High throughput, on-chip, in situ investgations of structural properties of polycrystalline silicon for microelectromechanical systems

Accurate measurement of material strength at small scales is of critical importance for the design and manufacture of reliable micro- and nano-scale devices. Polycrystalline silicon (polysilicon) is a material of choice for microsystem manufacture due to its high strength. However, only small strength measurement sample sizes are reported in literature because of the difficulties in applying high forces to these small high-strength specimens.;Because the measured strength is an average over a flaw population, the strength distribution data does not provide direct insight into the mechanics of brittle fracture. Obtaining quantitative assessments of high local stress has proven elusive. Due to the compact nature of the design and its high-confidence alignment, the device proves suitable for small working distance, high-resolution microscopy investigations. To this end, confocal Raman microscopy and electron back scatter diffraction are demonstrated as an application of the tester for in situ local stress mapping of fine grained thin film materials.;This thesis reports the development of a compact on-chip, in situ tensile tester that uses a thermal actuator to stress a self-aligning polysilicon tensile specimen via a prehensile grip mechanism. Investigations of polysilicon strength using large sample statistics are presented. An important result is that there is a threshold strength level below which polysilicon does not fail. The measurement methodology is supported with alignment precision data, temperature distribution calculations, sample compliance calibration, sample-to-gripper stiffness ratio measurements, and a force calibration technique.