Laser microfabrication and testing of silicon carbide diaphragms for MEMS applications

Laser microfabrication of silicon carbide for MEMS applications was explored. 3C-SiC and 6H-SiC were laser micromachined using various lasers. 3C-SiC thin films were patterned using an 800 nm 120fs Ti:Sapphire laser. Diaphragm structures 100-130 mum thick with lateral dimensions ranging from 1-2.5 mm were fabricated in bulk 6H-SiC using a 1064 nm, <100 ns, Q-switched Nd:YAG laser. The laser micromachined diaphragms were mechanically characterized by means of nanoindentation and a novel pressure testing apparatus. Mechanical tests indicate that the diaphragms remain sealed under applied gas pressure and that the heat effects and variations in pulse energy from the laser reduce the overall mechanical strength of the diaphragms.