Laser-induced explosive boiling during nanosecond laser ablation of silicon
Laser-induced explosive boiling during nanosecond laser ablation of silicon
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DOI：
10.1117/12.478637
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发表时间：
2002-01
期刊：
影响因子：
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通讯作者：
V. Craciun;N. Bassim;D. Craciun;C. Boulmer-Leborgne;J. Hermann;R. Singh
中科院分区：
文献类型：
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作者：
V. Craciun;N. Bassim;D. Craciun;C. Boulmer-Leborgne;J. Hermann;R. Singh
研究了Nd：YAG固体激光器发射的266 nm和1064 nm激光脉冲辐照（100）Si单晶片的表面形貌。在本研究中使用的最大能量密度为18 J/cm 2的266 nm单脉冲或多脉冲激光照射后，陨石坑底部的形态保持平坦，几乎没有特征。环形山的边缘显示出径向液体流动的迹象，但很明显，蒸发过程仅限于表面区域。在由1064 nm波长的激光脉冲形成的凹坑的底部上观察到不同的形态。由于该波长在体积上被吸收，（α）<104 cm-1，因此在表面形成相当厚的液态Si池。对于高于3-5 J/cm 2的激光能量密度，在弹坑底部观察到沸腾位点的证据，特别是对于多脉冲照射。随着脉冲数的增加，观察到表面形貌从波向深腔的演变。通过对空泡形成机理、空泡密度和空泡形状的分析，认为空泡是由非均质沸腾而非均质沸腾引起的。
The surface morphology of single crystal (100) Si wafers irradiated by 266 nm and 1064 nm laser pulses emitted by a solid state Nd:YAG laser has been investigated. The morphology of the bottom of craters remained flat and almost featureless after 266 nm single or multipulse laser irradiation up to the maximum fluence of 18 J/cm2 used in this study. The rims of the craters showed signs of radial liquid flow but it was apparent that the vaporization process was confined to the surface region. A different morphology was observed on the bottom of the craters formed by the 1064 nm wavelength laser pulses. Because this wavelength is absorbed in volume, (alpha) <104cm-1, a rather thick liquid Si pool formed at the surface. For laser fluences higher than 3-5 J/cm2 evidence of boiling sites were observed on the bottom of the crater, especially for multipulse irradiation. An evolution of surface morphology, from waves towards deep cavity was observed with the increase of pulse number. By analyzing the cavity formation mechanisms, their density and shape, we suggest that they were induced by heterogeneous boiling and not homogeneous boiling.