Method of manufacturing organic light emitting device having photo diode

1. A method of manufacturing a display device, the method comprising:

forming a semiconductor layer over a substrate;

forming a gate metal layer directly and selectively on a central region of the semiconductor layer;

forming a P doping region and a N doping region by injecting impurities into the semiconductor layer to form a photodiode; and

removing the gate metal layer from the semiconductor layer; and

wherein the display device further comprises:

a transistor comprising: source and drain regions, a channel region connected between the source and drain regions, a gate electrode corresponding to the channel region and a gate insulation layer insulating the gate electrode from the channel region; and

wherein the gate metal layer is used as a mask covering the central region corresponding to an intrinsic region of the photodiode when the impurities are injected.

2. The method of claim 1 , further comprising forming a reflective film over the substrate before forming the semiconductor layer over the substrate, wherein the reflective film is positioned to reflect light incident from outside the display device to the subsequently formed photodiode.

3. The method of claim 2 , wherein the reflective film comprises at least one metal selected from the group consisting of Ag, Mo, Ti, Al and Ni.

4. The method of claim 2 , wherein the reflective film has a thickness of 100 to 5,000 Å.

5. A method of forming a photodiode, the method comprising:

forming a semiconductor layer over a substrate;

forming a gate metal layer directly and selectively on a central region of the semiconductor layer;

forming a P doping region and a N doping region by injecting impurities into regions of the semiconductor layer not covered by the gate metal layer to form the photodiode; and

removing the gate metal layer from the central region of the semiconductor layer; and

wherein the gate metal layer is used as a mask covering the central region corresponding to an intrinsic region of the photodiode when the impurities are injected.

6. A method of manufacturing a display device including a photodiode and a transistor, the method comprising:

forming a first semiconductor layer and a second semiconductor layer separated from each other over a substrate;

forming a gate metal layer directly and selectively on a central region of the first semiconductor layer;

forming a P doping region and a N doping region in the first semiconductor layer by injecting impurities into regions of the first semiconductor layer not covered by the gate metal layer to form the photodiode;

forming source and drain regions and a channel region in the second semiconductor layer; and

removing the gate metal layer from the central region of the first semiconductor layer after injecting the impurities; and

wherein the transistor includes the second semiconductor layer having the source and drain regions and the channel region, a gate electrode corresponding to the channel region and a gate insulation layer insulating the gate electrode from the channel region; and

wherein the gate metal layer is used as a mask covering the central region corresponding to an intrinsic region of the photodiode when the impurities are injected.

7. The method of claim 6 , further comprising forming a reflective film over the substrate before forming the first semiconductor layer and the second semiconductor layer over the substrate, wherein the reflective film is positioned to reflect light incident from outside the display device to the subsequently formed photodiode.

8. The method of claim 7 , wherein the reflective film is formed of one selected from the group consisting of Ag, Mo, Ti, Al and Ni.

9. The method of claim 7 , wherein the reflective film is formed with a thickness of 100 to 5,000 Å.