Nanoindentation of laser micromachined 3C-SiC thin film micro-cantilevers

Research highlights: → Higher etch rates than traditional methods. → Young's modulus and fracture strength are comparable to chemical methods. → Beam follows nanoindentation elastic principles. -- Abstract: Single crystalline thin films of 3C-SiC with a thickness of 1.7 ± 0.2 μm were deposited on Si (100) substrate using atmospheric chemical vapor deposition technique. A Q-switched Nd:YAG laser in the fundamental wavelength with a pulse duration of 100 ns and average power of 1 W was then used to pattern 50 μm wide and 150 μm long cantilever beams in direct-writing mode. Following laser patterning, wet chemical etching using KOH anisotropic etchant was carried out to remove the underlying Si and form free-standing 3C-SiC cantilever beams. The cantilevers were subjected to nanoindentation test to obtain deflection versus load curves. The average Young's modulus and fracture strength were determined to be 423 GPa and 1.5 GPa respectively which are comparable to those obtained by the reactive ion etching. Laser patterning thus offers nearly identical properties as that of ion etching with the added benefit of much higher etch rates.