Wang Mingyuan, Zhang Tong, Yuan Yanping, Wang Zhiyong, Liu Yanlei, Chen Lin
School of Physics and Optoelectronic Engineering, Beijing University of Technology, Beijing 100124, China.
Henan Key Laboratory of Infrared Spectrum Measures, Applications College of Physics, Henan Normal University, Xinxiang 453007, China.
Micromachines (Basel). 2025 Jan 13;16(1):85. doi: 10.3390/mi16010085.
Gallium nitride (GaN) exhibits distinctive physical and chemical properties that render it indispensable in a multitude of electronic and optoelectronic devices. Given that GaN is a typical hard and brittle material that is difficult to machine, femtosecond laser technology provides an effective and convenient tool for processing such materials. However, GaN undergoes complex physical and chemical changes during high-power ablation, which poses a challenge to high-precision processing with controllable geometry. In this study, the quantitative relationship between the parameters of a single-pulse femtosecond laser and GaN ablation morphology was investigated using isotherm distribution. A multiphysics model using COMSOL Multiphysics was developed to generate the isothermal distributions. Experiments were conducted on the femtosecond laser ablation of GaN at various single-pulse energies, and the resulting ablation morphologies were compared with the predictions from the multiphysics model. The comparison demonstrated that the calculated isotherm distribution accurately predicted not only the ablation diameter and depth but also the crater shape across a broad range of laser fluences. The predicted errors of the ablation diameters and depths were within 4.71% and 10.9%, respectively. The root mean square error (RMSE) and coefficient of determination (R) were employed to evaluate the prediction errors associated with the crater shapes, which fell within the range of 0.018-0.032 μm and 0.77-0.91, respectively. This study can provide an important reference for utilizing femtosecond lasers in the precise ablation of GaN to achieve desired geometries.
氮化镓（GaN）具有独特的物理和化学性质，使其在众多电子和光电器件中不可或缺。鉴于GaN是一种典型的硬脆材料，难以加工，飞秒激光技术为加工此类材料提供了一种有效且便捷的工具。然而，GaN在高功率烧蚀过程中会发生复杂的物理和化学变化，这对具有可控几何形状的高精度加工构成了挑战。在本研究中，利用等温分布研究了单脉冲飞秒激光参数与GaN烧蚀形貌之间的定量关系。使用COMSOL Multiphysics开发了一个多物理场模型来生成等温分布。在不同单脉冲能量下对GaN进行了飞秒激光烧蚀实验，并将所得烧蚀形貌与多物理场模型的预测结果进行了比较。比较结果表明，计算得到的等温分布不仅能准确预测烧蚀直径和深度，还能在很宽的激光能量密度范围内准确预测坑洼形状。烧蚀直径和深度的预测误差分别在4.71%和10.9%以内。采用均方根误差（RMSE）和决定系数（R）来评估与坑洼形状相关的预测误差，其范围分别在0.018 - 0.032μm和0.77 - 0.91之间。本研究可为利用飞秒激光精确烧蚀GaN以实现所需几何形状提供重要参考。
