In-situ measurement of SiC/Si interfacial tensile strength of reaction bonded SiC/Si composite

Abstract

Reaction bonded SiC/Si (RBSC) ceramic composites have been extensively used in applications calling for outstanding mechanical and thermal properties such as high energy laser (HEL) mirrors, advanced armors and semiconductor fabrication platforms. The phase components of RBSC generally include preexisting α-SiC, reaction formed β-SiC, and residual crystalline silicon (c-Si). In addition, however, a minor phase, amorphous Si (a-Si), is often observed near the SiC/Si interface due to local temperature and structural fluctuations that can occur during the composite fabrication. An in-situ tensile testing system composed of piezo stages, force sensor and specimen holders is integrated and accommodated inside a field emission scanning electron microscope (FE-SEM) for the nanoscale tensile testing. Tensile specimens containing the SiC/Si interface are successfully prepared by focused ion beam (FIB). The interfacial tensile strength is directly measured for the first time and it reaches as high as 7.1 GPa. The a-Si phase on the fracture surfaces is confirmed by high resolution transmission electron microscopy (HRTEM).