Thin film transistor having a three-portion gate electrode and liquid crystal display using the same

Abstract

A thin film transistor and a liquid crystal display, in which a gate electrode is formed to include at least one portion extending in a direction perpendicular to a gain growing direction in order to make electrical charge mobility of TFTs uniform without increasing the size of the driving circuit. A thin film transistor according to the present invention includes a semiconductor pattern a thin film of poly-crystalline silicon containing grown grains on the insulating substrate. The semiconductor pattern includes a channel region and source and drain regions opposite with respect to the channel region. A gate insulating layer covers the semiconductor pattern. On the gate insulating layer, a gate electrode including at least one portion extending in a direction crossing the growing direction of the grains and overlapping the channel region is formed. In a liquid crystal display, a plurality of thin film transistors forming a data driver circuit include thin films of polycrystalline silicon formed by sequential lateral solidification, at least one portion of a gate electrode of each thin film transistor extends in a direction crossing the grain growing direction, and at least one of the plurality of thin film transistors has a gate electrode having a pattern different from other thin film transistors.