US 9,865,746 B2 · Semiconductor device

Abstract

A highly reliable semiconductor device having stable electrical characteristics is provided. Oxide films each containing one or more kinds of metal elements included in an oxide semiconductor film are formed in contact with an upper side and a lower side of the oxide semiconductor film where a channel is formed, whereby interface states are not easily generated at an upper interface and a lower interface of the oxide semiconductor film. A material which has a lower electron affinity than the oxide semiconductor film is used for the oxide films in contact with the oxide semiconductor film, whereby electrons flowing in the channel hardly move in the oxide films and mainly move in the oxide semiconductor film. Thus, even when an interface state exists between the oxide film and an insulating film formed on the outside of the oxide film, the state hardly influences the movement of electrons.

Claims18

Dependent claims

A semiconductor device comprising:

a first gate electrode;
a first insulating film over the first gate electrode;
an oxide semiconductor film comprising gallium over the first insulating film;
a first oxide film over and in contact with the oxide semiconductor film;
a source electrode and a drain electrode over the first oxide film;
a second oxide film over and in contact with the first oxide film, the source electrode, and the drain electrode;
a second insulating film over the second oxide film;
and
a second gate electrode over the second insulating film,
wherein each of the first oxide film and the second oxide film comprises indium, gallium, and zinc,
wherein in a channel length direction the oxide semiconductor film is smaller than the first gate electrode, and
wherein in a channel width direction the oxide semiconductor film is smaller than the first gate electrode.

9 more elements

Dependencies are inferred from the claim text.

Semiconductor device

Life of this patent

Semiconductor device

Life of this patent

Abstract

Claims18