3-D Simulator of Laser Crystallization for Polycrystalline-Silicon Thin-Film Transistors
A 3-D simulator of laser crystallization for polycrystalline-silicon thin-film transistors has been developed. Random nucleation, crystal growth velocity, latent heat emission, and partial crystallization are modeled, and a 2-D algorithm is extended to a 3-D algorithm. The <formula formulatype="inline"><tex Notation="TeX">$\mu$</tex></formula>-Czochralski technique is analyzed using the 3-D simulator, and it is found that the grain size becomes large when the initial temperature is high after the laser irradiation.
Laser pulse shape dependence of poly-Si crystallization
Poly-Si crystallization mechanism is examined by conducting numerical simulations, combining the thermal diffusion equation with a rigorous coupled wave analysis method. The ripples at the boundary of poly-Si grains are modeled as a grating surface structure. Under laser beam irradiation, the melting front profiles are accurately analyzed by including surface diffraction, polarization of the laser, and laser energy density. For two different lasers, XeCl excimer laser (λ = 308 nm) and Yb:YAG solid state laser (λ= 343 nm), the energy density range at which poly-Si grains are gradually ordered was determined. Furthermore, the energy density window of the Yb:YAG laser is found to be four times larger than that of XeCl laser. On the other hand, the Yb:YAG laser may produce amorphous-Si phase after completing the crystallization process. It is suggested that this amorphous-Si phase could be avoided, if a double pulse laser is used.
21.4L: Late‐News Paper: A Touch Panel Function Integrated LCD Including LTPS A/D Converter
New configuration of display device having image capture function suitable for LTPS TFT fabrication process is proposed. In this configuration, LTPS A/D converter integration to the glass substrate and operation to generate higher grayscale bitmap in the image processing LSI are involved.