Patent ID: 11869980
Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 8:
9. A semiconductor device comprising:
a first insulating film;
a first oxide semiconductor film;
a second oxide semiconductor film over the first oxide semiconductor film;
a source electrode and a drain electrode each being over and in direct contact with the second oxide semiconductor film;
a second insulating film over the source electrode, the drain electrode, and the second oxide semiconductor film;
an opening provided in the second insulating film;
a gate insulating film provided in the opening; and
a gate electrode provided in the opening, the gate electrode being over and in direct contact with the gate insulating film,
wherein the second oxide semiconductor film comprises a first region, a second region, and a third region,
wherein the first region comprises indium, an element M, and zinc,
wherein the element M is one or more of aluminum, gallium, yttrium, and tin,
wherein each of the second region and the third region comprises indium and zinc,
wherein a concentration of indium in the second region is higher than a concentration of indium in the first region,
wherein a concentration of indium in the third region is higher than the concentration of indium in the first region, and
wherein at least a part of the first region is between the second region and the third region.