New Laser Crystallization for LTPS on Panel

New Laser Crystallization using Blue Laser-Diodes is reported and discussed. As a result of the blue laser diode annealing (BLDA) scanning at 500 mm/s for 50 nm-thick Si films, remarkable crystallization occurred while maintaining the surface’s smoothness not only for CVD film but also for sputtered film. By changing the laser power, the grain size can be controlled from micro-grains to large grains as well as to anisotropic long crystal grains. For the Si films of heavily phosphorus doped condition, the resistivity decreased drastically depending on the increase in the electron mobility while the high carrier concentration values were retained for the various grained structures after BLDA. High activation rate of the impurity dopant in the Si network was realized. For undoped Si film as a channel in TFT which was fabricated by low temperature process without using ion implantation, good transfer curve was observed. A simple structure of poly Si TFTs with metal source/drain is proposed as a low cost fabrication process.