Thin film transistor, method for manufacturing same, and display device

A display device comprising:

• a thin film transistor including:
• a substrate;
• a gate electrode provided on a part of the substrate;
• a first insulating film covering the gate electrode;
• an oxide semiconductor film provided on the gate electrode via the first insulating film;
• a second insulating film provided on a part of the oxide semiconductor film;
• and
• a source electrode and a drain electrode, the source electrode being connected to a first portion of the oxide semiconductor film, the first portion being not covered with the second insulating film, the drain electrode being connected to a second portion of the oxide semiconductor film, the second portion being not covered with the second insulating film,
• the oxide semiconductor film including an oxide semiconductor including at least one element of In, Ga, and Zn, and a concentration of hydrogen contained in the first insulating film being not less than 5×1020 atm/cm3, and a concentration of hydrogen contained in the second insulating film being not more than 1019 atm/cm3;
• a first electrode connected to the source electrode or the drain electrode of the thin film transistor;
• a second electrode facing the first electrode;
• and
• a display layer provided between the first electrode and the second electrode.

A method for manufacturing a thin film transistor, comprising:

• forming a gate electrode on a part of a substrate;
• forming a first insulating film covering the gate electrode and containing a concentration of hydrogen not less than 5×1020 atm/cm3;
• forming an oxide semiconductor film on the first insulating film by using an oxide semiconductor including at least one element of In, Ga, and Zn so as to face the gate electrode;
• forming a second insulating film on a part of the oxide semiconductor film, the second insulating film containing a concentration of hydrogen not more than 1019 atm/cm3;
• and
• forming a source electrode and a drain electrode, the source electrode being connected to a first portion of the oxide semiconductor film, the first portion being not covered with the second insulating film, the drain electrode being connected to a second portion of the oxide semiconductor film, the second portion being not covered with the second insulating film.