Investigation on the laser ablation of SiC ceramics using micro-Raman mapping technique

Research on the laser ablation behavior of SiC ceramics has great significance for the improvement of their anti-laser ability as high-performance mirrors in space and lasers, or the laser surface micro-machining technology as electronic components in micro-electron mechanical systems (MEMS). In this work, the laser ablation of SiC ceramics has been performed by using laser pulses of 12 ns duration at 1064 nm. The laser induced damage threshold (LIDT) below 0.1 J/cm² was obtained by 1-on-1 mode and its damage morphology appeared in the form of “burning crater” with a clear boundary. Micro-Raman mapping technique was first introduced in our study on the laser ablation mechanisms of SiC surface by identifying physical and chemical changes between uninjured and laser-ablated areas. It has been concluded that during the ablation process, SiC surface mainly underwent decomposition to the elemental Si and C, accompanied by some transformation of crystal orientation. The oxidation of SiC also took place but only in small amount on the edges of target region, while there was no hint of SiO₂ in the center with higher energy density, maybe because of deficiency of O₂ atmosphere in the ablated area, elimination of SiO₂ by carbon at 1505 ℃, or evaporating at 2230 ℃.