[19p-Z29-1~13] 15.7 結晶評価，不純物・結晶欠陥

[19p-Z29-4] シリコン中のヒ素ドーパントの粒界偏析機構

〇大野 裕¹、清水 康雄^1,5、Jie Ren¹、横井 達也²、井上 耕治¹、永井 康介¹、吉田 秀人³、沓掛 健太朗⁴、藤原 航三¹、中村 篤智²、松永 克志² (1.東北大金研、2.名大工、3.阪大産研、4.理研、5.NIMS)

キーワード：シリコン、粒界偏析

Three-dimensional distribution of arsenic (As) atoms at grain boundaries in silicon s is examined by atom probe tomography (APT) combined with low-temperature focused ion beam (LT-FIB), STEM, and ab initio calculations. It is shown that As atoms would segregate at the lattice sites under tensile stresses via elastic interactions. Also, APT combined with LT-FIB suggests preferential As segregation at stretched <1-10> reconstructed bonds under high tensile stresses, that would be introduced in the <1-10> tilt GBs with the tilt angle larger than 70.5^o. It is hypothesized that As atoms would form As dimers at the reconstructed bonds via electronic interactions. The present work provides important insights on As segregation at GBs; it is determined not only by elastic interactions due to the intrinsic lattice distortions at GBs, but also by electronic interactions depending on the characteristics of valence electrons of As atoms as well as on local atomic configuration at GBs.