Thin film transistor substrates, methods of manufacturing the same and display devices including the same

Abstract

A thin film transistor substrate includes a data line, a gate line, a gate electrode, a source electrode, a first drain electrode, a semiconductor layer and a second drain electrode. The data line and the gate line cross each other on a base substrate. The gate electrode is electrically connected to the gate line. The source electrode is electrically connected to the data line. The first drain electrode and the source electrode face each other. The semiconductor layer serves as a channel between the source electrode and the first drain electrode. The second drain electrode is disposed on the first drain electrode. The second drain electrode is electrically connected to the first drain electrode.

What is claimed is: 
     
         1 . A method of manufacturing a thin film transistor substrate, comprising:
 forming a semiconductor layer which serves as a channel of a thin film transistor, on a base substrate;   forming a gate insulation layer which covers the semiconductor layer;   forming a gate electrode of the thin film transistor, overlapping the semiconductor layer and on the gate insulation layer;   forming a source electrode and a first drain electrode of the thin film transistor, respectively contacting with ends of the semiconductor layer; and   forming a second drain electrode of the thin film transistor, on the first drain electrode, wherein the second drain electrode is electrically connected to the first drain electrode.   
     
     
         2 . The method of  claim 1 , further comprising:
 forming an insulating interlayer which covers the source electrode, the first drain electrode and the gate electrode; and   forming a first contact which extends through the insulating interlayer and contacts the first drain electrode.   
     
     
         3 . The method of  claim 2 , wherein the forming the second drain electrode forms the second drain electrode on the insulating interlayer, in contact with the first contact and in a different layer than that of the first drain electrode. 
     
     
         4 . The method of  claim 1 , further comprising forming a gate line and a data line which cross each other on the base substrate,
 wherein   the forming the gate line simultaneously forms the gate electrode, and   the forming the data line simultaneously forms the source electrode and the first drain electrode.