Thin film transistor, method of fabricating the same and organic light emitting diode display device including the same

A method of fabricating a thin film transistor on a substrate, comprising:

• forming a polysilicon layer pattern on the substrate;
• forming a gate insulating layer on the polysilicon layer pattern;
• forming a gate electrode on the gate insulating layer, and a first insulating layer on the gate electrode;
• implanting ions into the polysilicon layer pattern on the first insulating layer to form a semiconductor layer including a channel region, source/drain regions and an offset region;
• forming a second insulating layer on the first insulating layer;
• and
• forming source/drain electrodes electrically connected to the source/drain regions of the semiconductor layer, respectively, on the second insulating layer,
• wherein the sum of thicknesses of the gate insulating layer and the first insulating layer disposed on the source/drain regions is less than the vertical penetration depth of the ions included in the source/drain regions.

An organic light emitting diode (OLED) display device, comprising:

• a substrate;
• a semiconductor layer disposed on the substrate, and including a channel region, source/drain regions and an offset region;
• a gate insulating layer disposed on the semiconductor layer;
• a gate electrode disposed on the gate insulating layer;
• a first insulating layer disposed on the gate electrode;
• a second insulating layer disposed on the first insulating layer;
• source/drain electrodes disposed on the second insulating layer, and electrically connected to the source/drain regions of the semiconductor layer, respectively;
• a first electrode electrically connected to one of the source/drain electrodes;
• an organic layer disposed on the first electrode and including an emission layer;
• and
• a second electrode disposed on the organic layer,
• wherein the sum of thicknesses of the gate insulating layer and the first insulating layer that are on the source/drain regions is less than the vertical penetration depth of the ions included in the source/drain regions.