采用纳米晶柱阵列衬底抑制失配位错形成的分子动力学模拟研究

运用分子动力学方法对纳米晶柱阵列衬底上铝簿膜的外延生长进行了模拟研究.所采用的原子间相互作用势为嵌入原子法(EAM)多体势.模拟结果表明：采用纳米晶柱阵列衬底可以在不形成失配位错的条件下释放其上生长的外延薄膜晶体中的失配应变，有效地抑制其中失配位错的形成，获得高质量的外延薄膜晶体；这种纳米晶柱阵列的几何设计应满足两个基本条件：1) 晶柱的横截面尺寸应大于对应温度下的晶柱热失稳临界尺寸，以克服纳米结构的热失稳，模拟显示700K下铝的热失稳临界尺寸为19nm；2) 晶柱的高度与间距之比应大于076，以保证 关键词： 失配位错 分子动力学 纳米晶柱 铝

Prevention of misfit dislocations by using nano pillar crystal array substrates

Three-dimensional molecular dynamics simulations of epitaxial growth of aluminum film on substrates of nano pillar crystal array have been carried out. The embedded atom method (EAM) potential was employed for computing atomic interaction in aluminum. The results show that，the nano pillar crystal array substrate can release the misfit strain in the epitaxial film without forming any misfit dislocations，achieving a high quality epitaxial crystal film. However，two conditions must be met: 1) the cross sectional size of pillar crystal should be larger than the critical size of thermal stability，which is 19nm for aluminum at 700K；2) the height-space interval ratio of pillar crystals should be higher than 076. The latter ensures that the epitaxial layers on the neighboring pillar crystals can bridge with each other，and form a continuous film free of misfit dislocations.