High-quality micro/nano structures of 4H-SiC patterning by vector femtosecond laser

Abstract

High-intensity femtosecond laser processing of hard and brittle materials such as silicon carbide (SiC) has poor surface quality and is prone to micro-cracks, making it difficult to meet the application requirements of silicon carbide microdevices. In this study, a method for fabricating high-quality micro-nanostructures of 4H-SiC using vector polarized light was proposed. The influences of linear polarization and vector polarization on the quality and surface morphology of processed SiC microgrooves were studied, and the micromachined size rule of microgrooves machined under different pulse numbers was summarized. The damage distribution of microstructures machined by linearly polarized light and vector polarized light were characterized by confocal Raman mapping. The study had shown that using vector beam, especially azimuthal polarization beam, can ensure the uniformity of the processing area, effectively reduce micro-cracks and chipping in the processing of hard and brittle materials, and obtain better processing quality. In addition, the vector polarized light can avoid the large microgroove taper during the processing, and ensure good structure size. Finally, a high-quality multi-ring structure was fabricated by an azimuthal polarization beam, which provides an accurate method for preparing microstructures with excellent performance.