Chagarov Evgueni A, Kummel Andrew C
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA.
J Chem Phys. 2009 Mar 28;130(12):124717. doi: 10.1063/1.3078035.
The local atomic structural properties of a-Al(2)O(3), a-ZrO(2) vacuum/oxide surfaces, and a-Al(2)O(3)Ge(100)(2x1), a-ZrO(2)Ge(100)(2x1) oxide/semiconductor interfaces were investigated by density-functional theory (DFT) molecular dynamics (MD) simulations. Realistic a-Al(2)O(3) and a-ZrO(2) bulk samples were generated using a hybrid classical-DFT MD approach. The interfaces were formed by annealing at 700 and 1100 K with subsequent cooling and relaxation. The a-Al(2)O(3) and a-ZrO(2) vacuum/oxide interfaces have strong oxygen enrichment. The a-Al(2)O(3)Ge interface demonstrates strong chemical selectivity with interface bonding exclusively through Al-O-Ge bonds. The a-ZrO(2)Ge interface has roughly equal number of Zr-O-Ge and O-Zr-Ge bonds. The a-Al(2)O(3)Ge junction creates a much more polar interface, greater deformation in Ge substrate and interface intermixing than a-ZrO(2)Ge consistent with experimental measurements. The differences in semiconductor deformation are consistent with the differences in the relative bulk moduli and angular distribution functions of the two oxides.
通过密度泛函理论（DFT）分子动力学（MD）模拟研究了α -Al₂O₃、α -ZrO₂真空/氧化物表面以及α -Al₂O₃Ge(100)(2x1)、α -ZrO₂Ge(100)(2x1)氧化物/半导体界面的局部原子结构性质。使用混合经典 - DFT MD方法生成了实际的α -Al₂O₃和α -ZrO₂块状样品。通过在700和1100 K下退火，随后冷却和弛豫形成界面。α -Al₂O₃和α -ZrO₂真空/氧化物界面具有强烈的氧富集。α -Al₂O₃Ge界面表现出很强的化学选择性，界面键合仅通过Al - O - Ge键。α -ZrO₂Ge界面中Zr - O - Ge键和O - Zr - Ge键的数量大致相等。与实验测量结果一致，α -Al₂O₃Ge结产生的界面极性更强，Ge衬底中的变形更大，界面混合程度比α -ZrO₂Ge更大。半导体变形的差异与两种氧化物的相对体模量和角分布函数的差异一致。
