Polysilicon layer, method of preparing the polysilicon layer, thin film transistor using the polysilicon layer, and organic light emitting display device including the thin film transistor

A thin film transistor (TFT) comprising:

• a substrate;
• a buffer layer disposed on the substrate;
• an active layer disposed on the buffer layer, comprising a source region, a drain region, and a channel region, and comprising a polysilicon layer;
• a gate insulation layer disposed on the active layer;
• a gate electrode facing the channel region on the gate insulation layer;
• and
• a source electrode and a drain electrode respectively contacting the source region and the drain region by penetrating through a first interlayer insulating layer disposed on the gate electrode, the active layer, and the buffer layer,
• wherein the polysilicon layer comprises a crystallization seed having a pyramid shape on an interface between the buffer layer and the polysilicon layer.

An organic light emitting display device comprising:

• a substrate;
• a buffer layer disposed on the substrate;
• an active layer disposed on the buffer layer, comprising a source region, a drain region, and a channel region, and comprising a polysilicon layer;
• a gate insulation layer disposed on the active layer;
• a gate electrode facing the channel region on the gate insulation layer;
• a source electrode and a drain electrode respectively contacting the source region and the drain region by penetrating through a first interlayer insulating layer disposed on the gate electrode, the active layer, and the buffer layer;
• a first electrode contacting any one of the source electrode and the drain electrode by penetrating through a second interlayer insulating layer formed on the source electrode, the drain electrode, and the first interlayer insulating layer, and extending above the second interlayer insulating layer;
• an organic layer comprising an emission layer disposed on the first electrode;
• and
• a second electrode disposed on the organic layer,
• wherein the polysilicon layer comprises a crystallization seed having a pyramid shape on an interface between the buffer layer and the polysilicon layer.