aluminum-related acceptors using hybrid density functional methods. Besides defect formation energies and thermodynamic transition levels, we present a quantitative look into the carrier capture kinetics within the multi-phonon emission framework. Our results reveal striking differences between the two most relevant p-type dopants. While $\textrm{B}_{\textrm{Si}}$ and $\textrm{B}_{\textrm{C}}$ exhibit nearly identical formation energies, consistent with the occurrence of both defects, the formation energy of $\textrm{Al}_{\textrm{C}}$ under intrinsic conditions is approximately 6.5 eV higher than that of $\textrm{Al}_{\textrm{Si}}$, confirming previous findings that the former is unlikely to occur. We further find that $\textrm{B}_{\textrm{Si}}$ possesses large electron and hole capture cross sections, identifying it as a plausible source of minority-carrier lifetime degradation of n-type material contaminated with boron. In addition, we predict a previously unexplored donor transition for $\textrm{B}_{\textrm{C}}$. If experimentally confirmed, this defect would represent additional problems to both p-type doped and boron contaminated 4H-SiC, not only because of its ineffectiveness as an electric dopant, but also due to trapping of up to two free holes, reducing the free-hole concentration and increasing scattering effects.
