High resolution laser flash photography for probing the new double laser recrystallization process

Summary form only given. Laser recrystallization has been demonstrated as an efficient technology for obtaining poly-Si TFTs for advanced flat panel display applications. In order to improve grain size, uniformity and hence device performance, the double laser recrystallization technique, which is a process that can produce ultra-large direction- and location-controlled lateral poly-Si grains, is developed. The technique uses a modulated CW Ar/sup +/ laser in conjunction with a superposed nanosecond laser pulse to achieve lateral grains. This process has a wide fluence process window and is insensitive to the power fluctuation of both lasers. The results show preheating and melting of the a-Si film with the Ar/sup +/ laser before firing the nanosecond laser is necessary for inducing lateral grain growth. The transient nanosecond laser irradiation is believed to generate nucleation sites for initiating the subsequent lateral grain growth. In order to clarify the ultralarge grain formation mechanism, high spatial and temporal resolution laser flash photography is used to probe the solidification process.