Silicon carbide, an emerging material with outstanding semiconducting and electrical properties, is increasingly triggering scientific and industrial interest for the development of cutting-edge high-power and high temperature electronics as well as ultrafast electronic devices. However, due to its high hardness mechanical processing is very difficult and its chemical inertness results in challenges in wet etching. Therefore, laser processing appears to be a promising approach for micromachining, cutting or drilling.
As a result of recent developments in laser and optics technology, frequency tripled ultra-short pulsed laser systems emitting in the ultraviolet spectral region with high power and pulse energy, and at the same time high beam quality and durability, motivating new applications of laser micromachining.
Against this background, we report on novel ultraviolet ultra-short pulsed laser processing of silicon carbide. Laser ablated cavities are evaluated with respect to their ablation rates, surface roughness and overall quality. In addition to pulse fluence variation, the influence of repetition rate and focus diameter are investigated. Besides to shaping of sophisticated geometries, functional surfaces are generated. The comparison with infrared wavelength underlines the advantages of the ultraviolet wavelength. Significant differences with respect to the measured ablation rates and roughness as well as generated micro- and nanostructures appear. While infrared ablation is dominated by a chipping mechanism above a critical threshold, higher ablation rates are observed with strong quality losses at the same time. In comparison to the infrared emission wavelength, in general, a significantly higher processing quality is achieved with the ultraviolet emission wavelength.