| 摘要 |
PURPOSE:To implement high quality of a recrystallized silicon layer, by providing a low intensity auxiliary laser beam, which is scanned in the same direction as a main laser beam for recrystallization, and controlling the temperature gradient at the boundary of diffusion and solidification. CONSTITUTION:Laser light from a laser 10 having Gaussian distribution intensity is guided to the direction of a wafer 22 by a carrier mirror 11. The beam diameter is adjusted by a beam expander 12. The intensity (c) of the beam is adjusted with a power adjuster 13. The intensity distribution is converted into a double- ridge shape by a beam-intensity-distribution converter 14. A part of the beam is split with a mirror 15. The main laser beam is inputted to semicylindrical lenses 16 and projected on the wafer 22. The intensity of the auxiliary laser beam, which is split with the mirror 15, is adjusted with a power adjuster 17. Then the deflecting direction of an electric-field vector, is turned to the vertical attitude. The spot is expanded with a mirror 18 and a beam expander 19. The beam is projected on the wafer 22 so that the rear part is scanned by a polarization beam splitter 21. Thus the causes of strain, which is produced by crystal defects, and abnormal growth can be eliminated.
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