Huang J, Loeffler M, Muehle U, Moeller W, Mulders J J L, Kwakman L F Tz, Van Dorp W F, Zschech E
Technische Universitaet Dresden, Center for Advancing Electronics Dresden (cfaed), Dresden Center for Nanoanalysis (DCN), Dresden, Germany.
Technische Universitaet Dresden, Center for Advancing Electronics Dresden (cfaed), Dresden Center for Nanoanalysis (DCN), Dresden, Germany.
Ultramicroscopy. 2018 Jan;184(Pt B):52-56. doi: 10.1016/j.ultramic.2017.10.011. Epub 2017 Oct 25.
A Ga focused ion beam (FIB) is often used in transmission electron microscopy (TEM) analysis sample preparation. In case of a crystalline Si sample, an amorphous near-surface layer is formed by the FIB process. In order to optimize the FIB recipe by minimizing the amorphization, it is important to predict the amorphous layer thickness from simulation. Molecular Dynamics (MD) simulation has been used to describe the amorphization, however, it is limited by computational power for a realistic FIB process simulation. On the other hand, Binary Collision Approximation (BCA) simulation is able and has been used to simulate ion-solid interaction process at a realistic scale. In this study, a Point Defect Density approach is introduced to a dynamic BCA simulation, considering dynamic ion-solid interactions. We used this method to predict the c-Si amorphization caused by FIB milling on Si. To validate the method, dedicated TEM studies are performed. It shows that the amorphous layer thickness predicted by the numerical simulation is consistent with the experimental data. In summary, the thickness of the near-surface Si amorphization layer caused by FIB milling can be well predicted using the Point Defect Density approach within the dynamic BCA model.
镓聚焦离子束（FIB）常用于透射电子显微镜（TEM）分析样品制备。对于晶体硅样品，FIB 工艺会形成非晶近表面层。为了通过最小化非晶化来优化 FIB 工艺，从模拟中预测非晶层厚度很重要。分子动力学（MD）模拟已被用于描述非晶化，然而，对于实际的 FIB 工艺模拟，它受到计算能力的限制。另一方面，二元碰撞近似（BCA）模拟能够且已被用于在实际尺度上模拟离子 - 固体相互作用过程。在本研究中，考虑动态离子 - 固体相互作用，将点缺陷密度方法引入动态 BCA 模拟。我们使用这种方法来预测 FIB 铣削硅时引起的 c - Si 非晶化。为了验证该方法，进行了专门的 TEM 研究。结果表明，数值模拟预测的非晶层厚度与实验数据一致。总之，使用动态 BCA 模型中的点缺陷密度方法可以很好地预测 FIB 铣削引起的近表面硅非晶化层的厚度。
