Semiconductor device and method of manufacture thereof

A method for fabricating a semiconductor device, the method comprising the steps of:

• (a) providing a substrate;
• (b) forming a gate electrode, a gate extended line, and a gate insulating layer on the substrate;
• (c) forming an oxide semiconductor film on the gate insulating layer;
• (d) forming a conductive film on the oxide semiconductor film and patterning the oxide semiconductor film and the conductive film through a single photomask, thereby forming an oxide semiconductor layer, a source electrode, a drain electrode and a source line;
• (e) forming a protective layer which protects a channel region of the oxide semiconductor layer and then performing a resistance lowering process to lower the resistance of a portion of the oxide semiconductor layer, thereby forming a conductor region and turning another portion of the oxide semiconductor layer that has not had its resistance lowered into a semiconductor region;
• (f) forming an insulating layer on the source and drain electrodes;
• and
• (g) forming a transparent electrode and a transparent connecting layer on the insulating layer,
• wherein the transparent electrode overlaps at least partially with the conductor region via the insulating layer interposed between them, and
• the source line is electrically connected to the gate extended line via the transparent connecting layer.