Composition dependence of Si and Ge diffusion in relaxed Si1-xGex alloys
Composition dependence of Si and Ge diffusion in relaxed Si1-xGex alloys
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DOI：
10.1063/1.3380853
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发表时间：
2010-04-01
影响因子：
3.2
通讯作者：
Lerch, W.
中科院分区：
文献类型：
--
作者：
Kube, R.;Bracht, H.;Lerch, W.
在690 ~ 1270℃的温度范围内，研究了Ge含量x=0、0.05、0.25、0.45和0.70的硅-锗si1 - xge同位素异质结构中硅（Si）和锗（Ge）在硅-锗si1 - xge同位素异质结构中的扩散。对实验剖面的分析表明，Si和Ge在单质Si中的扩散系数符合实验精度。随着Ge含量的增加，Ge的扩散速度明显快于Si。所有化合物的扩散都具有Arrhenius型的温度依赖性，且Ge的活化焓值略低于Si。更明显的Ge扩散表明，随着Ge浓度的增加，Ge原子的扩散跳跃比Si原子的扩散跳跃更成功。这一趋势可以用空位对Si1-xGex自扩散的贡献增加来解释。与先前的结果相比，自扩散的激活焓对成分的依赖显示出一个向上的弯曲。砷（As）和锑（Sb）在SiGe中的扩散也有类似的成分依赖关系，并从理论上预测了SiGe中磷空位和砷空位对的稳定性。非线性行为似乎是一个普遍的趋势，因此主要是SiGe合金系统的结果。(C) 2010年美国物理研究所。(doi: 10.1063/1.3380853)
Diffusion of silicon (Si) and germanium (Ge) in silicon-germanium Si1-xGex-isotope heterostructures with Ge contents x=0, 0.05, 0.25, 0.45, and 0.70 was investigated in a temperature range between 690 and 1270 degrees C. The concentration profiles of the stable Si-isotopes and Ge-isotopes were recorded by means of time-of-flight secondary ion mass spectrometry. Analysis of the experimental profiles shows that the Si and Ge diffusion coefficients in elemental Si agree within experimental accuracy. However with increasing Ge content the diffusion of Ge gets increasingly faster compared to that of Si. An Arrhenius type temperature dependence of diffusion is observed for all compositions with slightly lower values for the activation enthalpy of Ge compared to Si. The more pronounced Ge diffusion indicates that with increasing Ge concentration the diffusional jumps of Ge atoms become more successful compared to those of Si. This trend is explained with an increasing contribution of vacancies to self-diffusion in Si1-xGex with x. In contrast to earlier results the composition dependence of the activation enthalpy of self-diffusion reveals an upward bowing. A similar composition dependence is reported for the arsenic (As) and antimony (Sb) diffusion in SiGe and is predicted theoretically for the stability of phosphorus-vacancy and arsenic-vacancy pairs in SiGe. The nonlinear behavior seems to be a general trend and accordingly mainly a consequence of the SiGe alloy system. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3380853]