Thin-film transistor including source-drain electrodes connected to a semiconducting film and extending through a semiconductor auxiliary film

A display with a display element and a semiconductor device configured to drive the display element, the semiconductor device comprising:

• a semiconductor film including an oxide semiconductor material and having a channel region and a low-resistance region, the low-resistance region having an electric resistance lower than an electric resistance of the channel region;
• an interlayer insulating film covering the semiconductor film and having a through-hole opposed to the low-resistance region;
• a source-drain electrode including a source electrode and a drain electrode and being electrically coupled to the semiconductor film through the through-hole;
• and
• a semiconductor auxiliary film being in contact with the low-resistance region of the semiconductor film, reducing an electric resistance of the semiconductor film, having a first opening at least on a part of a portion opposed to the through-hole, and the semiconductor film extends along an entirety of a sidewall of the semiconductor auxiliary film.