Study of Strain Relaxation Mechanisms of Semiconductor Nanostructures by means of Atomistic Simulation

原子模拟研究半导体纳米结构的应变弛豫机制

基本信息

批准号：
12650074
负责人：
SHINTANI Kazuhito
金额：
$ 1.34万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

1. How the behavior of a Si adatom or a Ge adatom deposited on the Si substrate and the morphology of the deposited layers in the initial period depend on the substrate temperature was investigated by the molecular-dynamics simulations with the Stillinger-Weber potential and the Tersoff one. For Si/Si homo-deposition processes, it was concluded that (1) the deposited layers form an amorphous structure at 300K and 400K, (2) the deposited atoms construct the alternately perpendicular dimer rows in the successive atomic layers to form an epitaxial structure at 700K and 1000K, which agrees with experimental results, (3) the ranges of the trajectories of a single deposited atom at 300K and 400K do not extend beyond, those at 500K are of the order of, and those at 700K and 1000K extend beyond the length between the nearest-neighbor atoms at the substrate surface, which corresponds with the different morphologies of the deposited layers at the temperatures. For Ge/Si hetero-deposition process … More es, it was elucidated that (4) at 1000K, the deposited layers with the deposition energy 0.2eV grow in the layer-by-layer mode until the initial two to four monolayers are deposited, and then the growth mode changes into the amorphous one while the deposited layers form amorphous stractures in the other conditions.2. The temperature dependence of the strain distributions within Si/Ge/Si quantum dot structures was investigated using the molecular-dynamics simulation with the Tersoff potential, and the phonon densities of states for the optical mode were obtained. It was concluded that (1) the strain distributions within quantum dots computed by the molecular-dynamics method, at finite temperatures qualitatively agree with those computed by the conjugate-gradient method although the normal strain components perpendicular to the base of the quantum dots to the former are larger than those in the latter, and that (2) the positions of the peaks of the phonon densities of states for the optical mode in the quantum dots shift from those in bulk crystals3. The mechanical properties of carbon naotubes were investigated by the molecular-dynamics simulation. The interaction between carbon atoms were calculated by using the Brenner potential. The Poisson's ratios and the Young's modulus were obtained for the naotubes models with the same diameter and with six chiral angles. It was conluded that (1) the Poisson's ratios of naotubes depend on their chiral angles, (2) the Young's modulus of nanotubes does not depends on their chiral angles, and (3)the elastic region in the deformations of nanotubes are extremely broad. Less

1。通过具有Stillinger-Weber-Weber电位和Tersoff One的分子动力学模拟研究了SI ADATOM或GE ADATOM在SI基板上的行为以及沉积层的形态以及沉积层的形态取决于底物温度。对于Si/Si同胞沉积过程，可以得出结论，（1）沉积层在300K和400K处形成无晶体结构，（2）沉积原子在成功的原子层中交替垂直二聚体行以700K和1000K的单个垂直层形成垂直的原子层，并与经过经过经验的单个传播结果（3），（3），（3），（3），（3），（3），（3），（3），（3），（3），（3），（3）层（3），构成（3），构成（3），构成（3），构成（3），构成（3），构成（3），构成（3），构成层（3），构成层（3），构成层（3），构成了层面的层，则构成了构成的层面。 300k和400k的延伸不超过，500K处的范围为700k和1000k的范围，而底物表面的最近邻居原子之间的长度延伸，这与温度下沉积层的不同形态相对应。对于GE/Si异质沉积过程…更多的ES，可以阐明（4）在1000k处，在逐层模式下具有沉积能量0.2EV增长的沉积层，直到将最初的两到四个单层沉积到沉积，然后将生长模式沉积，然后将生长模式变化为非态层，而沉积的层则在其他条件下形成了不适合的条件。使用具有TERSOFF电位的分子动力学模拟研究了Si/Ge/Si量子点结构中应变分布的温度依赖性，并获得了光学模式的状态状态密度。得出的结论是，（1）在有限温度下，在有限温度下，量子点中的应变分布与由偶联物征服方法计算的有限温度同意，尽管正常的应变成分垂直于正常的应变成分垂直于量子点的基础，而量子点与前者的质量点相比，该质量比后者和（2）的位置（2）的位置（2）的位置（2）的位置（2）的位置（2）的位置。量子点从散装晶体中的那些转移3。通过分子动力学模拟研究了碳Nautubes的机械性能。碳原子之间的相互作用是通过使用Brenner电位来计算的。对于具有相同直径和六个手性角度的Nautubes模型获得了泊松比和年轻的模量。（1）（1）泊松的NaOtubes的比例取决于其手性角度，（2）纳米管的年轻模量不取决于其手性角，并且（3）纳米管变形中的弹性区域非常宽。较少的