Morphological Transition in Crystallization of Si from Undercooled Melt
Morphological Transition in Crystallization of Si from Undercooled Melt
复制标题
过冷熔体中硅结晶的形态转变
DOI：
10.1088/1742-6596/327/1/012018
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Katsuhisa Nagayama and Kazuhiko Kuribayashi
中科院分区：
文献类型：
--
作者：
Kazuki Watanabe;Katsuhisa Nagayama and Kazuhiko Kuribayashi
利用CO2激光器和电磁悬浮器，在0 ~ 2 0 0 K的过冷度下对Si进行了晶化。从界面形态的角度出发，生长速度与过冷度的关系分别分为I区和II区。在过冷度约小于100 K的区域I中，观察到针状薄板晶体，其界面由多面平面组成。在区域II中，生长的晶体的形态改变为大量的枝晶。虽然I区和II区的界面形貌看起来有很大的不同，但生长速度由二维（2D）成核控制的生长模型表示，并且在过冷度大于150 K时，生长速度渐近地接近单参数线性动力学生长模型的分析。在此阶段，动力学系数为0.1 m/sK相当于由扩散控制的生长模型导出的动力学系数。这一结果意味着，随着过冷度的增加，速率决定因素从二维形核的刻面界面上的粗糙界面上的原子的随机掺入。
Using CO 2 laser equipped electro-magnetic levitator, we carried out the crystallization of Si at undercoolings from 0 K to 200 K. From the point of the interface morphologies, the relationship between growth velocities and undercoolings was classified into two regions, I and II, respectively. In region I where the undercooling is approximately less than 100 K, needle-like thin plate crystals whose interface consists of faceted plane were observed. In region II, the morphology of growing crystals changed to massive dendrites. Although the interface morphologies look quite different between region I and II, the growth velocities are expressed by two dimensional (2D) nucleation-controlled growth model, and at undercoolings larger than 150 K, the growth velocities asymptotically close to the analysis of the mono-parametric linear kinetics growth model. In this stage, the kinetic coefficient of 0.1 m/sK is equivalent to that derived by the diffusion-controlled growth model. This result means that with increase of undercooling, the rate-determining factor changes from 2D nucleation on the faceted interface to random incorporation of atoms on the rough interface.