Patent ID: 7202096

Claim:
A method of fabricating a control thin film transistor for controlling a current of an OLED unit, comprising the steps of: providing a substrate; forming and defining a semiconductor layer on the substrate; forming a first photoresist layer covering a portion of the semiconductor layer, exposing predetermined portions on the semiconductor layer for a source and drain regions; performing a first ion implantation of the semiconductor layer using the first photoresist layer as a mask to form the source and drain regions thereon; removal of the first photoresist layer; forming a first insulating layer covering the surface of the substrate and the semiconductor layer; forming a second photoresist layer on the first insulating layer, which covers the un-implanted area of the semiconductor layer but exposes only a portion of the un-implanted area of the semiconductor layer adjacent to the drain region; performing a second ion implantation of the semiconductor layer using the second photoresist layer as a mask to form a lightly doped region with a doped concentration lower than that of the adjacent drain region; removal of the second photoresist layer; forming a gate layer on the first insulating layer and at approximately the right top of the un-doped semiconductor layer; forming a second insulating layer covering the surface of the first insulating layer and the gate layer; and forming a source and drain electrodes penetrating the first and second insulating layer in contact with the source and drain regions respectively, wherein the drain electrode receives a drain voltage and the source electrode is electrically connected to an OLED unit.