Abstract: A semiconductor device includes a semiconductor substrate, a first layer formed on the semiconductor substrate and including a semiconductor element and a first insulating film, a second layer formed above the first layer and including a channel including an oxide semiconductor and a second insulating film, and a third layer formed above the second layer, and including an electrode formed on the channel and a third insulating film having a film density less than at least one of a film density of the first insulating film or a film density of the second insulating film.