Thin-film transistor and manufacturing method thereof

A thin-film transistor comprising:

• a semiconductor film formed on the substrate;
• a gate insulating film formed on said semiconductor film;
• a gate electrode disposed so as to cross said semiconductor film on said gate insulating film;
• an interlayer insulating film formed so as to cover said gate electrode on said gate insulating film;
• and
• an electrode connected to said semiconductor film through said gate insulating film and said layer insulating film;
• said interlayer insulating film comprises the silicon nitride film, and the first and second silicon oxide films sandwiching the silicon nitride film.

A thin-film transistor having a gate electrode and semiconductor film formed so as to sandwich a gate insulating film on the substrate, and an interlayer insulating film, in which contact holes are formed, formed on said semiconductor film;

• said interlayer insulating film comprising:
• a lowermost insulating layer in contact with said semiconductor film and for matching with said semiconductor film;
• a middle insulating layer formed on said lowermost insulating layer as a hydrogen ion supply source for said semiconductor film;
• and
• an uppermost insulating layer formed on said middle insulating layer and having an etching rate faster than that of said middle insulating layer for etching during said contact hole formation.