Thin film transistor, method of forming the same and flat panel display device having the same

Abstract

A thin film transistor (TFT), a method of forming the same and a flat panel display device having the same are disclosed. The TFT includes a buffer layer and a semiconductor layer which are sequentially disposed on a substrate, a gate pattern including an insulating pattern and a gate electrode pattern which are sequentially disposed on the semiconductor layer, source and drain regions defining a portion of the semiconductor layer below the gate pattern as a channel area, formed by doping the semiconductor layer disposed at both sides of the gate pattern with impurities, and extending from both sides of the channel area, a passivation layer which covers the entire surface of the substrate having the gate pattern, a first metal electrode which penetrates a portion of the passivation layer disposed on the source area and a portion of the source region below the portion of the passivation layer to be electrically connected with the source region, and a second metal electrode which penetrates a portion of the passivation layer disposed on the drain area and a portion of the drain region below the portion of the passivation layer to be electrically connected with the drain region. According to the present invention, a metal is infiltrated into source and drain regions to disperse an electric current when a TFT operates, and thus charge mobility is improved, and damage of a drain region caused by the excessive current density is prevented, leading to the long lifespan and excellent performance.