Investigation of process-induced periodic structure on n-type 4H-SiC with corresponding mechanical characteristics estimation

Abstract

A dicing process that combines the laser scribing and mechanical breaking procedures is demonstrated to achieve high-quality n-type 4 H-silicon carbide (SiC) without generating the edge defect and chipping phenomenon. Presented dicing process is successfully implemented on a 40 mm × 40 mm SiC workpiece with a thickness of 150 μm, and it separated 1 mm × 1 mm and 2 mm × 2 mm chips. However, the process-induced stress introduces stress-induced amorphization into the cut cross section of fabricated SiC. Moreover, vertical thermal cracking is found on the periodic tip region treated with laser scribing. To investigate the influence of stress-induced damage on mechanical characteristics of fabricated SiC, the nanoindentation technique is utilized to identify modulus gradient and mapping behavior. Analysis results reveal that damage-induced degradation on modulus behavior is observed from the edge of the periodic tip region to the hinterland region, which the measured reduced modulus results of aforementioned regions are 325.87±56.21 and 284.85±30.02 GPa, respectively. Moreover, the thickness of the damaged layer that covers the cut cross section is estimated to be at least 150 nm by utilizing continuous stiffness measurement (CSM) nanoindentation. The modulus mapping characteristics on the molten and unmolten regions are within the range of 90–160 GPa and 180–300 GPa, respectively. The composition of molten region is investigated by the EDS analysis and the corresponding reduced modulus results is revealed as 105.86±16.46 GPa.