Ultrathin amorphization of single-crystal silicon by ultraviolet femtosecond laser pulse irradiation
Ultrathin amorphization of single-crystal silicon by ultraviolet femtosecond laser pulse irradiation
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DOI：
10.1063/1.3087754
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发表时间：
2009-03
影响因子：
3.2
通讯作者：
Y. Izawa;S. Tokita;M. Fujita;M. Nakai;T. Norimatsu;Y. Izawa
中科院分区：
文献类型：
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作者：
Y. Izawa;S. Tokita;M. Fujita;M. Nakai;T. Norimatsu;Y. Izawa
本文阐述了紫外飞秒激光辐照非晶硅（c-Si）的非晶化机理。激光脉冲的波长为267 nm，这是Ti：蓝宝石激光器的第三谐波。我们进行了激光扫描显微镜和透射电子显微镜的表面和结构分析和成像泵浦探测测量，以调查的过程中的动力学。从分析中，我们证实了非晶化层的厚度是相当均匀的，并且在非晶化部分之下没有晶格缺陷。非晶Si（a-Si）层的厚度为7 nm，并且非晶化的阈值能量密度为44 mJ/cm 2。从成像泵-探头测量它被揭示，熔化时间小于1纳秒，超高速熔化和再凝固过程发生。通过成像泵-探针测量估计的熔融深度为7 nm。熔化部分完全对应于非晶化部分。
The mechanisms of amorphization for crystalline Si (c-Si) induced by ultraviolet femtosecond laser irradiation are described in this paper. The wavelength of the laser pulse was 267 nm, which is the third harmonics of a Ti:sapphire laser. We performed a laser scanning microscopy and a transmission electron microscopy for surface and structural analysis and imaging pump-probe measurements to investigate the dynamics of the process. From the analyses, we confirmed that the thickness of the amorphized layer was quite uniform and there is no lattice defect under the amorphized section. The thickness of the amorphous Si (a-Si) layer was 7 nm and the threshold fluence of the amorphization was 44 mJ/cm2. From the Imaging Pump-Probe measurement it was revealed that the melting time is less than 1 ns and ultra high speed melting and re-solidification process was occurred. The melting depth estimated by the Imaging Pump-Probe measurement was 7 nm. The melted portion completely corresponded to the amorphized section.