Properties of Poly-Si Thin films and Their Transistors Fabricated Using Selective Excimer Laser Annealing

Selective laser annealing system was developed, and applied to fabricate low temperature poly-Si thin film transistors. The new system performs the laser annealing only for the selective area of TFT region by adopting micro lens array, which can apply the laser annealing even for large substrate, contrary to the conventional excimer laser annealing system having the limitation in substrate size due to the difficulty in obtaining uniform beam line. In this study, selectively-annealed poly-Si film structure and their TFT performance were investigated. Grain size increased as an increase in the laser energy density, and TFTs with the field effect mobility larger than 100 cm2V−1s−1 with the on-off ratio of drain current of 106 or more could be obtained.