Numerical study of femtosecond laser-assisted atom probe tomography
Numerical study of femtosecond laser-assisted atom probe tomography
复制标题
飞秒激光辅助原子探针层析成像的数值研究
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
B. Deconihout
中科院分区：
文献类型：
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作者：
E. Silaeva;N. Shcheblanov;T. Itina;A. Vella;J. Houard;N. Sévelin;F. Vurpillot;B. Deconihout
我们研究了激光辅助原子探针层析成像技术的机理。在这种方法中，亚波长尖端既受到很强的静电场，又受到飞秒激光脉冲的影响。结果，离子一个接一个地从尖端喷射出来。通过使用飞秒激光，人们不仅可以分析金属，还可以分析半导体和介电材料。为了更好地了解弹射过程，建立了基于漂移扩散方法的数值模型。该模型考虑了场穿透、空穴和电子运动以及激光吸收等效应。对于给定的直流电场，在硅尖表面观察到明显的能带弯曲和空穴密度的增加。这种弯曲效应改变了硅在表面的吸收系数，显著增加了激光诱导载流子的复合时间。
We investigate the mechanisms of a laser-assisted atom probe tomography technique. In this method, a sub-wavelength tip is subjected both to a very strong static electric field and to a femtosecond laser pulse. As a result, ions are ejected from the tip one by one. By using femtosecond lasers, one can analyze not only metals but also semiconductors and dielectric materials. To better understand the ejection process, a numerical model is developed based on the drift-diffusion approach. The model accounts for such effects as field penetration, hole and electron movement, and laser absorption. For the given value of the dc field, a substantial band bending and an increase in hole density at the surface of the silicon tip are observed. This bending effect changes silicon absorption coefficient at the surface and significantly increases recombination time of laser-induced carriers.