Study on Laser-Crystallization Process of Semiconductors

点击翻译按钮获取中文摘要

1. By using a recursive manner and Green's function solutions derived in a semi-infinite multilayer structure, a nonlinear heat equation including temperature-dependent thermal conductivity and diffusivity and fusion energy for melting has been able to be solved numerically.2. A two-dimensional boundary element method has been developed to solve in a complex composite material. In order to improve the numerical calculation accuracy at a corner, several methods were tried. A newly-developed mid-node method is found to give a good accuracy and an easiness in programming and dividing into elements.3. Thin silicon film during its melting by irradiation of a focused cw argon ion laser beam has been directly observed by using an optical microscope. As the power of laser beam is increased, a mixture region where the solid and liquid coexist appears and then a uniform molten pool is formed in the middle of the mixture region. It is demonstrated that this situation is strongly influenced by the mode and power of laser beam that is, the laser intensity profile. TEM00 mode is suitable to recrystallize SOI of good crystalline quality.4. A high-speed laser direct-drawing system has been constructed by using a galvanometer. This system was able to generate a pseudo-line beam. A trapezoid waveform is found to be good in generating the pseudo-line beam.