Environmental effects of H2O on fracture initiation in silicon: A hybrid electronic-density-functional/molecular-dynamics study
Environmental effects of H2O on fracture initiation in silicon: A hybrid electronic-density-functional/molecular-dynamics study
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DOI：
10.1063/1.1689004
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发表时间：
2004-05
影响因子：
3.2
通讯作者：
S. Ogata;F. Shimojo;R. Kalia;A. Nakano;P. Vashishta
中科院分区：
文献类型：
--
作者：
S. Ogata;F. Shimojo;R. Kalia;A. Nakano;P. Vashishta
采用量子力学/分子动力学混合模拟方法研究了环境分子对硅材料断裂起始的影响。在拉伸（模式I打开）下模拟（110）裂纹，裂纹前缘周围有多个H2O分子。用密度泛函理论计算了裂纹前缘附近的电子结构。为了精确地模拟长程应力场，量子力学描述嵌入在一个大型的经典分子动力学模拟。混合模拟结果表明，硅裂纹尖端H2O分子的反应对应力强度因子K敏感。当K=0.4 MPa·m时，H2O分子分解并附着在裂纹表面的悬空键上，或氧化Si，形成Si-O-Si结构。对于0.5 MPa·m的较高K值，H2O分子氧化或破坏Si-Si键。
A hybrid quantum-mechanical/molecular-dynamics simulation is performed to study the effects of environmental molecules on fracture initiation in silicon. A (110) crack under tension (mode-I opening) is simulated with multiple H2O molecules around the crack front. Electronic structure near the crack front is calculated with density functional theory. To accurately model the long-range stress field, the quantum-mechanical description is embedded in a large classical molecular-dynamics simulation. The hybrid simulation results show that the reaction of H2O molecules at a silicon crack tip is sensitive to the stress intensity factor K. For K=0.4 MPa⋅m, an H2O molecule either decomposes and adheres to dangling-bond sites on the crack surface or oxidizes Si, resulting in the formation of a Si–O–Si structure. For a higher K value of 0.5 MPa⋅m, an H2O molecule either oxidizes or breaks a Si–Si bond.