Display device and electronic device, and method of manufacturing display device

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

• forming a first insulating layer on a substrate;
• injecting oxygen into a portion of the first insulating layer to differentiate an oxygen concentration of a first portion of the first insulating layer and an oxygen concentration of a second portion of the first insulating layer;
• and
• forming a first transistor and a second transistor on the first portion and the second portion of the first insulating layer, respectively.

An electronic device comprising:

• a display module including a display panel;
• and
• a processor that transmits an image data signal to the display module,
• wherein the display panel comprises:
• a substrate comprising a display area and a non-display area;
• a first insulating layer disposed on the substrate and comprising oxygen;
• a first transistor comprising a first active layer disposed on a first portion of the first insulating layer and a first gate electrode overlapping the first active layer;
• and
• a second transistor comprising a second active layer disposed on a second portion of the first insulating layer and a second gate electrode overlapping the second active layer, and
• wherein an oxygen concentration of the second portion of the first insulating layer is higher than an oxygen concentration of the first portion of the first insulating layer.