Abstract: A method for forming a polycrystalline silicon thin film transistor. The method includes the steps of: forming a polycrystalline silicon layer including multiple protrusions by crystallizing the amorphous silicon layer according to a crystallization method in which the multiple protrusions are formed due to collision between crystal grains; patterning the polycrystalline silicon layer in an active pattern which includes only two protrusions of the multiple protrusions, which are apart from each other and located at both sides of a gate electrode-forming area; applying a barrier layer on the patterned polycrystalline silicon layer while partially covering the two protrusions; and forming a source electrode and a drain electrode at the protrusions of the polycrystalline silicon layer formed at both sides of the gate electrode-forming area by ion-implanting dopants into a resultant lamination.

Abstract: Disclosed is a method for forming a polycrystalline silicon film by crystallizing an amorphous silicon film. A mask has first to third shot regions having the same length. The first to third shot regions have transmission sections and non-transmission sections, which are alternately aligned. The transmission sections of the first shot region are positioned corresponding to the non-transmission sections of the second shot region, the non-transmission sections of the first shot region are positioned corresponding to the transmission sections of the second shot region, and the transmission sections of the third shot region are aligned corresponding to center portions of the transmission sections of the first and second shot regions. Primary to nth laser irradiation processes are performed with respect to the glass substrate, thereby crystallizing the amorphous silicon film into the polycrystalline silicon film.

Abstract: Disclosed is a method for crystallizing a single crystalline Si film on an amorphous substrate, such as a glass substrate or a plastic substrate. The method includes the steps of selectively irradiating the laser beam onto a pixel section TFT forming region and a peripheral circuit TFT forming region of the amorphous silicon film through primary and secondary laser irradiation processes, thereby forming a poly-silicon film and irradiating the laser beam onto one of grains formed in the poly-silicon film through a third laser irradiation process, thereby forming a single crystalline silicon region having a desired size on a predetermined portion of the amorphous silicon film. The amorphous silicon film is locally crystallized into the single crystalline silicon film so that characteristics of TFTs for the pixel section and the peripheral circuit are improved while ensuring high uniformity.

Abstract: The present invention relates to a method for fabricating a single crystal silicon thin film at the desired location to the desired size from an amorphous or polycrystalline thin film on a substrate using laser irradiation and laser beam movement along the substrate having the semiconductor thin films being irradiated. This method comprises the steps of: forming a semiconductor layer or a metal thin film on a transparent or semi-transparent substrate; forming a single crystal seed region on the substrate of the desired size by a crystallization method using laser irradiation; and converting the desired region of the semiconductor layer or metal thin film into a single crystal region, using the single crystal seed region.