Saltas Vassilis, Chroneos Alexander, Vallianatos Filippos
School of Applied Sciences, Technological Educational Institute of Crete, Crete, Greece.
Department of Materials, Imperial College London, London, SW7 2AZ, United Kingdom.
Sci Rep. 2017 May 2;7(1):1374. doi: 10.1038/s41598-017-01301-6.
The knowledge of diffusion processes in semiconducting alloys is very important both technologically and from a theoretical point of view. Here we show that, self-diffusion in Si Ge alloys as a function of temperature and Ge concentration can be described by the cBΩ thermodynamic model. This model connects the activation Gibbs free energy of point defects formation and migration with the elastic and expansion properties of the bulk material. The approach allows the systematic investigation of point defect thermodynamic parameters such as activation enthalpy, activation entropy and activation volume, based on the thermo-elastic properties (bulk modulus and its derivatives, mean atomic volume and thermal expansion coefficient) of the two end-members of the Si Ge alloy. Considerable deviations from Vegard's law are observed, due to the diversification of the bulk properties of Si and Ge, in complete agreement with the available experimental data.
从技术和理论角度来看，了解半导体合金中的扩散过程都非常重要。在此我们表明，SiGe合金中的自扩散作为温度和Ge浓度的函数，可以用cBΩ热力学模型来描述。该模型将点缺陷形成和迁移的活化吉布斯自由能与块状材料的弹性和膨胀特性联系起来。基于SiGe合金两种端元的热弹性性质（体模量及其导数、平均原子体积和热膨胀系数），该方法允许系统地研究点缺陷热力学参数，如活化焓、活化熵和活化体积。由于Si和Ge块状性质的差异，观察到与维加德定律有相当大的偏差，这与现有实验数据完全一致。
