Zhou Wenju, Zhang Zifeng, Zhang Qingwei, Qi Dongfeng, Xu Tianxiang, Dai Shixun, Shen Xiang
Laboratory of Infrared Materials and Devices, Ningbo University, Ningbo 315211, China.
Center for Advanced Laser Manufacturing (CALM), Shandong University of Technology, Zibo 255000, China.
Micromachines (Basel). 2021 May 27;12(6):616. doi: 10.3390/mi12060616.
Femtosecond laser-induced crystallization and ablation of GeSbTe (GST) phase change film is investigated by reflectivity pump-probing technology. Below the ablation threshold, the face-centered cubic structure (FCC) state in the central area can be formed, and cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter. The time of surface temperature dropping to the crystallization point needs about 30 ps for 5.86 mJ/cm and 82 ps for 7.04 mJ/cm, respectively. At higher laser fluence, crystallization GST island structures appear in the central ablation region due to the extremely short heating time (100 ps). Furthermore, crystallization rate is faster than the ablation rate of the GST film, which is caused by different reflectivity.
采用反射率泵浦探测技术研究了飞秒激光诱导的锗锑碲（GST）相变薄膜的结晶和烧蚀。在烧蚀阈值以下，中心区域可形成面心立方结构（FCC）态，由于传输物质的凝固，在外围去湿区形成圆柱形边缘。表面温度降至结晶点的时间，对于5.86 mJ/cm分别约为30 ps，对于7.04 mJ/cm分别约为82 ps。在较高的激光能量密度下，由于加热时间极短（100 ps），在中心烧蚀区域出现结晶GST岛状结构。此外，结晶速率比GST薄膜的烧蚀速率快，这是由不同的反射率引起的。
