Polycrystalline silicon (polysilicon) is a key component of integrated circuit technology, micromechanical systems and displays. High-mobility polysilicon thin-film transistors are replacing amorphous-silicon transistors in advanced active-matrix displays, and are also vital to the emerging fields of microsensors and microactuators [1]. In this study, the deposition processes (LPCVD) of polysilicon thin films were carefully studied and the basic kinetics were analyzed. The films were patterned into submicron islands and the relation of the deposition temperature versus the crystallinity of polysilicon islands was observed. A “threshold” deposition temperature for polysilicon crystals larger than 0.35 μm was found. The relationships of polysilicon crystal sizes vs. annealing temperature and vs. annealing duration were also systematically studied. Polysilicon islands of ∼ 0.1 μm lateral dimensions were successfully fabricated by ebeam lithography and several types of annealings were performed to increase micro-crystal size, with the goal of creating single-crystal high-mobility islands. Theoretically, transistors built from such islands should match the performance of state-of-the-art bulk CMOS devices. The crystal size was measured using TEM and AFM analysis. Moreover, EXAFS (Extended X-ray Absorption Fine Structure) measurements at SSRL (Stanford Synchrotron Radiation Lab) were employed to study the crystallization processes of polysilicon films and the correlation between the absorption curves, the thin-film electrical properties and the polysilicon grain sizes.