Demonstration of an<i>in situ</i>on-chip tensile tester

Abstract

Polycrystalline silicon (polysilicon) strength data reported in the literature usually present results from only a limited number of trials because of the difficulties in applying high forces to the high-strength specimens. These forces are most often applied by off-chip actuators, which can pose cumbersome alignment issues. Here we demonstrate a compact on-chip tester using a thermal actuator to apply stress to a self-aligning tensile specimen via a prehensile grip mechanism. Preliminary characteristic strength and Weibull modulus values of 3.05 GPa and 12.8, respectively, are reported, in good agreement with other literature data. By querying the fracture strain of the material, this distinct measurement approach complements other methods of testing the strength of brittle polysilicon. Instrinsic test time is 5 min or less, and the area occupied is relatively small compared to other on-chip tensile test devices. This will enable many trials for high confidence in polysilicon strength distribution in future work.