Thin film transistor substrate and display using the same

Abstract

The present disclosure relates to a thin film transistor substrate having two different types of thin film transistors on the same substrate. A thin film transistor substrate includes a substrate; a first thin film transistor disposed on the substrate, the first thin film transistor including a poly crystalline semiconductor layer, a first gate electrode over the poly crystalline semiconductor layer, a first source electrode, and a first drain electrode; a second thin film transistor disposed on the substrate, the second thin film transistor including a second gate electrode, an oxide semiconductor layer over the second gate electrode, a second source electrode, and a second drain electrode; and an intermediate insulating layer including a nitride layer and an oxide layer on the nitride layer, the intermediate insulating layer disposed over the first gate electrode and the second gate electrode and under the oxide semiconductor layer.

What is claimed is: 
     
         1 . A display device, comprising:
 a substrate on which a display area and a non-display area are defined;   a switching thin film transistor on the substrate, the switching thin film transistor comprises a first gate electrode, a first source electrode and a first drain transistor;   a driving thin film transistor on the substrate, the driving thin film transistor comprises a second gate electrode, a second source electrode and a second drain electrode;   a gate driving integrated circuit formed in the non-display area for supplying scan signals to gate lines;   a ground line formed on the outermost side of the substrate and outwardly from the gate driving integrated circuit so as to surround the substrate; and   a cathode electrode formed to cover a plurality of pixel areas in the display area,   wherein the cathode electrode extends from the display area to the non-display area, and the cathode electrode overlaps with at least a portion of the gate driving integrated circuit.   
     
     
         2 . The display device according to  claim 1 ,
 wherein ground line is formed at the same layer and made of the same material with the first and second gate electrodes.   
     
     
         3 . The display device according to  claim 2 , further comprising a passivation layer and a gate insulating layer over the ground line,
 wherein the ground line is electrically connected directly or indirectly to the cathode electrode through a contact hole penetrating the passivation layer and the gate insulating layer.   
     
     
         4 . The display device according to  claim 1 ,
 wherein the ground line is formed at the same layer and made of the same material with the first and second source electrodes or the first and second drain electrodes.   
     
     
         5 . The display device according to  claim 4 , further comprising a passivation layer over the ground line,
 wherein the ground line is electrically connected directly or indirectly to the cathode electrode through a contact hole penetrating the passivation layer.   
     
     
         6 . The display device according to  claim 1 ,
 wherein a distance between the gate driving integrated circuit and the switching thin film transistor is shorter than a distance between the gate driving integrated circuit and the driving thin film transistor.   
     
     
         7 . The display device according to  claim 1 ,
 wherein the cathode electrode overlaps with at least a portion of the display area and a portion of the non-display area so as to be electrically connected the ground line formed on the outermost side of the substrate.   
     
     
         8 . The display device according to  claim 1 ,
 wherein the cathode electrode overlaps with the display area and the non-display area so as to be electrically connected to the ground line formed on the outermost side of the substrate.   
     
     
         9 . The display device according to  claim 1 ,
 wherein each of the switching thin film transistor and the driving thin film transistor comprises an oxide semiconductor layer.   
     
     
         10 . The display device according to  claim 1 ,
 wherein each of the switching thin film transistor and the driving thin film transistor comprises a poly crystalline semiconductor layer.   
     
     
         11 . The display device according to  claim 1 ,
 wherein one of the switching thin film transistor and the driving thin film transistor comprises a poly crystalline semiconductor layer and the other of the switching thin film transistor and the driving thin film transistor comprises an oxide semiconductor layer.   
     
     
         12 . The display device according to  claim 1 ,
 wherein the gate driving integrated circuit comprises a thin film transistor comprising a poly crystalline semiconductor layer or an oxide semiconductor layer.   
     
     
         13 . The display device according to  claim 1 ,
 wherein a distance between the first gate electrode and the substrate is different than a distance between the second gate electrode and the substrate.   
     
     
         14 . The display device according to  claim 1 ,
 wherein each of the switching thin film transistor and the driving thin film transistor has a top gate structure.   
     
     
         15 . The display device according to  claim 1 ,
 wherein each of the switching thin film transistor and the driving thin film transistor has a bottom gate structure.   
     
     
         16 . The display device according to  claim 1 ,
 wherein one of the switching thin film transistor and the driving thin film transistor has a top gate structure and the other of the switching thin film transistor and the driving thin film transistor has a bottom gate structure.