Isotope effect on electron paramagnetic resonance of boron acceptors in silicon
Isotope effect on electron paramagnetic resonance of boron acceptors in silicon
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DOI：
10.1103/physrevb.82.115213
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发表时间：
2010-09-27
影响因子：
3.7
通讯作者：
Itoh, K. M.
中科院分区：
文献类型：
--
作者：
Stegner, A. R.;Tezuka, H.;Itoh, K. M.
硅中硼受体基态的四重简并性，很容易被任何破缺微扰所提升，使得与硼相关的电子顺磁共振（EPR）谱线，e.例如，在一个实施例中，由局部应变的随机分布引起。然而，由于EPR的外部无应变硅中的硼受体的最初报道，无论是线的形状，也没有在样品中观察到的残余加宽的幅度与高结晶纯度的低浓度的碳和氧的点缺陷，是随机局部应变的主要来源是不兼容的。适应的理论模型已被应用于理解受体基态分裂的情况下，由于存在不同的硅同位素的磁场作为一种效果，我们表明，由于不同的同位素配置附近的硼受体的价带边缘的局部波动可以定量地解释所有的不均匀加宽效应在高纯硅与天然同位素组成。我们的计算表明，这样的同位素扰动也会导致不同的硼相关的共振，我们可以在我们的实验中验证的g值的移动。此外，我们的研究结果提供了一个独立的测试和验证的价带之间的偏移不同的Si同位素在以前的工作中确定。
The fourfold degeneracy of the boron acceptor ground state in silicon, which is easily lifted by any symmetry-breaking perturbation, allows for a strong inhomogeneous broadening of the boron-related electron paramagnetic resonance (EPR) lines, e. g., by a random distribution of local strains. However, since EPR of boron acceptors in externally unstrained silicon was reported initially, neither the line shape nor the magnitude of the residual broadening observed in samples with high-crystalline purity were compatible with the low concentrations of carbon and oxygen point defects, being the predominant source of random local strain. Adapting a theoretical model which has been applied to understand the acceptor ground-state splitting in the absence of a magnetic field as an effect due to the presence of different silicon isotopes, we show that local fluctuations of the valence-band edge due to different isotopic configurations in the vicinity of the boron acceptors can quantitatively account for all inhomogeneous broadening effects in high-purity Si with a natural isotope composition. Our calculations show that such an isotopic perturbation also leads to a shift in the g value of different boron-related resonances, which we could verify in our experiments. Further, our results provide an independent test and verification of the valence-band offsets between the different Si isotopes determined in previous works.