4H-SiC激光烧蚀的三维分子动力学研究  

Study of Laser Ablation on 4H-SiC by Three-Dimensional Molecular Dynamics

作　　者：安豪杰 王金石[1,2] 房丰洲 An Haojie;Wang Jinshi;Fang Fengzhou(State Key Laboratory of Precision Measuring Technology&Instruments,Tianjin University,Tianjin 300072,China;Laboratory of Micro/Nano Manufacturing Technology(MNMT),School of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学精密测试技术及仪器全国重点实验室,天津300072 [2]天津大学精密仪器与光电子工程学院微纳制造实验室(MNMT),天津300072

出　　处：《中国激光》2024年第20期261-268,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(52105475,52035009)。

摘　　要：飞秒激光直写在原子及近原子尺度制造领域中表现出独特的优势。为了研究飞秒激光与材料在原子及近原子尺度的相互作用过程,给出了一种基于双温方程的三维分子动力学模型,开展了4H-SiC表面飞秒激光烧蚀过程与机制的研究,对不同能量密度激光辐照产生的原子轨迹、温度场、结构形貌和烧蚀产物进行了分析,并探讨了能量密度对表面改性和材料去除的影响。研究结果表明:在低能量密度下,碳化硅材料经激光诱导主要发生晶相结构向非晶相结构的转变;而在高能量密度下,中心区材料的爆炸沸腾是材料喷射去除以及边缘材料堆积的主要原因。烧蚀产物为气与液的两相混合物,其组分占比依赖于激光能量密度。该三维模型为原子及近原子尺度飞秒激光加工提供了理论分析的新途径。Objective Silicon carbide(SiC)is a high-performance third-generation semiconductor material that is poised to meet the growing demand in the optoelectronic field.Further exploration of SiC processing at atomic and close-to-atomic scales is of great importance for both fundamental science and industrial applications.The hard and brittle nature of SiC renders traditional methods,such as ultraprecision machining,impractical for achieving high-quality surface treatments.Although some approaches,such as ion implantation or laser heating,can improve the machinability of hard and brittle materials,achieving high-quality processing remains elusive.Laser direct writing emerges as a potential solution for atomic-and close-to-atomic-scale manufacturing(ACSM).However,there is a lack of understanding regarding the laser-material interactions at the atomic and close-to-atomic scales.A hybrid twotemperature model-based molecular dynamics(TTM-MD)method can reveal the interactions from an atomic perspective;however,the one-dimensional(1D)TTM-MD model ignores the lateral propagation of heat and stress,which limits the understanding of surface modification and ablation.In this study,a three-dimensional(3D)TTM-MD model is developed to study the femtosecond laser ablation of 4H-SiC at varying fluences.The atomic trajectories,temperature fields,structural morphologies,and ablation products are analyzed.We hope that the 3D TTM-MD model will be helpful in the material processing of femtosecond lasers at the atomic and close-to-atomic scales.Methods A 3D profile of the absorption of laser energy by materials is obtained by analyzing a Gaussian beam.A 3D TTM-MD code is developed using the open-source software LAMMPS.The coupling of the TTM and MD is achieved by using a coarse-grained electron temperature grid.The dimensions of the simulation box are 1000Å×502Å×500Å.The size of the laser beam is 200Å,and the absorption depth is set to 50Å.The femtosecond laser ablation of 4H-SiC is simulated based on this model,and the influence of

关 键 词：激光技术 材料加工 双温模型 分子动力学 原子及近原子尺度制造 

分 类 号：TN249[电子电信—物理电子学]