Method of manufacturing laterally crystallized semiconductor layer and method of manufacturing thin film transistor using the same method

A method of manufacturing a thin film transistor (TFT), the method comprising:

• forming a semiconductor layer on a substrate;
• irradiating laser beams onto the semiconductor layer;
• splitting the laser beams using a prism sheet comprising an array of a plurality of prisms,
• advancing the laser beams toward the semiconductor layer to alternately form first and second areas in the semiconductor layer so as to fully melt the first areas, wherein the laser beams are irradiated onto the first areas, and the laser beams are not irradiated onto the second areas;
• inducing the first areas to be laterally crystallized using the second areas as seeds so as to form a channel area between the second areas wherein the channel area comprises at least two sides;
• sequentially forming a gate insulating layer and a gate electrode on the channel area;
• and
• doping dopant ions into the second areas to form a source and a drain beside two sides of the channel area.