Laser Ablation: A supporting technique to micromachining of SiC

We present an effective fabrication method of AlGaN/GaN membrane on SiC for MEMS sensors applications. It employs laser ablation as a supporting technique to the plasma enhanced etching methods. Circular patterns transferred deeply into bulk SiC substrates fabricated by ablation using (1) excimer laser and (2) femtosecond (fs) laser tools were compared. We found that the fs laser tool is more suitable for bulk micromachining of SiC because of the clearness of the process. The additional higher thermal load can be also suppressed. A simple laser cleaning procedure was found allowing us to fabricate deep structures without the ablation process retardation by debris formation.