Optimization of 200-W excimer laser for TFT annealing

Polycrystalline-silicon TFT technology is opening the door to highly reliable, high-resolution, high-performance, large AMLCD's that will be inevitable for HDTV and other advanced applications. For formation of polycrystalline silicon, excimer laser annealing has shown to be superior to all other techniques with respect to quality, reliability and economy. In excimer laser annealing a high-power laser beam is scanned over the surface of the substrate, coated with amorphous silicon. The amorphous silicon is heated up within a few nanoseconds, melts and recrystallizes into polycrystalline silicon. The substrate remains unaffected. The pronounced nonlinearity of the annealing process, the high quality requirements and the high process speeds in production lines make high demands on the laser beam parameters such as energy stability and beam uniformity, and on laser output power. This presentation will discuss the results of recent development in high-power excimer laser for annealing, and their impact on production of AMLCD's.