Display device with driving transistor having upper and lower gate electrodes

A display device comprising, on a substrate,

• a pixel circuit including a drive transistor and a switching transistor formed by layering an inorganic insulating film, an oxide semiconductor layer, an upper gate insulating layer, an upper gate electrode, and an interlayer insulating film,
• wherein the drive transistor and the switching transistor include an oxide semiconductor film formed of the oxide semiconductor layer and provided in an island shape corresponding to the drive transistor and an island shape corresponding to the switching transistor,
• the oxide semiconductor film includes a channel region overlapping with the upper gate electrode corresponding to the oxide semiconductor film, and a source region and a drain region provided sandwiching the channel region between the source region and the drain region,
• in the drive transistor and the switching transistor, the upper gate electrode, the upper gate insulating layer, and the channel region corresponding to each of the drive transistor and the switching transistor are aligned in a plan view,
• the drive transistor is provided with a lower gate electrode and a lower gate insulating layer between the inorganic insulating film and the oxide semiconductor layer,
• in the drive transistor, a film thickness of the lower gate insulating layer between an uppermost surface of the lower gate electrode and the oxide semiconductor film is greater than a film thickness of the upper gate insulating layer,
• the upper gate electrode includes a plurality of conductive films, and
• in a channel length direction in which the source region and the drain region are opposite each other, a length of the lower gate electrode of the drive transistor is less than or equal to a length of each of the plurality of conductive films.