Orientation-dependent fracture strain in single-crystal silicon beams under uniaxial tensile conditions

The proposed method for testing the uniaxial tensile characteristics of thin film materials is integrated onto a silicon chip. The developed process for fabricating the test chips starts with SOI wafers whose top silicon layer is prepared for the test materials. The results of testing single-crystal silicon films having orientations of <100>, <110>, and <111> were compared with those from bending tests of bulk silicon. The measured Young's moduli and fracture strains clearly showed orientation dependence, and the measured values were reasonable compared with those of the bulk materials. The fracture strains varied from 0.4 to 2.2% depending on the orientation and were the lowest in the <111> direction.