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利用动力学蒙特卡罗方法模拟了异质外延超薄膜生长中的成核过程 .研究了薄膜与衬底的晶格失配对超薄膜生长中成核密度、平均核尺寸、标度关系及生长模式的影响 .结果发现产生压 (张 )应变的晶格负 (正 )失配使生长过程更早 (迟 )从成核区进入过渡区 ,失配越大 ,这一效应越明显 .在相同的沉积条件下 ,负失配导致超薄膜形成较低的成核密度与较大的平均核尺寸 ,而正失配则相反 .成核密度满足标度关系Ns≈ (F D)χ ,随着失配度从 - 0 0 4增加到 0 0 2 ,标度系数 χ从 0 37逐渐减小到 0 33,对应超薄膜生长过程从包含二聚体扩散模式转变到无二聚体扩散模式 .此外 ,模拟结果还表明 ,核尺寸分布的标度关系理论在晶格失配的异质外延生长中仍是有效的
The kinetic Monte Carlo method was used to simulate the nucleation process in the growth of heteroepitaxial ultrathin films.The nucleation density, average core size, scaling relationship and growth mode in the growth of ultrathin films were studied by lattice mismatch between the film and the substrate The results show that the negative (positive) mismatch of lattice (lattice) strain which causes the strain of strain (strain) makes the growth process enter the transition zone earlier and later from the nucleation zone, and the greater the mismatch, the more obvious Under the deposition conditions, the negative mismatch leads to the formation of a lower nucleation density and a larger average nucleus size, whereas the positive mismatch is opposite. The nucleation density satisfies the scaling relation Ns ≈ (FD) χ, Degree increased from-0 0 4 to 0 0 2, the scaling coefficient χ decreased from 0 37 to 0 33, corresponding to the transition from the dimer diffusion mode to the non-dimer diffusion mode in the growth of ultra-thin films.In addition, The results also show that the scaling relationship theory of nucleus size distribution is still effective in heteroepitaxial growth of lattice mismatch