Laser Precision Machining Technology of SiC Substrate +
PAM-XIAMEN can provide conductive and semi-insulating 4H-SiC substrates. For wafer specifications, please contact our sales team: [email protected]. Silicon carbide (SiC) has shown broad application prospects in high-power devices, high-frequency electronic equipment, aerospace and other fields due to its excellent properties such as wide bandgap, high breakdown field strength, and high thermal conductivity. However, its extremely high hardness and chemical inertness make traditional mechanical and chemical mechanical polishing methods inefficient and costly, making it difficult to achieve efficient precision machining. Ultra short pulse laser processing technology, with its ultra fast and ultra strong characteristics, can achieve near non thermal ablation precision material removal, providing a new approach for high-quality and efficient processing of SiC. The systematic study of the laser ablation mechanism of SiC is of great significance for optimizing laser processing technology, improving subsequent polishing efficiency, and achieving high-precision microstructure manufacturing. It is a key foundation for promoting the practical application of SiC in high-performance semiconductor devices.
1. Mechanism of Ultraviolet Nanosecond Laser on SiC Substrate
Hsin Yi Tsai et al. studied the dry etching effect of ultraviolet nanosecond laser on the Si and C surfaces of SiC substrates, with a focus on analyzing the effects of scanning speed and processing times on surface morphology, composition, lattice structure, and hardness.
The research results indicate that there are significant differences in the response behavior of Si surface and C surface under laser action: Si surface exhibits the best processing effect at a scanning speed of 200 mm/s and C surface at 100 mm/s. When the scanning speed is below 400 mm/s, the material removal depth and surface roughness on both sides significantly increase. Composition analysis shows that the Si and C surfaces of SiC exhibit consistent Si, O, and C ratios before and after ablation. After ablation, the ratio of Si and C decreases with the increase of oxygen content. When the scanning speed is below 200 mm/s, the change in speed has little effect on the composition ratio, indicating that although there are differences in processing speed, the distribution of surface elements is stable. In terms of crystal structure, there is a phase transition between moissanite-5H SiC and cubic silicon on the Si surface, while the C surface partially retains the SiC crystal structure but also undergoes a transformation of elemental silicon. After etching, the microhardness of both sides decreased to below 1% of the original value.
Fig. 1 Surface roughness of SiC ablated at different scanning speeds
This study indicates that scanning speed and repetition rate are key parameters for regulating the laser processing effect, and highlights the necessity of precise control of parameters and material properties in double-sided processing. In addition, laser etching can effectively soften the surface and change the microstructure, providing a new approach for improving the efficiency of subsequent chemical mechanical polishing (CMP).
2. Analysis of SiC Carbonization Behavior Induced by Femtosecond Picosecond Laser
Erxi Wang et al. investigated the processing characteristics of femtosecond picosecond pulse lasers on the surfaces of high-purity 4H-SiC and N-doped 4H-SiC materials. By combining Raman spectroscopy mapping and spatial resolution analysis methods, the laser-induced removal threshold (LIAT) and laser-induced carbonization threshold (LICT) of two materials under different pulse widths were experimentally determined, and the experimental results were verified and simulated using a dual temperature model.
Research has shown that ultra short pulse lasers, with their non thermal processing mechanism, can effectively avoid mechanical and thermal damage, significantly improving the machining accuracy of SiC materials. Due to changes in optical and electrical properties, the LIAT of N-doped SiC is lower than that of high-purity SiC. In addition, Raman spectroscopy analysis (see Fig. 2) shows that there are differences in the carbonization behavior of the two types of materials in different crystal orientations (the appearance of D and G peaks is an important basis for determining carbonization occurrence): the C surface of high-purity SiC is more prone to carbonization, while the carbonization behavior of the C surface and Si surface of N-doped SiC tends to be consistent. The dual temperature model has been proven to effectively simulate the temperature evolution during laser action, providing key theoretical support for understanding and optimizing ultra short pulse laser processing of SiC.
Fig. 2 Raman spectra of (a) irradiated and non irradiated regions of N doped 4H-SiC, (b) Si and C surfaces of high-purity 4H-SiC
This study lays a theoretical and experimental foundation for the development of high-precision and high-efficiency SiC processing technology, which is of great significance for promoting the application of SiC in fields such as power electronics, aerospace, and quantum information.
Whether you need SiC wafer for research or for industrial applications, please contact us email at [email protected] and [email protected].
Reference:
1. Tsai, H. Y., Lin, Y. H., Huang, K. C., Yeh, J. A., Yang, Y., & Ding, C. F. (2025). A Comparative Analysis of Laser-Ablated Surface Characteristics Between the Si Face and C Face of Silicon Carbide Substrates. Micromachines, 16(1), 62.
2. Wang, E., Han, P., Shan, C., Zhao, X., Li, F., Kou, H., … & Gao, Y. (2025). Ablation and carbonization effects of femtosecond-picosecond pulsed laser processing on different 4H-SiC materials. Optical Materials Express, 15(9), 2244-2254.